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authorMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>2008-04-24 11:03:33 -0400
committerIngo Molnar <mingo@elte.hu>2008-04-25 19:54:07 +0200
commitb7b66baa8bc3f8e0cda6576e31e9bde09382565d (patch)
tree302533b2a5199d4958b87638b1bba5447c60152e
parent8b132ecbcfea8b1b556a832df7290379df79ad79 (diff)
x86: clean up text_poke()
Clean up the codepath, remove alignment restrictions and do sanity checking of the end result, to make sure we patched the right site. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/kernel/alternative.c38
1 files changed, 18 insertions, 20 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 7ab3a977476..60299f61843 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -511,31 +511,29 @@ void *__kprobes text_poke(void *addr, const void *opcode, size_t len)
unsigned long flags;
char *vaddr;
int nr_pages = 2;
+ struct page *pages[2];
+ int i;
- BUG_ON(len > sizeof(long));
- BUG_ON((((long)addr + len - 1) & ~(sizeof(long) - 1))
- - ((long)addr & ~(sizeof(long) - 1)));
- if (core_kernel_text((unsigned long)addr)) {
- struct page *pages[2] = { virt_to_page(addr),
- virt_to_page(addr + PAGE_SIZE) };
- if (!pages[1])
- nr_pages = 1;
- vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
- BUG_ON(!vaddr);
- local_irq_save(flags);
- memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len);
- local_irq_restore(flags);
- vunmap(vaddr);
+ if (!core_kernel_text((unsigned long)addr)) {
+ pages[0] = vmalloc_to_page(addr);
+ pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
} else {
- /*
- * modules are in vmalloc'ed memory, always writable.
- */
- local_irq_save(flags);
- memcpy(addr, opcode, len);
- local_irq_restore(flags);
+ pages[0] = virt_to_page(addr);
+ pages[1] = virt_to_page(addr + PAGE_SIZE);
}
+ BUG_ON(!pages[0]);
+ if (!pages[1])
+ nr_pages = 1;
+ vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
+ BUG_ON(!vaddr);
+ local_irq_save(flags);
+ memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len);
+ local_irq_restore(flags);
+ vunmap(vaddr);
sync_core();
/* Could also do a CLFLUSH here to speed up CPU recovery; but
that causes hangs on some VIA CPUs. */
+ for (i = 0; i < len; i++)
+ BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]);
return addr;
}