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authorGustavo Romero <gromero@linux.vnet.ibm.com>2017-09-13 22:13:48 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-10-05 09:44:01 +0200
commitf89f25b531471a6ba43f0b5658f9359fcf33a285 (patch)
tree0528cf5fe8ea6a700e7af38c435a3ad5fdb706f2 /arch/powerpc
parent5c23dcf86e2d66f40d39e1cefb9f8c2eabf83543 (diff)
powerpc/tm: Flush TM only if CPU has TM feature
commit c1fa0768a8713b135848f78fd43ffc208d8ded70 upstream. Commit cd63f3c ("powerpc/tm: Fix saving of TM SPRs in core dump") added code to access TM SPRs in flush_tmregs_to_thread(). However flush_tmregs_to_thread() does not check if TM feature is available on CPU before trying to access TM SPRs in order to copy live state to thread structures. flush_tmregs_to_thread() is indeed guarded by CONFIG_PPC_TRANSACTIONAL_MEM but it might be the case that kernel was compiled with CONFIG_PPC_TRANSACTIONAL_MEM enabled and ran on a CPU without TM feature available, thus rendering the execution of TM instructions that are treated by the CPU as illegal instructions. The fix is just to add proper checking in flush_tmregs_to_thread() if CPU has the TM feature before accessing any TM-specific resource, returning immediately if TM is no available on the CPU. Adding that checking in flush_tmregs_to_thread() instead of in places where it is called, like in vsr_get() and vsr_set(), is better because avoids the same problem cropping up elsewhere. Fixes: cd63f3c ("powerpc/tm: Fix saving of TM SPRs in core dump") Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com> Reviewed-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/ptrace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index dcbb9144c16d..d97370866a5f 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -131,7 +131,7 @@ static void flush_tmregs_to_thread(struct task_struct *tsk)
* in the appropriate thread structures from live.
*/
- if (tsk != current)
+ if ((!cpu_has_feature(CPU_FTR_TM)) || (tsk != current))
return;
if (MSR_TM_SUSPENDED(mfmsr())) {