powerpc/32: Fix unpaired stwcx. on interrupt exit

[ Upstream commit 10e1c77c3636d815db802ceef588522c2d2d947c ]

Commit b96bae3ae2cb ("powerpc/32: Replace ASM exception exit by C
exception exit from ppc64") erroneouly copied to powerpc/32 the logic
from powerpc/64 based on feature CPU_FTR_STCX_CHECKS_ADDRESS which is
always 0 on powerpc/32.

Re-instate the logic implemented by commit b64f87c16f3c ("[POWERPC]
Avoid unpaired stwcx. on some processors") which is based on
CPU_FTR_NEED_PAIRED_STWCX feature.

Fixes: b96bae3ae2cb ("powerpc/32: Replace ASM exception exit by C exception exit from ppc64")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/6040b5dbcf5cdaa1cd919fcf0790f12974ea6e5a.1757666244.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index f4a8c98772491a88fa15f9bb582baa231655d11e..1beb578c641147bacab8c466d0caa6578a5c6e0f 100644 (file)
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -263,10 +263,9 @@ interrupt_return:
        mtspr   SPRN_SRR1,r12
 
 BEGIN_FTR_SECTION
+       lwarx   r0,0,r1
+END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
        stwcx.  r0,0,r1         /* to clear the reservation */
-FTR_SECTION_ELSE
-       lwarx   r0,0,r1
-ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
 
        lwz     r3,_CCR(r1)
        lwz     r4,_LINK(r1)
@@ -306,10 +305,9 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
        mtspr   SPRN_SRR1,r12
 
 BEGIN_FTR_SECTION
+       lwarx   r0,0,r1
+END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
        stwcx.  r0,0,r1         /* to clear the reservation */
-FTR_SECTION_ELSE
-       lwarx   r0,0,r1
-ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
 
        lwz     r3,_LINK(r1)
        lwz     r4,_CTR(r1)