Patch set updated for coreboot: 33191fd Intel: Return and warn when NULL is passed to `intel_update_microcode`

[Paul Menzel]

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

-gerrit

commit 33191fd5e9fee00f23eea172402a57070430d5c5
Author: Vladimir Serbinenko 
Date:   Tue Mar 12 15:53:44 2013 +0100

Intel: Return and warn when NULL is passed to `intel_update_microcode`

Not selecting `CPU_MICROCODE_IN_CBFS` in Kconfig and calling the
    function `intel_update_microcode` with NULL results in a crash due
    to the null pointer being dereferenced later on.

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

Fix this by just returning if `microcode_updates` is `NULL` and by
    printing a warning.

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 | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/cpu/intel/microcode/microcode.c b/src/cpu/intel/microcode/microcode.c
index d908c25..440afa9 100644
--- a/src/cpu/intel/microcode/microcode.c
+++ b/src/cpu/intel/microcode/microcode.c
@@ -131,7 +131,10 @@ const void *intel_microcode_find(void)
 #endif

if (!microcode_updates)
-		return microcode_updates;
+		/* No need for an explicit error message since the user
+		 * already gets "file not found" from CBFS.
+		 */
+		return microcode_updates; /* NULL */

/* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
    msr.lo = 0;
@@ -202,6 +205,12 @@ void intel_update_microcode(const void *microcode_updates)
    const char *c;
    msr_t msr;

+	if (!microcode_updates) {
+		printk(BIOS_WARNING, "%s: No microcode update was passed! (microcode_updates = NULL)\n",
+		       __func__);
+		return;
+	}
+
    /* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
    msr.lo = 0;
    msr.hi = 0;