linux-kernel - [12/28] x86, cpu: Clean up AMD erratum 400 workaround

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Date:	Tue, 19 Apr 2011 13:30:50 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Hans Rosenfeld <hans.rosenfeld@....com>,
	"H. Peter Anvin" <hpa@...ux.intel.com>
Subject: [12/28] x86, cpu: Clean up AMD erratum 400 workaround

2.6.32-longterm review patch.  If anyone has any objections, please let us know.

------------------

From: Hans Rosenfeld <hans.rosenfeld@....com>

commit 9d8888c2a214aece2494a49e699a097c2ba9498b upstream.

Remove check_c1e_idle() and use the new AMD errata checking framework
instead.

Signed-off-by: Hans Rosenfeld <hans.rosenfeld@....com>
LKML-Reference: <1280336972-865982-2-git-send-email-hans.rosenfeld@....com>
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 arch/x86/include/asm/processor.h |    1 +
 arch/x86/kernel/cpu/amd.c        |    5 +++++
 arch/x86/kernel/process.c        |   39 ++-------------------------------------
 3 files changed, 8 insertions(+), 37 deletions(-)

--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -1033,6 +1033,7 @@ unsigned long calc_aperfmperf_ratio(stru
  * 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 }
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -629,6 +629,11 @@ 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;
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -438,42 +438,6 @@ static int __cpuinit mwait_usable(const
 	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;
 
@@ -551,7 +515,8 @@ void __cpuinit select_idle_routine(const
 		 */
 		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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