Subject: [PATCH v5 18/23] powerpc/book3s64/kuap: Use Key 3 to implement KUAP with hash translation.

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Thu, 27 Aug 2020 09:39:26 +0530

Radix use AMR Key 0 and hash translation use AMR key 3.

Signed-off-by: Aneesh Kumar K.V <[email-masked]>
---
 arch/powerpc/include/asm/book3s/64/kup.h | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index 9c85e4397b2d..f326be9e0db7 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -5,11 +5,10 @@
 #include <linux/const.h>
 #include <asm/reg.h>
 
-#define AMR_KUAP_BLOCK_READ	UL(0x4000000000000000)
-#define AMR_KUAP_BLOCK_WRITE	UL(0x8000000000000000)
+#define AMR_KUAP_BLOCK_READ	UL(0x5455555555555555)
+#define AMR_KUAP_BLOCK_WRITE	UL(0xa8aaaaaaaaaaaaaa)
 #define AMR_KUEP_BLOCKED	(1UL << 62)
 #define AMR_KUAP_BLOCKED	(AMR_KUAP_BLOCK_READ | AMR_KUAP_BLOCK_WRITE)
-#define AMR_KUAP_SHIFT		62
 
 #ifdef __ASSEMBLY__
 
@@ -61,8 +60,8 @@
 #ifdef CONFIG_PPC_KUAP_DEBUG
 	BEGIN_MMU_FTR_SECTION_NESTED(67)
 	mfspr	\gpr1, SPRN_AMR
-	li	\gpr2, (AMR_KUAP_BLOCKED >> AMR_KUAP_SHIFT)
-	sldi	\gpr2, \gpr2, AMR_KUAP_SHIFT
+	/* Prevent access to userspace using any key values */
+	LOAD_REG_IMMEDIATE(\gpr2, AMR_KUAP_BLOCKED)
 999:	tdne	\gpr1, \gpr2
 	EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
 	END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_KUAP, 67)
-- 
2.26.2