There's no point in validating only 16-byte alignment when XSAVE is in
use - 64-byte alignment is required here.
There's also no point in enforcing 64-btye alignment when XSAVE is not
in use - 16-byte alignment suffices here.
Also restrict the visibility of task_xstate_cachep by moving it to the
correct internal header (instead of it being declared in one included
by [almost] everyone).
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
arch/x86/include/asm/fpu-internal.h | 5 ++++-
arch/x86/include/asm/processor.h | 1 -
arch/x86/kernel/process.c | 6 ++++--
3 files changed, 8 insertions(+), 4 deletions(-)
--- 3.12-rc5/arch/x86/include/asm/fpu-internal.h
+++ 3.12-rc5-x86-xstate-alignment/arch/x86/include/asm/fpu-internal.h
@@ -38,6 +38,7 @@ int ia32_setup_frame(int sig, struct ksi
# define ia32_setup_rt_frame __setup_rt_frame
#endif
+extern struct kmem_cache *task_xstate_cachep;
extern unsigned int mxcsr_feature_mask;
extern void fpu_init(void);
extern void eager_fpu_init(void);
@@ -573,7 +574,9 @@ static inline int fpu_alloc(struct fpu *
fpu->state = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
if (!fpu->state)
return -ENOMEM;
- WARN_ON((unsigned long)fpu->state & 15);
+ WARN_ON((unsigned long)fpu->state & (use_xsave() ?
+ __alignof(fpu->state->xsave) - 1 :
+ __alignof(fpu->state->fxsave) -
1));
return 0;
}
--- 3.12-rc5/arch/x86/include/asm/processor.h
+++ 3.12-rc5-x86-xstate-alignment/arch/x86/include/asm/processor.h
@@ -436,7 +436,6 @@ DECLARE_PER_CPU_ALIGNED(struct stack_can
extern unsigned int xstate_size;
extern void free_thread_xstate(struct task_struct *);
-extern struct kmem_cache *task_xstate_cachep;
struct perf_event;
--- 3.12-rc5/arch/x86/kernel/process.c
+++ 3.12-rc5-x86-xstate-alignment/arch/x86/kernel/process.c
@@ -87,11 +87,13 @@ void arch_release_task_struct(struct tas
free_thread_xstate(tsk);
}
-void arch_task_cache_init(void)
+void __init arch_task_cache_init(void)
{
task_xstate_cachep =
kmem_cache_create("task_xstate", xstate_size,
- __alignof__(union thread_xstate),
+ boot_cpu_has(X86_FEATURE_XSAVE) ?
+ __alignof(struct xsave_struct) :
+ __alignof(struct i387_fxsave_struct),
SLAB_PANIC | SLAB_NOTRACK, NULL);
}
--
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