| Message ID | 20231031-module_relocations-v7-2-6f4719b64bf7@rivosinc.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | riscv: Add remaining module relocations and tests | expand |
Charlie Jenkins wrote: > Add all final module relocations and add error logs explaining the ones > that are not supported. Implement overflow checks for > ADD/SUB/SET/ULEB128 relocations. > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> > --- > arch/riscv/include/uapi/asm/elf.h | 5 +- > arch/riscv/kernel/module.c | 534 ++++++++++++++++++++++++++++++++++++-- > 2 files changed, 511 insertions(+), 28 deletions(-) > > diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h > index d696d6610231..11a71b8533d5 100644 > --- a/arch/riscv/include/uapi/asm/elf.h > +++ b/arch/riscv/include/uapi/asm/elf.h > @@ -49,6 +49,7 @@ typedef union __riscv_fp_state elf_fpregset_t; > #define R_RISCV_TLS_DTPREL64 9 > #define R_RISCV_TLS_TPREL32 10 > #define R_RISCV_TLS_TPREL64 11 > +#define R_RISCV_IRELATIVE 58 > > /* Relocation types not used by the dynamic linker */ > #define R_RISCV_BRANCH 16 > @@ -81,7 +82,6 @@ typedef union __riscv_fp_state elf_fpregset_t; > #define R_RISCV_ALIGN 43 > #define R_RISCV_RVC_BRANCH 44 > #define R_RISCV_RVC_JUMP 45 > -#define R_RISCV_LUI 46 > #define R_RISCV_GPREL_I 47 > #define R_RISCV_GPREL_S 48 > #define R_RISCV_TPREL_I 49 > @@ -93,6 +93,9 @@ typedef union __riscv_fp_state elf_fpregset_t; > #define R_RISCV_SET16 55 > #define R_RISCV_SET32 56 > #define R_RISCV_32_PCREL 57 > +#define R_RISCV_PLT32 59 > +#define R_RISCV_SET_ULEB128 60 > +#define R_RISCV_SUB_ULEB128 61 > > > #endif /* _UAPI_ASM_RISCV_ELF_H */ > diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c > index a9e94e939cb5..230172ecb26e 100644 > --- a/arch/riscv/kernel/module.c > +++ b/arch/riscv/kernel/module.c > @@ -7,6 +7,9 @@ > #include <linux/elf.h> > #include <linux/err.h> > #include <linux/errno.h> > +#include <linux/hashtable.h> > +#include <linux/kernel.h> > +#include <linux/log2.h> > #include <linux/moduleloader.h> > #include <linux/vmalloc.h> > #include <linux/sizes.h> > @@ -14,6 +17,27 @@ > #include <asm/alternative.h> > #include <asm/sections.h> > > +struct used_bucket { > + struct list_head head; > + struct hlist_head *bucket; > +}; > + > +struct relocation_head { > + struct hlist_node node; > + struct list_head *rel_entry; > + void *location; > +}; > + > +struct relocation_entry { > + struct list_head head; > + Elf_Addr value; > + unsigned int type; > +}; > + > +struct hlist_head *relocation_hashtable; > + > +struct list_head used_buckets_list; > + > /* > * The auipc+jalr instruction pair can reach any PC-relative offset > * in the range [-2^31 - 2^11, 2^31 - 2^11) > @@ -269,6 +293,12 @@ static int apply_r_riscv_align_rela(struct module *me, void *location, > return -EINVAL; > } > > +static int apply_r_riscv_add8_rela(struct module *me, void *location, Elf_Addr v) > +{ > + *(u8 *)location += (u8)v; > + return 0; > +} > + > static int apply_r_riscv_add16_rela(struct module *me, void *location, > Elf_Addr v) > { > @@ -290,6 +320,12 @@ static int apply_r_riscv_add64_rela(struct module *me, void *location, > return 0; > } > > +static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v) > +{ > + *(u8 *)location -= (u8)v; > + return 0; > +} > + > static int apply_r_riscv_sub16_rela(struct module *me, void *location, > Elf_Addr v) > { > @@ -311,33 +347,470 @@ static int apply_r_riscv_sub64_rela(struct module *me, void *location, > return 0; > } > > -static int (*reloc_handlers_rela[]) (struct module *me, void *location, > - Elf_Addr v) = { > - [R_RISCV_32] = apply_r_riscv_32_rela, > - [R_RISCV_64] = apply_r_riscv_64_rela, > - [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, > - [R_RISCV_JAL] = apply_r_riscv_jal_rela, > - [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, > - [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, > - [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, > - [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, > - [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, > - [R_RISCV_HI20] = apply_r_riscv_hi20_rela, > - [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, > - [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, > - [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, > - [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, > - [R_RISCV_CALL] = apply_r_riscv_call_rela, > - [R_RISCV_RELAX] = apply_r_riscv_relax_rela, > - [R_RISCV_ALIGN] = apply_r_riscv_align_rela, > - [R_RISCV_ADD16] = apply_r_riscv_add16_rela, > - [R_RISCV_ADD32] = apply_r_riscv_add32_rela, > - [R_RISCV_ADD64] = apply_r_riscv_add64_rela, > - [R_RISCV_SUB16] = apply_r_riscv_sub16_rela, > - [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, > - [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, > +static int dynamic_linking_not_supported(struct module *me, void *location, > + Elf_Addr v) > +{ > + pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n", > + me->name, location); > + return -EINVAL; > +} > + > +static int tls_not_supported(struct module *me, void *location, Elf_Addr v) > +{ > + pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n", > + me->name, location); > + return -EINVAL; > +} > + > +static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v) > +{ > + *(u8 *)location = (*(u8 *)location - ((u8)v & 0x3F)) & 0x3F; > + return 0; > +} > + > +static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v) > +{ > + *(u8 *)location = ((*(u8 *)location & 0xc0) | ((u8)v & 0x3F)); Most of these casts are simple enough for here and above I'd consider something like this for readability: u8 *byte = location; u8 value = v; *byte = (*byte & 0xc0) | (value & 0x3f) The compiler should generate the same code. > + return 0; > +} > + > +static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v) > +{ > + *(u8 *)location = (u8)v; > + return 0; > +} > + > +static int apply_r_riscv_set16_rela(struct module *me, void *location, > + Elf_Addr v) > +{ > + *(u16 *)location = (u16)v; > + return 0; > +} > + > +static int apply_r_riscv_set32_rela(struct module *me, void *location, > + Elf_Addr v) > +{ > + *(u32 *)location = (u32)v; > + return 0; > +} > + > +static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location, > + Elf_Addr v) > +{ > + *(u32 *)location = v - (unsigned long)location; > + return 0; > +} > + > +static int apply_r_riscv_plt32_rela(struct module *me, void *location, > + Elf_Addr v) > +{ > + ptrdiff_t offset = (void *)v - location; > + > + if (!riscv_insn_valid_32bit_offset(offset)) { > + /* Only emit the plt entry if offset over 32-bit range */ > + if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { > + offset = (void *)module_emit_plt_entry(me, v) - location; > + } else { > + pr_err("%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", > + me->name, (long long)v, location); > + return -EINVAL; > + } > + } > + > + *(u32 *)location = (u32)offset; > + return 0; > +} > + > +static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v) > +{ > + *(long *)location = v; > + return 0; > +} > + > +static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v) > +{ > + *(long *)location -= v; > + return 0; > +} > + > +/* > + * Relocations defined in the riscv-elf-psabi-doc. > + * This handles static linking only. > + */ > +static int (*reloc_handlers_rela[])(struct module *me, void *location, > + Elf_Addr v) = { > + [R_RISCV_32] = apply_r_riscv_32_rela, > + [R_RISCV_64] = apply_r_riscv_64_rela, > + [R_RISCV_RELATIVE] = dynamic_linking_not_supported, > + [R_RISCV_COPY] = dynamic_linking_not_supported, > + [R_RISCV_JUMP_SLOT] = dynamic_linking_not_supported, > + [R_RISCV_TLS_DTPMOD32] = dynamic_linking_not_supported, > + [R_RISCV_TLS_DTPMOD64] = dynamic_linking_not_supported, > + [R_RISCV_TLS_DTPREL32] = dynamic_linking_not_supported, > + [R_RISCV_TLS_DTPREL64] = dynamic_linking_not_supported, > + [R_RISCV_TLS_TPREL32] = dynamic_linking_not_supported, > + [R_RISCV_TLS_TPREL64] = dynamic_linking_not_supported, > + /* 12-15 undefined */ > + [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, > + [R_RISCV_JAL] = apply_r_riscv_jal_rela, > + [R_RISCV_CALL] = apply_r_riscv_call_rela, > + [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, > + [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, > + [R_RISCV_TLS_GOT_HI20] = tls_not_supported, > + [R_RISCV_TLS_GD_HI20] = tls_not_supported, > + [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, > + [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, > + [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, > + [R_RISCV_HI20] = apply_r_riscv_hi20_rela, > + [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, > + [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, > + [R_RISCV_TPREL_HI20] = tls_not_supported, > + [R_RISCV_TPREL_LO12_I] = tls_not_supported, > + [R_RISCV_TPREL_LO12_S] = tls_not_supported, > + [R_RISCV_TPREL_ADD] = tls_not_supported, > + [R_RISCV_ADD8] = apply_r_riscv_add8_rela, > + [R_RISCV_ADD16] = apply_r_riscv_add16_rela, > + [R_RISCV_ADD32] = apply_r_riscv_add32_rela, > + [R_RISCV_ADD64] = apply_r_riscv_add64_rela, > + [R_RISCV_SUB8] = apply_r_riscv_sub8_rela, > + [R_RISCV_SUB16] = apply_r_riscv_sub16_rela, > + [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, > + [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, > + /* 41-42 reserved for future standard use */ > + [R_RISCV_ALIGN] = apply_r_riscv_align_rela, > + [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, > + [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, > + /* 46-50 reserved for future standard use */ > + [R_RISCV_RELAX] = apply_r_riscv_relax_rela, > + [R_RISCV_SUB6] = apply_r_riscv_sub6_rela, > + [R_RISCV_SET6] = apply_r_riscv_set6_rela, > + [R_RISCV_SET8] = apply_r_riscv_set8_rela, > + [R_RISCV_SET16] = apply_r_riscv_set16_rela, > + [R_RISCV_SET32] = apply_r_riscv_set32_rela, > + [R_RISCV_32_PCREL] = apply_r_riscv_32_pcrel_rela, > + [R_RISCV_IRELATIVE] = dynamic_linking_not_supported, > + [R_RISCV_PLT32] = apply_r_riscv_plt32_rela, > + [R_RISCV_SET_ULEB128] = apply_r_riscv_set_uleb128, > + [R_RISCV_SUB_ULEB128] = apply_r_riscv_sub_uleb128, > + /* 62-191 reserved for future standard use */ > + /* 192-255 nonstandard ABI extensions */ > +}; > + > +static bool accumulate_relocations[] = { > + [R_RISCV_32] = false, > + [R_RISCV_64] = false, > + [R_RISCV_RELATIVE] = false, > + [R_RISCV_COPY] = false, > + [R_RISCV_JUMP_SLOT] = false, > + [R_RISCV_TLS_DTPMOD32] = false, > + [R_RISCV_TLS_DTPMOD64] = false, > + [R_RISCV_TLS_DTPREL32] = false, > + [R_RISCV_TLS_DTPREL64] = false, > + [R_RISCV_TLS_TPREL32] = false, > + [R_RISCV_TLS_TPREL64] = false, > + /* 12-15 undefined */ > + [R_RISCV_BRANCH] = false, > + [R_RISCV_JAL] = false, > + [R_RISCV_CALL] = false, > + [R_RISCV_CALL_PLT] = false, > + [R_RISCV_GOT_HI20] = false, > + [R_RISCV_TLS_GOT_HI20] = false, > + [R_RISCV_TLS_GD_HI20] = false, > + [R_RISCV_PCREL_HI20] = false, > + [R_RISCV_PCREL_LO12_I] = false, > + [R_RISCV_PCREL_LO12_S] = false, > + [R_RISCV_HI20] = false, > + [R_RISCV_LO12_I] = false, > + [R_RISCV_LO12_S] = false, > + [R_RISCV_TPREL_HI20] = false, > + [R_RISCV_TPREL_LO12_I] = false, > + [R_RISCV_TPREL_LO12_S] = false, > + [R_RISCV_TPREL_ADD] = false, > + [R_RISCV_ADD8] = true, > + [R_RISCV_ADD16] = true, > + [R_RISCV_ADD32] = true, > + [R_RISCV_ADD64] = true, > + [R_RISCV_SUB8] = true, > + [R_RISCV_SUB16] = true, > + [R_RISCV_SUB32] = true, > + [R_RISCV_SUB64] = true, > + /* 41-42 reserved for future standard use */ > + [R_RISCV_ALIGN] = false, > + [R_RISCV_RVC_BRANCH] = false, > + [R_RISCV_RVC_JUMP] = false, > + /* 46-50 reserved for future standard use */ > + [R_RISCV_RELAX] = false, > + [R_RISCV_SUB6] = true, > + [R_RISCV_SET6] = true, > + [R_RISCV_SET8] = true, > + [R_RISCV_SET16] = true, > + [R_RISCV_SET32] = true, > + [R_RISCV_32_PCREL] = false, > + [R_RISCV_IRELATIVE] = false, > + [R_RISCV_PLT32] = false, > + [R_RISCV_SET_ULEB128] = true, > + [R_RISCV_SUB_ULEB128] = true, > + /* 62-191 reserved for future standard use */ > + /* 192-255 nonstandard ABI extensions */ > +}; > + > +static int accumulation_not_supported(struct module *me, void *location, long buffer) > +{ > + pr_err("%s: Internal error. Only ADD/SUB/SET/ULEB128 should be accumulated.", me->name); > + return -EINVAL; > +} > + > +static int apply_6_bit_accumulation(struct module *me, void *location, long buffer) > +{ > + if (buffer != (buffer & 0x3F)) { It may be a matter of taste, but I'd find something like this easier to read: if (buffer > 0x3f) { To me that more directly conveys that you're just checking if any if the higher bits are set. > + pr_err("%s: value %ld out of range for 6-bit relocation.\n", > + me->name, buffer); > + return -EINVAL; > + } > + *(u8 *)location = ((*(u8 *)location & 0xc0) | ((u8)buffer & 0x3F)); Here the casts also get a bit much. > + return 0; > +} > + > +static int apply_8_bit_accumulation(struct module *me, void *location, long buffer) > +{ > + if (buffer != (u8)buffer) { > + pr_err("%s: value %ld out of range for 8-bit relocation.\n", > + me->name, buffer); > + return -EINVAL; > + } > + *(u8 *)location = (u8)buffer; > + return 0; > +} > + > +static int apply_16_bit_accumulation(struct module *me, void *location, long buffer) > +{ > + if (buffer != (u16)buffer) { if (buffer > U16_MAX) { > + pr_err("%s: value %ld out of range for 16-bit relocation.\n", > + me->name, buffer); > + return -EINVAL; > + } > + *(u16 *)location = (u16)buffer; > + return 0; > +} > + > +static int apply_32_bit_accumulation(struct module *me, void *location, long buffer) > +{ > + if (buffer != (u32)buffer) { if (buffer > U32_MAX) { > + pr_err("%s: value %ld out of range for 32-bit relocation.\n", > + me->name, buffer); > + return -EINVAL; > + } > + *(u32 *)location = (u32)buffer; > + return 0; > +} > + > +static int apply_64_bit_accumulation(struct module *me, void *location, long buffer) > +{ > + *(u64 *)location = (u64)buffer; > + return 0; > +} > + > +static int apply_uleb128_accumulation(struct module *me, void *location, long buffer) > +{ > + /* > + * ULEB128 is a variable length encoding. Encode the buffer into > + * the ULEB128 data format. > + */ > + while (buffer != 0) { > + *(u8 *)location = (u8)buffer & 0x7F; > + buffer >>= 7; > + *(u8 *)location |= (buffer != 0) << 7; > + location = (u8 *)location + 1; > + } How about something like u8 *p = location; while (buffer) { u8 value = buffer & 0x7f; buffer >>= 7; value |= (!!buffer) << 7; *p++ = value; } This sould do the same as above, but if buffer == 0 it doesn't write anything. Is that the right thing to do? > + return 0; > +} > + > +/* > + * Need to duplicate this a third time to capture the handlers for accumulation. > + */ > +static int (*accumulate_handlers[])(struct module *me, void *location, long buffer) = { > + [R_RISCV_32] = accumulation_not_supported, > + [R_RISCV_64] = accumulation_not_supported, > + [R_RISCV_RELATIVE] = accumulation_not_supported, > + [R_RISCV_COPY] = accumulation_not_supported, > + [R_RISCV_JUMP_SLOT] = accumulation_not_supported, > + [R_RISCV_TLS_DTPMOD32] = accumulation_not_supported, > + [R_RISCV_TLS_DTPMOD64] = accumulation_not_supported, > + [R_RISCV_TLS_DTPREL32] = accumulation_not_supported, > + [R_RISCV_TLS_DTPREL64] = accumulation_not_supported, > + [R_RISCV_TLS_TPREL32] = accumulation_not_supported, > + [R_RISCV_TLS_TPREL64] = accumulation_not_supported, > + /* 12-15 undefined */ > + [R_RISCV_BRANCH] = accumulation_not_supported, > + [R_RISCV_JAL] = accumulation_not_supported, > + [R_RISCV_CALL] = accumulation_not_supported, > + [R_RISCV_CALL_PLT] = accumulation_not_supported, > + [R_RISCV_GOT_HI20] = accumulation_not_supported, > + [R_RISCV_TLS_GOT_HI20] = accumulation_not_supported, > + [R_RISCV_TLS_GD_HI20] = accumulation_not_supported, > + [R_RISCV_PCREL_HI20] = accumulation_not_supported, > + [R_RISCV_PCREL_LO12_I] = accumulation_not_supported, > + [R_RISCV_PCREL_LO12_S] = accumulation_not_supported, > + [R_RISCV_HI20] = accumulation_not_supported, > + [R_RISCV_LO12_I] = accumulation_not_supported, > + [R_RISCV_LO12_S] = accumulation_not_supported, > + [R_RISCV_TPREL_HI20] = accumulation_not_supported, > + [R_RISCV_TPREL_LO12_I] = accumulation_not_supported, > + [R_RISCV_TPREL_LO12_S] = accumulation_not_supported, > + [R_RISCV_TPREL_ADD] = accumulation_not_supported, > + [R_RISCV_ADD8] = apply_8_bit_accumulation, > + [R_RISCV_ADD16] = apply_16_bit_accumulation, > + [R_RISCV_ADD32] = apply_32_bit_accumulation, > + [R_RISCV_ADD64] = apply_64_bit_accumulation, > + [R_RISCV_SUB8] = apply_8_bit_accumulation, > + [R_RISCV_SUB16] = apply_16_bit_accumulation, > + [R_RISCV_SUB32] = apply_32_bit_accumulation, > + [R_RISCV_SUB64] = apply_64_bit_accumulation, > + /* 41-42 reserved