diff options
| author | Andi Kleen <ak@suse.de> | 2007-08-10 22:31:03 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-08-11 15:58:13 -0700 |
| commit | ab144f5ec64c42218a555ec1dbde6b60cf2982d6 (patch) | |
| tree | e3a4532e1db116e87060c9b18f4cfbf6258fdba3 /arch/i386/xen/enlighten.c | |
| parent | d3f3c9346979bfa074c64eac5fc3ed5bba4f40ed (diff) | |
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 'arch/i386/xen/enlighten.c')
| -rw-r--r-- | arch/i386/xen/enlighten.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/i386/xen/enlighten.c b/arch/i386/xen/enlighten.c index 9a8c1181c00..f0c37511d8d 100644 --- a/arch/i386/xen/enlighten.c +++ b/arch/i386/xen/enlighten.c @@ -842,7 +842,8 @@ void __init xen_setup_vcpu_info_placement(void) } } -static unsigned xen_patch(u8 type, u16 clobbers, void *insns, unsigned len) +static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, + unsigned long addr, unsigned len) { char *start, *end, *reloc; unsigned ret; @@ -869,7 +870,7 @@ static unsigned xen_patch(u8 type, u16 clobbers, void *insns, unsigned len) if (start == NULL || (end-start) > len) goto default_patch; - ret = paravirt_patch_insns(insns, len, start, end); + ret = paravirt_patch_insns(insnbuf, len, start, end); /* Note: because reloc is assigned from something that appears to be an array, gcc assumes it's non-null, @@ -877,8 +878,8 @@ static unsigned xen_patch(u8 type, u16 clobbers, void *insns, unsigned len) end. */ if (reloc > start && reloc < end) { int reloc_off = reloc - start; - long *relocp = (long *)(insns + reloc_off); - long delta = start - (char *)insns; + long *relocp = (long *)(insnbuf + reloc_off); + long delta = start - (char *)addr; *relocp += delta; } @@ -886,7 +887,8 @@ static unsigned xen_patch(u8 type, u16 clobbers, void *insns, unsigned len) default_patch: default: - ret = paravirt_patch_default(type, clobbers, insns, len); + ret = paravirt_patch_default(type, clobbers, insnbuf, + addr, len); break; } |