[PATCH] powerpc/ppc476: Disable BTAC
From: Alistair Popple <hidden>
Date: 2014-08-06 07:05:43
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
This patch disables the branch target address CAM which under specific circumstances may cause the processor to skip execution of 1-4 instructions. This fixes IBM Erratum #47. Signed-off-by: Alistair Popple <redacted> --- arch/powerpc/kernel/head_44x.S | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
index c334f53..b5061ab 100644
--- a/arch/powerpc/kernel/head_44x.S
+++ b/arch/powerpc/kernel/head_44x.S@@ -1210,10 +1210,12 @@ clear_utlb_entry: /* We configure icbi to invalidate 128 bytes at a time since the * current 32-bit kernel code isn't too happy with icache != dcache - * block size + * block size. We also disable the BTAC as this can cause errors + * in some circumstances (see IBM Erratum 47). */ mfspr r3,SPRN_CCR0 oris r3,r3,0x0020 + ori r3,r3,0x0040 mtspr SPRN_CCR0,r3 isync
--
1.8.3.2