for future standard use */ > + [R_RISCV_ALIGN] = accumulation_not_supported, > + [R_RISCV_RVC_BRANCH] = accumulation_not_supported, > + [R_RISCV_RVC_JUMP] = accumulation_not_supported, > + /* 46-50 reserved for future standard use */ > + [R_RISCV_RELAX] = accumulation_not_supported, > + [R_RISCV_SUB6] = apply_6_bit_accumulation, > + [R_RISCV_SET6] = apply_6_bit_accumulation, > + [R_RISCV_SET8] = apply_8_bit_accumulation, > + [R_RISCV_SET16] = apply_16_bit_accumulation, > + [R_RISCV_SET32] = apply_32_bit_accumulation, > + [R_RISCV_32_PCREL] = accumulation_not_supported, > + [R_RISCV_IRELATIVE] = accumulation_not_supported, > + [R_RISCV_PLT32] = accumulation_not_supported, > + [R_RISCV_SET_ULEB128] = apply_uleb128_accumulation, > + [R_RISCV_SUB_ULEB128] = apply_uleb128_accumulation, > + /* 62-191 reserved for future standard use */ > + /* 192-255 nonstandard ABI extensions */ > }; > > +void process_accumulated_relocations(struct module *me) > +{ > + /* > + * Only ADD/SUB/SET/ULEB128 should end up here. > + * > + * Each bucket may have more than one relocation location. All > + * relocations for a location are stored in a list in a bucket. > + * > + * Relocations are applied to a temp variable before being stored to the > + * provided location to check for overflow. This also allows ULEB128 to > + * properly decide how many entries are needed before storing to > + * location. The final value is stored into location using the handler > + * for the last relocation to an address. > + * > + * Three layers of indexing: > + * - Each of the buckets in use > + * - Groups of relocations in each bucket by location address > + * - Each relocation entry for a location address > + */ > + struct used_bucket *bucket_iter; > + struct relocation_head *rel_head_iter; > + struct relocation_entry *rel_entry_iter; > + int curr_type; > + void *location; > + long buffer; > + > + list_for_each_entry(bucket_iter, &used_buckets_list, head) { > + hlist_for_each_entry(rel_head_iter, bucket_iter->bucket, node) { > + buffer = 0; > + location = rel_head_iter->location; > + list_for_each_entry(rel_entry_iter, rel_head_iter->rel_entry, head) { > + curr_type = rel_entry_iter->type; > + reloc_handlers_rela[curr_type](me, &buffer, rel_entry_iter->value); > + kfree(rel_entry_iter); > + } > + accumulate_handlers[curr_type](me, location, buffer); > + kfree(rel_head_iter); > + } > + kfree(bucket_iter); > + } > + > + kfree(relocation_hashtable); > +} > + > +int add_relocation_to_accumulate(struct module *me, int type, void *location, > + unsigned int hashtable_bits, Elf_Addr v) > +{ > + struct relocation_entry *entry; > + struct relocation_head *rel_head; > + struct hlist_head *current_head; > + struct hlist_node *first; > + struct used_bucket *bucket; > + unsigned long hash; > + > + entry = kmalloc(sizeof(*entry), GFP_KERNEL); > + INIT_LIST_HEAD(&entry->head); > + entry->type = type; > + entry->value = v; > + > + hash = hash_min((unsigned long)location, hashtable_bits); > + > + current_head = &relocation_hashtable[hash]; > + first = current_head->first; > + > + /* Find matching location (if any) */ > + bool found = false; > + struct relocation_head *rel_head_iter; > + > + hlist_for_each_entry(rel_head_iter, current_head, node) { > + if (rel_head_iter->location == location) { > + found = true; > + rel_head = rel_head_iter; > + break; > + } > + } > + > + if (!found) { > + rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); > + rel_head->rel_entry = > + kmalloc(sizeof(struct list_head), GFP_KERNEL); > + INIT_LIST_HEAD(rel_head->rel_entry); > + rel_head->location = location; > + INIT_HLIST_NODE(&rel_head->node); > + if (!current_head->first) { > + bucket = > + kmalloc(sizeof(struct used_bucket), GFP_KERNEL); > + INIT_LIST_HEAD(&bucket->head); > + bucket->bucket = current_head; > + list_add(&bucket->head, &used_buckets_list); > + } > + hlist_add_head(&rel_head->node, current_head); > + } > + > + /* Add relocation to head of discovered rel_head */ > + list_add_tail(&entry->head, rel_head->rel_entry); > + > + return 0; > +} > + > +unsigned int initialize_relocation_hashtable(unsigned int num_relocations) > +{ > + /* Can safely assume that bits is not greater than sizeof(long) */ > + unsigned long hashtable_size = roundup_pow_of_two(num_relocations); > + unsigned int hashtable_bits = ilog2(hashtable_size); > + > + /* > + * Double size of hashtable if num_relocations * 1.25 is greater than > + * hashtable_size. > + */ > + int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); > + > + hashtable_bits += should_double_size; > + > + hashtable_size <<= should_double_size; > + > + relocation_hashtable = kmalloc_array(hashtable_size, > + sizeof(*relocation_hashtable), > + GFP_KERNEL); > + __hash_init(relocation_hashtable, hashtable_size); > + > + INIT_LIST_HEAD(&used_buckets_list); > + > + return hashtable_bits; > +} > + > int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > unsigned int symindex, unsigned int relsec, > struct module *me) > @@ -349,11 +822,13 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > unsigned int i, type; > Elf_Addr v; > int res; > + unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); > + unsigned int hashtable_bits = initialize_relocation_hashtable(num_relocations); > > pr_debug("Applying relocate section %u to %u\n", relsec, > sechdrs[relsec].sh_info); > > - for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { > + for (i = 0; i < num_relocations; i++) { > /* This is where to make the change */ > location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr > + rel[i].r_offset; > @@ -428,11 +903,16 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > } > } > > - res = handler(me, location, v); > + if (accumulate_relocations[type]) > + res = add_relocation_to_accumulate(me, type, location, hashtable_bits, v); > + else > + res = handler(me, location, v); > if (res) > return res; > } > > + process_accumulated_relocations(me); > + > return 0; > } > > > -- > 2.34.1 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
On Tue, Oct 31, 2023 at 06:43:19AM -0700, Emil Renner Berthing wrote: > Charlie Jenkins wrote: > > Add all final module relocations and add error logs explaining the ones > > that are not supported. Implement overflow checks for > > ADD/SUB/SET/ULEB128 relocations. > > > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> > > --- > > arch/riscv/include/uapi/asm/elf.h | 5 +- > > arch/riscv/kernel/module.c | 534 ++++++++++++++++++++++++++++++++++++-- > > 2 files changed, 511 insertions(+), 28 deletions(-) > > > > diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h > > index d696d6610231..11a71b8533d5 100644 > > --- a/arch/riscv/include/uapi/asm/elf.h > > +++ b/arch/riscv/include/uapi/asm/elf.h > > @@ -49,6 +49,7 @@ typedef union __riscv_fp_state elf_fpregset_t; > > #define R_RISCV_TLS_DTPREL64 9 > > #define R_RISCV_TLS_TPREL32 10 > > #define R_RISCV_TLS_TPREL64 11 > > +#define R_RISCV_IRELATIVE 58 > > > > /* Relocation types not used by the dynamic linker */ > > #define R_RISCV_BRANCH 16 > > @@ -81,7 +82,6 @@ typedef union __riscv_fp_state elf_fpregset_t; > > #define R_RISCV_ALIGN 43 > > #define R_RISCV_RVC_BRANCH 44 > > #define R_RISCV_RVC_JUMP 45 > > -#define R_RISCV_LUI 46 > > #define R_RISCV_GPREL_I 47 > > #define R_RISCV_GPREL_S 48 > > #define R_RISCV_TPREL_I 49 > > @@ -93,6 +93,9 @@ typedef union __riscv_fp_state elf_fpregset_t; > > #define R_RISCV_SET16 55 > > #define R_RISCV_SET32 56 > > #define R_RISCV_32_PCREL 57 > > +#define R_RISCV_PLT32 59 > > +#define R_RISCV_SET_ULEB128 60 > > +#define R_RISCV_SUB_ULEB128 61 > > > > > > #endif /* _UAPI_ASM_RISCV_ELF_H */ > > diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c > > index a9e94e939cb5..230172ecb26e 100644 > > --- a/arch/riscv/kernel/module.c > > +++ b/arch/riscv/kernel/module.c > > @@ -7,6 +7,9 @@ > > #include <linux/elf.h> > > #include <linux/err.h> > > #include <linux/errno.h> > > +#include <linux/hashtable.h> > > +#include <linux/kernel.h> > > +#include <linux/log2.h> > > #include <linux/moduleloader.h> > > #include <linux/vmalloc.h> > > #include <linux/sizes.h> > > @@ -14,6 +17,27 @@ > > #include <asm/alternative.h> > > #include <asm/sections.h> > > > > +struct used_bucket { > > + struct list_head head; > > + struct hlist_head *bucket; > > +}; > > + > > +struct relocation_head { > > + struct hlist_node node; > > + struct