On Wed, 2008-09-03 at 17:01 -0700, Linus Torvalds wrote: > > On Wed, 3 Sep 2008, James Bottomley wrote: > > > > Oh ... because Arjan has a patch to export > > dereference_function_descriptor. I suppose I could make him do the > > heavy lifting, but it seemed sensible to make it easy for him (and me) > > by putting it in a header. > > > > http://marc.info/?l=linux-kernel&m=121976793429869 > > Ahh. > > NOW it all starts to make sense. > > Or perhaps not sense, but I at least understand why people want to move it > around. The kernel.h location kind of goes together with that > core_kernel_text() thing, although it seems to be more of a "random > collection of routines" thing than anything else (but hey, that's the very > definition of "kernel.h" for you). > > The module.h location still seems to be more of a "oh, both > kernel/extable.c and lib/vsprintf.c already included <linux/module.h>" and > it's a bit sad, since it really has nothing at all to do with modules. > > Grr. It does seem like we don't have any kind of "abi" header file. > <linux/kernel.h> and <asm/processor.h> has various random things. > > So yea, there doesn't seem to be any _obvious_ place that makes sense. > > Linus > > Not-very-strong-opinion: How about <asm/sections.h>? That does seem to be > where we already hide things like "in_kernel_text()" at least on powerpc. > In fact, since we already always have a generic version, the patch would > actually be something like > > - in <asm-generic/sections.h>, just do > > #define dereference_function_descriptor(p) (p) > > - in architectures that want to override it > > #undef dereference_function_descriptor > > followed by > > static inline void *dereference_function_descriptor(..) .. > or > #define dereference_function_descriptor my_fn_dereference > > since they all include the generic one as a base > > Hmm? I do admit that "<asm/sections.h>" doesn't really strike me as a very > natural name for this, but kernel/extable.c does already include it for > other reasons, and it's at least no worse than module.h. Well, good as any other I suppose. So this is what you want? James --- It was introduced by commit 0fe1ef24f7bd0020f29ffe287dfdb9ead33ca0b2 Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Date: Sun Jul 6 16:43:12 2008 -0700 vsprintf: add support for '%pS' and '%pF' pointer formats However, the current way its coded doesn't work on parisc64. For two reasons: 1) parisc isn't in the #ifdef and 2) parisc has a different format for function descriptors Make dereference_function_descriptor() more accommodating by allowing architecture overrides. I put the three overrides (for parisc64, ppc64 and ia64) in arch/kernel/module.c because that's where the kernel internal linker which knows how to deal with function descriptors sits. Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> --- arch/ia64/include/asm/sections.h | 3 +++ arch/ia64/kernel/module.c | 12 ++++++++++++ arch/parisc/kernel/module.c | 14 ++++++++++++++ arch/powerpc/include/asm/sections.h | 3 +++ arch/powerpc/kernel/module_64.c | 13 ++++++++++++- include/asm-generic/sections.h | 6 ++++++ include/asm-parisc/sections.h | 5 +++++ lib/vsprintf.c | 11 +---------- 8 files changed, 56 insertions(+), 11 deletions(-) diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h index 7286e4a..a7acad2 100644 --- a/arch/ia64/include/asm/sections.h +++ b/arch/ia64/include/asm/sections.h @@ -21,5 +21,8 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b extern char __start_unwind[], __end_unwind[]; extern char __start_ivt_text[], __end_ivt_text[]; +#undef dereference_function_descriptor +void *dereference_function_descriptor(void *); + #endif /* _ASM_IA64_SECTIONS_H */ diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c index 29aad34..545626f 100644 --- a/arch/ia64/kernel/module.c +++ b/arch/ia64/kernel/module.c @@ -31,9 +31,11 @@ #include <linux/elf.h> #include <linux/moduleloader.h> #include <linux/string.h> +#include <linux/uaccess.h> #include <linux/vmalloc.h> #include <asm/patch.h> +#include <asm/sections.h> #include <asm/unaligned.h> #define ARCH_MODULE_DEBUG 0 @@ -941,3 +943,13 @@ module_arch_cleanup (struct module *mod) if (mod->arch.core_unw_table) unw_remove_unwind_table(mod->arch.core_unw_table); } + +void *dereference_function_descriptor(void *ptr) +{ + struct fdesc *desc = ptr; + void *p; + + if (!probe_kernel_address(&desc->ip, p)) + ptr = p; + return ptr; +} diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index fdacdd4..44138c3 100644 --- a/arch/parisc/kernel/module.c +++ b/arch/parisc/kernel/module.c @@ -47,7 +47,9 @@ #include <linux/string.h> #include <linux/kernel.h> #include <linux/bug.h> +#include <linux/uaccess.h> +#include <asm/sections.h> #include <asm/unwind.h> #if 0 @@ -860,3 +862,15 @@ void module_arch_cleanup(struct module *mod) deregister_unwind_table(mod); module_bug_cleanup(mod); } + +#ifdef CONFIG_64BIT +void *dereference_function_descriptor(void *ptr) +{ + Elf64_Fdesc *desc = ptr; + void *p; + + if (!probe_kernel_address(&desc->addr, p)) + ptr = p; + return ptr; +} +#endif diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h index 916018e..7710e9e 100644 --- a/arch/powerpc/include/asm/sections.h +++ b/arch/powerpc/include/asm/sections.h @@ -16,6 +16,9 @@ static inline int in_kernel_text(unsigned long addr) return 0; } +#undef dereference_function_descriptor +void *dereference_function_descriptor(void *); + #endif #endif /* __KERNEL__ */ diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index ee6a298..ad79de2 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -21,8 +21,9 @@ #include <linux/err.h> #include <linux/vmalloc.h> #include <linux/bug.h> +#include <linux/uaccess.h> #include <asm/module.h> -#include <asm/uaccess.h> +#include <asm/sections.h> #include <asm/firmware.h> #include <asm/code-patching.h> #include <linux/sort.h> @@ -451,3 +452,13 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, return 0; } + +void *dereference_function_descriptor(void *ptr) +{ + struct ppc64_opd_entry *desc = ptr; + void *p; + + if (!probe_kernel_address(&desc->funcaddr, p)) + ptr = p; + return ptr; +} diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 8feeae1..79a7ff9 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -14,4 +14,10 @@ extern char __kprobes_text_start[], __kprobes_text_end[]; extern char __initdata_begin[], __initdata_end[]; extern char __start_rodata[], __end_rodata[]; +/* function descriptor handling (if any). Override + * in asm/sections.h */ +#ifndef dereference_function_descriptor +#define dereference_function_descriptor(p) (p) +#endif + #endif /* _ASM_GENERIC_SECTIONS_H_ */ diff --git a/include/asm-parisc/sections.h b/include/asm-parisc/sections.h index fdd43ec..9d13c35 100644 --- a/include/asm-parisc/sections.h +++ b/include/asm-parisc/sections.h @@ -4,4 +4,9 @@ /* nothing to see, move along */ #include <asm-generic/sections.h> +#ifdef CONFIG_64BIT +#undef dereference_function_descriptor +void *dereference_function_descriptor(void *); +#endif + #endif diff --git a/lib/vsprintf.c b/lib/vsprintf.c index d8d1d11..c399bc1 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -27,6 +27,7 @@ #include <asm/page.h> /* for PAGE_SIZE */ #include <asm/div64.h> +#include <asm/sections.h> /* for dereference_function_descriptor() */ /* Works only for digits and letters, but small and fast */ #define TOLOWER(x) ((x) | 0x20) @@ -513,16 +514,6 @@ static char *string(char *buf, char *end, char *s, int field_width, int precisio return buf; } -static inline void *dereference_function_descriptor(void *ptr) -{ -#if defined(CONFIG_IA64) || defined(CONFIG_PPC64) - void *p; - if (!probe_kernel_address(ptr, p)) - ptr = p; -#endif - return ptr; -} - static char *symbol_string(char *buf, char *end, void *ptr, int field_width, int precision, int flags) { unsigned long value = (unsigned long) ptr; -- 1.5.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
