Drop broken fix for stalls on AMD processors.

kernel.spec

@@ -716,8 +716,6 @@ Patch12401: mm-slub-do-not-wake-kswapd-for-slubs-speculative-high-order-allocati
 Patch12402: mm-slub-do-not-take-expensive-steps-for-slubs-speculative-high-order-allocations.patch
 Patch12403: mm-vmscan-if-kswapd-has-been-running-too-long-allow-it-to-sleep.patch
 
-Patch12500: x86-amd-fix-another-erratum-400-bug.patch
-
 %endif
 
 BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@@ -1328,8 +1326,6 @@ ApplyPatch mm-slub-do-not-wake-kswapd-for-slubs-speculative-high-order-allocatio
 ApplyPatch mm-slub-do-not-take-expensive-steps-for-slubs-speculative-high-order-allocations.patch
 ApplyPatch mm-vmscan-if-kswapd-has-been-running-too-long-allow-it-to-sleep.patch
 
-ApplyPatch x86-amd-fix-another-erratum-400-bug.patch
-
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -1938,6 +1934,9 @@ fi
 # and build.
 
 %changelog
+* Fri May 20 2011 Chuck Ebbert <cebbert@redhat.com>
+- Drop broken fix for stalls on AMD processors.
+
 * Fri May 20 2011 Dave Jones <davej@redhat.com>
 - Rebuild to fix versioning.
 

x86-amd-fix-another-erratum-400-bug.patch

@@ -1,70 +0,0 @@
-Fix a bug that causes CPU hangs due to missing timer interrupts,
-introduced by these three patches:
-
-(1) commit d78d671db478eb8b14c78501c0cee1cc7baf6967
-    "x86, cpu: AMD errata checking framework"
-
-(2) commit 9d8888c2a214aece2494a49e699a097c2ba9498b
-    "x86, cpu: Clean up AMD erratum 400 workaround"
-
-(3) commit b87cf80af3ba4b4c008b4face3c68d604e1715c6
-    "x86, AMD: Set ARAT feature on AMD processors"
-
-Patch (1) introduced a new framework that allowed checking for errata
-using AMD's OSVW (OS visible workaround) feature combined with
-explicit lists of models. It checked OSVW first, and completely
-relied on that if it was present and usable.
-
-Patch (2) switched the checking for erratum 400 to use the new
-framework. But the original code checked for an explicit model range
-first, then used OSVW if the CPU was not within that range. Patch (2)
-also inexplicably added a second model range (for Family 10h) that
-was never in the original code.
-
-Then patch (3) used the new erratum 400 checks to decide whether
-to enable the ARAT feature (always running APIC timer.) However,
-this causes notebooks using the Sempron processor (Family 10h
-Model 6 Stepping 2) to enable ARAT when they shouldn't because the
-explicit check for that model gets skipped.
-
-The fix is to check the model list first, then use OSVW if the CPU
-is not in that list.
-
-Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
-
---- a/arch/x86/kernel/cpu/amd.c
-+++ b/arch/x86/kernel/cpu/amd.c
-@@ -723,6 +723,17 @@ bool cpu_has_amd_erratum(const int *erra
- 	if (cpu->x86_vendor != X86_VENDOR_AMD)
- 		return false;
- 
-+	/*
-+	 * Must match family-model-stepping range first so that the
-+	 * range checks will override OSVW checking.
-+	 */
-+	ms = (cpu->x86_model << 4) | cpu->x86_mask;
-+	while ((range = *erratum++))
-+		if ((cpu->x86 == AMD_MODEL_RANGE_FAMILY(range)) &&
-+		    (ms >= AMD_MODEL_RANGE_START(range)) &&
-+		    (ms <= AMD_MODEL_RANGE_END(range)))
-+			return true;
-+
- 	if (osvw_id >= 0 && osvw_id < 65536 &&
- 	    cpu_has(cpu, X86_FEATURE_OSVW)) {
- 		u64 osvw_len;
-@@ -737,15 +748,6 @@ bool cpu_has_amd_erratum(const int *erra
- 		}
- 	}
- 
--	/* OSVW unavailable or ID unknown, match family-model-stepping range */
--	ms = (cpu->x86_model << 4) | cpu->x86_mask;
--	while ((range = *erratum++))
--		if ((cpu->x86 == AMD_MODEL_RANGE_FAMILY(range)) &&
--		    (ms >= AMD_MODEL_RANGE_START(range)) &&
--		    (ms <= AMD_MODEL_RANGE_END(range)))
--			return true;
--
- 	return false;
- }
--
- EXPORT_SYMBOL_GPL(cpu_has_amd_erratum);