list_head *rel_entry; > > + void *location; > > +}; > > + > > +struct relocation_entry { > > + struct list_head head; > > + Elf_Addr value; > > + unsigned int type; > > +}; > > + > > +struct hlist_head *relocation_hashtable; > > + > > +struct list_head used_buckets_list; > > + > > /* > > * The auipc+jalr instruction pair can reach any PC-relative offset > > * in the range [-2^31 - 2^11, 2^31 - 2^11) > > @@ -269,6 +293,12 @@ static int apply_r_riscv_align_rela(struct module *me, void *location, > > return -EINVAL; > > } > > > > +static int apply_r_riscv_add8_rela(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(u8 *)location += (u8)v; > > + return 0; > > +} > > + > > static int apply_r_riscv_add16_rela(struct module *me, void *location, > > Elf_Addr v) > > { > > @@ -290,6 +320,12 @@ static int apply_r_riscv_add64_rela(struct module *me, void *location, > > return 0; > > } > > > > +static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(u8 *)location -= (u8)v; > > + return 0; > > +} > > + > > static int apply_r_riscv_sub16_rela(struct module *me, void *location, > > Elf_Addr v) > > { > > @@ -311,33 +347,470 @@ static int apply_r_riscv_sub64_rela(struct module *me, void *location, > > return 0; > > } > > > > -static int (*reloc_handlers_rela[]) (struct module *me, void *location, > > - Elf_Addr v) = { > > - [R_RISCV_32] = apply_r_riscv_32_rela, > > - [R_RISCV_64] = apply_r_riscv_64_rela, > > - [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, > > - [R_RISCV_JAL] = apply_r_riscv_jal_rela, > > - [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, > > - [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, > > - [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, > > - [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, > > - [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, > > - [R_RISCV_HI20] = apply_r_riscv_hi20_rela, > > - [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, > > - [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, > > - [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, > > - [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, > > - [R_RISCV_CALL] = apply_r_riscv_call_rela, > > - [R_RISCV_RELAX] = apply_r_riscv_relax_rela, > > - [R_RISCV_ALIGN] = apply_r_riscv_align_rela, > > - [R_RISCV_ADD16] = apply_r_riscv_add16_rela, > > - [R_RISCV_ADD32] = apply_r_riscv_add32_rela, > > - [R_RISCV_ADD64] = apply_r_riscv_add64_rela, > > - [R_RISCV_SUB16] = apply_r_riscv_sub16_rela, > > - [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, > > - [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, > > +static int dynamic_linking_not_supported(struct module *me, void *location, > > + Elf_Addr v) > > +{ > > + pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n", > > + me->name, location); > > + return -EINVAL; > > +} > > + > > +static int tls_not_supported(struct module *me, void *location, Elf_Addr v) > > +{ > > + pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n", > > + me->name, location); > > + return -EINVAL; > > +} > > + > > +static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(u8 *)location = (*(u8 *)location - ((u8)v & 0x3F)) & 0x3F; > > + return 0; > > +} > > + > > +static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(u8 *)location = ((*(u8 *)location & 0xc0) | ((u8)v & 0x3F)); > > Most of these casts are simple enough for here and above I'd consider > something like this for readability: > > u8 *byte = location; > u8 value = v; > > *byte = (*byte & 0xc0) | (value & 0x3f) > > The compiler should generate the same code. > > > + return 0; > > +} > > + > > +static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(u8 *)location = (u8)v; > > + return 0; > > +} > > + > > +static int apply_r_riscv_set16_rela(struct module *me, void *location, > > + Elf_Addr v) > > +{ > > + *(u16 *)location = (u16)v; > > + return 0; > > +} > > + > > +static int apply_r_riscv_set32_rela(struct module *me, void *location, > > + Elf_Addr v) > > +{ > > + *(u32 *)location = (u32)v; > > + return 0; > > +} > > + > > +static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location, > > + Elf_Addr v) > > +{ > > + *(u32 *)location = v - (unsigned long)location; > > + return 0; > > +} > > + > > +static int apply_r_riscv_plt32_rela(struct module *me, void *location, > > + Elf_Addr v) > > +{ > > + ptrdiff_t offset = (void *)v - location; > > + > > + if (!riscv_insn_valid_32bit_offset(offset)) { > > + /* Only emit the plt entry if offset over 32-bit range */ > > + if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { > > + offset = (void *)module_emit_plt_entry(me, v) - location; > > + } else { > > + pr_err("%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", > > + me->name, (long long)v, location); > > + return -EINVAL; > > + } > > + } > > + > > + *(u32 *)location = (u32)offset; > > + return 0; > > +} > > + > > +static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(long *)location = v; > > + return 0; > > +} > > + > > +static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(long *)location -= v; > > + return 0; > > +} > > + > > +/* > > + * Relocations defined in the riscv-elf-psabi-doc. > > + * This handles static linking only. > > + */ > > +static int (*reloc_handlers_rela[])(struct module *me, void *location, > > + Elf_Addr v) = { > > + [R_RISCV_32] = apply_r_riscv_32_rela, > > + [R_RISCV_64] = apply_r_riscv_64_rela, > > + [R_RISCV_RELATIVE] = dynamic_linking_not_supported, > > + [R_RISCV_COPY] = dynamic_linking_not_supported, > > + [R_RISCV_JUMP_SLOT] = dynamic_linking_not_supported, > > + [R_RISCV_TLS_DTPMOD32] = dynamic_linking_not_supported, > > + [R_RISCV_TLS_DTPMOD64] = dynamic_linking_not_supported, > > + [R_RISCV_TLS_DTPREL32] = dynamic_linking_not_supported, > > + [R_RISCV_TLS_DTPREL64] = dynamic_linking_not_supported, > > + [R_RISCV_TLS_TPREL32] = dynamic_linking_not_supported, > > + [R_RISCV_TLS_TPREL64] = dynamic_linking_not_supported, > > + /* 12-15 undefined */ > > + [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, > > + [R_RISCV_JAL] = apply_r_riscv_jal_rela, > > + [R_RISCV_CALL] = apply_r_riscv_call_rela, > > + [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, > > + [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, > > + [R_RISCV_TLS_GOT_HI20] = tls_not_supported, > > + [R_RISCV_TLS_GD_HI20] = tls_not_supported, > > + [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, > > + [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, > > + [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, > > + [R_RISCV_HI20] = apply_r_riscv_hi20_rela, > > + [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, > > + [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, > > + [R_RISCV_TPREL_HI20] = tls_not_supported, > > + [R_RISCV_TPREL_LO12_I] = tls_not_supported, > > + [R_RISCV_TPREL_LO12_S] = tls_not_supported, > > + [R_RISCV_TPREL_ADD] = tls_not_supported, > > + [R_RISCV_ADD8] = apply_r_riscv_add8_rela, > > + [R_RISCV_ADD16] = apply_r_riscv_add16_rela, > > + [R_RISCV_ADD32] = apply_r_riscv_add32_rela, > > + [R_RISCV_ADD64] = apply_r_riscv_add64_rela, > > + [R_RISCV_SUB8] = apply_r_riscv_sub8_rela, > > + [R_RISCV_SUB16] = apply_r_riscv_sub16_rela, > > + [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, > > + [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, > > + /* 41-42 reserved for future standard use */ > > + [R_RISCV_ALIGN] = apply_r_riscv_align_rela, > > + [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, > > + [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, > > + /* 46-50 reserved for future standard use */ > > + [R_RISCV_RELAX] = apply_r_riscv_relax_rela, > > + [R_RISCV_SUB6] = apply_r_riscv_sub6_rela, > > + [R_RISCV_SET6] = apply_r_riscv_set6_rela, > > + [R_RISCV_SET8] = apply_r_riscv_set8_rela, > > + [R_RISCV_SET16] = apply_r_riscv_set16_rela, > > + [R_RISCV_SET32] = apply_r_riscv_set32_rela, > > + [R_RISCV_32_PCREL] = apply_r_riscv_32_pcrel_rela, > > + [R_RISCV_IRELATIVE] = dynamic_linking_not_supported, > > + [R_RISCV_PLT32] = apply_r_riscv_plt32_rela, > > + [R_RISCV_SET_ULEB128] = apply_r_riscv_set_uleb128, > > + [R_RISCV_SUB_ULEB128] = apply_r_riscv_sub_uleb128, > > + /* 62-191 reserved for future standard use */ > > + /* 192-255 nonstandard ABI extensions */ > > +}; > > + > > +static bool