From: Jiang Liu <jiang....@huawei.com> Introduce aarch64_insn_patch_text() and __aarch64_insn_patch_text() to patch kernel and module code.
Function aarch64_insn_patch_text() is a heavy version which may use stop_machine() to serialize all online CPUs, and function __aarch64_insn_patch_text() is light version without explicitly serialization. Signed-off-by: Jiang Liu <jiang....@huawei.com> Cc: Jiang Liu <liu...@gmail.com> --- arch/arm64/include/asm/insn.h | 2 ++ arch/arm64/kernel/insn.c | 64 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+) diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index e7d1bc8..0ea7193 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -49,5 +49,7 @@ __AARCH64_INSN_FUNCS(nop, 0xFFFFFFFF, 0xD503201F) enum aarch64_insn_class aarch64_get_insn_class(u32 insn); bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn); +int aarch64_insn_patch_text(void *addr, u32 *insns, int cnt); +int __aarch64_insn_patch_text(void *addr, u32 *insns, int cnt); #endif /* _ASM_ARM64_INSN_H */ diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index 8541c3a..50facfc 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -15,6 +15,8 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <linux/kernel.h> +#include <linux/stop_machine.h> +#include <asm/cacheflush.h> #include <asm/insn.h> static int aarch64_insn_cls[] = { @@ -69,3 +71,65 @@ bool __kprobes aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn) return __aarch64_insn_hotpatch_safe(old_insn) && __aarch64_insn_hotpatch_safe(new_insn); } + +struct aarch64_insn_patch { + void *text_addr; + u32 *new_insns; + int insn_cnt; +}; + +int __kprobes __aarch64_insn_patch_text(void *addr, u32 *insns, int cnt) +{ + int i; + u32 *tp = addr; + + /* instructions must be word aligned */ + if (cnt <= 0 || ((uintptr_t)addr & 0x3)) + return -EINVAL; + + for (i = 0; i < cnt; i++) + tp[i] = insns[i]; + + flush_icache_range((uintptr_t)tp, (uintptr_t)tp + cnt * sizeof(u32)); + + return 0; +} + +static int __kprobes aarch64_insn_patch_text_cb(void *arg) +{ + struct aarch64_insn_patch *pp = arg; + + return __aarch64_insn_patch_text(pp->text_addr, pp->new_insns, + pp->insn_cnt); +} + +int __kprobes aarch64_insn_patch_text(void *addr, u32 *insns, int cnt) +{ + int ret; + bool safe = false; + + /* instructions must be word aligned */ + if (cnt <= 0 || ((uintptr_t)addr & 0x3)) + return -EINVAL; + + if (cnt == 1) + safe = aarch64_insn_hotpatch_safe(*(u32 *)addr, insns[0]); + + if (safe) { + ret = __aarch64_insn_patch_text(addr, insns, cnt); + } else { + struct aarch64_insn_patch patch = { + .text_addr = addr, + .new_insns = insns, + .insn_cnt = cnt, + }; + + /* + * Execute __aarch64_insn_patch_text() on every online CPU, + * which ensure serialization among all online CPUs. + */ + ret = stop_machine(aarch64_insn_patch_text_cb, &patch, NULL); + } + + return ret; +} -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
