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Work around Erratum 721 for AMD Family 10h and 12h processors.

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"Under a highly specific and detailed set of internal timing conditions,
the processor may incorrectly update the stack pointer after a long series
of push and/or near-call instructions, or a long series of pop and/or
near-return instructions.  The processor must be in 64-bit mode for this
erratum to occur."

MFC after:	3 days
This commit is contained in:
jkim 2012-03-30 16:32:41 +00:00
parent 07d4fd218f
commit 6cd4f25011
1 changed files with 28 additions and 1 deletions
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29
sys/amd64/amd64/initcpu.c
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@ -79,6 +79,27 @@ SYSCTL_UINT(_hw, OID_AUTO, via_feature_rng, CTLFLAG_RD,
SYSCTL_UINT(_hw, OID_AUTO, via_feature_xcrypt, CTLFLAG_RD,
&via_feature_xcrypt, 0, "VIA xcrypt feature available in CPU");
static void
init_amd(void)
{
/*
* Work around Erratum 721 for Family 10h and 12h processors.
* These processors may incorrectly update the stack pointer
* after a long series of push and/or near-call instructions,
* or a long series of pop and/or near-return instructions.
*
* http://support.amd.com/us/Processor_TechDocs/41322_10h_Rev_Gd.pdf
* http://support.amd.com/us/Processor_TechDocs/44739_12h_Rev_Gd.pdf
*/
switch (CPUID_TO_FAMILY(cpu_id)) {
case 0x10:
case 0x12:
wrmsr(0xc0011029, rdmsr(0xc0011029) | 1);
break;
}
}
/*
* Initialize special VIA features
*/
@ -135,8 +156,14 @@ initializecpu(void)
wrmsr(MSR_EFER, msr);
pg_nx = PG_NX;
}
if (cpu_vendor_id == CPU_VENDOR_CENTAUR)
switch (cpu_vendor_id) {
case CPU_VENDOR_AMD:
init_amd();
break;
case CPU_VENDOR_CENTAUR:
init_via();
break;
}
}
void