accumulate_relocations[] = { > > + [R_RISCV_32] = false, > > + [R_RISCV_64] = false, > > + [R_RISCV_RELATIVE] = false, > > + [R_RISCV_COPY] = false, > > + [R_RISCV_JUMP_SLOT] = false, > > + [R_RISCV_TLS_DTPMOD32] = false, > > + [R_RISCV_TLS_DTPMOD64] = false, > > + [R_RISCV_TLS_DTPREL32] = false, > > + [R_RISCV_TLS_DTPREL64] = false, > > + [R_RISCV_TLS_TPREL32] = false, > > + [R_RISCV_TLS_TPREL64] = false, > > + /* 12-15 undefined */ > > + [R_RISCV_BRANCH] = false, > > + [R_RISCV_JAL] = false, > > + [R_RISCV_CALL] = false, > > + [R_RISCV_CALL_PLT] = false, > > + [R_RISCV_GOT_HI20] = false, > > + [R_RISCV_TLS_GOT_HI20] = false, > > + [R_RISCV_TLS_GD_HI20] = false, > > + [R_RISCV_PCREL_HI20] = false, > > + [R_RISCV_PCREL_LO12_I] = false, > > + [R_RISCV_PCREL_LO12_S] = false, > > + [R_RISCV_HI20] = false, > > + [R_RISCV_LO12_I] = false, > > + [R_RISCV_LO12_S] = false, > > + [R_RISCV_TPREL_HI20] = false, > > + [R_RISCV_TPREL_LO12_I] = false, > > + [R_RISCV_TPREL_LO12_S] = false, > > + [R_RISCV_TPREL_ADD] = false, > > + [R_RISCV_ADD8] = true, > > + [R_RISCV_ADD16] = true, > > + [R_RISCV_ADD32] = true, > > + [R_RISCV_ADD64] = true, > > + [R_RISCV_SUB8] = true, > > + [R_RISCV_SUB16] = true, > > + [R_RISCV_SUB32] = true, > > + [R_RISCV_SUB64] = true, > > + /* 41-42 reserved for future standard use */ > > + [R_RISCV_ALIGN] = false, > > + [R_RISCV_RVC_BRANCH] = false, > > + [R_RISCV_RVC_JUMP] = false, > > + /* 46-50 reserved for future standard use */ > > + [R_RISCV_RELAX] = false, > > + [R_RISCV_SUB6] = true, > > + [R_RISCV_SET6] = true, > > + [R_RISCV_SET8] = true, > > + [R_RISCV_SET16] = true, > > + [R_RISCV_SET32] = true, > > + [R_RISCV_32_PCREL] = false, > > + [R_RISCV_IRELATIVE] = false, > > + [R_RISCV_PLT32] = false, > > + [R_RISCV_SET_ULEB128] = true, > > + [R_RISCV_SUB_ULEB128] = true, > > + /* 62-191 reserved for future standard use */ > > + /* 192-255 nonstandard ABI extensions */ > > +}; > > + > > +static int accumulation_not_supported(struct module *me, void *location, long buffer) > > +{ > > + pr_err("%s: Internal error. Only ADD/SUB/SET/ULEB128 should be accumulated.", me->name); > > + return -EINVAL; > > +} > > + > > +static int apply_6_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + if (buffer != (buffer & 0x3F)) { > > It may be a matter of taste, but I'd find something like this easier to read: > > if (buffer > 0x3f) { > > To me that more directly conveys that you're just checking if any if the higher > bits are set. > > > + pr_err("%s: value %ld out of range for 6-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + *(u8 *)location = ((*(u8 *)location & 0xc0) | ((u8)buffer & 0x3F)); > > Here the casts also get a bit much. > > > + return 0; > > +} > > + > > +static int apply_8_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + if (buffer != (u8)buffer) { > > + pr_err("%s: value %ld out of range for 8-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + *(u8 *)location = (u8)buffer; > > + return 0; > > +} > > + > > +static int apply_16_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + if (buffer != (u16)buffer) { > > if (buffer > U16_MAX) { > > > + pr_err("%s: value %ld out of range for 16-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + *(u16 *)location = (u16)buffer; > > + return 0; > > +} > > + > > +static int apply_32_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + if (buffer != (u32)buffer) { > > if (buffer > U32_MAX) { > > > + pr_err("%s: value %ld out of range for 32-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + *(u32 *)location = (u32)buffer; > > + return 0; > > +} > > + > > +static int apply_64_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + *(u64 *)location = (u64)buffer; > > + return 0; > > +} > > + > > +static int apply_uleb128_accumulation(struct module *me, void *location, long buffer) > > +{ > > + /* > > + * ULEB128 is a variable length encoding. Encode the buffer into > > + * the ULEB128 data format. > > + */ > > + while (buffer != 0) { > > + *(u8 *)location = (u8)buffer & 0x7F; > > + buffer >>= 7; > > + *(u8 *)location |= (buffer != 0) << 7; > > + location = (u8 *)location + 1; > > + } > > How about something like > > u8 *p = location; > > while (buffer) { > u8 value = buffer & 0x7f; > > buffer >>= 7; > value |= (!!buffer) << 7; > > *p++ = value; > } > > > This sould do the same as above, but if buffer == 0 it doesn't write anything. > Is that the right thing to do? > All great suggestions, thank you. Yes, that is the right thing to do when buffer == 0. - Charlie > > + return 0; > > +} > > + > > +/* > > + * Need to duplicate this a third time to capture the handlers for accumulation. > > + */ > > +static int (*accumulate_handlers[])(struct module *me, void *location, long buffer) = { > > + [R_RISCV_32] = accumulation_not_supported, > > + [R_RISCV_64] = accumulation_not_supported, > > + [R_RISCV_RELATIVE] = accumulation_not_supported, > > + [R_RISCV_COPY] = accumulation_not_supported, > > + [R_RISCV_JUMP_SLOT] = accumulation_not_supported, > > + [R_RISCV_TLS_DTPMOD32] = accumulation_not_supported, > > + [R_RISCV_TLS_DTPMOD64] = accumulation_not_supported, > > + [R_RISCV_TLS_DTPREL32] = accumulation_not_supported, > > + [R_RISCV_TLS_DTPREL64] = accumulation_not_supported, > > + [R_RISCV_TLS_TPREL32] = accumulation_not_supported, > > + [R_RISCV_TLS_TPREL64] = accumulation_not_supported, > > + /* 12-15 undefined */ > > + [R_RISCV_BRANCH] = accumulation_not_supported, > > + [R_RISCV_JAL] = accumulation_not_supported, > > + [R_RISCV_CALL] = accumulation_not_supported, > > + [R_RISCV_CALL_PLT] = accumulation_not_supported, > > + [R_RISCV_GOT_HI20] = accumulation_not_supported, > > + [R_RISCV_TLS_GOT_HI20] = accumulation_not_supported, > > + [R_RISCV_TLS_GD_HI20] = accumulation_not_supported, > > + [R_RISCV_PCREL_HI20] = accumulation_not_supported, > > + [R_RISCV_PCREL_LO12_I] = accumulation_not_supported, > > + [R_RISCV_PCREL_LO12_S] = accumulation_not_supported, > > + [R_RISCV_HI20] = accumulation_not_supported, > > + [R_RISCV_LO12_I] = accumulation_not_supported, > > + [R_RISCV_LO12_S] = accumulation_not_supported, > > + [R_RISCV_TPREL_HI20] = accumulation_not_supported, > > + [R_RISCV_TPREL_LO12_I] = accumulation_not_supported, > > + [R_RISCV_TPREL_LO12_S] = accumulation_not_supported, > > + [R_RISCV_TPREL_ADD] = accumulation_not_supported, > > + [R_RISCV_ADD8] = apply_8_bit_accumulation, > > + [R_RISCV_ADD16] = apply_16_bit_accumulation, > > + [R_RISCV_ADD32] = apply_32_bit_accumulation, > > + [R_RISCV_ADD64] = apply_64_bit_accumulation, > > + [R_RISCV_SUB8] = apply_8_bit_accumulation, > > + [R_RISCV_SUB16] = apply_16_bit_accumulation, > > + [R_RISCV_SUB32] = apply_32_bit_accumulation, > > + [R_RISCV_SUB64] = apply_64_bit_accumulation, > > + /* 41-42 reserved for future standard use */ > > + [R_RISCV_ALIGN] = accumulation_not_supported, > > + [R_RISCV_RVC_BRANCH] = accumulation_not_supported, > > + [R_RISCV_RVC_JUMP] = accumulation_not_supported, > > + /* 46-50 reserved for future standard use */ > > + [R_RISCV_RELAX] = accumulation_not_supported, > > + [R_RISCV_SUB6] = apply_6_bit_accumulation, > > + [R_RISCV_SET6] = apply_6_bit_accumulation, > > + [R_RISCV_SET8] = apply_8_bit_accumulation, > > + [R_RISCV_SET16] = apply_16_bit_accumulation, > > + [R_RISCV_SET32] = apply_32_bit_accumulation, > > + [R_RISCV_32_PCREL] = accumulation_not_supported, > > + [R_RISCV_IRELATIVE] = accumulation_not_supported, > > + [R_RISCV_PLT32] = accumulation_not_supported, > > + [R_RISCV_SET_ULEB128] = apply_uleb128_accumulation, > > + [R_RISCV_SUB_ULEB128] = apply_uleb128_accumulation, > > + /* 62-191 reserved for future standard use */ > > + /* 192-255 nonstandard ABI extensions */ > > }; > > > > +void process_accumulated_relocations(struct module *me) > > +{ > > + /* > > + * Only ADD/SUB/SET/ULEB128 should end up here. > > + * > > + * Each bucket may have more than one relocation location. All > > + * relocations for a location are stored in a list in a bucket. > > + * > > + * Relocations are applied to a temp variable before being stored to the > > + * provided location to check for overflow. This also allows ULEB128 to > > + * properly decide how many entries are needed before storing to > > + * location. The final value is stored into location using the handler > > + * for the last relocation to an address. > > + * > > + * Three layers of indexing: > > + * - Each of the buckets in use > > + * - Groups of relocations