diff options
| author | Andi Kleen <ak@suse.de> | 2007-08-11 00:31:03 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-12 02:58:13 +0400 |
| commit | ab144f5ec64c42218a555ec1dbde6b60cf2982d6 (patch) | |
| tree | e3a4532e1db116e87060c9b18f4cfbf6258fdba3 /drivers/lguest | |
| parent | d3f3c9346979bfa074c64eac5fc3ed5bba4f40ed (diff) | |
| download | linux-ab144f5ec64c42218a555ec1dbde6b60cf2982d6.tar.xz | |
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>
Diffstat (limited to 'drivers/lguest')
| -rw-r--r-- | drivers/lguest/lguest.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/lguest/lguest.c b/drivers/lguest/lguest.c index 524beea7fb19..6e135ac0834f 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; } |