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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-04-18 02:56:17 -0400
committerPaul Mackerras <paulus@samba.org>2008-04-24 06:57:33 -0400
commitf6a616800e68b61807d0f7bb0d5dc70665ef8046 (patch)
tree62f8224cb6a7da0bc203de1be8a7f3485f4b583b /include/asm-powerpc/thread_info.h
parent8c9843e57a7d9d7a090d6467a0f1f3afb8031527 (diff)
[POWERPC] Fix kernel stack allocation alignment
The powerpc kernel stacks need to be naturally aligned, as they contain the thread info at the bottom, which is obtained by clearing the low bits of the stack pointer. However, when using 64K pages, the stack is smaller than a page, so we use kmalloc to allocate it, but that doesn't provide the alignment guarantee we need. It appeared to work so far... until one enables SLUB debugging which then returns unaligned pointers. Ooops... This fixes it by using a slab cache with enforced alignment. It relies on my previous patch that adds a thread_info_cache_init() callback. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'include/asm-powerpc/thread_info.h')
-rw-r--r--include/asm-powerpc/thread_info.h8
1 files changed, 2 insertions, 6 deletions
diff --git a/include/asm-powerpc/thread_info.h b/include/asm-powerpc/thread_info.h
index 40d5f98c44fc..d030f5ce39ad 100644
--- a/include/asm-powerpc/thread_info.h
+++ b/include/asm-powerpc/thread_info.h
@@ -80,12 +80,8 @@ struct thread_info {
80 80
81#else /* THREAD_SHIFT < PAGE_SHIFT */ 81#else /* THREAD_SHIFT < PAGE_SHIFT */
82 82
83#ifdef CONFIG_DEBUG_STACK_USAGE 83extern struct thread_info *alloc_thread_info(struct task_struct *tsk);
84#define alloc_thread_info(tsk) kzalloc(THREAD_SIZE, GFP_KERNEL) 84extern void free_thread_info(struct thread_info *ti);
85#else
86#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
87#endif
88#define free_thread_info(ti) kfree(ti)
89 85
90#endif /* THREAD_SHIFT < PAGE_SHIFT */ 86#endif /* THREAD_SHIFT < PAGE_SHIFT */
91 87