linux-kernel - [PATCH v3 13/13] powerpc/40x: Don't save CR in SPRN_SPRG

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Message-Id: <b6b9b7f710a21d9dc0ab60825ad10bb568835726.1586852082.git.christophe.leroy@c-s.fr>
Date:   Tue, 14 Apr 2020 08:19:29 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, michal.simek@...inx.com,
        arnd@...db.de
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v3 13/13] powerpc/40x: Don't save CR in SPRN_SPRG_SCRATCH6

We have r12 available, use it to keep CR around and don't
save it in SPRN_SPRG_SCRATCH6.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/head_40x.S | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 804cbd0899ac..f9b880235aee 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -253,9 +253,8 @@ _ENTRY(saved_ksp_limit)
 	mtspr	SPRN_SPRG_SCRATCH1, r11
 	mtspr	SPRN_SPRG_SCRATCH3, r12
 	mtspr	SPRN_SPRG_SCRATCH4, r9
-	mfcr	r11
+	mfcr	r12
 	mfspr	r9, SPRN_PID
-	mtspr	SPRN_SPRG_SCRATCH6, r11
 	mtspr	SPRN_SPRG_SCRATCH5, r9
 	mfspr	r10, SPRN_DEAR		/* Get faulting address */
 
@@ -322,9 +321,8 @@ _ENTRY(saved_ksp_limit)
 	 * and call the heavyweights to help us out.
 	 */
 	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mfspr	r11, SPRN_SPRG_SCRATCH6
 	mtspr	SPRN_PID, r9
-	mtcr	r11
+	mtcr	r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
 	mfspr	r11, SPRN_SPRG_SCRATCH1
@@ -340,9 +338,8 @@ _ENTRY(saved_ksp_limit)
 	mtspr	SPRN_SPRG_SCRATCH1, r11
 	mtspr	SPRN_SPRG_SCRATCH3, r12
 	mtspr	SPRN_SPRG_SCRATCH4, r9
-	mfcr	r11
+	mfcr	r12
 	mfspr	r9, SPRN_PID
-	mtspr	SPRN_SPRG_SCRATCH6, r11
 	mtspr	SPRN_SPRG_SCRATCH5, r9
 	mfspr	r10, SPRN_SRR0		/* Get faulting address */
 
@@ -409,9 +406,8 @@ _ENTRY(saved_ksp_limit)
 	 * and call the heavyweights to help us out.
 	 */
 	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mfspr	r11, SPRN_SPRG_SCRATCH6
 	mtspr	SPRN_PID, r9
-	mtcr	r11
+	mtcr	r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
 	mfspr	r11, SPRN_SPRG_SCRATCH1
@@ -555,9 +551,8 @@ finish_tlb_load:
 	/* Done...restore registers and get out of here.
 	*/
 	mfspr	r9, SPRN_SPRG_SCRATCH5
-	mfspr	r11, SPRN_SPRG_SCRATCH6
 	mtspr	SPRN_PID, r9
-	mtcr	r11
+	mtcr	r12
 	mfspr	r9, SPRN_SPRG_SCRATCH4
 	mfspr	r12, SPRN_SPRG_SCRATCH3
 	mfspr	r11, SPRN_SPRG_SCRATCH1
-- 
2.25.0