[PATCH 05/16] x86/microcode/AMD: Cleanup verify_patch_size() more

From: Borislav Petkov
Date: Wed Nov 07 2018 - 12:02:37 EST


From: Borislav Petkov <bp@xxxxxxx>

Rename the variable which contains the patch size read out from the
section header to sh_psize for better differentiation of all the "sizes"
in that function.

Also, improve the comment above it.

No functional changes.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/kernel/cpu/microcode/amd.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index bf682deb84e8..a94a15aacfe7 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -175,16 +175,18 @@ static bool verify_patch_section(const u8 *buf, size_t buf_size, bool early)
}

/*
- * Check whether the passed remaining file @size is large enough to contain a
- * patch of the indicated @patch_size (and also whether this size does not
- * exceed the per-family maximum).
+ * Check whether the passed remaining file @buf_size is large enough to contain
+ * a patch of the indicated @sh_psize (and also whether this size does not
+ * exceed the per-family maximum). @sh_psize is the size read from the section
+ * header.
*/
-static unsigned int verify_patch_size(u8 family, u32 patch_size, unsigned int size)
+static unsigned int
+verify_patch_size(u8 family, u32 sh_psize, unsigned int buf_size)
{
u32 max_size;

if (family >= 0x15)
- return min_t(u32, patch_size, size);
+ return min_t(u32, sh_psize, buf_size);

#define F1XH_MPB_MAX_SIZE 2048
#define F14H_MPB_MAX_SIZE 1824
@@ -202,12 +204,12 @@ static unsigned int verify_patch_size(u8 family, u32 patch_size, unsigned int si
break;
}

- if (patch_size > min_t(u32, size, max_size)) {
+ if (sh_psize > min_t(u32, buf_size, max_size)) {
pr_err("patch size mismatch\n");
return 0;
}

- return patch_size;
+ return sh_psize;
}

/*
@@ -693,14 +695,14 @@ static void cleanup(void)
*/
static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
{
+ unsigned int sh_psize, crnt_size, ret;
struct microcode_header_amd *mc_hdr;
struct ucode_patch *patch;
- unsigned int patch_size, crnt_size, ret;
u32 proc_fam;
u16 proc_id;

- patch_size = *(u32 *)(fw + 4);
- crnt_size = patch_size + SECTION_HDR_SIZE;
+ sh_psize = *(u32 *)(fw + 4);
+ crnt_size = sh_psize + SECTION_HDR_SIZE;
mc_hdr = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
proc_id = mc_hdr->processor_rev_id;

@@ -726,7 +728,7 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
* but is present in the leftover file length so we need to subtract
* it before passing this value to the function below.
*/
- ret = verify_patch_size(family, patch_size, leftover - SECTION_HDR_SIZE);
+ ret = verify_patch_size(family, sh_psize, leftover - SECTION_HDR_SIZE);
if (!ret) {
pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
return crnt_size;
@@ -738,7 +740,7 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
return -EINVAL;
}

- patch->data = kmemdup(fw + SECTION_HDR_SIZE, patch_size, GFP_KERNEL);
+ patch->data = kmemdup(fw + SECTION_HDR_SIZE, sh_psize, GFP_KERNEL);
if (!patch->data) {
pr_err("Patch data allocation failure.\n");
kfree(patch);
--
2.19.1