powerpc: Allow 64bit VDSO __kernel_sync_dicache to work across ranges >4GB

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>

diff --git a/arch/powerpc/kernel/vdso64/cacheflush.S b/arch/powerpc/kernel/vdso64/cacheflush.S
index 69c5af2..228a4a2 100644 (file)
--- a/arch/powerpc/kernel/vdso64/cacheflush.S
+++ b/arch/powerpc/kernel/vdso64/cacheflush.S
@@ -39,7 +39,7 @@ 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
@@ -56,7 +56,7 @@ 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