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x86: PAT: fix ambiguous paranoia check in pat_init()

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Starting with commit 8d4a430085 (x86:
cleanup PAT cpu validation) the PAT CPU feature flag is not cleared
anymore. Now the error message

  "PAT enabled, but CPU feature cleared"

in pat_init() is misleading.

Furthermore the current code does not check for existence of the PAT
CPU feature flag if a CPU is whitelisted in validate_pat_support.

This patch clears pat_wc_enabled if boot CPU has no PAT feature flag
and adapts the paranoia check.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Andreas Herrmann 2008-06-10 16:05:18 +02:00 committed by Ingo Molnar
parent ee863ba7ab
commit 97cfab6ac4
2 changed files with 10 additions and 8 deletions
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7
arch/x86/kernel/cpu/addon_cpuid_features.c
View file

@ -53,6 +53,9 @@ void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
#ifdef CONFIG_X86_PAT
void __cpuinit validate_pat_support(struct cpuinfo_x86 *c)
{
if (!cpu_has_pat)
pat_disable("PAT not supported by CPU.");
switch (c->x86_vendor) {
case X86_VENDOR_INTEL:
if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))
@ -64,8 +67,6 @@ void __cpuinit validate_pat_support(struct cpuinfo_x86 *c)
return;
}
pat_disable(cpu_has_pat ?
"PAT disabled. Not yet verified on this CPU type." :
"PAT not supported by CPU.");
pat_disable("PAT disabled. Not yet verified on this CPU type.");
}
#endif

11
arch/x86/mm/pat.c
View file

@ -76,14 +76,15 @@ void pat_init(void)
return;
/* Paranoia check. */
if (!cpu_has_pat) {
printk(KERN_ERR "PAT enabled, but CPU feature cleared\n");
if (!cpu_has_pat && boot_pat_state) {
/*
* Panic if this happens on the secondary CPU, and we
* If this happens we are on a secondary CPU, but
* switched to PAT on the boot CPU. We have no way to
* undo PAT.
*/
BUG_ON(boot_pat_state);
*/
printk(KERN_ERR "PAT enabled, "
"but not supported by secondary CPU\n");
BUG();
}
/* Set PWT to Write-Combining. All other bits stay the same */