in each bucket by location address > > + * - Each relocation entry for a location address > > + */ > > + struct used_bucket *bucket_iter; > > + struct relocation_head *rel_head_iter; > > + struct relocation_entry *rel_entry_iter; > > + int curr_type; > > + void *location; > > + long buffer; > > + > > + list_for_each_entry(bucket_iter, &used_buckets_list, head) { > > + hlist_for_each_entry(rel_head_iter, bucket_iter->bucket, node) { > > + buffer = 0; > > + location = rel_head_iter->location; > > + list_for_each_entry(rel_entry_iter, rel_head_iter->rel_entry, head) { > > + curr_type = rel_entry_iter->type; > > + reloc_handlers_rela[curr_type](me, &buffer, rel_entry_iter->value); > > + kfree(rel_entry_iter); > > + } > > + accumulate_handlers[curr_type](me, location, buffer); > > + kfree(rel_head_iter); > > + } > > + kfree(bucket_iter); > > + } > > + > > + kfree(relocation_hashtable); > > +} > > + > > +int add_relocation_to_accumulate(struct module *me, int type, void *location, > > + unsigned int hashtable_bits, Elf_Addr v) > > +{ > > + struct relocation_entry *entry; > > + struct relocation_head *rel_head; > > + struct hlist_head *current_head; > > + struct hlist_node *first; > > + struct used_bucket *bucket; > > + unsigned long hash; > > + > > + entry = kmalloc(sizeof(*entry), GFP_KERNEL); > > + INIT_LIST_HEAD(&entry->head); > > + entry->type = type; > > + entry->value = v; > > + > > + hash = hash_min((unsigned long)location, hashtable_bits); > > + > > + current_head = &relocation_hashtable[hash]; > > + first = current_head->first; > > + > > + /* Find matching location (if any) */ > > + bool found = false; > > + struct relocation_head *rel_head_iter; > > + > > + hlist_for_each_entry(rel_head_iter, current_head, node) { > > + if (rel_head_iter->location == location) { > > + found = true; > > + rel_head = rel_head_iter; > > + break; > > + } > > + } > > + > > + if (!found) { > > + rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); > > + rel_head->rel_entry = > > + kmalloc(sizeof(struct list_head), GFP_KERNEL); > > + INIT_LIST_HEAD(rel_head->rel_entry); > > + rel_head->location = location; > > + INIT_HLIST_NODE(&rel_head->node); > > + if (!current_head->first) { > > + bucket = > > + kmalloc(sizeof(struct used_bucket), GFP_KERNEL); > > + INIT_LIST_HEAD(&bucket->head); > > + bucket->bucket = current_head; > > + list_add(&bucket->head, &used_buckets_list); > > + } > > + hlist_add_head(&rel_head->node, current_head); > > + } > > + > > + /* Add relocation to head of discovered rel_head */ > > + list_add_tail(&entry->head, rel_head->rel_entry); > > + > > + return 0; > > +} > > + > > +unsigned int initialize_relocation_hashtable(unsigned int num_relocations) > > +{ > > + /* Can safely assume that bits is not greater than sizeof(long) */ > > + unsigned long hashtable_size = roundup_pow_of_two(num_relocations); > > + unsigned int hashtable_bits = ilog2(hashtable_size); > > + > > + /* > > + * Double size of hashtable if num_relocations * 1.25 is greater than > > + * hashtable_size. > > + */ > > + int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); > > + > > + hashtable_bits += should_double_size; > > + > > + hashtable_size <<= should_double_size; > > + > > + relocation_hashtable = kmalloc_array(hashtable_size, > > + sizeof(*relocation_hashtable), > > + GFP_KERNEL); > > + __hash_init(relocation_hashtable, hashtable_size); > > + > > + INIT_LIST_HEAD(&used_buckets_list); > > + > > + return hashtable_bits; > > +} > > + > > int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > > unsigned int symindex, unsigned int relsec, > > struct module *me) > > @@ -349,11 +822,13 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > > unsigned int i, type; > > Elf_Addr v; > > int res; > > + unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); > > + unsigned int hashtable_bits = initialize_relocation_hashtable(num_relocations); > > > > pr_debug("Applying relocate section %u to %u\n", relsec, > > sechdrs[relsec].sh_info); > > > > - for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { > > + for (i = 0; i < num_relocations; i++) { > > /* This is where to make the change */ > > location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr > > + rel[i].r_offset; > > @@ -428,11 +903,16 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > > } > > } > > > > - res = handler(me, location, v); > > + if (accumulate_relocations[type]) > > + res = add_relocation_to_accumulate(me, type, location, hashtable_bits, v); > > + else > > + res = handler(me, location, v); > > if (res) > > return res; > > } > > > > + process_accumulated_relocations(me); > > + > > return 0; > > } > > > > > > -- > > 2.34.1 > > > > > > _______________________________________________ > > linux-riscv mailing list > > linux-riscv@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-riscv
diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h index d696d6610231..11a71b8533d5 100644 --- a/arch/riscv/include/uapi/asm/elf.h +++ b/arch/riscv/include/uapi/asm/elf.h @@ -49,6 +49,7 @@ typedef union __riscv_fp_state elf_fpregset_t; #define R_RISCV_TLS_DTPREL64 9 #define R_RISCV_TLS_TPREL32 10 #define R_RISCV_TLS_TPREL64 11 +#define R_RISCV_IRELATIVE 58 /* Relocation types not used by the dynamic linker */ #define R_RISCV_BRANCH 16 @@ -81,7 +82,6 @@ typedef union __riscv_fp_state elf_fpregset_t; #define R_RISCV_ALIGN 43 #define R_RISCV_RVC_BRANCH 44 #define R_RISCV_RVC_JUMP 45 -#define R_RISCV_LUI 46 #define R_RISCV_GPREL_I 47 #define R_RISCV_GPREL_S 48 #define R_RISCV_TPREL_I 49 @@ -93,6 +93,9 @@ typedef union __riscv_fp_state elf_fpregset_t; #define R_RISCV_SET16 55 #define R_RISCV_SET32 56 #define R_RISCV_32_PCREL 57 +#define R_RISCV_PLT32 59 +#define R_RISCV_SET_ULEB128 60 +#define R_RISCV_SUB_ULEB128 61 #endif /* _UAPI_ASM_RISCV_ELF_H */ diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c index a9e94e939cb5..230172ecb26e 100644 --- a/arch/riscv/kernel/module.c +++ b/arch/riscv/kernel/module.c @@ -7,6 +7,9 @@ #include <linux/elf.h> #include <linux/err.h> #include <linux/errno.h> +#include <linux/hashtable.h> +#include <linux/kernel.h> +#include <linux/log2.h> #include <linux/moduleloader.h> #include <linux/vmalloc.h> #include <linux/sizes.h> @@ -14,6 +17,27 @@ #include <asm/alternative.h> #include <asm/sections.h> +struct used_bucket { + struct list_head head; + struct hlist_head *bucket; +}; + +struct relocation_head { + struct hlist_node node; + struct list_head *rel_entry; + void *location; +}; + +struct relocation_entry { + struct list_head head; + Elf_Addr value; + unsigned int type; +}; + +struct hlist_head *relocation_hashtable; + +struct list_head used_buckets_list; + /* * The auipc+jalr instruction pair can reach any PC-relative offset * in the range [-2^31 - 2^11, 2^31 - 2^11) @@ -269,6 +293,12 @@ static int apply_r_riscv_align_rela(struct module *me, void *location, return -EINVAL; } +static int apply_r_riscv_add8_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location += (u8)v; + return 0; +} + static int apply_r_riscv_add16_rela(struct module *me, void *location, Elf_Addr v) { @@ -290,6 +320,12 @@ static int apply_r_riscv_add64_rela(struct module *me, void *location, return 0; } +static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location -= (u8)v; + return 0; +} + static int apply_r_riscv_sub16_rela(struct module *me, void *location, Elf_Addr v) { @@ -311,33 +347,470 @@ static int apply_r_riscv_sub64_rela(struct module *me, void *location, return 0; } -static int (*reloc_handlers_rela[]) (struct module *me, void *location, - Elf_Addr v) = { - [R_RISCV_32] = apply_r_riscv_32_rela, - [R_RISCV_64] = apply_r_riscv_64_rela, - [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, - [R_RISCV_JAL] = apply_r_riscv_jal_rela, - [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, - [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, - [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, - [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, - [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, - [R_RISCV_HI20] = apply_r_riscv_hi20_rela, - [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, - [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, - [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, - [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, - [R_RISCV_CALL] = apply_r_riscv_call_rela, - [R_RISCV_RELAX] = apply_r_riscv_relax_rela, - [R_RISCV_ALIGN] = apply_r_riscv_align_rela, - [R_RISCV_ADD16] = apply_r_riscv_add16_rela, - [R_RISCV_ADD32] = apply_r_riscv_add32_rela, - [R_RISCV_ADD64] = apply_r_riscv_add64_rela, - [R_RISCV_SUB16] = apply_r_riscv_sub16_rela, - [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, - [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, +static