verify_and_add_patch() returned a single "int" value which encoded both
this function error status and also a length of microcode container data to
skip.
Unfortunately, ranges of these two values collide: the length of data to
skip can be any value between 1 and UINT_MAX, so, for example, error status
of -EINVAL maps to a valid return value of 4294967274 bytes.
That's why these two values need to be split.
Let's keep the common convention that a function zero return value means
success while a negative value means an error while moving the returned
length of microcode container data to skip to a separate output parameter.
Signed-off-by: Maciej S. Szmigiero <m...@maciej.szmigiero.name>
---
arch/x86/kernel/cpu/microcode/amd.c | 33 +++++++++++++++--------------
1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/amd.c
b/arch/x86/kernel/cpu/microcode/amd.c
index f4c7479a961c..f8bd74341ed8 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -730,40 +730,41 @@ static void cleanup(void)
}
/*
- * We return the current size even if some of the checks failed so that
- * we can skip over the next patch. If we return a negative value, we
- * signal a grave error like a memory allocation has failed and the
- * driver cannot continue functioning normally. In such cases, we tear
- * down everything we've used up so far and exit.
+ * We return zero (success) and the current patch data size in @crnt_size
+ * even if some of the checks failed so that we can skip over the next patch.
+ * If we return a negative value, we signal a grave error like a memory
+ * allocation has failed and the driver cannot continue functioning normally.
+ * In such cases, we tear down everything we've used up so far and exit.
*/
-static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover)
+static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
+ unsigned int *crnt_size)
{
struct microcode_header_amd *mc_hdr;
struct ucode_patch *patch;
- unsigned int patch_size, crnt_size, ret;
+ unsigned int patch_size, ret;
u32 proc_fam;
u16 proc_id;
patch_size = *(u32 *)(fw + 4);
- crnt_size = patch_size + SECTION_HDR_SIZE;
+ *crnt_size = patch_size + SECTION_HDR_SIZE;
mc_hdr = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
proc_id = mc_hdr->processor_rev_id;
proc_fam = find_cpu_family_by_equiv_cpu(proc_id);
if (!proc_fam) {
pr_err("No patch family for equiv ID: 0x%04x\n", proc_id);
- return crnt_size;
+ return 0;
}
/* check if patch is for the current family */
proc_fam = ((proc_fam >> 8) & 0xf) + ((proc_fam >> 20) & 0xff);
if (proc_fam != family)
- return crnt_size;
+ return 0;
if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {
pr_err("Patch-ID 0x%08x: chipset-specific code unsupported.\n",
mc_hdr->patch_id);
- return crnt_size;
+ return 0;
}
/*
@@ -774,7 +775,7 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned
int leftover)
ret = verify_patch_size(family, patch_size, leftover -
SECTION_HDR_SIZE);
if (!ret) {
pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
- return crnt_size;
+ return 0;
}
patch = kzalloc(sizeof(*patch), GFP_KERNEL);
@@ -800,7 +801,7 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned
int leftover)
/* ... and add to cache. */
update_cache(patch);
- return crnt_size;
+ return 0;
}
static enum ucode_state __load_microcode_amd(u8 family, const u8 *data,
@@ -809,7 +810,6 @@ static enum ucode_state __load_microcode_amd(u8 family,
const u8 *data,
enum ucode_state ret = UCODE_ERROR;
unsigned int leftover;
u8 *fw = (u8 *)data;
- int crnt_size = 0;
int offset;
offset = install_equiv_cpu_table(data);
@@ -827,8 +827,9 @@ static enum ucode_state __load_microcode_amd(u8 family,
const u8 *data,
}
while (leftover) {
- crnt_size = verify_and_add_patch(family, fw, leftover);
- if (crnt_size < 0)
+ unsigned int crnt_size;
+
+ if (verify_and_add_patch(family, fw, leftover, &crnt_size) < 0)
return ret;
fw += crnt_size;
