| Message ID | 1343775898-28345-3-git-send-email-cyril@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 31 Jul 2012, Cyril Chemparathy wrote: > This patch replaces the original physical offset patching implementation > with one that uses the newly added patching framework. In the process, we now > unconditionally initialize the __pv_phys_offset and __pv_offset globals in the > head.S code. Why unconditionally initializing those? There is no reason for that. > Signed-off-by: Cyril Chemparathy <cyril@ti.com> Comments below. > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index 835898e..d165896 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S [...] > .data > .globl __pv_phys_offset > .type __pv_phys_offset, %object > __pv_phys_offset: > .long 0 > .size __pv_phys_offset, . - __pv_phys_offset > + > + .globl __pv_offset > + .type __pv_offset, %object > __pv_offset: > .long 0 > -#endif > + .size __pv_offset, . - __pv_offset Please move those to C code. They aren't of much use in this file anymore. This will allow you to use pphys_addr_t for them as well in your subsequent patch. And more importantly get rid of that ugly pv_offset_high that you introduced iin another patch. > diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c > index df5e897..39f8fce 100644 > --- a/arch/arm/kernel/module.c > +++ b/arch/arm/kernel/module.c > @@ -317,11 +317,6 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, > maps[i].txt_sec->sh_addr, > maps[i].txt_sec->sh_size); > #endif > -#ifdef CONFIG_ARM_PATCH_PHYS_VIRT > - s = find_mod_section(hdr, sechdrs, ".pv_table"); > - if (s) > - fixup_pv_table((void *)s->sh_addr, s->sh_size); > -#endif > s = find_mod_section(hdr, sechdrs, ".patch.table"); > if (s) > patch_kernel((void *)s->sh_addr, s->sh_size); The patch_kernel code and its invokation should still be conditional on CONFIG_ARM_PATCH_PHYS_VIRT. This ability may still be configured out irrespective of the implementation used. > diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S > index bacb275..13731e3 100644 > --- a/arch/arm/kernel/vmlinux.lds.S > +++ b/arch/arm/kernel/vmlinux.lds.S > @@ -162,11 +162,6 @@ SECTIONS > __smpalt_end = .; > } > #endif > - .init.pv_table : { > - __pv_table_begin = .; > - *(.pv_table) > - __pv_table_end = .; > - } > .init.patch_table : { > __patch_table_begin = .; > *(.patch.table) Since you're changing the module ABI,it is important to also modify the module vermagic string in asm/module.h to prevent the loading of incompatible kernel modules. Nicolas
Hi Nicolas, On 8/4/2012 2:15 AM, Nicolas Pitre wrote: > On Tue, 31 Jul 2012, Cyril Chemparathy wrote: > >> This patch replaces the original physical offset patching implementation >> with one that uses the newly added patching framework. In the process, we now >> unconditionally initialize the __pv_phys_offset and __pv_offset globals in the >> head.S code. > > Why unconditionally initializing those? There is no reason for that. > We could keep this conditional on LPAE, but do you see any specific need for keeping it conditional? >> Signed-off-by: Cyril Chemparathy <cyril@ti.com> > > Comments below. > >> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S >> index 835898e..d165896 100644 >> --- a/arch/arm/kernel/head.S >> +++ b/arch/arm/kernel/head.S > [...] >> .data >> .globl __pv_phys_offset >> .type __pv_phys_offset, %object >> __pv_phys_offset: >> .long 0 >> .size __pv_phys_offset, . - __pv_phys_offset >> + >> + .globl __pv_offset >> + .type __pv_offset, %object >> __pv_offset: >> .long 0 >> -#endif >> + .size __pv_offset, . - __pv_offset > > Please move those to C code. They aren't of much use in this file > anymore. This will allow you to use