x86/microcode/AMD: Cleanup verify_patch_size() more

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@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-6-bp@alien8.de

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index bf682de..a94a15a 100644 (file)
--- 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);