diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2006-11-01 15:11:39 +1100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2006-11-01 15:16:04 +1100 |
| commit | 4393c4f6788cee65095dd838cfeca6edefbfeb52 (patch) | |
| tree | bf485a8f67b2e5860fefab58eecb77a7f0d254c5 /arch/ppc/kernel | |
| parent | 0d69a052d4d7c4085706b9ac0d1bd28ff90c9fca (diff) | |
| download | lwn-4393c4f6788cee65095dd838cfeca6edefbfeb52.tar.gz lwn-4393c4f6788cee65095dd838cfeca6edefbfeb52.zip | |
[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.c | 18 |
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) |