diff options
| author | Yinghai Lu <yhlu.kernel@gmail.com> | 2008-08-22 17:40:05 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-09-08 03:20:14 -0700 |
| commit | 8e023f85b670c9f6008df675b6b213025b3387b3 (patch) | |
| tree | 60b9df1d2d303a477e25586a397044ea75345209 /arch | |
| parent | 96dc683b1e342144af1fbd2187f0ab04dad497c2 (diff) | |
x86: work around MTRR mask setting
commit 38cc1c3df77c1bb739a4766788eb9fa49f16ffdf upstream
Joshua Hoblitt reported that only 3 GB of his 16 GB of RAM is
usable. Booting with mtrr_show showed us the BIOS-initialized
MTRR settings - which are all wrong.
So the root cause is that the BIOS has not set the mask correctly:
> [ 0.429971] MSR00000200: 00000000d0000000
> [ 0.433305] MSR00000201: 0000000ff0000800
> should be ==> [ 0.433305] MSR00000201: 0000003ff0000800
>
> [ 0.436638] MSR00000202: 00000000e0000000
> [ 0.439971] MSR00000203: 0000000fe0000800
> should be ==> [ 0.439971] MSR00000203: 0000003fe0000800
>
> [ 0.443304] MSR00000204: 0000000000000006
> [ 0.446637] MSR00000205: 0000000c00000800
> should be ==> [ 0.446637] MSR00000205: 0000003c00000800
>
> [ 0.449970] MSR00000206: 0000000400000006
> [ 0.453303] MSR00000207: 0000000fe0000800
> should be ==> [ 0.453303] MSR00000207: 0000003fe0000800
>
> [ 0.456636] MSR00000208: 0000000420000006
> [ 0.459970] MSR00000209: 0000000ff0000800
> should be ==> [ 0.459970] MSR00000209: 0000003ff0000800
So detect this borkage and add the prefix 111.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/generic.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index 3e18db4cefee..f49c9706b928 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -229,6 +229,7 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base, unsigned long *size, mtrr_type *type) { unsigned int mask_lo, mask_hi, base_lo, base_hi; + unsigned int tmp, hi; rdmsr(MTRRphysMask_MSR(reg), mask_lo, mask_hi); if ((mask_lo & 0x800) == 0) { @@ -242,8 +243,18 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base, rdmsr(MTRRphysBase_MSR(reg), base_lo, base_hi); /* Work out the shifted address mask. */ - mask_lo = size_or_mask | mask_hi << (32 - PAGE_SHIFT) - | mask_lo >> PAGE_SHIFT; + tmp = mask_hi << (32 - PAGE_SHIFT) | mask_lo >> PAGE_SHIFT; + mask_lo = size_or_mask | tmp; + /* Expand tmp with high bits to all 1s*/ + hi = fls(tmp); + if (hi > 0) { + tmp |= ~((1<<(hi - 1)) - 1); + + if (tmp != mask_lo) { + WARN_ON("mtrr: your BIOS has set up an incorrect mask, fixing it up.\n"); + mask_lo = tmp; + } + } /* This works correctly if size is a power of two, i.e. a contiguous range. */ |