linux-kernel - [PATCH v3 18/22] powerpc/kuap: Wire-up KUAP on 44x

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Message-Id: <7d6c3f1978a26feada74b084f651e8cf1e3b3a47.1634627931.git.christophe.leroy@csgroup.eu>
Date:   Tue, 19 Oct 2021 09:29:29 +0200
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v3 18/22] powerpc/kuap: Wire-up KUAP on 44x

This adds KUAP support to 44x. This is done by checking
the content of SPRN_PID at the time it is read and written
into SPRN_MMUCR.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/head_44x.S         | 16 ++++++++++++++++
 arch/powerpc/platforms/Kconfig.cputype |  1 +
 2 files changed, 17 insertions(+)

diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index 916f7e91c6de..b73a56466903 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S
@@ -334,6 +334,10 @@ interrupt_base:
 	mfspr	r12,SPRN_MMUCR
 	mfspr   r13,SPRN_PID		/* Get PID */
 	rlwimi	r12,r13,0,24,31		/* Set TID */
+#ifdef CONFIG_PPC_KUAP
+	cmpwi	r13,0
+	beq	2f			/* KUAP Fault */
+#endif
 
 4:
 	mtspr	SPRN_MMUCR,r12
@@ -444,6 +448,10 @@ interrupt_base:
 	mfspr	r12,SPRN_MMUCR
 	mfspr   r13,SPRN_PID		/* Get PID */
 	rlwimi	r12,r13,0,24,31		/* Set TID */
+#ifdef CONFIG_PPC_KUAP
+	cmpwi	r13,0
+	beq	2f			/* KUAP Fault */
+#endif
 
 4:
 	mtspr	SPRN_MMUCR,r12
@@ -572,6 +580,10 @@ finish_tlb_load_44x:
 3:	mfspr	r11,SPRN_SPRG3
 	lwz	r11,PGDIR(r11)
 	mfspr   r12,SPRN_PID		/* Get PID */
+#ifdef CONFIG_PPC_KUAP
+	cmpwi	r12,0
+	beq	2f			/* KUAP Fault */
+#endif
 4:	mtspr	SPRN_MMUCR,r12		/* Set MMUCR */
 
 	/* Mask of required permission bits. Note that while we
@@ -669,6 +681,10 @@ finish_tlb_load_44x:
 3:	mfspr	r11,SPRN_SPRG_THREAD
 	lwz	r11,PGDIR(r11)
 	mfspr   r12,SPRN_PID		/* Get PID */
+#ifdef CONFIG_PPC_KUAP
+	cmpwi	r12,0
+	beq	2f			/* KUAP Fault */
+#endif
 4:	mtspr	SPRN_MMUCR,r12		/* Set MMUCR */
 
 	/* Make up the required permissions */
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index fad34f28bd3a..e989eeca4c7e 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -64,6 +64,7 @@ config 44x
 	select PHYS_64BIT
 	select PPC_HAVE_KUEP
 	select PPC_KUEP
+	select PPC_HAVE_KUAP
 
 endchoice
 
-- 
2.31.1