Commit a8e91016 authored by Heiko Stuebner's avatar Heiko Stuebner Committed by Palmer Dabbelt

riscv: implement module alternatives

This allows alternatives to also be applied when loading modules
and follows the implementation of other architectures (e.g. arm64).
Signed-off-by: default avatarHeiko Stuebner <heiko@sntech.de>
Reviewed-by: default avatarPhilipp Tomsich <philipp.tomsich@vrull.eu>
Link: https://lore.kernel.org/r/20220511192921.2223629-4-heiko@sntech.deSigned-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent d14ca1f8
......@@ -4,6 +4,7 @@
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/bug.h>
#include <asm/patch.h>
......@@ -54,7 +55,8 @@ static struct errata_info_t errata_list[ERRATA_SIFIVE_NUMBER] = {
},
};
static u32 __init sifive_errata_probe(unsigned long archid, unsigned long impid)
static u32 __init_or_module sifive_errata_probe(unsigned long archid,
unsigned long impid)
{
int idx;
u32 cpu_req_errata = 0;
......@@ -66,7 +68,7 @@ static u32 __init sifive_errata_probe(unsigned long archid, unsigned long impid)
return cpu_req_errata;
}
static void __init warn_miss_errata(u32 miss_errata)
static void __init_or_module warn_miss_errata(u32 miss_errata)
{
int i;
......@@ -79,8 +81,10 @@ static void __init warn_miss_errata(u32 miss_errata)
pr_warn("----------------------------------------------------------------\n");
}
void __init sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
unsigned long archid, unsigned long impid,
void __init_or_module sifive_errata_patch_func(struct alt_entry *begin,
struct alt_entry *end,
unsigned long archid,
unsigned long impid,
unsigned int stage)
{
struct alt_entry *alt;
......
......@@ -20,8 +20,10 @@
#include <asm/hwcap.h>
#define RISCV_ALTERNATIVES_BOOT 0 /* alternatives applied during regular boot */
#define RISCV_ALTERNATIVES_MODULE 1 /* alternatives applied during module-init */
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 */
......@@ -43,6 +45,7 @@ void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
#else /* CONFIG_RISCV_ALTERNATIVE */
static inline void apply_boot_alternatives(void) { }
static inline void apply_module_alternatives(void *start, size_t length) { }
#endif /* CONFIG_RISCV_ALTERNATIVE */
......
......@@ -7,6 +7,7 @@
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/uaccess.h>
#include <asm/alternative.h>
......@@ -23,7 +24,7 @@ static struct cpu_manufacturer_info_t {
static void (*vendor_patch_func)(struct alt_entry *begin, struct alt_entry *end,
unsigned long archid, unsigned long impid,
unsigned int stage) __initdata;
unsigned int stage) __initdata_or_module;
static inline void __init riscv_fill_cpu_mfr_info(void)
{
......@@ -58,7 +59,7 @@ 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(struct alt_entry *begin,
static void __init_or_module _apply_alternatives(struct alt_entry *begin,
struct alt_entry *end,
unsigned int stage)
{
......@@ -81,3 +82,12 @@ void __init apply_boot_alternatives(void)
(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
......@@ -11,6 +11,7 @@
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/pgtable.h>
#include <asm/alternative.h>
#include <asm/sections.h>
/*
......@@ -427,3 +428,31 @@ 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;
}
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