| Message ID | 20210125191923.1060122-17-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: MMU enabled kexec relocation | expand |
I forgot to make changes to arch/arm64/Kconfig. The correct patch is below. --- From a2bc374320d7c7efd3c40644ad3d6d59a024b301 Mon Sep 17 00:00:00 2001 From: Pavel Tatashin <pasha.tatashin@soleen.com> Date: Mon, 29 Jul 2019 21:24:25 -0400 Subject: [PATCH v10 16/18] arm64: kexec: configure trans_pgd page table for kexec Configure a page table located in kexec-safe memory that has the following mappings: 1. identity mapping for text of relocation function with executable permission. 2. va mappings for all source ranges 3. va mappings for all destination ranges. Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> --- arch/arm64/Kconfig | 2 +- arch/arm64/include/asm/kexec.h | 12 ++++ arch/arm64/kernel/asm-offsets.c | 6 ++ arch/arm64/kernel/machine_kexec.c | 91 ++++++++++++++++++++++++++++++- 4 files changed, 109 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index fc0ed9d6e011..440abd0c0ee1 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1134,7 +1134,7 @@ config CRASH_DUMP config TRANS_TABLE def_bool y - depends on HIBERNATION + depends on HIBERNATION || KEXEC_CORE config XEN_DOM0 def_bool y diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h index b96d8a6aac80..049cde429b1b 100644 --- a/arch/arm64/include/asm/kexec.h +++ b/arch/arm64/include/asm/kexec.h @@ -105,6 +105,12 @@ extern const char arm64_kexec_el2_vectors[]; * el2_vector If present means that relocation routine will go to EL1 * from EL2 to do the copy, and then back to EL2 to do the jump * to new world. + * trans_ttbr0 idmap for relocation function and its argument + * trans_ttbr1 map for source/destination addresses. + * trans_t0sz t0sz for idmap page in trans_ttbr0 + * src_addr start address for source pages. + * dst_addr start address for destination pages. + * copy_len Number of bytes that need to be copied */ struct kern_reloc_arg { phys_addr_t head; @@ -114,6 +120,12 @@ struct kern_reloc_arg { phys_addr_t kern_arg2; phys_addr_t kern_arg3; phys_addr_t el2_vector; + phys_addr_t trans_ttbr0; + phys_addr_t trans_ttbr1; + unsigned long trans_t0sz; + unsigned long src_addr; + unsigned long dst_addr; + unsigned long copy_len; }; #define ARCH_HAS_KIMAGE_ARCH diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 8a9475be1b62..06278611451d 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -160,6 +160,12 @@ int main(void) DEFINE(KEXEC_KRELOC_KERN_ARG2, offsetof(struct kern_reloc_arg, kern_arg2)); DEFINE(KEXEC_KRELOC_KERN_ARG3, offsetof(struct kern_reloc_arg, kern_arg3)); DEFINE(KEXEC_KRELOC_EL2_VECTOR, offsetof(struct kern_reloc_arg, el2_vector)); + DEFINE(KEXEC_KRELOC_TRANS_TTBR0, offsetof(struct kern_reloc_arg, trans_ttbr0)); + DEFINE(KEXEC_KRELOC_TRANS_TTBR1, offsetof(struct kern_reloc_arg, trans_ttbr1)); + DEFINE(KEXEC_KRELOC_TRANS_T0SZ, offsetof(struct kern_reloc_arg, trans_t0sz)); + DEFINE(KEXEC_KRELOC_SRC_ADDR, offsetof(struct kern_reloc_arg, src_addr)); + DEFINE(KEXEC_KRELOC_DST_ADDR, offsetof(struct kern_reloc_arg, dst_addr)); + DEFINE(KEXEC_KRELOC_COPY_LEN, offsetof(struct kern_reloc_arg, copy_len)); #endif return 0; } diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index 41d1e3ca13f8..dc1b7e5a54fb 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -21,6 +21,7 @@ #include <asm/mmu_context.h> #include <asm/page.h> #include <asm/sections.h> +#include <asm/trans_pgd.h> #include "cpu-reset.h" @@ -71,11 +72,91 @@ static void *kexec_page_alloc(void *arg) return page_address(page); } +/* + * Map source segments starting from src_va, and map destination + * segments starting from dst_va, and return size of copy in + * *copy_len argument. + * Relocation function essentially needs to do: + * memcpy(dst_va, src_va, copy_len); + */ +static int map_segments(struct kimage *kimage, pgd_t *pgdp, + struct trans_pgd_info *info, + unsigned long src_va, + unsigned long dst_va, + unsigned long *copy_len) +{ + unsigned long *ptr = 0; + unsigned long dest = 0; + unsigned long len = 0; + unsigned long entry, addr; + int rc; + + for (entry = kimage->head; !(entry & IND_DONE); entry = *ptr++) { + addr = entry & PAGE_MASK; + + switch (entry & IND_FLAGS) { + case IND_DESTINATION: + dest = addr; + break; + case IND_INDIRECTION: + ptr = __va(addr); + if (rc) + return rc; + break; + case IND_SOURCE: + rc = trans_pgd_map_page(info, pgdp, __va(addr), + src_va, PAGE_KERNEL); + if (rc) + return rc; + rc = trans_pgd_map_page(info, pgdp, __va(dest), + dst_va, PAGE_KERNEL); + if (rc) + return rc; + dest += PAGE_SIZE; + src_va += PAGE_SIZE; + dst_va += PAGE_SIZE; + len += PAGE_SIZE; + } + } + *copy_len = len; + + return 0; +} + +static int mmu_relocate_setup(struct kimage *kimage, void *reloc_code, + struct kern_reloc_arg *kern_reloc_arg) +{ + struct trans_pgd_info info = { + .trans_alloc_page = kexec_page_alloc, + .trans_alloc_arg = kimage, + }; + pgd_t *trans_pgd = kexec_page_alloc(kimage); + int rc; + + if (!trans_pgd) + return -ENOMEM; + + /* idmap relocation function */ + rc = trans_pgd_idmap_page(&info, &kern_reloc_arg->trans_ttbr0, + &kern_reloc_arg->trans_t0sz, reloc_code); + if (rc) + return rc; + + kern_reloc_arg->src_addr = _PAGE_OFFSET(VA_BITS_MIN); + kern_reloc_arg->dst_addr = _PAGE_OFFSET(VA_BITS_MIN - 1); + kern_reloc_arg->trans_ttbr1 = phys_to_ttbr(__pa(trans_pgd)); + + rc = map_segments(kimage, trans_pgd, &info, kern_reloc_arg->src_addr, + kern_reloc_arg->dst_addr, &kern_reloc_arg->copy_len); + return rc; +} + int machine_kexec_post_load(struct kimage *kimage) { void *reloc_code = page_to_virt(kimage->control_code_page); struct kern_reloc_arg *kern_reloc_arg = kexec_page_alloc(kimage); long func_offset, vector_offset, reloc_size; + int rc = 0; if (!kern_reloc_arg) return -ENOMEM; @@ -95,6 +176,14 @@ int machine_kexec_post_load(struct kimage *kimage) if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) kern_reloc_arg->el2_vector = __pa(reloc_code) + vector_offset; + /* + * If relocation is not needed, we do not need to enable MMU in + * relocation routine, therefore do not create page tables for + * scenarios such as crash kernel + */ + if (!(kimage->head & IND_DONE)) + rc = mmu_relocate_setup(kimage, reloc_code, kern_reloc_arg); + kexec_image_info(kimage); /* Flush the reloc_code in preparation for its execution. */ @@ -103,7 +192,7 @@ int machine_kexec_post_load(struct kimage *kimage) reloc_size); __flush_dcache_area(kern_reloc_arg, sizeof(struct kern_reloc_arg)); - return 0; + return rc; } /**
