summaryrefslogtreecommitdiff
path: root/arch/x86/mm
diff options
context:
space:
mode:
authorMikulas Patocka <mpatocka@redhat.com>2017-07-05 02:04:23 +0300
committerThomas Gleixner <tglx@linutronix.de>2017-07-05 10:01:24 +0300
commit99c13b8c8896d7bcb92753bf0c63a8de4326e78d (patch)
treeb8f8cf4f4fba6e34ba7d090dbdb852b9588d0e5d /arch/x86/mm
parent5122daa017578ebc4818de8fb3c9d0e131f8b335 (diff)
downloadlinux-99c13b8c8896d7bcb92753bf0c63a8de4326e78d.tar.xz
x86/mm/pat: Don't report PAT on CPUs that don't support it
The pat_enabled() logic is broken on CPUs which do not support PAT and where the initialization code fails to call pat_init(). Due to that the enabled flag stays true and pat_enabled() returns true wrongfully. As a consequence the mappings, e.g. for Xorg, are set up with the wrong caching mode and the required MTRR setups are omitted. To cure this the following changes are required: 1) Make pat_enabled() return true only if PAT initialization was invoked and successful. 2) Invoke init_cache_modes() unconditionally in setup_arch() and remove the extra callsites in pat_disable() and the pat disabled code path in pat_init(). Also rename __pat_enabled to pat_disabled to reflect the real purpose of this variable. Fixes: 9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it is disabled") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Bernhard Held <berny156@gmx.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: "Luis R. Rodriguez" <mcgrof@suse.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1707041749300.3456@file01.intranet.prod.int.rdu2.redhat.com
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/pat.c28
1 files changed, 12 insertions, 16 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 9b78685b66e6..45979502f64b 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -37,14 +37,14 @@
#undef pr_fmt
#define pr_fmt(fmt) "" fmt
-static bool boot_cpu_done;
-
-static int __read_mostly __pat_enabled = IS_ENABLED(CONFIG_X86_PAT);
-static void init_cache_modes(void);
+static bool __read_mostly boot_cpu_done;
+static bool __read_mostly pat_disabled = !IS_ENABLED(CONFIG_X86_PAT);
+static bool __read_mostly pat_initialized;
+static bool __read_mostly init_cm_done;
void pat_disable(const char *reason)
{
- if (!__pat_enabled)
+ if (pat_disabled)
return;
if (boot_cpu_done) {
@@ -52,10 +52,8 @@ void pat_disable(const char *reason)
return;
}
- __pat_enabled = 0;
+ pat_disabled = true;
pr_info("x86/PAT: %s\n", reason);
-
- init_cache_modes();
}
static int __init nopat(char *str)
@@ -67,7 +65,7 @@ early_param("nopat", nopat);
bool pat_enabled(void)
{
- return !!__pat_enabled;
+ return pat_initialized;
}
EXPORT_SYMBOL_GPL(pat_enabled);
@@ -205,6 +203,8 @@ static void __init_cache_modes(u64 pat)
update_cache_mode_entry(i, cache);
}
pr_info("x86/PAT: Configuration [0-7]: %s\n", pat_msg);
+
+ init_cm_done = true;
}
#define PAT(x, y) ((u64)PAT_ ## y << ((x)*8))
@@ -225,6 +225,7 @@ static void pat_bsp_init(u64 pat)
}
wrmsrl(MSR_IA32_CR_PAT, pat);
+ pat_initialized = true;
__init_cache_modes(pat);
}
@@ -242,10 +243,9 @@ static void pat_ap_init(u64 pat)
wrmsrl(MSR_IA32_CR_PAT, pat);
}
-static void init_cache_modes(void)
+void init_cache_modes(void)
{
u64 pat = 0;
- static int init_cm_done;
if (init_cm_done)
return;
@@ -287,8 +287,6 @@ static void init_cache_modes(void)
}
__init_cache_modes(pat);
-
- init_cm_done = 1;
}
/**
@@ -306,10 +304,8 @@ void pat_init(void)
u64 pat;
struct cpuinfo_x86 *c = &boot_cpu_data;
- if (!pat_enabled()) {
- init_cache_modes();
+ if (pat_disabled)
return;
- }
if ((c->x86_vendor == X86_VENDOR_INTEL) &&
(((c->x86 == 0x6) && (c->x86_model <= 0xd)) ||