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authorIngo Molnar <mingo@kernel.org>2017-06-01 15:52:23 +0200
committerIngo Molnar <mingo@kernel.org>2017-06-01 15:52:23 +0200
commitc08d517480ea342cc43acdacc5cf4a795e18151d (patch)
treec5cfabb9bf33ddd1336b4d5bb25385d9475cfd8b /arch/x86/mm/pat.c
parent5d9070b1f0fc9a159a9a3240c43004828408444b (diff)
Revert "x86/PAT: Fix Xorg regression on CPUs that don't support PAT"
This reverts commit cbed27cdf0e3f7ea3b2259e86b9e34df02be3fe4. As Andy Lutomirski observed: "I think this patch is bogus. pat_enabled() sure looks like it's supposed to return true if PAT is *enabled*, and these days PAT is 'enabled' even if there's no HW PAT support." Reported-by: Bernhard Held <berny156@gmx.de> Reported-by: Chris Wilson <chris@chris-wilson.co.uk> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: stable@vger.kernel.org # v4.2+ Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/pat.c')
-rw-r--r--arch/x86/mm/pat.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 83a59a67757a..9b78685b66e6 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -65,11 +65,9 @@ static int __init nopat(char *str)
}
early_param("nopat", nopat);
-static bool __read_mostly __pat_initialized = false;
-
bool pat_enabled(void)
{
- return __pat_initialized;
+ return !!__pat_enabled;
}
EXPORT_SYMBOL_GPL(pat_enabled);
@@ -227,14 +225,13 @@ static void pat_bsp_init(u64 pat)
}
wrmsrl(MSR_IA32_CR_PAT, pat);
- __pat_initialized = true;
__init_cache_modes(pat);
}
static void pat_ap_init(u64 pat)
{
- if (!this_cpu_has(X86_FEATURE_PAT)) {
+ if (!boot_cpu_has(X86_FEATURE_PAT)) {
/*
* If this happens we are on a secondary CPU, but switched to
* PAT on the boot CPU. We have no way to undo PAT.
@@ -309,7 +306,7 @@ void pat_init(void)
u64 pat;
struct cpuinfo_x86 *c = &boot_cpu_data;
- if (!__pat_enabled) {
+ if (!pat_enabled()) {
init_cache_modes();
return;
}