Paul Menzel (paulepanter@users.sourceforge.net) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/2990 -gerrit commit 33191fd5e9fee00f23eea172402a57070430d5c5 Author: Vladimir Serbinenko <phcoder@gmail.com> 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 <phcoder@gmail.com> Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net> --- 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;