diff options
| author | Andreas Herrmann <andreas.herrmann3@amd.com> | 2010-09-30 14:32:35 +0200 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2010-10-01 16:18:31 -0700 |
| commit | 3fdbf004c1706480a7c7fac3c9d836fa6df20d7d (patch) | |
| tree | 67c1d3c0fe55e01cdc8e509d03c6f5a100ddf10e /arch/x86/kernel/cpu/mtrr/cleanup.c | |
| parent | 86ffb08519d6fe1e9c4fe5a110ffa5fcb868cb1c (diff) | |
x86, mtrr: Assume SYS_CFG[Tom2ForceMemTypeWB] exists on all future AMD CPUs
Instead of adapting the CPU family check in amd_special_default_mtrr()
for each new CPU family assume that all new AMD CPUs support the
necessary bits in SYS_CFG MSR.
Tom2Enabled is architectural (defined in APM Vol.2).
Tom2ForceMemTypeWB is defined in all BKDGs starting with K8 NPT.
In pre K8-NPT BKDG this bit is reserved (read as zero).
W/o this adaption Linux would unnecessarily complain about bad MTRR
settings on every new AMD CPU family, e.g.
[ 0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 4863MB of RAM.
Cc: stable@kernel.org # .32.x, .35.x
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100930123235.GB20545@loge.amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel/cpu/mtrr/cleanup.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/cleanup.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c index c5f59d071425..ac140c7be396 100644 --- a/arch/x86/kernel/cpu/mtrr/cleanup.c +++ b/arch/x86/kernel/cpu/mtrr/cleanup.c @@ -827,7 +827,7 @@ int __init amd_special_default_mtrr(void) if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) return 0; - if (boot_cpu_data.x86 < 0xf || boot_cpu_data.x86 > 0x11) + if (boot_cpu_data.x86 < 0xf) return 0; /* In case some hypervisor doesn't pass SYSCFG through: */ if (rdmsr_safe(MSR_K8_SYSCFG, &l, &h) < 0) |