linux/debian/patches-debian/amd64-tlb-flush-sigsegv-fix...

48 lines
1.3 KiB
Diff

From: Linus Torvalds <torvalds@g5.osdl.org>
Date: Sat, 17 Sep 2005 22:41:04 +0000 (-0700)
Subject: x86-64/smp: fix random SIGSEGV issues
X-Git-Url: http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=bc5e8fdfc622b03acf5ac974a1b8b26da6511c99
x86-64/smp: fix random SIGSEGV issues
They seem to have been due to AMD errata 63/122; the fix is to disable
TLB flush filtering in SMP configurations.
Confirmed to fix the problem by Andrew Walrond <andrew@walrond.org>
[ Let's see if we'll have a better fix eventually, this is the Q&D
"let's get this fixed and out there" version ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -793,11 +793,26 @@
#endif
}
+#define HWCR 0xc0010015
+
static int __init init_amd(struct cpuinfo_x86 *c)
{
int r;
int level;
+#ifdef CONFIG_SMP
+ unsigned long value;
+
+ // Disable TLB flush filter by setting HWCR.FFDIS:
+ // bit 6 of msr C001_0015
+ //
+ // Errata 63 for SH-B3 steppings
+ // Errata 122 for all(?) steppings
+ rdmsrl(HWCR, value);
+ value |= 1 << 6;
+ wrmsrl(HWCR, value);
+#endif
+
/* Bit 31 in normal CPUID used for nonstandard 3DNow ID;
3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway */
clear_bit(0*32+31, &c->x86_capability);