From 0cfbfe0c4bf7140146d7d6973143bd97466a2799 Mon Sep 17 00:00:00 2001 From: Heiko Stuebner Date: Thu, 9 Dec 2021 18:04:40 +0100 Subject: [PATCH 05/12] riscv: implement module alternatives This allows alternatives to also be applied when loading modules and follows somewhat closely to the arm64 variant of this. Signed-off-by: Heiko Stuebner --- arch/riscv/include/asm/alternative.h | 3 ++- arch/riscv/kernel/alternative.c | 20 +++++++++++++++---- arch/riscv/kernel/module.c | 29 ++++++++++++++++++++++++++++ 3 files changed, 47 insertions(+), 5 deletions(-) diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h index bee2eb579252..973892e61c07 100644 --- a/arch/riscv/include/asm/alternative.h +++ b/arch/riscv/include/asm/alternative.h @@ -18,8 +18,10 @@ #include #define RISCV_ALTERNATIVES_BOOT 0 +#define RISCV_ALTERNATIVES_MODULE 1 void __init apply_boot_alternatives(void); +void apply_module_alternatives(void *start, size_t length); struct alt_entry { void *old_ptr; /* address of original instruciton or data */ @@ -37,6 +39,5 @@ struct errata_checkfunc_id { void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end, unsigned long archid, unsigned long impid, unsigned int stage); - #endif #endif diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c index 416e7a380ee4..8ad76b290c59 100644 --- a/arch/riscv/kernel/alternative.c +++ b/arch/riscv/kernel/alternative.c @@ -58,13 +58,14 @@ static void __init init_alternative(void) * a feature detect on the boot CPU). No need to worry about other CPUs * here. */ -static void __init _apply_alternatives(unsigned int stage) +static void __init_or_module _apply_alternatives(struct alt_entry *begin, + struct alt_entry *end, + unsigned int stage) { if (!vendor_patch_func) return; - vendor_patch_func((struct alt_entry *)__alt_start, - (struct alt_entry *)__alt_end, + vendor_patch_func(begin, end, cpu_mfr_info.arch_id, cpu_mfr_info.imp_id, stage); } @@ -76,5 +77,16 @@ void __init apply_boot_alternatives(void) init_alternative(); - _apply_alternatives(RISCV_ALTERNATIVES_BOOT); + _apply_alternatives((struct alt_entry *)__alt_start, + (struct alt_entry *)__alt_end, + RISCV_ALTERNATIVES_BOOT); } + +#ifdef CONFIG_MODULES +void apply_module_alternatives(void *start, size_t length) +{ + _apply_alternatives((struct alt_entry *)start, + (struct alt_entry *)(start + length), + RISCV_ALTERNATIVES_MODULE); +} +#endif diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c index 68a9e3d1fe16..a778abd5b8b9 100644 --- a/arch/riscv/kernel/module.c +++ b/arch/riscv/kernel/module.c @@ -11,6 +11,7 @@ #include #include #include +#include #include static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v) @@ -416,3 +417,31 @@ void *module_alloc(unsigned long size) __builtin_return_address(0)); } #endif + +static const Elf_Shdr *find_section(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + const char *name) +{ + const Elf_Shdr *s, *se; + const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + + for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) { + if (strcmp(name, secstrs + s->sh_name) == 0) + return s; + } + + return NULL; +} + +int module_finalize(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *me) +{ + const Elf_Shdr *s; + + s = find_section(hdr, sechdrs, ".alternative"); + if (s) + apply_module_alternatives((void *)s->sh_addr, s->sh_size); + + return 0; +} -- 2.30.2