redonkable/remarkable-linux
redonkable/remarkable-linux
1
0
Fork 0
Code Releases Activity

x86/microcode: Do the family check first

Browse source 
On CPUs like AMD's Geode, for example, we shouldn't even try to load
microcode because they do not support the modern microcode loading
interface.

However, we do the family check *after* the other checks whether the
loader has been disabled on the command line or whether we're running in
a guest.

So move the family checks first in order to exit early if we're being
loaded on an unsupported family.

Reported-and-tested-by: Sven Glodowski <glodi1@arcor.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.11..
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://bugzilla.suse.com/show_bug.cgi?id=1061396
Link: http://lkml.kernel.org/r/20171012112316.977-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Borislav Petkov 2017-10-12 13:23:16 +02:00 committed by Ingo Molnar
parent b956575bed
commit 1f161f67a2
1 changed files with 18 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
arch/x86/kernel/cpu/microcode/core.c
View file

@ -122,9 +122,6 @@ static bool __init check_loader_disabled_bsp(void)
bool *res = &dis_ucode_ldr;
#endif
if (!have_cpuid_p())
return *res;
/*
* CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
* completely accurate as xen pv guests don't see that CPUID bit set but
@ -166,24 +163,36 @@ bool get_builtin_firmware(struct cpio_data *cd, const char *name)
void __init load_ucode_bsp(void)
{
unsigned int cpuid_1_eax;
bool intel = true;
if (check_loader_disabled_bsp())
if (!have_cpuid_p())
return;
cpuid_1_eax = native_cpuid_eax(1);
switch (x86_cpuid_vendor()) {
case X86_VENDOR_INTEL:
if (x86_family(cpuid_1_eax) >= 6)
load_ucode_intel_bsp();
if (x86_family(cpuid_1_eax) < 6)
return;
break;
case X86_VENDOR_AMD:
if (x86_family(cpuid_1_eax) >= 0x10)
load_ucode_amd_bsp(cpuid_1_eax);
if (x86_family(cpuid_1_eax) < 0x10)
return;
intel = false;
break;
default:
break;
return;
}
if (check_loader_disabled_bsp())
return;
if (intel)
load_ucode_intel_bsp();
else
load_ucode_amd_bsp(cpuid_1_eax);
}
static bool check_loader_disabled_ap(void)