x86: PAT: fix ambiguous paranoia check in pat_init()
Starting with commit 8d4a4300854f3971502e81dacd930704cb88f606 (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>
diff --git a/arch/x86/kernel/cpu/addon_cpuid_features.c b/arch/x86/kernel/cpu/addon_cpuid_features.c
index 0fbd062..2df461f 100644
--- a/arch/x86/kernel/cpu/addon_cpuid_features.c
+++ b/arch/x86/kernel/cpu/addon_cpuid_features.c
@@ -53,6 +53,9 @@
#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 @@
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
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 320d644..65105b1 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -76,14 +76,15 @@
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 */
