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authorChristophe Leroy <christophe.leroy@c-s.fr>2020-04-17 11:58:36 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2020-04-22 20:24:02 +1000
commitfeb8e960d780e170e992a70491eec9dd68f4dbf2 (patch)
treef39964da6fd4d8526bdb818e915dd584087f5893
parentb61c38baa98056d4802ff5be5cfb979efc2d0f7a (diff)
downloadlinux-feb8e960d780e170e992a70491eec9dd68f4dbf2.tar.bz2
powerpc/mm: Fix CONFIG_PPC_KUAP_DEBUG on PPC32
CONFIG_PPC_KUAP_DEBUG is not selectable because it depends on PPC_32 which doesn't exists. Fixing it leads to a deadlock due to a vital register getting clobbered in _switch(). Change dependency to PPC32 and use r0 instead of r4 in _switch() Fixes: e2fb9f544431 ("powerpc/32: Prepare for Kernel Userspace Access Protection") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/540242f7d4573f7cdf1b3bf46bb35f743b2cd68f.1587124651.git.christophe.leroy@c-s.fr
-rw-r--r--arch/powerpc/kernel/entry_32.S2
-rw-r--r--arch/powerpc/platforms/Kconfig.cputype2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index a6371fb8f761..8420abd4ea1c 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -732,7 +732,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_SPE)
stw r10,_CCR(r1)
stw r1,KSP(r3) /* Set old stack pointer */
- kuap_check r2, r4
+ kuap_check r2, r0
#ifdef CONFIG_SMP
/* We need a sync somewhere here to make sure that if the
* previous task gets rescheduled on another CPU, it sees all
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 0c3c1902135c..27a81c291be8 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -397,7 +397,7 @@ config PPC_KUAP
config PPC_KUAP_DEBUG
bool "Extra debugging for Kernel Userspace Access Protection"
- depends on PPC_KUAP && (PPC_RADIX_MMU || PPC_32)
+ depends on PPC_KUAP && (PPC_RADIX_MMU || PPC32)
help
Add extra debugging for Kernel Userspace Access Protection (KUAP)
If you're unsure, say N.