Commit 97b3be1e authored Aug 06, 2014 by Alistair Popple Committed by Benjamin Herrenschmidt Aug 13, 2014

powerpc/ppc476: Disable BTAC



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 <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

parent 763fe0ad

arch/powerpc/kernel/head_44x.S

+3 −1

Original line number	Diff line number	Diff line
		@@ -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