[PATCH] x86, microcode, AMD: Cocci spatch "memdup.spatch"

[PATCH] x86, microcode, AMD: Cocci spatch "memdup.spatch"

[Thomas Meyer]

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
---

diff -u -p a/arch/x86/kernel/microcode_amd.c b/arch/x86/kernel/microcode_amd.c
--- a/arch/x86/kernel/microcode_amd.c
+++ b/arch/x86/kernel/microcode_amd.c
@@ -345,7 +345,7 @@ static int verify_and_add_patch(unsigned
 		return -EINVAL;
 	}
 
-	patch->data = kzalloc(patch_size, GFP_KERNEL);
+	patch->data = kmemdup(fw + SECTION_HDR_SIZE, patch_size, GFP_KERNEL);
 	if (!patch->data) {
 		pr_err("Patch data allocation failure.\n");
 		kfree(patch);
@@ -353,7 +353,6 @@ static int verify_and_add_patch(unsigned
 	}
 
 	/* All looks ok, copy patch... */
-	memcpy(patch->data, fw + SECTION_HDR_SIZE, patch_size);
 	INIT_LIST_HEAD(&patch->plist);
 	patch->patch_id  = mc_hdr->patch_id;
 	patch->equiv_cpu = proc_id;

Re: [PATCH] x86, microcode, AMD: Cocci spatch "memdup.spatch"

[Borislav Petkov]

On Sat, Jun 01, 2013 at 11:42:11AM +0200, Thomas Meyer wrote:
> 
> Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
> ---
> 
> diff -u -p a/arch/x86/kernel/microcode_amd.c b/arch/x86/kernel/microcode_amd.c
> --- a/arch/x86/kernel/microcode_amd.c
> +++ b/arch/x86/kernel/microcode_amd.c
> @@ -345,7 +345,7 @@ static int verify_and_add_patch(unsigned
>  		return -EINVAL;
>  	}
>  
> -	patch->data = kzalloc(patch_size, GFP_KERNEL);
> +	patch->data = kmemdup(fw + SECTION_HDR_SIZE, patch_size, GFP_KERNEL);
>  	if (!patch->data) {
>  		pr_err("Patch data allocation failure.\n");
>  		kfree(patch);
> @@ -353,7 +353,6 @@ static int verify_and_add_patch(unsigned
>  	}
>  
>  	/* All looks ok, copy patch... */
> -	memcpy(patch->data, fw + SECTION_HDR_SIZE, patch_size);
>  	INIT_LIST_HEAD(&patch->plist);
>  	patch->patch_id  = mc_hdr->patch_id;
>  	patch->equiv_cpu = proc_id;

I can see what happens with a little code browsing of the definition of
kmemdup but patches without a commit message are most times not a very
elegant thing.

So please add a nice commit message explaining why you're doing what
you're doing. If the coccinelle script is not in the kernel tree,
then referring to it doesn't mean a whole lot so don't do it. Rather,
explaining why you're doing the change, is a much better thing to do.

Thanks.