Re: [PATCH v1 3/3] powerpc/code-patching: Optimise patch_memcpy() to 4 byte chunks
From: Christophe Leroy <hidden>
Date: 2024-03-15 06:40:30
Le 15/03/2024 à 03:57, Benjamin Gray a écrit :
As we are patching instructions, we can assume the length is a multiple of 4 and the destination address is aligned. Atomicity of patching a prefixed instruction is not a concern, as the original implementation doesn't provide it anyway.
This patch looks unnecessary. copy_to_kernel_nofault() is what you want to use instead.
quoted hunk ↗ jump to hunk
Signed-off-by: Benjamin Gray <redacted> --- arch/powerpc/lib/code-patching.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index c6633759b509..ed450a32918c 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c@@ -394,10 +394,10 @@ static int patch_memset32(u32 *addr, u32 val, size_t count) return -EPERM; } -static int patch_memcpy(void *dst, void *src, size_t len) +static int patch_memcpy32(u32 *dst, u32 *src, size_t count) { - for (void *end = src + len; src < end; dst++, src++) - __put_kernel_nofault(dst, src, u8, failed); + for (u32 *end = src + count; src < end; dst++, src++) + __put_kernel_nofault(dst, src, u32, failed); return 0;@@ -424,7 +424,7 @@ static int __patch_instructions(u32 *patch_addr, u32 *code, size_t len, bool rep err = patch_memset32(patch_addr, val, len / 4); } } else { - err = patch_memcpy(patch_addr, code, len); + err = patch_memcpy32(patch_addr, code, len / 4); } smp_wmb(); /* smp write barrier */