From ab144f5ec64c42218a555ec1dbde6b60cf2982d6 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 10 Aug 2007 22:31:03 +0200 Subject: 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 Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- drivers/lguest/lguest.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'drivers/lguest') diff --git a/drivers/lguest/lguest.c b/drivers/lguest/lguest.c index 524beea7fb1..6e135ac0834 100644 --- a/drivers/lguest/lguest.c +++ b/drivers/lguest/lguest.c @@ -936,23 +936,24 @@ static const struct lguest_insns /* Now our patch routine is fairly simple (based on the native one in * paravirt.c). If we have a replacement, we copy it in and return how much of * the available space we used. */ -static unsigned lguest_patch(u8 type, u16 clobber, void *insns, unsigned len) +static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf, + unsigned long addr, unsigned len) { unsigned int insn_len; /* Don't do anything special if we don't have a replacement */ if (type >= ARRAY_SIZE(lguest_insns) || !lguest_insns[type].start) - return paravirt_patch_default(type, clobber, insns, len); + return paravirt_patch_default(type, clobber, ibuf, addr, len); insn_len = lguest_insns[type].end - lguest_insns[type].start; /* Similarly if we can't fit replacement (shouldn't happen, but let's * be thorough). */ if (len < insn_len) - return paravirt_patch_default(type, clobber, insns, len); + return paravirt_patch_default(type, clobber, ibuf, addr, len); /* Copy in our instructions. */ - memcpy(insns, lguest_insns[type].start, insn_len); + memcpy(ibuf, lguest_insns[type].start, insn_len); return insn_len; } -- cgit v1.2.3