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Message-ID: <20130723194049.59ee11bb@googlemail.com>
Date: Tue, 23 Jul 2013 19:40:49 +0200
From: Torsten Kaiser <just.for.lkml@...glemail.com>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...en8.de>,
Jacob Shin <jacob.shin@....com>,
Johannes Hirte <johannes.hirte@....tu-ilmenau.de>,
linux-kernel@...r.kernel.org
Subject: [PATCH v2] x86, AMD: Make cpu_has_amd_erratum() use the correct
struct cpuinfo_x86
cpu_has_amd_erratum() is buggy, because it uses the per-cpu cpu_info
before it is filled by smp_store_boot_cpu_info() / smp_store_cpu_info().
If early microcode loading is enabled its collect_cpu_info_amd_early() will
fill ->x86 and so the fallback to boot_cpu_data is not used.
But ->x86_vendor was not filled and is still 0 == X86_VENDOR_INTEL resulting in
no errata fixes getting applied and my system hangs on boot.
Using cpu_info in cpu_has_amd_erratum() is wrong anyway: Its only caller
init_amd() will have a struct cpuinfo_x86 as parameter and the set_cpu_bug()
that is controlled by cpu_has_amd_erratum() also only uses that struct.
So pass the struct cpuinfo_x86 from init_amd() to cpu_has_amd_erratum() and
the broken fallback can be dropped.
I also added an WARN_ON() into the vendor check because init_amd() can only
be used by AMD CPUs and if the current failure hadn't been silent this bug
would have been much more obvious.
V2: At request of Borislav Petkov: BUG_ON -> WARN_ON and subject change
Signed-off-by: Torsten Kaiser <just.for.lkml@...glemail.com>
--- a/arch/x86/kernel/cpu/amd.c 2013-07-22 06:33:10.027931005 +0200
+++ b/arch/x86/kernel/cpu/amd.c 2013-07-22 06:35:15.757931265 +0200
@@ -512,7 +512,7 @@ static void early_init_amd(struct cpuinf
static const int amd_erratum_383[];
static const int amd_erratum_400[];
-static bool cpu_has_amd_erratum(const int *erratum);
+static bool cpu_has_amd_erratum(struct cpuinfo_x86 *cpu, const int *erratum);
static void init_amd(struct cpuinfo_x86 *c)
{
@@ -729,11 +729,11 @@ static void init_amd(struct cpuinfo_x86
value &= ~(1ULL << 24);
wrmsrl_safe(MSR_AMD64_BU_CFG2, value);
- if (cpu_has_amd_erratum(amd_erratum_383))
+ if (cpu_has_amd_erratum(c, amd_erratum_383))
set_cpu_bug(c, X86_BUG_AMD_TLB_MMATCH);
}
- if (cpu_has_amd_erratum(amd_erratum_400))
+ if (cpu_has_amd_erratum(c, amd_erratum_400))
set_cpu_bug(c, X86_BUG_AMD_APIC_C1E);
rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);
@@ -878,22 +878,16 @@ static const int amd_erratum_400[] =
static const int amd_erratum_383[] =
AMD_OSVW_ERRATUM(3, AMD_MODEL_RANGE(0x10, 0, 0, 0xff, 0xf));
-static bool cpu_has_amd_erratum(const int *erratum)
+
+static bool cpu_has_amd_erratum(struct cpuinfo_x86 *cpu, const int *erratum)
{
- struct cpuinfo_x86 *cpu = __this_cpu_ptr(&cpu_info);
int osvw_id = *erratum++;
u32 range;
u32 ms;
- /*
- * If called early enough that current_cpu_data hasn't been initialized
- * yet, fall back to boot_cpu_data.
- */
- if (cpu->x86 == 0)
- cpu = &boot_cpu_data;
-
- if (cpu->x86_vendor != X86_VENDOR_AMD)
- return false;
+ /* Should never be called on non-AMD-CPUs */
+ if (WARN_ON(cpu->x86_vendor != X86_VENDOR_AMD))
+ return false;
if (osvw_id >= 0 && osvw_id < 65536 &&
cpu_has(cpu, X86_FEATURE_OSVW)) {
--
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