diff options
| author | Borislav Petkov <borislav.petkov@amd.com> | 2009-12-11 18:14:40 +0100 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-12-11 10:59:21 -0800 |
| commit | 505422517d3f126bb939439e9d15dece94e11d2c (patch) | |
| tree | a2d58c0b3cdf2b1c6b66eee6d78a283224ae1ac3 /arch/x86 | |
| parent | 5c6baba84e1ac6a79b266b40e17e692aab6604a1 (diff) | |
x86, msr: Add support for non-contiguous cpumasks
The current rd/wrmsr_on_cpus helpers assume that the supplied
cpumasks are contiguous. However, there are machines out there
like some K8 multinode Opterons which have a non-contiguous core
enumeration on each node (e.g. cores 0,2 on node 0 instead of 0,1), see
http://www.gossamer-threads.com/lists/linux/kernel/1160268.
This patch fixes out-of-bounds writes (see URL above) by adding per-CPU
msr structs which are used on the respective cores.
Additionally, two helpers, msrs_{alloc,free}, are provided for use by
the callers of the MSR accessors.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20091211171440.GD31998@aftab>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/msr.h | 3 | ||||
| -rw-r--r-- | arch/x86/lib/msr.c | 26 |
2 files changed, 25 insertions, 4 deletions
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 5bef931f8b1..2d228fc9b4b 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -244,6 +244,9 @@ do { \ #define write_rdtscp_aux(val) wrmsr(0xc0000103, (val), 0) +struct msr *msrs_alloc(void); +void msrs_free(struct msr *msrs); + #ifdef CONFIG_SMP int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h); int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h); diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c index 41628b104b9..87283417793 100644 --- a/arch/x86/lib/msr.c +++ b/arch/x86/lib/msr.c @@ -7,7 +7,6 @@ struct msr_info { u32 msr_no; struct msr reg; struct msr *msrs; - int off; int err; }; @@ -18,7 +17,7 @@ static void __rdmsr_on_cpu(void *info) int this_cpu = raw_smp_processor_id(); if (rv->msrs) - reg = &rv->msrs[this_cpu - rv->off]; + reg = per_cpu_ptr(rv->msrs, this_cpu); else reg = &rv->reg; @@ -32,7 +31,7 @@ static void __wrmsr_on_cpu(void *info) int this_cpu = raw_smp_processor_id(); if (rv->msrs) - reg = &rv->msrs[this_cpu - rv->off]; + reg = per_cpu_ptr(rv->msrs, this_cpu); else reg = &rv->reg; @@ -80,7 +79,6 @@ static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no, memset(&rv, 0, sizeof(rv)); - rv.off = cpumask_first(mask); rv.msrs = msrs; rv.msr_no = msr_no; @@ -120,6 +118,26 @@ void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs) } EXPORT_SYMBOL(wrmsr_on_cpus); +struct msr *msrs_alloc(void) +{ + struct msr *msrs = NULL; + + msrs = alloc_percpu(struct msr); + if (!msrs) { + pr_warning("%s: error allocating msrs\n", __func__); + return NULL; + } + + return msrs; +} +EXPORT_SYMBOL(msrs_alloc); + +void msrs_free(struct msr *msrs) +{ + free_percpu(msrs); +} +EXPORT_SYMBOL(msrs_free); + /* These "safe" variants are slower and should be used when the target MSR may not actually exist. */ static void __rdmsr_safe_on_cpu(void *info) |