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x86: clean up text_poke()

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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>
This commit is contained in:
Mathieu Desnoyers 2008-04-24 11:03:33 -04:00 committed by Ingo Molnar
parent 8b132ecbcf
commit b7b66baa8b
1 changed files with 18 additions and 20 deletions
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38
arch/x86/kernel/alternative.c
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@ -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;
}