Patch set updated for coreboot: 9cb3cfc Intel: Return on missing microcode file to fix null pointer dereference

[Stefan Reinauer]

Stefan Reinauer ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/2990

-gerrit

commit 9cb3cfcc7446fefd2819c240a2a708ba385566ba
Author: Vladimir Serbinenko 
Date:   Sat Mar 30 12:04:23 2013 +0100

Intel: Return on missing microcode file to fix null pointer dereference

Selecting `CPU_MICROCODE_IN_CBFS` in Kconfig but not having the
    microcode blob `cpu_microcode_blob.bin` in CBFS results in a
    null pointer dereference later on resulting in a crash.

for(c = microcode_updates; m->hdrver; m = (const struct microcode *)c) {

Fix this by returning if `microcode_updates` is `NULL`, that means
    no file is found.

This patch is successfully tested on the Lenovo X201.

Change-Id: I6e18fd37256910bf047061e4633a66cf29ad7b69
    Signed-off-by: Vladimir Serbinenko 
    Signed-off-by: Paul Menzel 
---
 src/cpu/intel/microcode/microcode.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/cpu/intel/microcode/microcode.c b/src/cpu/intel/microcode/microcode.c
index d908c25..1991ed8 100644
--- a/src/cpu/intel/microcode/microcode.c
+++ b/src/cpu/intel/microcode/microcode.c
@@ -21,6 +21,7 @@
 /* Microcode update for Intel PIII and later CPUs */

#include <stdint.h>
+#include <stddef.h>
 #if !defined(__ROMCC__)
 #include <console/console.h>
 #endif
@@ -131,7 +132,7 @@ const void *intel_microcode_find(void)
 #endif

if (!microcode_updates)
-		return microcode_updates;
+		return NULL;

/* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
    msr.lo = 0;
@@ -202,6 +203,13 @@ void intel_update_microcode(const void *microcode_updates)
    const char *c;
    msr_t msr;

+	if (!microcode_updates) {
+#if !defined(__ROMCC__)
+		printk(BIOS_WARNING, "No microcode updates found.\n");
+#endif
+		return;
+	}
+
    /* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
    msr.lo = 0;
    msr.hi = 0;