pphys_addr_t for them as well in > your subsequent patch. And more importantly get rid of that ugly > pv_offset_high that you introduced iin another patch. > Moving it to C-code caused problems because these get filled in prior to BSS being cleared. We could potentially have this initialized in C with a mystery dummy value to prevent it from landing in BSS. Would that be acceptable? >> diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c >> index df5e897..39f8fce 100644 >> --- a/arch/arm/kernel/module.c >> +++ b/arch/arm/kernel/module.c >> @@ -317,11 +317,6 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, >> maps[i].txt_sec->sh_addr, >> maps[i].txt_sec->sh_size); >> #endif >> -#ifdef CONFIG_ARM_PATCH_PHYS_VIRT >> - s = find_mod_section(hdr, sechdrs, ".pv_table"); >> - if (s) >> - fixup_pv_table((void *)s->sh_addr, s->sh_size); >> -#endif >> s = find_mod_section(hdr, sechdrs, ".patch.table"); >> if (s) >> patch_kernel((void *)s->sh_addr, s->sh_size); > > The patch_kernel code and its invokation should still be conditional on > CONFIG_ARM_PATCH_PHYS_VIRT. This ability may still be configured out > irrespective of the implementation used. > Maybe CONFIG_ARM_PATCH_PHYS_VIRT is not quite appropriate if this is used to patch up other things in addition to phys-virt stuff? I could have this dependent on CONFIG_ARM_INIT_PATCH (or whatever nomenclature we chose for this) and have CONFIG_ARM_PATCH_PHYS_VIRT depend on it. >> diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S >> index bacb275..13731e3 100644 >> --- a/arch/arm/kernel/vmlinux.lds.S >> +++ b/arch/arm/kernel/vmlinux.lds.S >> @@ -162,11 +162,6 @@ SECTIONS >> __smpalt_end = .; >> } >> #endif >> - .init.pv_table : { >> - __pv_table_begin = .; >> - *(.pv_table) >> - __pv_table_end = .; >> - } >> .init.patch_table : { >> __patch_table_begin = .; >> *(.patch.table) > > Since you're changing the module ABI,it is important to also modify the > module vermagic string in asm/module.h to prevent the loading of > incompatible kernel modules. > Absolutely. Thanks. > > Nicolas >
On Sun, 5 Aug 2012, Cyril Chemparathy wrote: > Hi Nicolas, > > On 8/4/2012 2:15 AM, Nicolas Pitre wrote: > > On Tue, 31 Jul 2012, Cyril Chemparathy wrote: > > > > > This patch replaces the original physical offset patching implementation > > > with one that uses the newly added patching framework. In the process, we > > > now > > > unconditionally initialize the __pv_phys_offset and __pv_offset globals in > > > the > > > head.S code. > > > > Why unconditionally initializing those? There is no reason for that. > > > > We could keep this conditional on LPAE, but do you see any specific need for > keeping it conditional? This has nothing to do with LPAe. This is about CONFIG_ARM_PATCH_PHYS_VIRT only. If not selected, those global vaariables have no need to exist. > > Comments below. > > > > > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > > > index 835898e..d165896 100644 > > > --- a/arch/arm/kernel/head.S > > > +++ b/arch/arm/kernel/head.S > > [...] > > > .data > > > .globl __pv_phys_offset > > > .type __pv_phys_offset, %object > > > __pv_phys_offset: > > > .long 0 > > > .size __pv_phys_offset, . - __pv_phys_offset > > > + > > > + .globl __pv_offset > > > + .type __pv_offset, %object > > > __pv_offset: > > > .long 0 > > > -#endif > > > + .size __pv_offset, . - __pv_offset > > > > Please move those to C code. They aren't of much use in this file > > anymore. This will allow you to use pphys_addr_t for them as well in > > your subsequent patch. And more importantly get rid of that ugly > > pv_offset_high that you introduced iin another patch. > > > > Moving it to C-code caused problems because these get