i386: Make patching more robust, fix paravirt issue
Commit 19d36ccdc34f5ed444f8a6af0cbfdb6790eb1177 "x86: Fix alternatives
and kprobes to remap write-protected kernel text" uses code which is
being patched for patching.
In particular, paravirt_ops does patching in two stages: first it
calls paravirt_ops.patch, then it fills any remaining instructions
with nop_out(). nop_out calls text_poke() which calls
lookup_address() which calls pgd_val() (aka paravirt_ops.pgd_val):
that call site is one of the places we patch.
If we always do patching as one single call to text_poke(), we only
need make sure we're not patching the memcpy in text_poke itself.
This means the prototype to paravirt_ops.patch needs to change, to
marshal the new code into a buffer rather than patching in place as it
does now. It also means all patching goes through text_poke(), which
is known to be safe (apply_alternatives is also changed to make a
single patch).
AK: fix compilation on x86-64 (bad rusty!)
AK: fix boot on x86-64 (sigh)
AK: merged with other patches
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index 7df88be..9fa3fa9e 100644
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -47,7 +47,8 @@
* The patch function should return the number of bytes of code
* generated, as we nop pad the rest in generic code.
*/
- unsigned (*patch)(u8 type, u16 clobber, void *firstinsn, unsigned len);
+ unsigned (*patch)(u8 type, u16 clobber, void *insnbuf,
+ unsigned long addr, unsigned len);
/* Basic arch-specific setup */
void (*arch_setup)(void);
@@ -253,13 +254,16 @@
unsigned paravirt_patch_nop(void);
unsigned paravirt_patch_ignore(unsigned len);
-unsigned paravirt_patch_call(void *target, u16 tgt_clobbers,
- void *site, u16 site_clobbers,
+unsigned paravirt_patch_call(void *insnbuf,
+ const void *target, u16 tgt_clobbers,
+ unsigned long addr, u16 site_clobbers,
unsigned len);
-unsigned paravirt_patch_jmp(void *target, void *site, unsigned len);
-unsigned paravirt_patch_default(u8 type, u16 clobbers, void *site, unsigned len);
+unsigned paravirt_patch_jmp(const void *target, void *insnbuf,
+ unsigned long addr, unsigned len);
+unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
+ unsigned long addr, unsigned len);
-unsigned paravirt_patch_insns(void *site, unsigned len,
+unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
const char *start, const char *end);
int paravirt_disable_iospace(void);