[PATCH 5.3 124/180] powerpc: Allow 64bit VDSO __kernel_sync_dicache to work across ranges >4GB

Greg Kroah-Hartman
2019-12-16T18:29:30Z

From: Alastair D'Silva <alastair@d-silva.org>

commit f9ec11165301982585e5e5f606739b5bae5331f3 upstream.

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@d-silva.org>
Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191104023305.9581-3-alastair@au1.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/kernel/vdso64/cacheflush.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- 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