linux-kernel - [PATCH v4 2/6] powerpc: Allow 64bit VDSO __kernel_sync

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Date:   Thu, 26 Sep 2019 14:54:08 +1000
From:   "Alastair D'Silva" <alastair@....ibm.com>
To:     alastair@...ilva.org
Cc:     stable@...r.kernel.org,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Christophe Leroy <christophe.leroy@....fr>,
        Thomas Gleixner <tglx@...utronix.de>, Qian Cai <cai@....pw>,
        Nicholas Piggin <npiggin@...il.com>,
        Allison Randal <allison@...utok.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH v4 2/6] powerpc: Allow 64bit VDSO __kernel_sync_dicache to work across ranges >4GB

From: Alastair D'Silva <alastair@...ilva.org>

When calling __kernel_sync_dicache with a size >4GB, we were masking
off the upper 32 bits, so we would incorrectly flush a range smaller
than intended.

This patch replaces the 32 bit shifts with 64 bit ones, so that
the full size is accounted for.

Signed-off-by: Alastair D'Silva <alastair@...ilva.org>
Cc: stable@...r.kernel.org
---
 arch/powerpc/kernel/vdso64/cacheflush.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/vdso64/cacheflush.S b/arch/powerpc/kernel/vdso64/cacheflush.S
index 3f92561a64c4..526f5ba2593e 100644
--- a/arch/powerpc/kernel/vdso64/cacheflush.S
+++ b/arch/powerpc/kernel/vdso64/cacheflush.S
@@ -35,7 +35,7 @@ V_FUNCTION_BEGIN(__kernel_sync_dicache)
 	subf	r8,r6,r4		/* compute length */
 	add	r8,r8,r5		/* ensure we get enough */
 	lwz	r9,CFG_DCACHE_LOGBLOCKSZ(r10)
-	srw.	r8,r8,r9		/* compute line count */
+	srd.	r8,r8,r9		/* compute line count */
 	crclr	cr0*4+so
 	beqlr				/* nothing to do? */
 	mtctr	r8
@@ -52,7 +52,7 @@ V_FUNCTION_BEGIN(__kernel_sync_dicache)
 	subf	r8,r6,r4		/* compute length */
 	add	r8,r8,r5
 	lwz	r9,CFG_ICACHE_LOGBLOCKSZ(r10)
-	srw.	r8,r8,r9		/* compute line count */
+	srd.	r8,r8,r9		/* compute line count */
 	crclr	cr0*4+so
 	beqlr				/* nothing to do? */
 	mtctr	r8
-- 
2.21.0