Re: [PATCH 1/2] powerpc: Allow flush_icache_range to work across ranges >4GB

From: Christophe Leroy
Date: Fri Aug 09 2019 - 04:59:05 EST




Le 09/08/2019 Ã 02:45, Alastair D'Silva a ÃcritÂ:
From: Alastair D'Silva <alastair@xxxxxxxxxxx>

When calling flush_icache_range 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.

Heads-up for backporters: the old version of flush_dcache_range is
subject to a similar bug (this has since been replaced with a C
implementation).

Can you submit a patch to stable, explaining this ?


Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>

Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxx>

Should add:

Cc: stable@xxxxxxxxxxxxxxx

Christophe

---
arch/powerpc/kernel/misc_64.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index b55a7b4cb543..9bc0aa9aeb65 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -82,7 +82,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
subf r8,r6,r4 /* compute length */
add r8,r8,r5 /* ensure we get enough */
lwz r9,DCACHEL1LOGBLOCKSIZE(r10) /* Get log-2 of cache block size */
- srw. r8,r8,r9 /* compute line count */
+ srd. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
1: dcbst 0,r6
@@ -98,7 +98,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
subf r8,r6,r4 /* compute length */
add r8,r8,r5
lwz r9,ICACHEL1LOGBLOCKSIZE(r10) /* Get log-2 of Icache block size */
- srw. r8,r8,r9 /* compute line count */
+ srd. r8,r8,r9 /* compute line count */
beqlr /* nothing to do? */
mtctr r8
2: icbi 0,r6