linux-kernel - [PATCH 3.16 263/306] parisc: Also flush data TLB in flush_icache_page

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Date:   Wed, 15 Feb 2017 22:41:40 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Helge Deller" <deller@....de>,
        "John David Anglin" <dave.anglin@...l.net>
Subject: [PATCH 3.16 263/306] parisc: Also flush data TLB in
 flush_icache_page_asm

3.16.40-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: John David Anglin <dave.anglin@...l.net>

commit 5035b230e7b67ac12691ed3b5495bbb617027b68 upstream.

This is the second issue I noticed in reviewing the parisc TLB code.

The fic instruction may use either the instruction or data TLB in
flushing the instruction cache.  Thus, on machines with a split TLB, we
should also flush the data TLB after setting up the temporary alias
registers.

Although this has no functional impact, I changed the pdtlb and pitlb
instructions to consistently use the index register %r0.  These
instructions do not support integer displacements.

Tested on rp3440 and c8000.

Signed-off-by: John David Anglin  <dave.anglin@...l.net>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/parisc/kernel/pacache.S | 37 ++++++++++++++++++++++---------------
 1 file changed, 22 insertions(+), 15 deletions(-)

--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -96,7 +96,7 @@ fitmanyloop:					/* Loop if LOOP >= 2 */
 
 fitmanymiddle:					/* Loop if LOOP >= 2 */
 	addib,COND(>)		-1, %r31, fitmanymiddle	/* Adjusted inner loop decr */
-	pitlbe		0(%sr1, %r28)
+	pitlbe		%r0(%sr1, %r28)
 	pitlbe,m	%arg1(%sr1, %r28)	/* Last pitlbe and addr adjust */
 	addib,COND(>)		-1, %r29, fitmanymiddle	/* Middle loop decr */
 	copy		%arg3, %r31		/* Re-init inner loop count */
@@ -139,7 +139,7 @@ fdtmanyloop:					/* Loop if LOOP >= 2 */
 
 fdtmanymiddle:					/* Loop if LOOP >= 2 */
 	addib,COND(>)		-1, %r31, fdtmanymiddle	/* Adjusted inner loop decr */
-	pdtlbe		0(%sr1, %r28)
+	pdtlbe		%r0(%sr1, %r28)
 	pdtlbe,m	%arg1(%sr1, %r28)	/* Last pdtlbe and addr adjust */
 	addib,COND(>)		-1, %r29, fdtmanymiddle	/* Middle loop decr */
 	copy		%arg3, %r31		/* Re-init inner loop count */
@@ -620,12 +620,12 @@ ENTRY(copy_user_page_asm)
 	/* Purge any old translations */
 
 #ifdef CONFIG_PA20
-	pdtlb,l		0(%r28)
-	pdtlb,l		0(%r29)
+	pdtlb,l		%r0(%r28)
+	pdtlb,l		%r0(%r29)
 #else
 	tlb_lock	%r20,%r21,%r22
-	pdtlb		0(%r28)
-	pdtlb		0(%r29)
+	pdtlb		%r0(%r28)
+	pdtlb		%r0(%r29)
 	tlb_unlock	%r20,%r21,%r22
 #endif
 
@@ -768,10 +768,10 @@ ENTRY(clear_user_page_asm)
 	/* Purge any old translation */
 
 #ifdef CONFIG_PA20
-	pdtlb,l		0(%r28)
+	pdtlb,l		%r0(%r28)
 #else
 	tlb_lock	%r20,%r21,%r22
-	pdtlb		0(%r28)
+	pdtlb		%r0(%r28)
 	tlb_unlock	%r20,%r21,%r22
 #endif
 
@@ -852,10 +852,10 @@ ENTRY(flush_dcache_page_asm)
 	/* Purge any old translation */
 
 #ifdef CONFIG_PA20
-	pdtlb,l		0(%r28)
+	pdtlb,l		%r0(%r28)
 #else
 	tlb_lock	%r20,%r21,%r22
-	pdtlb		0(%r28)
+	pdtlb		%r0(%r28)
 	tlb_unlock	%r20,%r21,%r22
 #endif
 
@@ -892,10 +892,10 @@ ENTRY(flush_dcache_page_asm)
 	sync
 
 #ifdef CONFIG_PA20
-	pdtlb,l		0(%r25)
+	pdtlb,l		%r0(%r25)
 #else
 	tlb_lock	%r20,%r21,%r22
-	pdtlb		0(%r25)
+	pdtlb		%r0(%r25)
 	tlb_unlock	%r20,%r21,%r22
 #endif
 
@@ -925,13 +925,18 @@ ENTRY(flush_icache_page_asm)
 	depwi		0, 31,PAGE_SHIFT, %r28	/* Clear any offset bits */
 #endif
 
-	/* Purge any old translation */
+	/* Purge any old translation.  Note that the FIC instruction
+	 * may use either the instruction or data TLB.  Given that we
+	 * have a flat address space, it's not clear which TLB will be
+	 * used.  So, we purge both entries.  */
 
 #ifdef CONFIG_PA20
+	pdtlb,l		%r0(%r28)
 	pitlb,l         %r0(%sr4,%r28)
 #else
 	tlb_lock        %r20,%r21,%r22
-	pitlb           (%sr4,%r28)
+	pdtlb		%r0(%r28)
+	pitlb           %r0(%sr4,%r28)
 	tlb_unlock      %r20,%r21,%r22
 #endif
 
@@ -970,10 +975,12 @@ ENTRY(flush_icache_page_asm)
 	sync
 
 #ifdef CONFIG_PA20
+	pdtlb,l		%r0(%r28)
 	pitlb,l         %r0(%sr4,%r25)
 #else
 	tlb_lock        %r20,%r21,%r22
-	pitlb           (%sr4,%r25)
+	pdtlb		%r0(%r28)
+	pitlb           %r0(%sr4,%r25)
 	tlb_unlock      %r20,%r21,%r22
 #endif