int dynamic_linking_not_supported(struct module *me, void *location, + Elf_Addr v) +{ + pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n", + me->name, location); + return -EINVAL; +} + +static int tls_not_supported(struct module *me, void *location, Elf_Addr v) +{ + pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n", + me->name, location); + return -EINVAL; +} + +static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location = (*(u8 *)location - ((u8)v & 0x3F)) & 0x3F; + return 0; +} + +static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location = ((*(u8 *)location & 0xc0) | ((u8)v & 0x3F)); + return 0; +} + +static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location = (u8)v; + return 0; +} + +static int apply_r_riscv_set16_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u16 *)location = (u16)v; + return 0; +} + +static int apply_r_riscv_set32_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u32 *)location = (u32)v; + return 0; +} + +static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u32 *)location = v - (unsigned long)location; + return 0; +} + +static int apply_r_riscv_plt32_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - location; + + if (!riscv_insn_valid_32bit_offset(offset)) { + /* Only emit the plt entry if offset over 32-bit range */ + if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { + offset = (void *)module_emit_plt_entry(me, v) - location; + } else { + pr_err("%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", + me->name, (long long)v, location); + return -EINVAL; + } + } + + *(u32 *)location = (u32)offset; + return 0; +} + +static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v) +{ + *(long *)location = v; + return 0; +} + +static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v) +{ + *(long *)location -= v; + return 0; +} + +/* + * Relocations defined in the riscv-elf-psabi-doc. + * This handles static linking only. + */ +static int (*reloc_handlers_rela[])(struct module *me, void *location, + Elf_Addr v) = { + [R_RISCV_32] = apply_r_riscv_32_rela, + [R_RISCV_64] = apply_r_riscv_64_rela, + [R_RISCV_RELATIVE] = dynamic_linking_not_supported, + [R_RISCV_COPY] = dynamic_linking_not_supported, + [R_RISCV_JUMP_SLOT] = dynamic_linking_not_supported, + [R_RISCV_TLS_DTPMOD32] = dynamic_linking_not_supported, + [R_RISCV_TLS_DTPMOD64] = dynamic_linking_not_supported, + [R_RISCV_TLS_DTPREL32] = dynamic_linking_not_supported, + [R_RISCV_TLS_DTPREL64] = dynamic_linking_not_supported, + [R_RISCV_TLS_TPREL32] = dynamic_linking_not_supported, + [R_RISCV_TLS_TPREL64] = dynamic_linking_not_supported, + /* 12-15 undefined */ + [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, + [R_RISCV_JAL] = apply_r_riscv_jal_rela, + [R_RISCV_CALL] = apply_r_riscv_call_rela, + [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, + [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, + [R_RISCV_TLS_GOT_HI20] = tls_not_supported, + [R_RISCV_TLS_GD_HI20] = tls_not_supported, + [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, + [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, + [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, + [R_RISCV_HI20] = apply_r_riscv_hi20_rela, + [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, + [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, + [R_RISCV_TPREL_HI20] = tls_not_supported, + [R_RISCV_TPREL_LO12_I] = tls_not_supported, + [R_RISCV_TPREL_LO12_S] = tls_not_supported, + [R_RISCV_TPREL_ADD] = tls_not_supported, + [R_RISCV_ADD8] = apply_r_riscv_add8_rela, + [R_RISCV_ADD16] = apply_r_riscv_add16_rela, + [R_RISCV_ADD32] = apply_r_riscv_add32_rela, + [R_RISCV_ADD64] = apply_r_riscv_add64_rela, + [R_RISCV_SUB8] = apply_r_riscv_sub8_rela, + [R_RISCV_SUB16] = apply_r_riscv_sub16_rela, + [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, + [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, + /* 41-42 reserved for future standard use */ + [R_RISCV_ALIGN] = apply_r_riscv_align_rela, + [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, + [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, + /* 46-50 reserved for future standard use */ + [R_RISCV_RELAX] = apply_r_riscv_relax_rela, + [R_RISCV_SUB6] = apply_r_riscv_sub6_rela, + [R_RISCV_SET6] = apply_r_riscv_set6_rela, + [R_RISCV_SET8] = apply_r_riscv_set8_rela, + [R_RISCV_SET16] = apply_r_riscv_set16_rela, + [R_RISCV_SET32] = apply_r_riscv_set32_rela, + [R_RISCV_32_PCREL] = apply_r_riscv_32_pcrel_rela, + [R_RISCV_IRELATIVE] = dynamic_linking_not_supported, + [R_RISCV_PLT32] = apply_r_riscv_plt32_rela, + [R_RISCV_SET_ULEB128] = apply_r_riscv_set_uleb128, + [R_RISCV_SUB_ULEB128] = apply_r_riscv_sub_uleb128, + /* 62-191 reserved for future standard use */ + /* 192-255 nonstandard ABI extensions */ +}; + +static bool accumulate_relocations[] = { + [R_RISCV_32] = false, + [R_RISCV_64] = false, + [R_RISCV_RELATIVE] = false, + [R_RISCV_COPY] = false, + [R_RISCV_JUMP_SLOT] = false, + [R_RISCV_TLS_DTPMOD32] = false, + [R_RISCV_TLS_DTPMOD64] = false, + [R_RISCV_TLS_DTPREL32] = false, + [R_RISCV_TLS_DTPREL64] = false, + [R_RISCV_TLS_TPREL32] = false, + [R_RISCV_TLS_TPREL64] = false, + /* 12-15 undefined */ + [R_RISCV_BRANCH] = false, + [R_RISCV_JAL] = false, + [R_RISCV_CALL] = false, + [R_RISCV_CALL_PLT] = false, + [R_RISCV_GOT_HI20] = false, + [R_RISCV_TLS_GOT_HI20] = false, + [R_RISCV_TLS_GD_HI20] = false, + [R_RISCV_PCREL_HI20] = false, + [R_RISCV_PCREL_LO12_I] = false, + [R_RISCV_PCREL_LO12_S] = false, + [R_RISCV_HI20] = false, + [R_RISCV_LO12_I] = false, + [R_RISCV_LO12_S] = false, + [R_RISCV_TPREL_HI20] = false, + [R_RISCV_TPREL_LO12_I] = false, + [R_RISCV_TPREL_LO12_S] = false, + [R_RISCV_TPREL_ADD] = false, + [R_RISCV_ADD8] = true, + [R_RISCV_ADD16] = true, + [R_RISCV_ADD32] = true, + [R_RISCV_ADD64] = true, + [R_RISCV_SUB8] = true, + [R_RISCV_SUB16] = true, + [R_RISCV_SUB32] = true, + [R_RISCV_SUB64] = true, + /* 41-42 reserved for future standard use */ + [R_RISCV_ALIGN] = false, + [R_RISCV_RVC_BRANCH] = false, + [R_RISCV_RVC_JUMP] = false, + /* 46-50 reserved for future standard use */ + [R_RISCV_RELAX] = false, + [R_RISCV_SUB6] = true, + [R_RISCV_SET6] = true, + [R_RISCV_SET8] = true, + [R_RISCV_SET16] = true, + [R_RISCV_SET32] = true, + [R_RISCV_32_PCREL] = false, + [R_RISCV_IRELATIVE] = false, + [R_RISCV_PLT32] = false, + [R_RISCV_SET_ULEB128] = true, + [R_RISCV_SUB_ULEB128] = true, + /* 62-191 reserved for future standard use */ + /* 192-255 nonstandard ABI extensions */ +}; + +static int accumulation_not_supported(struct module *me, void *location, long buffer) +{ + pr_err("%s: Internal error. Only ADD/SUB/SET/ULEB128 should be accumulated.", me->name); + return -EINVAL; +} + +static int apply_6_bit_accumulation(struct module *me, void *location, long buffer) +{ + if (buffer != (buffer & 0x3F)) { + pr_err("%s: value %ld out of range for 6-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + *(u8 *)location = ((*(u8 *)location & 0xc0) | ((u8)buffer & 0x3F)); + return 0; +} + +static int apply_8_bit_accumulation(struct module *me, void *location, long buffer) +{ + if (buffer != (u8)buffer) { + pr_err("%s: value %ld out of range for 8-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + *(u8 *)location = (u8)buffer; + return 0; +} + +static int apply_16_bit_accumulation(struct module *me, void *location, long buffer) +{ + if (buffer != (u16)buffer) { + pr_err("%s: value %ld out of range for 16-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + *(u16 *)location = (u16)buffer; + return 0; +} + +static int apply_32_bit_accumulation(struct module *me, void *location, long buffer) +{ + if (buffer != (u32)buffer) { + pr_err("%s: value %ld out of range for 32-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + *(u32 *)location = (u32)buffer; + return 0; +} + +static int apply_64_bit_accumulation(struct module *me, void *location, long buffer) +{ + *(u64 *)location = (u64)buffer; + return 0; +} + +static int