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x86, cpu: Clean up AMD erratum 400 workaround
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Remove check_c1e_idle() and use the new AMD errata checking framework
instead.

Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
LKML-Reference: <1280336972-865982-2-git-send-email-hans.rosenfeld@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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Hans Rosenfeld authored and H. Peter Anvin committed Jul 28, 2010
1 parent d78d671 commit 9d8888c
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Showing 3 changed files with 8 additions and 37 deletions.
1 change: 1 addition & 0 deletions arch/x86/include/asm/processor.h
Original file line number Diff line number Diff line change
Expand Up @@ -1029,6 +1029,7 @@ unsigned long calc_aperfmperf_ratio(struct aperfmperf *old,
* AMD errata checking
*/
#ifdef CONFIG_CPU_SUP_AMD
extern const int amd_erratum_400[];
extern bool cpu_has_amd_erratum(const int *);

#define AMD_LEGACY_ERRATUM(...) { -1, __VA_ARGS__, 0 }
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5 changes: 5 additions & 0 deletions arch/x86/kernel/cpu/amd.c
Original file line number Diff line number Diff line change
Expand Up @@ -628,6 +628,11 @@ cpu_dev_register(amd_cpu_dev);
* AMD_MODEL_RANGE(0x10, 0x9, 0x0, 0x9, 0x0));
*/

const int amd_erratum_400[] =
AMD_OSVW_ERRATUM(1, AMD_MODEL_RANGE(0xf, 0x41, 0x2, 0xff, 0xf),
AMD_MODEL_RANGE(0x10, 0x2, 0x1, 0xff, 0xf));


bool cpu_has_amd_erratum(const int *erratum)
{
struct cpuinfo_x86 *cpu = &current_cpu_data;
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39 changes: 2 additions & 37 deletions arch/x86/kernel/process.c
Original file line number Diff line number Diff line change
Expand Up @@ -525,42 +525,6 @@ static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
return (edx & MWAIT_EDX_C1);
}

/*
* Check for AMD CPUs, where APIC timer interrupt does not wake up CPU from C1e.
* For more information see
* - Erratum #400 for NPT family 0xf and family 0x10 CPUs
* - Erratum #365 for family 0x11 (not affected because C1e not in use)
*/
static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c)
{
u64 val;
if (c->x86_vendor != X86_VENDOR_AMD)
goto no_c1e_idle;

/* Family 0x0f models < rev F do not have C1E */
if (c->x86 == 0x0F && c->x86_model >= 0x40)
return 1;

if (c->x86 == 0x10) {
/*
* check OSVW bit for CPUs that are not affected
* by erratum #400
*/
if (cpu_has(c, X86_FEATURE_OSVW)) {
rdmsrl(MSR_AMD64_OSVW_ID_LENGTH, val);
if (val >= 2) {
rdmsrl(MSR_AMD64_OSVW_STATUS, val);
if (!(val & BIT(1)))
goto no_c1e_idle;
}
}
return 1;
}

no_c1e_idle:
return 0;
}

static cpumask_var_t c1e_mask;
static int c1e_detected;

Expand Down Expand Up @@ -638,7 +602,8 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
*/
printk(KERN_INFO "using mwait in idle threads.\n");
pm_idle = mwait_idle;
} else if (check_c1e_idle(c)) {
} else if (cpu_has_amd_erratum(amd_erratum_400)) {
/* E400: APIC timer interrupt does not wake up CPU from C1e */
printk(KERN_INFO "using C1E aware idle routine\n");
pm_idle = c1e_idle;
} else
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