On 2021-01-25 19:21:22, Pavel Tatashin wrote: > I forgot to make changes to arch/arm64/Kconfig. The correct patch is > below. > > --- > > From a2bc374320d7c7efd3c40644ad3d6d59a024b301 Mon Sep 17 00:00:00 2001 > From: Pavel Tatashin <pasha.tatashin@soleen.com> > Date: Mon, 29 Jul 2019 21:24:25 -0400 > Subject: [PATCH v10 16/18] arm64: kexec: configure trans_pgd page table for > kexec > > Configure a page table located in kexec-safe memory that has > the following mappings: > > 1. identity mapping for text of relocation function with executable > permission. > 2. va mappings for all source ranges > 3. va mappings for all destination ranges. > > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> > --- > arch/arm64/Kconfig | 2 +- > arch/arm64/include/asm/kexec.h | 12 ++++ > arch/arm64/kernel/asm-offsets.c | 6 ++ > arch/arm64/kernel/machine_kexec.c | 91 ++++++++++++++++++++++++++++++- > 4 files changed, 109 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index fc0ed9d6e011..440abd0c0ee1 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1134,7 +1134,7 @@ config CRASH_DUMP > > config TRANS_TABLE > def_bool y > - depends on HIBERNATION > + depends on HIBERNATION || KEXEC_CORE > > config XEN_DOM0 > def_bool y > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h > index b96d8a6aac80..049cde429b1b 100644 > --- a/arch/arm64/include/asm/kexec.h > +++ b/arch/arm64/include/asm/kexec.h > @@ -105,6 +105,12 @@ extern const char arm64_kexec_el2_vectors[]; > * el2_vector If present means that relocation routine will go to EL1 > * from EL2 to do the copy, and then back to EL2 to do the jump > * to new world. > + * trans_ttbr0 idmap for relocation function and its argument > + * trans_ttbr1 map for source/destination addresses. > + * trans_t0sz t0sz for idmap page in trans_ttbr0 > + * src_addr start address for source pages. > + * dst_addr start address for destination pages. > + * copy_len Number of bytes that need to be copied > */ > struct kern_reloc_arg { > phys_addr_t head; > @@ -114,6 +120,12 @@ struct kern_reloc_arg { > phys_addr_t kern_arg2; > phys_addr_t kern_arg3; > phys_addr_t el2_vector; > + phys_addr_t trans_ttbr0; > + phys_addr_t trans_ttbr1; > + unsigned long trans_t0sz; > + unsigned long src_addr; > + unsigned long dst_addr; > + unsigned long copy_len; > }; > > #define ARCH_HAS_KIMAGE_ARCH > diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c > index 8a9475be1b62..06278611451d 100644 > --- a/arch/arm64/kernel/asm-offsets.c > +++ b/arch/arm64/kernel/asm-offsets.c > @@ -160,6 +160,12 @@ int main(void) > DEFINE(KEXEC_KRELOC_KERN_ARG2, offsetof(struct kern_reloc_arg, kern_arg2)); > DEFINE(KEXEC_KRELOC_KERN_ARG3, offsetof(struct kern_reloc_arg, kern_arg3)); > DEFINE(KEXEC_KRELOC_EL2_VECTOR, offsetof(struct kern_reloc_arg, el2_vector)); > + DEFINE(KEXEC_KRELOC_TRANS_TTBR0, offsetof(struct kern_reloc_arg, trans_ttbr0)); > + DEFINE(KEXEC_KRELOC_TRANS_TTBR1, offsetof(struct kern_reloc_arg, trans_ttbr1)); > + DEFINE(KEXEC_KRELOC_TRANS_T0SZ, offsetof(struct kern_reloc_arg, trans_t0sz)); > + DEFINE(KEXEC_KRELOC_SRC_ADDR, offsetof(struct kern_reloc_arg, src_addr)); > + DEFINE(KEXEC_KRELOC_DST_ADDR, offsetof(struct kern_reloc_arg, dst_addr)); > + DEFINE(KEXEC_KRELOC_COPY_LEN, offsetof(struct kern_reloc_arg, copy_len)); > #endif > return 0; > } > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > index 41d1e3ca13f8..dc1b7e5a54fb 100644 > --- a/arch/arm64/kernel/machine_kexec.c > +++ b/arch/arm64/kernel/machine_kexec.c > @@ -21,6 +21,7 @@ > #include <asm/mmu_context.h> > #include <asm/page.h> > #include <asm/sections.h> > +#include <asm/trans_pgd.h> > > #include "cpu-reset.h" > > @@ -71,11 +72,91 @@ static void *kexec_page_alloc(void *arg) > return page_address(page); > } > > +/* > + * Map source segments starting from src_va, and map destination > + * segments starting from dst_va, and return size of copy in > + * *copy_len argument. > + * Relocation function essentially needs to do: > + * memcpy(dst_va, src_va, copy_len); > + */ > +static int map_segments(struct kimage *kimage, pgd_t *pgdp, > + struct trans_pgd_info *info, > + unsigned long src_va, > + unsigned long dst_va, > + unsigned long *copy_len) > +{ > + unsigned long *ptr = 0; > + unsigned long dest = 0; > + unsigned long len = 0; > + unsigned long entry, addr; > + int rc; > + > + for (entry = kimage->head; !