apply_uleb128_accumulation(struct module *me, void *location, long buffer) +{ + /* + * ULEB128 is a variable length encoding. Encode the buffer into + * the ULEB128 data format. + */ + while (buffer != 0) { + *(u8 *)location = (u8)buffer & 0x7F; + buffer >>= 7; + *(u8 *)location |= (buffer != 0) << 7; + location = (u8 *)location + 1; + } + return 0; +} + +/* + * Need to duplicate this a third time to capture the handlers for accumulation. + */ +static int (*accumulate_handlers[])(struct module *me, void *location, long buffer) = { + [R_RISCV_32] = accumulation_not_supported, + [R_RISCV_64] = accumulation_not_supported, + [R_RISCV_RELATIVE] = accumulation_not_supported, + [R_RISCV_COPY] = accumulation_not_supported, + [R_RISCV_JUMP_SLOT] = accumulation_not_supported, + [R_RISCV_TLS_DTPMOD32] = accumulation_not_supported, + [R_RISCV_TLS_DTPMOD64] = accumulation_not_supported, + [R_RISCV_TLS_DTPREL32] = accumulation_not_supported, + [R_RISCV_TLS_DTPREL64] = accumulation_not_supported, + [R_RISCV_TLS_TPREL32] = accumulation_not_supported, + [R_RISCV_TLS_TPREL64] = accumulation_not_supported, + /* 12-15 undefined */ + [R_RISCV_BRANCH] = accumulation_not_supported, + [R_RISCV_JAL] = accumulation_not_supported, + [R_RISCV_CALL] = accumulation_not_supported, + [R_RISCV_CALL_PLT] = accumulation_not_supported, + [R_RISCV_GOT_HI20] = accumulation_not_supported, + [R_RISCV_TLS_GOT_HI20] = accumulation_not_supported, + [R_RISCV_TLS_GD_HI20] = accumulation_not_supported, + [R_RISCV_PCREL_HI20] = accumulation_not_supported, + [R_RISCV_PCREL_LO12_I] = accumulation_not_supported, + [R_RISCV_PCREL_LO12_S] = accumulation_not_supported, + [R_RISCV_HI20] = accumulation_not_supported, + [R_RISCV_LO12_I] = accumulation_not_supported, + [R_RISCV_LO12_S] = accumulation_not_supported, + [R_RISCV_TPREL_HI20] = accumulation_not_supported, + [R_RISCV_TPREL_LO12_I] = accumulation_not_supported, + [R_RISCV_TPREL_LO12_S] = accumulation_not_supported, + [R_RISCV_TPREL_ADD] = accumulation_not_supported, + [R_RISCV_ADD8] = apply_8_bit_accumulation, + [R_RISCV_ADD16] = apply_16_bit_accumulation, + [R_RISCV_ADD32] = apply_32_bit_accumulation, + [R_RISCV_ADD64] = apply_64_bit_accumulation, + [R_RISCV_SUB8] = apply_8_bit_accumulation, + [R_RISCV_SUB16] = apply_16_bit_accumulation, + [R_RISCV_SUB32] = apply_32_bit_accumulation, + [R_RISCV_SUB64] = apply_64_bit_accumulation, + /* 41-42 reserved for future standard use */ + [R_RISCV_ALIGN] = accumulation_not_supported, + [R_RISCV_RVC_BRANCH] = accumulation_not_supported, + [R_RISCV_RVC_JUMP] = accumulation_not_supported, + /* 46-50 reserved for future standard use */ + [R_RISCV_RELAX] = accumulation_not_supported, + [R_RISCV_SUB6] = apply_6_bit_accumulation, + [R_RISCV_SET6] = apply_6_bit_accumulation, + [R_RISCV_SET8] = apply_8_bit_accumulation, + [R_RISCV_SET16] = apply_16_bit_accumulation, + [R_RISCV_SET32] = apply_32_bit_accumulation, + [R_RISCV_32_PCREL] = accumulation_not_supported, + [R_RISCV_IRELATIVE] = accumulation_not_supported, + [R_RISCV_PLT32] = accumulation_not_supported, + [R_RISCV_SET_ULEB128] = apply_uleb128_accumulation, + [R_RISCV_SUB_ULEB128] = apply_uleb128_accumulation, + /* 62-191 reserved for future standard use */ + /* 192-255 nonstandard ABI extensions */ }; +void process_accumulated_relocations(struct module *me) +{ + /* + * Only ADD/SUB/SET/ULEB128 should end up here. + * + * Each bucket may have more than one relocation location. All + * relocations for a location are stored in a list in a bucket. + * + * Relocations are applied to a temp variable before being stored to the + * provided location to check for overflow. This also allows ULEB128 to + * properly decide how many entries are needed before storing to + * location. The final value is stored into location using the handler + * for the last relocation to an address. + * + * Three layers of indexing: + * - Each of the buckets in use + * - Groups of relocations in each bucket by location address + * - Each relocation entry for a location address + */ + struct used_bucket *bucket_iter; + struct relocation_head *rel_head_iter; + struct relocation_entry *rel_entry_iter; + int curr_type; + void *location; + long buffer; + + list_for_each_entry(bucket_iter, &used_buckets_list, head) { + hlist_for_each_entry(rel_head_iter, bucket_iter->bucket, node) { + buffer = 0; + location = rel_head_iter->location; + list_for_each_entry(rel_entry_iter, rel_head_iter->rel_entry, head) { + curr_type = rel_entry_iter->type; + reloc_handlers_rela[curr_type](me, &buffer, rel_entry_iter->value); + kfree(rel_entry_iter); + } + accumulate_handlers[curr_type](me, location, buffer); + kfree(rel_head_iter); + } + kfree(bucket_iter); + } + + kfree(relocation_hashtable); +} + +int add_relocation_to_accumulate(struct module *me, int type, void *location, + unsigned int hashtable_bits, Elf_Addr v) +{ + struct relocation_entry *entry; + struct relocation_head *rel_head; + struct hlist_head *current_head; + struct hlist_node *first; + struct used_bucket *bucket; + unsigned long hash; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + INIT_LIST_HEAD(&entry->head); + entry->type = type; + entry->value = v; + + hash = hash_min((unsigned long)location, hashtable_bits); + + current_head = &relocation_hashtable[hash]; + first = current_head->first; + + /* Find matching location (if any) */ + bool found = false; + struct relocation_head *rel_head_iter; + + hlist_for_each_entry(rel_head_iter, current_head, node) { + if (rel_head_iter->location == location) { + found = true; + rel_head = rel_head_iter; + break; + } + } + + if (!found) { + rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); + rel_head->rel_entry = + kmalloc(sizeof(struct list_head), GFP_KERNEL); + INIT_LIST_HEAD(rel_head->rel_entry); + rel_head->location = location; + INIT_HLIST_NODE(&rel_head->node); + if (!current_head->first) { + bucket = + kmalloc(sizeof(struct used_bucket), GFP_KERNEL); + INIT_LIST_HEAD(&bucket->head); + bucket->bucket = current_head; + list_add(&bucket->head, &used_buckets_list); + } + hlist_add_head(&rel_head->node, current_head); + } + + /* Add relocation to head of discovered rel_head */ + list_add_tail(&entry->head, rel_head->rel_entry); + + return 0; +} + +unsigned int initialize_relocation_hashtable(unsigned int num_relocations) +{ + /* Can safely assume that bits is not greater than sizeof(long) */ + unsigned long hashtable_size = roundup_pow_of_two(num_relocations); + unsigned int hashtable_bits = ilog2(hashtable_size); + + /* + * Double size of hashtable if num_relocations * 1.25 is greater than + * hashtable_size. + */ + int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); + + hashtable_bits += should_double_size; + + hashtable_size <<= should_double_size; + + relocation_hashtable = kmalloc_array(hashtable_size, + sizeof(*relocation_hashtable), + GFP_KERNEL); + __hash_init(relocation_hashtable, hashtable_size); + + INIT_LIST_HEAD(&used_buckets_list); + + return hashtable_bits; +} + int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, unsigned int symindex, unsigned int relsec, struct module *me) @@ -349,11 +822,13 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, unsigned int i, type; Elf_Addr v; int res; + unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); + unsigned int hashtable_bits = initialize_relocation_hashtable(num_relocations); pr_debug("Applying relocate section %u to %u\n", relsec, sechdrs[relsec].sh_info); - for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { + for (i = 0; i < num_relocations; i++) { /* This is where to make the change */ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + rel[i].r_offset; @@ -428,11 +903,16 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, } } - res = handler(me, location, v); + if (accumulate_relocations[type]) + res = add_relocation_to_accumulate(me, type, location, hashtable_bits, v); + else + res = handler(me, location, v); if (res) return res; } + process_accumulated_relocations(me); + return 0; }
Add all final module relocations and add error logs explaining the ones that are not supported. Implement overflow checks for ADD/SUB/SET/ULEB128 relocations. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> --- arch/riscv/include/uapi/asm/elf.h | 5 +- arch/riscv/kernel/module.c | 534 ++++++++++++++++++++++++++++++++++++-- 2 files changed, 511 insertions(+), 28 deletions(-)