filled in prior to BSS > being cleared. > > We could potentially have this initialized in C with a mystery dummy value to > prevent it from landing in BSS. Would that be acceptable? Just initialize them explicitly to zero. They will end up in .ddata section. > > > > index df5e897..39f8fce 100644 > > > --- a/arch/arm/kernel/module.c > > > +++ b/arch/arm/kernel/module.c > > > @@ -317,11 +317,6 @@ int module_finalize(const Elf32_Ehdr *hdr, const > > > Elf_Shdr *sechdrs, > > > maps[i].txt_sec->sh_addr, > > > maps[i].txt_sec->sh_size); > > > #endif > > > -#ifdef CONFIG_ARM_PATCH_PHYS_VIRT > > > - s = find_mod_section(hdr, sechdrs, ".pv_table"); > > > - if (s) > > > - fixup_pv_table((void *)s->sh_addr, s->sh_size); > > > -#endif > > > s = find_mod_section(hdr, sechdrs, ".patch.table"); > > > if (s) > > > patch_kernel((void *)s->sh_addr, s->sh_size); > > > > The patch_kernel code and its invokation should still be conditional on > > CONFIG_ARM_PATCH_PHYS_VIRT. This ability may still be configured out > > irrespective of the implementation used. > > > > Maybe CONFIG_ARM_PATCH_PHYS_VIRT is not quite appropriate if this is used to > patch up other things in addition to phys-virt stuff? Maybe, but at the moment this is not the case. > I could have this dependent on CONFIG_ARM_INIT_PATCH (or whatever nomenclature > we chose for this) and have CONFIG_ARM_PATCH_PHYS_VIRT depend on it. Let's cross that bridge in time. FWIW, I don't like "init patch" much. I feel like the "runtime" qualifier more pricisely describe this code than "init". Nicolas
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h index fcb5757..01c710d 100644 --- a/arch/arm/include/asm/memory.h +++ b/arch/arm/include/asm/memory.h @@ -17,6 +17,7 @@ #include <linux/const.h> #include <linux/types.h> #include <asm/sizes.h> +#include <asm/patch.h> #ifdef CONFIG_NEED_MACH_MEMORY_H #include <mach/memory.h> @@ -151,35 +152,22 @@ #ifndef __virt_to_phys #ifdef CONFIG_ARM_PATCH_PHYS_VIRT -/* - * Constants used to force the right instruction encodings and shifts - * so that all we need to do is modify the 8-bit constant field. - */ -#define __PV_BITS_31_24 0x81000000 - extern unsigned long __pv_phys_offset; #define PHYS_OFFSET __pv_phys_offset -#define __pv_stub(from,to,instr,type) \ - __asm__("@ __pv_stub\n" \ - "1: " instr " %0, %1, %2\n" \ - " .pushsection .pv_table,\"a\"\n" \ - " .long 1b\n" \ - " .popsection\n" \ - : "=r" (to) \ - : "r" (from), "I" (type)) +extern unsigned long __pv_offset; static inline unsigned long __virt_to_phys(unsigned long x) { unsigned long t; - __pv_stub(x, t, "add", __PV_BITS_31_24); + early_patch_imm8(x, t, "add", __pv_offset); return t; } static inline unsigned long __phys_to_virt(unsigned long x) { unsigned long t; - __pv_stub(x, t, "sub", __PV_BITS_31_24); + early_patch_imm8(x, t, "sub", __pv_offset); return t; } #else diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 835898e..d165896 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -109,9 +109,13 @@ ENTRY(stext) #ifndef CONFIG_XIP_KERNEL adr r3, 2f - ldmia r3, {r4, r8} + ldmia r3, {r4, r5, r6, r8} sub r4, r3, r4 @ (PHYS_OFFSET - PAGE_OFFSET) add r8, r8, r4 @ PHYS_OFFSET + add r5, r5, r4 + str r8, [r5] @ set __pv_phys_offset + add r6, r6, r4 + str r4, [r6] @ set __pv_offset #else ldr r8, =PHYS_OFFSET @ always constant in this case #endif @@ -124,9 +128,6 @@ ENTRY(stext) #ifdef CONFIG_SMP_ON_UP bl __fixup_smp #endif -#ifdef CONFIG_ARM_PATCH_PHYS_VIRT - bl __fixup_pv_table -#endif bl __create_page_tables /* @@ -148,6 +149,8 @@ ENDPROC(stext) .ltorg #ifndef CONFIG_XIP_KERNEL 2: .long . + .long __pv_phys_offset + .long __pv_offset .long PAGE_OFFSET #endif @@ -522,94 +525,17 @@ ENTRY(fixup_smp) ldmfd