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Subject[PATCH] x86, ucode-amd: Ensure ucode update on suspend/resume after CPU off/online cycle
When switching a CPU offline/online and then doing suspend/resume,
ucode is not updated on this CPU.

This is due to the microcode_fini_cpu() call which frees uci->mc
when setting the CPU offline:

static void microcode_fini_cpu_amd(int cpu)
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

vfree(uci->mc);
uci->mc = NULL;
}

When the CPU is set online uci->mc is still NULL because no ucode
update is required.

Finally this prevents ucode update when resuming after suspend:

static enum ucode_state microcode_resume_cpu(int cpu)
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

if (!uci->mc)
return UCODE_NFOUND;

...
}

Fix is to check whether uci->mc is valid before microcode_resume_cpu()
is called.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
---
arch/x86/kernel/microcode_core.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index 230fb09..e68aae3 100644
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -391,7 +391,7 @@ static enum ucode_state microcode_update_cpu(int cpu)
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
enum ucode_state ustate;

- if (uci->valid)
+ if (uci->valid && uci->mc)
ustate = microcode_resume_cpu(cpu);
else
ustate = microcode_init_cpu(cpu);
--
1.6.5.2


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