(entry & IND_DONE); entry = *ptr++) { > + addr = entry & PAGE_MASK; > + > + switch (entry & IND_FLAGS) { > + case IND_DESTINATION: > + dest = addr; > + break; > + case IND_INDIRECTION: > + ptr = __va(addr); > + if (rc) We're checking a potentially uninitialized value here. I think this whole "if (rc) return rc;" conditional can go away. Tyler > + return rc; > + break; > + case IND_SOURCE: > + rc = trans_pgd_map_page(info, pgdp, __va(addr), > + src_va, PAGE_KERNEL); > + if (rc) > + return rc; > + rc = trans_pgd_map_page(info, pgdp, __va(dest), > + dst_va, PAGE_KERNEL); > + if (rc) > + return rc; > + dest += PAGE_SIZE; > + src_va += PAGE_SIZE; > + dst_va += PAGE_SIZE; > + len += PAGE_SIZE; > + } > + } > + *copy_len = len; > + > + return 0; > +} > + > +static int mmu_relocate_setup(struct kimage *kimage, void *reloc_code, > + struct kern_reloc_arg *kern_reloc_arg) > +{ > + struct trans_pgd_info info = { > + .trans_alloc_page = kexec_page_alloc, > + .trans_alloc_arg = kimage, > + }; > + pgd_t *trans_pgd = kexec_page_alloc(kimage); > + int rc; > + > + if (!trans_pgd) > + return -ENOMEM; > + > + /* idmap relocation function */ > + rc = trans_pgd_idmap_page(&info, &kern_reloc_arg->trans_ttbr0, > + &kern_reloc_arg->trans_t0sz, reloc_code); > + if (rc) > + return rc; > + > + kern_reloc_arg->src_addr = _PAGE_OFFSET(VA_BITS_MIN); > + kern_reloc_arg->dst_addr = _PAGE_OFFSET(VA_BITS_MIN - 1); > + kern_reloc_arg->trans_ttbr1 = phys_to_ttbr(__pa(trans_pgd)); > + > + rc = map_segments(kimage, trans_pgd, &info, kern_reloc_arg->src_addr, > + kern_reloc_arg->dst_addr, &kern_reloc_arg->copy_len); > + return rc; > +} > + > int machine_kexec_post_load(struct kimage *kimage) > { > void *reloc_code = page_to_virt(kimage->control_code_page); > struct kern_reloc_arg *kern_reloc_arg = kexec_page_alloc(kimage); > long func_offset, vector_offset, reloc_size; > + int rc = 0; > > if (!kern_reloc_arg) > return -ENOMEM; > @@ -95,6 +176,14 @@ int machine_kexec_post_load(struct kimage *kimage) > if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) > kern_reloc_arg->el2_vector = __pa(reloc_code) + vector_offset; > > + /* > + * If relocation is not needed, we do not need to enable MMU in > + * relocation routine, therefore do not create page tables for > + * scenarios such as crash kernel > + */ > + if (!(kimage->head & IND_DONE)) > + rc = mmu_relocate_setup(kimage, reloc_code, kern_reloc_arg); > + > kexec_image_info(kimage); > > /* Flush the reloc_code in preparation for its execution. */ > @@ -103,7 +192,7 @@ int machine_kexec_post_load(struct kimage *kimage) > reloc_size); > __flush_dcache_area(kern_reloc_arg, sizeof(struct kern_reloc_arg)); > > - return 0; > + return rc; > } > > /** > -- > 2.25.1 >
