| Message ID | 1507783525-28940-1-git-send-email-mpe@ellerman.id.au (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 632f0574167ad3f5d646dad6af87d976a703d93e |
| Headers | show |
| Series | powerpc/tm: Don't check for WARN in TM Bad Thing handling | expand |
On Thu, 2017-10-12 at 15:45 +1100, Michael Ellerman wrote: > Currently when we take a TM Bad Thing program check exception, we > search the bug table to see if the program check was generated by a > WARN/WARN_ON etc. > > That makes no sense, the WARN macros use trap instructions, which > should never generate a TM Bad Thing exception. If they ever did that > would be a bug and we should oops. > > We do have some hand-coded bugs in tm.S, using EMIT_BUG_ENTRY, but > those are all BUGs not WARNs, and they all use trap instructions > anyway. Almost certainly this check was incorrectly copied from the > REASON_TRAP handling in the same function. > > Remove it. > > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> LGTM Acked-By: Michael Neuling <mikey@neuling.org> > --- > arch/powerpc/kernel/traps.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > index 9ae1924c7d1a..0e4099fef198 100644 > --- a/arch/powerpc/kernel/traps.c > +++ b/arch/powerpc/kernel/traps.c > @@ -1337,13 +1337,8 @@ void program_check_exception(struct pt_regs *regs) > * - A treclaim is attempted when non transactional. > * - A tend is illegally attempted. > * - writing a TM SPR when transactional. > - */ > - if (!user_mode(regs) && > - report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) { > - regs->nip += 4; > - goto bail; > - } > - /* If usermode caused this, it's done something illegal and > + * > + * If usermode caused this, it's done something illegal and > * gets a SIGILL slap on the wrist. We call it an illegal > * operand to distinguish from the instruction just being bad > * (e.g. executing a 'tend' on a CPU without TM!); it's an
On Thu, 2017-10-12 at 04:45:25 UTC, Michael Ellerman wrote: > Currently when we take a TM Bad Thing program check exception, we > search the bug table to see if the program check was generated by a > WARN/WARN_ON etc. > > That makes no sense, the WARN macros use trap instructions, which > should never generate a TM Bad Thing exception. If they ever did that > would be a bug and we should oops. > > We do have some hand-coded bugs in tm.S, using EMIT_BUG_ENTRY, but > those are all BUGs not WARNs, and they all use trap instructions > anyway. Almost certainly this check was incorrectly copied from the > REASON_TRAP handling in the same function. > > Remove it. > > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > Acked-By: Michael Neuling <mikey@neuling.org> Applied to powerpc next. https://git.kernel.org/powerpc/c/632f0574167ad3f5d646dad6af87d9 cheers
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 9ae1924c7d1a..0e4099fef198 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1337,13 +1337,8 @@ void program_check_exception(struct pt_regs *regs) * - A treclaim is attempted when non transactional. * - A tend is illegally attempted. * - writing a TM SPR when transactional. - */ - if (!user_mode(regs) && - report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) { - regs->nip += 4; - goto bail; - } - /* If usermode caused this, it's done something illegal and + * + * If usermode caused this, it's done something illegal and * gets a SIGILL slap on the wrist. We call it an illegal * operand to distinguish from the instruction just being bad * (e.g. executing a 'tend' on a CPU without TM!); it's an
Currently when we take a TM Bad Thing program check exception, we search the bug table to see if the program check was generated by a WARN/WARN_ON etc. That makes no sense, the WARN macros use trap instructions, which should never generate a TM Bad Thing exception. If they ever did that would be a bug and we should oops. We do have some hand-coded bugs in tm.S, using EMIT_BUG_ENTRY, but those are all BUGs not WARNs, and they all use trap instructions anyway. Almost certainly this check was incorrectly copied from the REASON_TRAP handling in the same function. Remove it. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- arch/powerpc/kernel/traps.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)