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

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

[Shaohua Li]

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;
+
 			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)
_

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

[Mikael Pettersson]

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