As per the ISA, context synchronizing instructions is needed before and after
SPRN_AMR update. Use isync before and the CSI after is implied by the rfid
that we will use to switch to a new context.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
arch/powerpc/include/asm/book3s/64/kup-radix.h | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h
b/arch/powerpc/include/asm/book3s/64/kup-radix.h
index 3bcef989a35d..224658efe2fd 100644
--- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
@@ -16,6 +16,7 @@
#ifdef CONFIG_PPC_KUAP
BEGIN_MMU_FTR_SECTION_NESTED(67)
ld \gpr, STACK_REGS_KUAP(r1)
+ isync
mtspr SPRN_AMR, \gpr
END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
#endif
@@ -62,8 +63,14 @@
static inline void kuap_restore_amr(struct pt_regs *regs)
{
- if (mmu_has_feature(MMU_FTR_RADIX_KUAP))
+ if (mmu_has_feature(MMU_FTR_RADIX_KUAP)) {
+ isync();
mtspr(SPRN_AMR, regs->kuap);
+ /*
+ * No following isync/CSI required because we will be
+ * returning to a different context using rfid
+ */
+ }
}
static inline void kuap_check_amr(void)
--
2.25.2
