On Wed, 25 Sep 2013 18:44:22 +0800
Jiang Liu <liu...@gmail.com> wrote:
> 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;
On aarch64, are instructions always word aligned? If not, it should be
safe for stop machine to modify non word aligned instructions, but this
patch looks like it doesn't allow stop_machine() to do so.
-- Steve
> +
> + 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;
> +}
--
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/
