2005-09-29 00:55:38

by Shaohua Li

Subject: [PATCH]CPUID workaround for intel CPU - Re: [PROBLEM] mtrr's not set, 2.6.13

Hi Andrew,
This is patch to fix the Jim McCloskey's MTRR issue.
CPUID workaround for steppings 0F33h(supporting x86) and 0F34h(supporting x86
and EM64T). Detail info can be found at:
http://download.intel.com/design/Xeon/specupdt/30240216.pdf
http://download.intel.com/design/Pentium4/specupdt/30235221.pdf

Signed-off-by: Shaohua Li<[email protected]>
---

linux-2.6.14-rc2-root/arch/i386/kernel/cpu/mtrr/main.c | 8 ++++++++
linux-2.6.14-rc2-root/arch/x86_64/kernel/setup.c | 6 ++++++
2 files changed, 14 insertions(+)

diff -puN arch/i386/kernel/cpu/mtrr/main.c~cpuid_errta arch/i386/kernel/cpu/mtrr/main.c
--- linux-2.6.14-rc2/arch/i386/kernel/cpu/mtrr/main.c~cpuid_errta 2005-09-29 08:35:34.000000000 +0800
+++ linux-2.6.14-rc2-root/arch/i386/kernel/cpu/mtrr/main.c 2005-09-29 08:37:16.000000000 +0800
@@ -626,6 +626,14 @@ void __init mtrr_bp_init(void)
if (cpuid_eax(0x80000000) >= 0x80000008) {
u32 phys_addr;
phys_addr = cpuid_eax(0x80000008) & 0xff;
+ /* CPUID workaround for Intel 0F33/0F34 CPU */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
+ boot_cpu_data.x86 == 0xF &&
+ boot_cpu_data.x86_model == 0x3 &&
+ (boot_cpu_data.x86_mask == 0x3 ||
+ boot_cpu_data.x86_mask == 0x4))
+ phys_addr = 36;
+
size_or_mask = ~((1 << (phys_addr - PAGE_SHIFT)) - 1);
size_and_mask = ~size_or_mask & 0xfff00000;
} else if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR &&
diff -puN arch/x86_64/kernel/setup.c~cpuid_errta arch/x86_64/kernel/setup.c
--- linux-2.6.14-rc2/arch/x86_64/kernel/setup.c~cpuid_errta 2005-09-29 08:35:34.000000000 +0800
+++ linux-2.6.14-rc2-root/arch/x86_64/kernel/setup.c 2005-09-29 08:37:48.000000000 +0800
@@ -992,6 +992,12 @@ static void __cpuinit init_intel(struct
unsigned eax = cpuid_eax(0x80000008);
c->x86_virt_bits = (eax >> 8) & 0xff;
c->x86_phys_bits = eax & 0xff;
+ /* CPUID workaround for Intel 0F34 CPU */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
+ boot_cpu_data.x86 == 0xF &&
+ boot_cpu_data.x86_model == 0x3 &&
+ boot_cpu_data.x86_mask == 0x4)
+ c->x86_phys_bits = 36;
}

if (c->x86 == 15)
_

2005-09-29 09:59:05

by Mikael Pettersson

Subject: Re: [PATCH]CPUID workaround for intel CPU - Re: [PROBLEM] mtrr's not set, 2.6.13

Shaohua Li writes:
> Hi Andrew,
> This is patch to fix the Jim McCloskey's MTRR issue.
> CPUID workaround for steppings 0F33h(supporting x86) and 0F34h(supporting x86
> and EM64T). Detail info can be found at:
> http://download.intel.com/design/Xeon/specupdt/30240216.pdf
> http://download.intel.com/design/Pentium4/specupdt/30235221.pdf
>
> Signed-off-by: Shaohua Li<[email protected]>
> ---
>
> linux-2.6.14-rc2-root/arch/i386/kernel/cpu/mtrr/main.c | 8 ++++++++
> linux-2.6.14-rc2-root/arch/x86_64/kernel/setup.c | 6 ++++++
> 2 files changed, 14 insertions(+)
>
> diff -puN arch/i386/kernel/cpu/mtrr/main.c~cpuid_errta arch/i386/kernel/cpu/mtrr/main.c
> --- linux-2.6.14-rc2/arch/i386/kernel/cpu/mtrr/main.c~cpuid_errta 2005-09-29 08:35:34.000000000 +0800
> +++ linux-2.6.14-rc2-root/arch/i386/kernel/cpu/mtrr/main.c 2005-09-29 08:37:16.000000000 +0800
> @@ -626,6 +626,14 @@ void __init mtrr_bp_init(void)
> if (cpuid_eax(0x80000000) >= 0x80000008) {
> u32 phys_addr;
> phys_addr = cpuid_eax(0x80000008) & 0xff;
> + /* CPUID workaround for Intel 0F33/0F34 CPU */
> + if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
> + boot_cpu_data.x86 == 0xF &&
> + boot_cpu_data.x86_model == 0x3 &&
> + (boot_cpu_data.x86_mask == 0x3 ||
> + boot_cpu_data.x86_mask == 0x4))
> + phys_addr = 36;

Please change the comment to indicate the actual erratum number.
Something like "Work around P4 Erratum #<N>" should do.

/Mikael