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| author | Breno Leitao <leitao@debian.org> | 2019-04-08 16:32:38 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-17 08:38:39 +0200 |
| commit | 902eca1a0ccfd2661106731db3a74b2304f31217 (patch) | |
| tree | c40b833795ec23d331a4ac2af61e4b93cc2e492c /arch/powerpc | |
| parent | 8ad895bf4b8bb365d074af01ab9deead7130246d (diff) | |
| download | linux-rpi3-902eca1a0ccfd2661106731db3a74b2304f31217.tar.gz linux-rpi3-902eca1a0ccfd2661106731db3a74b2304f31217.tar.bz2 linux-rpi3-902eca1a0ccfd2661106731db3a74b2304f31217.zip | |
powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM
commit 897bc3df8c5aebb54c32d831f917592e873d0559 upstream.
Commit e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
moved a code block around and this block uses a 'msr' variable outside of
the CONFIG_PPC_TRANSACTIONAL_MEM, however the 'msr' variable is declared
inside a CONFIG_PPC_TRANSACTIONAL_MEM block, causing a possible error when
CONFIG_PPC_TRANSACTION_MEM is not defined.
error: 'msr' undeclared (first use in this function)
This is not causing a compilation error in the mainline kernel, because
'msr' is being used as an argument of MSR_TM_ACTIVE(), which is defined as
the following when CONFIG_PPC_TRANSACTIONAL_MEM is *not* set:
#define MSR_TM_ACTIVE(x) 0
This patch just fixes this issue avoiding the 'msr' variable usage outside
the CONFIG_PPC_TRANSACTIONAL_MEM block, avoiding trusting in the
MSR_TM_ACTIVE() definition.
Cc: stable@vger.kernel.org
Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Fixes: e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/signal_64.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index bbd1c73243d7..14b0f5b6a373 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -755,12 +755,25 @@ SYSCALL_DEFINE0(rt_sigreturn) if (restore_tm_sigcontexts(current, &uc->uc_mcontext, &uc_transact->uc_mcontext)) goto badframe; - } - else - /* Fall through, for non-TM restore */ + } else #endif - if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext)) - goto badframe; + { + /* + * Fall through, for non-TM restore + * + * Unset MSR[TS] on the thread regs since MSR from user + * context does not have MSR active, and recheckpoint was + * not called since restore_tm_sigcontexts() was not called + * also. + * + * If not unsetting it, the code can RFID to userspace with + * MSR[TS] set, but without CPU in the proper state, + * causing a TM bad thing. + */ + current->thread.regs->msr &= ~MSR_TS_MASK; + if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext)) + goto badframe; + } if (restore_altstack(&uc->uc_stack)) goto badframe; |