sp!, {r4 - r6, pc} ENDPROC(fixup_smp) -#ifdef CONFIG_ARM_PATCH_PHYS_VIRT - -/* __fixup_pv_table - patch the stub instructions with the delta between - * PHYS_OFFSET and PAGE_OFFSET, which is assumed to be 16MiB aligned and - * can be expressed by an immediate shifter operand. The stub instruction - * has a form of '(add|sub) rd, rn, #imm'. - */ - __HEAD -__fixup_pv_table: - adr r0, 1f - ldmia r0, {r3-r5, r7} - sub r3, r0, r3 @ PHYS_OFFSET - PAGE_OFFSET - add r4, r4, r3 @ adjust table start address - add r5, r5, r3 @ adjust table end address - add r7, r7, r3 @ adjust __pv_phys_offset address - str r8, [r7] @ save computed PHYS_OFFSET to __pv_phys_offset - mov r6, r3, lsr #24 @ constant for add/sub instructions - teq r3, r6, lsl #24 @ must be 16MiB aligned -THUMB( it ne @ cross section branch ) - bne __error - str r6, [r7, #4] @ save to __pv_offset - b __fixup_a_pv_table -ENDPROC(__fixup_pv_table) - - .align -1: .long . - .long __pv_table_begin - .long __pv_table_end -2: .long __pv_phys_offset - - .text -__fixup_a_pv_table: -#ifdef CONFIG_THUMB2_KERNEL - lsls r6, #24 - beq 2f - clz r7, r6 - lsr r6, #24 - lsl r6, r7 - bic r6, #0x0080 - lsrs r7, #1 - orrcs r6, #0x0080 - orr r6, r6, r7, lsl #12 - orr r6, #0x4000 - b 2f -1: add r7, r3 - ldrh ip, [r7, #2] - and ip, 0x8f00 - orr ip, r6 @ mask in offset bits 31-24 - strh ip, [r7, #2] -2: cmp r4, r5 - ldrcc r7, [r4], #4 @ use branch for delay slot - bcc 1b - bx lr -#else - b 2f -1: ldr ip, [r7, r3] - bic ip, ip, #0x000000ff - orr ip, ip, r6 @ mask in offset bits 31-24 - str ip, [r7, r3] -2: cmp r4, r5 - ldrcc r7, [r4], #4 @ use branch for delay slot - bcc 1b - mov pc, lr -#endif -ENDPROC(__fixup_a_pv_table) - -ENTRY(fixup_pv_table) - stmfd sp!, {r4 - r7, lr} - ldr r2, 2f @ get address of __pv_phys_offset - mov r3, #0 @ no offset - mov r4, r0 @ r0 = table start - add r5, r0, r1 @ r1 = table size - ldr r6, [r2, #4] @ get __pv_offset - bl __fixup_a_pv_table - ldmfd sp!, {r4 - r7, pc} -ENDPROC(fixup_pv_table) - - .align -2: .long __pv_phys_offset - .data .globl __pv_phys_offset .type __pv_phys_offset, %object __pv_phys_offset: .long 0 .size __pv_phys_offset, . - __pv_phys_offset + + .globl __pv_offset + .type __pv_offset, %object __pv_offset: .long 0 -#endif + .size __pv_offset, . - __pv_offset #include "head-common.S" diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c index df5e897..39f8fce 100644 --- a/arch/arm/kernel/module.c +++ b/arch/arm/kernel/module.c @@ -317,11 +317,6 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, maps[i].txt_sec->sh_addr, maps[i].txt_sec->sh_size); #endif -#ifdef CONFIG_ARM_PATCH_PHYS_VIRT - s = find_mod_section(hdr, sechdrs, ".pv_table"); - if (s) - fixup_pv_table((void *)s->sh_addr, s->sh_size); -#endif s = find_mod_section(hdr, sechdrs, ".patch.table"); if (s) patch_kernel((void *)s->sh_addr, s->sh_size); diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index bacb275..13731e3 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -162,11 +162,6 @@ SECTIONS __smpalt_end = .; } #endif - .init.pv_table : { - __pv_table_begin = .; - *(.pv_table) - __pv_table_end = .; - } .init.patch_table : { __patch_table_begin = .; *(.patch.table)
This patch replaces the original physical offset patching implementation with one that uses the newly added patching framework. In the process, we now unconditionally initialize the __pv_phys_offset and __pv_offset globals in the head.S code. Signed-off-by: Cyril Chemparathy <cyril@ti.com> --- arch/arm/include/asm/memory.h | 20 ++------- arch/arm/kernel/head.S | 96 +++++------------------------------------ arch/arm/kernel/module.c | 5 --- arch/arm/kernel/vmlinux.lds.S | 5 --- 4 files changed, 15 insertions(+), 111 deletions(-)