diff options
Diffstat (limited to 'arch/riscv/kernel/patch.c')
| -rw-r--r-- | arch/riscv/kernel/patch.c | 102 |
1 files changed, 61 insertions, 41 deletions
diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 30e12b310cab..db13c9ddf9e3 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -13,13 +13,13 @@ #include <asm/cacheflush.h> #include <asm/fixmap.h> #include <asm/ftrace.h> -#include <asm/patch.h> +#include <asm/text-patching.h> #include <asm/sections.h> struct patch_insn { void *addr; u32 *insns; - int ninsns; + size_t len; atomic_t cpu_count; }; @@ -54,7 +54,7 @@ static __always_inline void *patch_map(void *addr, const unsigned int fixmap) BUG_ON(!page); return (void *)set_fixmap_offset(fixmap, page_to_phys(page) + - (uintaddr & ~PAGE_MASK)); + offset_in_page(addr)); } static void patch_unmap(int fixmap) @@ -65,8 +65,8 @@ NOKPROBE_SYMBOL(patch_unmap); static int __patch_insn_set(void *addr, u8 c, size_t len) { + bool across_pages = (offset_in_page(addr) + len) > PAGE_SIZE; void *waddr = addr; - bool across_pages = (((uintptr_t)addr & ~PAGE_MASK) + len) > PAGE_SIZE; /* * Only two pages can be mapped at a time for writing. @@ -89,6 +89,14 @@ static int __patch_insn_set(void *addr, u8 c, size_t len) memset(waddr, c, len); + /* + * We could have just patched a function that is about to be + * called so make sure we don't execute partially patched + * instructions by flushing the icache as soon as possible. + */ + local_flush_icache_range((unsigned long)waddr, + (unsigned long)waddr + len); + patch_unmap(FIX_TEXT_POKE0); if (across_pages) @@ -102,8 +110,8 @@ NOKPROBE_SYMBOL(__patch_insn_set); static int __patch_insn_write(void *addr, const void *insn, size_t len) { + bool across_pages = (offset_in_page(addr) + len) > PAGE_SIZE; void *waddr = addr; - bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE; int ret; /* @@ -135,6 +143,14 @@ static int __patch_insn_write(void *addr, const void *insn, size_t len) ret = copy_to_kernel_nofault(waddr, insn, len); + /* + * We could have just patched a function that is about to be + * called so make sure we don't execute partially patched + * instructions by flushing the icache as soon as possible. + */ + local_flush_icache_range((unsigned long)waddr, + (unsigned long)waddr + len); + patch_unmap(FIX_TEXT_POKE0); if (across_pages) @@ -163,69 +179,70 @@ NOKPROBE_SYMBOL(__patch_insn_write); static int patch_insn_set(void *addr, u8 c, size_t len) { - size_t patched = 0; size_t size; - int ret = 0; + int ret; /* * __patch_insn_set() can only work on 2 pages at a time so call it in a * loop with len <= 2 * PAGE_SIZE. */ - while (patched < len && !ret) { - size = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(addr + patched), len - patched); - ret = __patch_insn_set(addr + patched, c, size); - - patched += size; + while (len) { + size = min(len, PAGE_SIZE * 2 - offset_in_page(addr)); + ret = __patch_insn_set(addr, c, size); + if (ret) + return ret; + + addr += size; + len -= size; } - return ret; + return 0; } NOKPROBE_SYMBOL(patch_insn_set); int patch_text_set_nosync(void *addr, u8 c, size_t len) { - u32 *tp = addr; int ret; - ret = patch_insn_set(tp, c, len); - + ret = patch_insn_set(addr, c, len); if (!ret) - flush_icache_range((uintptr_t)tp, (uintptr_t)tp + len); + flush_icache_range((uintptr_t)addr, (uintptr_t)addr + len); return ret; } NOKPROBE_SYMBOL(patch_text_set_nosync); -static int patch_insn_write(void *addr, const void *insn, size_t len) +int patch_insn_write(void *addr, const void *insn, size_t len) { - size_t patched = 0; size_t size; - int ret = 0; + int ret; /* * Copy the instructions to the destination address, two pages at a time * because __patch_insn_write() can only handle len <= 2 * PAGE_SIZE. */ - while (patched < len && !ret) { - size = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(addr + patched), len - patched); - ret = __patch_insn_write(addr + patched, insn + patched, size); - - patched += size; + while (len) { + size = min(len, PAGE_SIZE * 2 - offset_in_page(addr)); + ret = __patch_insn_write(addr, insn, size); + if (ret) + return ret; + + addr += size; + insn += size; + len -= size; } - return ret; + return 0; } NOKPROBE_SYMBOL(patch_insn_write); int patch_text_nosync(void *addr, const void *insns, size_t len) { - u32 *tp = addr; int ret; - ret = patch_insn_write(tp, insns, len); - + ret = patch_insn_write(addr, insns, len); if (!ret) - flush_icache_range((uintptr_t) tp, (uintptr_t) tp + len); + flush_icache_range((uintptr_t)addr, (uintptr_t)addr + len); return ret; } @@ -234,33 +251,36 @@ NOKPROBE_SYMBOL(patch_text_nosync); static int patch_text_cb(void *data) { struct patch_insn *patch = data; - unsigned long len; - int i, ret = 0; + int ret = 0; if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) { - for (i = 0; ret == 0 && i < patch->ninsns; i++) { - len = GET_INSN_LENGTH(patch->insns[i]); - ret = patch_text_nosync(patch->addr + i * len, - &patch->insns[i], len); - } - atomic_inc(&patch->cpu_count); + ret = patch_insn_write(patch->addr, patch->insns, patch->len); + /* + * Make sure the patching store is effective *before* we + * increment the counter which releases all waiting CPUs + * by using the release variant of atomic increment. The + * release pairs with the call to local_flush_icache_all() + * on the waiting CPU. + */ + atomic_inc_return_release(&patch->cpu_count); } else { while (atomic_read(&patch->cpu_count) <= num_online_cpus()) cpu_relax(); - smp_mb(); + + local_flush_icache_all(); } return ret; } NOKPROBE_SYMBOL(patch_text_cb); -int patch_text(void *addr, u32 *insns, int ninsns) +int patch_text(void *addr, u32 *insns, size_t len) { int ret; struct patch_insn patch = { .addr = addr, .insns = insns, - .ninsns = ninsns, + .len = len, .cpu_count = ATOMIC_INIT(0), }; |