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| author | Gautham R. Shenoy <ego@linux.vnet.ibm.com> | 2017-02-27 08:40:07 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-03-03 03:24:50 +0300 |
| commit | 424f8acd328a111319ae30bf384e5dfb9bc8f8cb (patch) | |
| tree | 348d5c63218de5501791d521fd5df93ce7a7cf59 /arch/powerpc/kernel | |
| parent | 7a70d7288c926ae88e0c773fbb506aa374e99c2d (diff) | |
| download | linux-424f8acd328a111319ae30bf384e5dfb9bc8f8cb.tar.xz | |
powerpc/powernv: Fix bug due to labeling ambiguity in power_enter_stop
Commit 09206b600c76 ("powernv: Pass PSSCR value and mask to
power9_idle_stop") added additional code in power_enter_stop() to
distinguish between stop requests whose PSSCR had ESL=EC=1 from those
which did not. When ESL=EC=1, we do a forward-jump to a location
labelled by "1", which had the code to handle the ESL=EC=1 case.
Unfortunately just a couple of instructions before this label, is the
macro IDLE_STATE_ENTER_SEQ() which also has a label "1" in its
expansion.
As a result, the current code can result in directly executing stop
instruction for deep stop requests with PSSCR ESL=EC=1, without saving
the hypervisor state.
Fix this BUG by labeling the location that handles ESL=EC=1 case with
a more descriptive label ".Lhandle_esl_ec_set" (local label suggestion
a la .Lxx from Anton Blanchard).
While at it, rename the label "2" labelling the location of the code
handling entry into deep stop states with ".Lhandle_deep_stop".
For a good measure, change the label in IDLE_STATE_ENTER_SEQ() macro
to an not-so commonly used value in order to avoid similar mishaps in
the future.
Fixes: 09206b600c76 ("powernv: Pass PSSCR value and mask to power9_idle_stop")
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 5f61cc0349c0..995728736677 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -276,19 +276,21 @@ power_enter_stop: */ andis. r4,r3,PSSCR_EC_ESL_MASK_SHIFTED clrldi r3,r3,60 /* r3 = Bits[60:63] = Requested Level (RL) */ - bne 1f + bne .Lhandle_esl_ec_set IDLE_STATE_ENTER_SEQ(PPC_STOP) li r3,0 /* Since we didn't lose state, return 0 */ b pnv_wakeup_noloss + +.Lhandle_esl_ec_set: /* * Check if the requested state is a deep idle state. */ -1: LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state) + LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state) ld r4,ADDROFF(pnv_first_deep_stop_state)(r5) cmpd r3,r4 - bge 2f + bge .Lhandle_deep_stop IDLE_STATE_ENTER_SEQ_NORET(PPC_STOP) -2: +.Lhandle_deep_stop: /* * Entering deep idle state. * Clear thread bit in PACA_CORE_IDLE_STATE, save SPRs to |