[PATCH] cpuid x87 bit on AMD falsely marked as PNI

[PATCH] cpuid x87 bit on AMD falsely marked as PNI

[Zwane Mwaikambo]

http://bugme.osdl.org/show_bug.cgi?id=4426

vendor_id       : AuthenticAMD
cpu family      : 6
model           : 10
model name      : AMD Athlon(tm) XP
stepping        : 0
cpu MHz         : 2204.807
<snipped>
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 mmx fxsr sse pni syscall mmxext 3dnowext 3dnow
bogomips        : 4358.14

We're marking bit 0 of extended function 0x80000001 cpuid as PNI support 
on AMD processors, when it actually denotes x87 FPU present. Patch for 
i386 and x86_64 below.

Signed-off-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>

Index: linux-2.6.12-rc2-mm3/arch/i386/kernel/cpu/proc.c
===================================================================
RCS file: /home/cvsroot/linux-2.6.12-rc2-mm3/arch/i386/kernel/cpu/proc.c,v
retrieving revision 1.1.1.1
diff -u -p -B -r1.1.1.1 proc.c
--- linux-2.6.12-rc2-mm3/arch/i386/kernel/cpu/proc.c	17 Apr 2005 14:03:42 -0000	1.1.1.1
+++ linux-2.6.12-rc2-mm3/arch/i386/kernel/cpu/proc.c	27 Apr 2005 00:46:18 -0000
@@ -25,7 +25,7 @@ static int show_cpuinfo(struct seq_file 
 	        "fxsr", "sse", "sse2", "ss", "ht", "tm", "ia64", "pbe",
 
 		/* AMD-defined */
-		"pni", NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 		NULL, NULL, NULL, "syscall", NULL, NULL, NULL, NULL,
 		NULL, NULL, NULL, "mp", "nx", NULL, "mmxext", NULL,
 		NULL, "fxsr_opt", NULL, NULL, NULL, "lm", "3dnowext", "3dnow",
Index: linux-2.6.12-rc2-mm3/arch/x86_64/kernel/setup.c
===================================================================
RCS file: /home/cvsroot/linux-2.6.12-rc2-mm3/arch/x86_64/kernel/setup.c,v
retrieving revision 1.1.1.1
diff -u -p -B -r1.1.1.1 setup.c
--- linux-2.6.12-rc2-mm3/arch/x86_64/kernel/setup.c	17 Apr 2005 14:03:51 -0000	1.1.1.1
+++ linux-2.6.12-rc2-mm3/arch/x86_64/kernel/setup.c	27 Apr 2005 00:46:31 -0000
@@ -1103,7 +1103,7 @@ static int show_cpuinfo(struct seq_file 
 	        "fxsr", "sse", "sse2", "ss", "ht", "tm", "ia64", NULL,
 
 		/* AMD-defined */
-		"pni", NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 		NULL, NULL, NULL, "syscall", NULL, NULL, NULL, NULL,
 		NULL, NULL, NULL, NULL, "nx", NULL, "mmxext", NULL,
 		NULL, "fxsr_opt", NULL, NULL, NULL, "lm", "3dnowext", "3dnow",

Re: [PATCH] cpuid x87 bit on AMD falsely marked as PNI

[Denis Vlasenko]

On Wednesday 27 April 2005 04:20, Zwane Mwaikambo wrote:
> http://bugme.osdl.org/show_bug.cgi?id=4426
> 
> vendor_id       : AuthenticAMD
> cpu family      : 6
> model           : 10
> model name      : AMD Athlon(tm) XP
> stepping        : 0
> cpu MHz         : 2204.807
> <snipped>
> cpuid level     : 1
> wp              : yes
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
> pat pse36 mmx fxsr sse pni syscall mmxext 3dnowext 3dnow
> bogomips        : 4358.14
> 
> We're marking bit 0 of extended function 0x80000001 cpuid as PNI support 
> on AMD processors, when it actually denotes x87 FPU present. Patch for 
> i386 and x86_64 below.

I just yesterday noticed that my Athlon (non-64bit) has 'pni' in CPU
flags and was very puzzled.

Thanks Zwane.
--
vda