From d4703aefdbc8f9f347f6dcefcddd791294314eb7 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 15 Dec 2009 16:28:32 -0600 Subject: [PATCH] module: handle ppc64 relocating kcrctabs when CONFIG_RELOCATABLE=y powerpc applies relocations to the kcrctab. They're absolute symbols, but it's not completely unreasonable: other archs may too, but the relocation is often 0. http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-November/077972.html Inspired-by: Neil Horman Signed-off-by: Rusty Russell Tested-by: Neil Horman Acked-by: Paul Mackerras --- arch/powerpc/include/asm/module.h | 5 +++++ arch/powerpc/kernel/vmlinux.lds.S | 3 +++ kernel/module.c | 28 +++++++++++++++++++++------- 3 files changed, 29 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h index 08454880a2c0..0192a4ee2bc2 100644 --- a/arch/powerpc/include/asm/module.h +++ b/arch/powerpc/include/asm/module.h @@ -87,5 +87,10 @@ struct exception_table_entry; void sort_ex_table(struct exception_table_entry *start, struct exception_table_entry *finish); +#ifdef CONFIG_MODVERSIONS +#define ARCH_RELOCATES_KCRCTAB + +extern const unsigned long reloc_start[]; +#endif #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_MODULE_H */ diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 27735a7ac12b..dcd01c82e701 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -38,6 +38,9 @@ jiffies = jiffies_64 + 4; #endif SECTIONS { + . = 0; + reloc_start = .; + . = KERNELBASE; /* diff --git a/kernel/module.c b/kernel/module.c index 12afc5a3ddd3..a65dc787a27b 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -880,11 +880,23 @@ static int try_to_force_load(struct module *mod, const char *reason) } #ifdef CONFIG_MODVERSIONS +/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */ +static unsigned long maybe_relocated(unsigned long crc, + const struct module *crc_owner) +{ +#ifdef ARCH_RELOCATES_KCRCTAB + if (crc_owner == NULL) + return crc - (unsigned long)reloc_start; +#endif + return crc; +} + static int check_version(Elf_Shdr *sechdrs, unsigned int versindex, const char *symname, struct module *mod, - const unsigned long *crc) + const unsigned long *crc, + const struct module *crc_owner) { unsigned int i, num_versions; struct modversion_info *versions; @@ -905,10 +917,10 @@ static int check_version(Elf_Shdr *sechdrs, if (strcmp(versions[i].name, symname) != 0) continue; - if (versions[i].crc == *crc) + if (versions[i].crc == maybe_relocated(*crc, crc_owner)) return 1; DEBUGP("Found checksum %lX vs module %lX\n", - *crc, versions[i].crc); + maybe_relocated(*crc, crc_owner), versions[i].crc); goto bad_version; } @@ -931,7 +943,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs, if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL, &crc, true, false)) BUG(); - return check_version(sechdrs, versindex, "module_layout", mod, crc); + return check_version(sechdrs, versindex, "module_layout", mod, crc, + NULL); } /* First part is kernel version, which we ignore if module has crcs. */ @@ -949,7 +962,8 @@ static inline int check_version(Elf_Shdr *sechdrs, unsigned int versindex, const char *symname, struct module *mod, - const unsigned long *crc) + const unsigned long *crc, + const struct module *crc_owner) { return 1; } @@ -984,8 +998,8 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs, /* use_module can fail due to OOM, or module initialization or unloading */ if (sym) { - if (!check_version(sechdrs, versindex, name, mod, crc) || - !use_module(mod, owner)) + if (!check_version(sechdrs, versindex, name, mod, crc, owner) + || !use_module(mod, owner)) sym = NULL; } return sym; -- 2.20.1