On Wed, Jan 27, 2021 at 11:42 AM Tyler Hicks <tyhicks@linux.microsoft.com> wrote: > > On 2021-01-25 19:21:22, Pavel Tatashin wrote: > > I forgot to make changes to arch/arm64/Kconfig. The correct patch is > > below. > > > > --- > > > > From a2bc374320d7c7efd3c40644ad3d6d59a024b301 Mon Sep 17 00:00:00 2001 > > From: Pavel Tatashin <pasha.tatashin@soleen.com> > > Date: Mon, 29 Jul 2019 21:24:25 -0400 > > Subject: [PATCH v10 16/18] arm64: kexec: configure trans_pgd page table for > > kexec > > > > Configure a page table located in kexec-safe memory that has > > the following mappings: > > > > 1. identity mapping for text of relocation function with executable > > permission. > > 2. va mappings for all source ranges > > 3. va mappings for all destination ranges. > > > > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> > > --- > > arch/arm64/Kconfig | 2 +- > > arch/arm64/include/asm/kexec.h | 12 ++++ > > arch/arm64/kernel/asm-offsets.c | 6 ++ > > arch/arm64/kernel/machine_kexec.c | 91 ++++++++++++++++++++++++++++++- > > 4 files changed, 109 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index fc0ed9d6e011..440abd0c0ee1 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -1134,7 +1134,7 @@ config CRASH_DUMP > > > > config TRANS_TABLE > > def_bool y > > - depends on HIBERNATION > > + depends on HIBERNATION || KEXEC_CORE > > > > config XEN_DOM0 > > def_bool y > > diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h > > index b96d8a6aac80..049cde429b1b 100644 > > --- a/arch/arm64/include/asm/kexec.h > > +++ b/arch/arm64/include/asm/kexec.h > > @@ -105,6 +105,12 @@ extern const char arm64_kexec_el2_vectors[]; > > * el2_vector If present means that relocation routine will go to EL1 > > * from EL2 to do the copy, and then back to EL2 to do the jump > > * to new world. > > + * trans_ttbr0 idmap for relocation function and its argument > > + * trans_ttbr1 map for source/destination addresses. > > + * trans_t0sz t0sz for idmap page in trans_ttbr0 > > + * src_addr start address for source pages. > > + * dst_addr start address for destination pages. > > + * copy_len Number of bytes that need to be copied > > */ > > struct kern_reloc_arg { > > phys_addr_t head; > > @@ -114,6 +120,12 @@ struct kern_reloc_arg { > > phys_addr_t kern_arg2; > > phys_addr_t kern_arg3; > > phys_addr_t el2_vector; > > + phys_addr_t trans_ttbr0; > > + phys_addr_t trans_ttbr1; > > + unsigned long trans_t0sz; > > + unsigned long src_addr; > > + unsigned long dst_addr; > > + unsigned long copy_len; > > }; > > > > #define ARCH_HAS_KIMAGE_ARCH > > diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c > > index 8a9475be1b62..06278611451d 100644 > > --- a/arch/arm64/kernel/asm-offsets.c > > +++ b/arch/arm64/kernel/asm-offsets.c > > @@ -160,6 +160,12 @@ int main(void) > > DEFINE(KEXEC_KRELOC_KERN_ARG2, offsetof(struct kern_reloc_arg, kern_arg2)); > > DEFINE(KEXEC_KRELOC_KERN_ARG3, offsetof(struct kern_reloc_arg, kern_arg3)); > > DEFINE(KEXEC_KRELOC_EL2_VECTOR, offsetof(struct kern_reloc_arg, el2_vector)); > > + DEFINE(KEXEC_KRELOC_TRANS_TTBR0, offsetof(struct kern_reloc_arg, trans_ttbr0)); > > + DEFINE(KEXEC_KRELOC_TRANS_TTBR1, offsetof(struct kern_reloc_arg, trans_ttbr1)); > > + DEFINE(KEXEC_KRELOC_TRANS_T0SZ, offsetof(struct kern_reloc_arg, trans_t0sz)); > > + DEFINE(KEXEC_KRELOC_SRC_ADDR, offsetof(struct kern_reloc_arg, src_addr)); > > + DEFINE(KEXEC_KRELOC_DST_ADDR, offsetof(struct kern_reloc_arg, dst_addr)); > > + DEFINE(KEXEC_KRELOC_COPY_LEN, offsetof(struct kern_reloc_arg, copy_len)); > > #endif > > return 0; > > } > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > > index 41d1e3ca13f8..dc1b7e5a54fb 100644 > > --- a/arch/arm64/kernel/machine_kexec.c > > +++ b/arch/arm64/kernel/machine_kexec.c > > @@ -21,6 +21,7 @@ > > #include <asm/mmu_context.h> > > #include <asm/page.h> > > #include <asm/sections.h> > > +#include <asm/trans_pgd.h> > > > > #include "cpu-reset.h" > > > > @@ -71,11 +72,91 @@ static void *kexec_page_alloc(void *arg) > > return page_address(page); > > } > > > > +/* > > + * Map source segments starting from src_va, and map destination > > + * segments starting from dst_va, and return size of copy in > > + * *copy_len argument. > > + * Relocation function essentially needs to do: > > + * memcpy(dst_va, src_va, copy_len); > > + */ > > +static int map_segments(struct kimage *kimage, pgd_t *pgdp, > > + struct trans_pgd_info *info, > > + unsigned long src_va, > > + unsigned long dst_va, > > + unsigned long *copy_len) > > +{ > > + unsigned long *ptr = 0; > > + unsigned long dest = 0; > > + unsigned long len = 0; > > + unsigned long entry, addr; > > + int rc; > > + > > + for (entry = kimage->head; !(entry & IND_DONE); entry = *ptr++) { > > + addr = entry & PAGE_MASK; > > + > > + switch (entry & IND_FLAGS) { > > + case IND_DESTINATION: > > + dest = addr; > > + break; > > + case IND_INDIRECTION: > > + ptr = __va(addr); > > + if (rc) > > We're checking a potentially uninitialized value here. I think this > whole "if (rc) return rc;" conditional can go away. Thank you Tyler. This is indeed not needed. Pasha
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h index b96d8a6aac80..049cde429b1b 100644 --- a/arch/arm64/include/asm/kexec.h +++ b/arch/arm64/include/asm/kexec.h @@ -105,6 +105,12 @@ extern const char arm64_kexec_el2_vectors[]; * el2_vector If present means that relocation routine will go to EL1 * from EL2 to do the copy, and then back to EL2 to do the jump * to new world. + * trans_ttbr0 idmap for relocation function and its argument + * trans_ttbr1 map for source/destination addresses. + * trans_t0sz t0sz for idmap page in trans_ttbr0 + * src_addr start address for source pages. + * dst_addr start address for destination pages. + * copy_len Number of bytes that need to be copied */ struct kern_reloc_arg { phys_addr_t head; @@ -114,6 +120,12 @@ struct kern_reloc_arg { phys_addr_t kern_arg2; phys_addr_t kern_arg3; phys_addr_t el2_vector; + phys_addr_t trans_ttbr0; + phys_addr_t trans_ttbr1; + unsigned long trans_t0sz; + unsigned long src_addr; + unsigned long dst_addr; + unsigned long copy_len; }; #define ARCH_HAS_KIMAGE_ARCH diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 8a9475be1b62..06278611451d 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -160,6 +160,12 @@ int main(void) DEFINE(KEXEC_KRELOC_KERN_ARG2, offsetof(struct kern_reloc_arg, kern_arg2)); DEFINE(KEXEC_KRELOC_KERN_ARG3, offsetof(struct kern_reloc_arg, kern_arg3)); DEFINE(KEXEC_KRELOC_EL2_VECTOR, offsetof(struct kern_reloc_arg, el2_vector)); + DEFINE(KEXEC_KRELOC_TRANS_TTBR0, offsetof(struct kern_reloc_arg, trans_ttbr0)); + DEFINE(KEXEC_KRELOC_TRANS_TTBR1, offsetof(struct kern_reloc_arg, trans_ttbr1)); + DEFINE(KEXEC_KRELOC_TRANS_T0SZ, offsetof(struct kern_reloc_arg, trans_t0sz)); + DEFINE(KEXEC_KRELOC_SRC_ADDR, offsetof(struct kern_reloc_arg, src_addr)); + DEFINE(KEXEC_KRELOC_DST_ADDR, offsetof(struct kern_reloc_arg, dst_addr)); + DEFINE(KEXEC_KRELOC_COPY_LEN, offsetof(struct kern_reloc_arg, copy_len)); #endif return 0; } diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index 41d1e3ca13f8..dc1b7e5a54fb 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -21,6 +21,7 @@ #include <asm/mmu_context.h> #include <asm/page.h> #include <asm/sections.h> +#include <asm/trans_pgd.h> #include "cpu-reset.h" @@ -71,11 +72,91 @@ static void *kexec_page_alloc(void *arg) return page_address(page); } +/* + * Map source segments starting from src_va, and map destination + * segments starting from dst_va, and return size of copy in + * *copy_len argument. + * Relocation function essentially needs to do: + * memcpy(dst_va, src_va, copy_len); + */ +static int map_segments(struct kimage *kimage, pgd_t *pgdp, + struct trans_pgd_info *info, + unsigned long src_va, + unsigned long dst_va, + unsigned long *copy_len) +{ + unsigned long *ptr = 0; + unsigned long dest = 0; + unsigned long len = 0; + unsigned long entry, addr; + int rc; + + for (entry = kimage->head; !(entry & IND_DONE); entry = *ptr++) { + addr = entry & PAGE_MASK; + + switch (entry & IND_FLAGS) { + case IND_DESTINATION: + dest = addr; + break; + case IND_INDIRECTION: + ptr = __va(addr); + if (rc) + return rc; + break; + case IND_SOURCE: + rc = trans_pgd_map_page(info, pgdp, __va(addr), + src_va, PAGE_KERNEL); + if (rc) + return rc; + rc = trans_pgd_map_page(info, pgdp, __va(dest), + dst_va, PAGE_KERNEL); + if (rc) + return rc; + dest += PAGE_SIZE; + src_va += PAGE_SIZE; + dst_va += PAGE_SIZE; + len += PAGE_SIZE; + } + } + *copy_len = len; + + return 0; +} + +static int mmu_relocate_setup(struct kimage *kimage, void *reloc_code, + struct kern_reloc_arg *kern_reloc_arg) +{ + struct trans_pgd_info info = { + .trans_alloc_page = kexec_page_alloc, + .trans_alloc_arg = kimage, + }; + pgd_t *trans_pgd = kexec_page_alloc(kimage); + int rc; + + if (!trans_pgd) + return -ENOMEM; + + /* idmap relocation function */ + rc = trans_pgd_idmap_page(&info, &kern_reloc_arg->trans_ttbr0, + &kern_reloc_arg->trans_t0sz, reloc_code); + if (rc) + return rc; + + kern_reloc_arg->src_addr = _PAGE_OFFSET(VA_BITS_MIN); + kern_reloc_arg->dst_addr = _PAGE_OFFSET(VA_BITS_MIN - 1); + kern_reloc_arg->trans_ttbr1 = phys_to_ttbr(__pa(trans_pgd)); + + rc = map_segments(kimage, trans_pgd, &info, kern_reloc_arg->src_addr, + kern_reloc_arg->dst_addr, &kern_reloc_arg->copy_len); + return rc; +} + int machine_kexec_post_load(struct kimage *kimage) { void *reloc_code = page_to_virt(kimage->control_code_page); struct kern_reloc_arg *kern_reloc_arg = kexec_page_alloc(kimage); long func_offset, vector_offset, reloc_size; + int rc = 0; if (!kern_reloc_arg) return -ENOMEM; @@ -95,6 +176,14 @@ int machine_kexec_post_load(struct kimage *kimage) if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) kern_reloc_arg->el2_vector = __pa(reloc_code) + vector_offset; + /* + * If relocation is not needed, we do not need to enable MMU in + * relocation routine, therefore do not create page tables for + * scenarios such as crash kernel + */ + if (!(kimage->head & IND_DONE)) + rc = mmu_relocate_setup(kimage, reloc_code, kern_reloc_arg); + kexec_image_info(kimage); /* Flush the reloc_code in preparation for its execution. */ @@ -103,7 +192,7 @@ int machine_kexec_post_load(struct kimage *kimage) reloc_size); __flush_dcache_area(kern_reloc_arg, sizeof(struct kern_reloc_arg)); - return 0; + return rc; } /**
Configure a page table located in kexec-safe memory that has the following mappings: 1. identity mapping for text of relocation function with executable permission. 2. va mappings for all source ranges 3. va mappings for all destination ranges. Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> --- arch/arm64/include/asm/kexec.h | 12 ++++ arch/arm64/kernel/asm-offsets.c | 6 ++ arch/arm64/kernel/machine_kexec.c | 91 ++++++++++++++++++++++++++++++- 3 files changed, 108 insertions(+), 1 deletion(-)