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

Mikael Pettersson
2005-09-29T09:59:05Z

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<shaohua.li@intel.com>
> ---
>
> 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