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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2006-11-01 15:11:39 +1100
committerPaul Mackerras <paulus@samba.org>2006-11-01 15:16:04 +1100
commit4393c4f6788cee65095dd838cfeca6edefbfeb52 (patch)
treebf485a8f67b2e5860fefab58eecb77a7f0d254c5 /arch/ppc/kernel
parent0d69a052d4d7c4085706b9ac0d1bd28ff90c9fca (diff)
downloadlinux-linaro-stable-4393c4f6788cee65095dd838cfeca6edefbfeb52.tar.gz
[POWERPC] Make alignment exception always check exception table
The alignment exception used to only check the exception table for -EFAULT, not for other errors. That opens an oops window if we can coerce the kernel into getting an alignment exception for other reasons in what would normally be a user-protected accessor, which can be done via some of the futex ops. This fixes it by always checking the exception tables. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/ppc/kernel')
-rw-r--r--arch/ppc/kernel/traps.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/arch/ppc/kernel/traps.c b/arch/ppc/kernel/traps.c
index aafc8e8893d1..9661a91183b3 100644
--- a/arch/ppc/kernel/traps.c
+++ b/arch/ppc/kernel/traps.c
@@ -708,7 +708,7 @@ void single_step_exception(struct pt_regs *regs)
void alignment_exception(struct pt_regs *regs)
{
- int fixed;
+ int sig, code, fixed = 0;
fixed = fix_alignment(regs);
if (fixed == 1) {
@@ -717,14 +717,16 @@ void alignment_exception(struct pt_regs *regs)
return;
}
if (fixed == -EFAULT) {
- /* fixed == -EFAULT means the operand address was bad */
- if (user_mode(regs))
- _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
- else
- bad_page_fault(regs, regs->dar, SIGSEGV);
- return;
+ sig = SIGSEGV;
+ code = SEGV_ACCERR;
+ } else {
+ sig = SIGBUS;
+ code = BUS_ADRALN;
}
- _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
+ if (user_mode(regs))
+ _exception(sig, regs, code, regs->dar);
+ else
+ bad_page_fault(regs, regs->dar, sig);
}
void StackOverflow(struct pt_regs *regs)