diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2009-09-10 02:53:50 +0100 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-09-10 16:50:19 -0700 |
| commit | 5367b6887e7d8c870a5da7d9b8c6e9c207684e43 (patch) | |
| tree | eab362078a7964850b00f8d781aa9c9f5ff01df7 /arch/x86/kernel | |
| parent | b19ae3999891cad21a3995c34d313dda5df014e2 (diff) | |
x86: Fix code patching for paravirt-alternatives on 486
As reported in <http://bugs.debian.org/511703> and
<http://bugs.debian.org/515982>, kernels with paravirt-alternatives
enabled crash in text_poke_early() on at least some 486-class
processors.
The problem is that text_poke_early() itself uses inline functions
affected by paravirt-alternatives and so will modify instructions that
have already been prefetched. Pentium and later processors will
invalidate the prefetched instructions in this case, but 486-class
processors do not.
Change sync_core() to limit prefetching on 486-class (and 386-class)
processors, and move the call to sync_core() above the call to the
modifiable local_irq_restore().
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
LKML-Reference: <1252547631.3423.134.camel@localhost>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index f5765870257..b8ebd0b689b 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -490,8 +490,8 @@ void *text_poke_early(void *addr, const void *opcode, size_t len) unsigned long flags; local_irq_save(flags); memcpy(addr, opcode, len); - local_irq_restore(flags); sync_core(); + local_irq_restore(flags); /* Could also do a CLFLUSH here to speed up CPU recovery; but that causes hangs on some VIA CPUs. */ return addr; |