From a515348fc69fd1d9e8ebd34a16f1026d7fe32048 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Wed, 29 May 2013 19:34:27 +0000 Subject: [PATCH] powerpc/pseries: Kill all prefetch streams on context switch On context switch, we should have no prefetch streams leak from one userspace process to another. This frees up prefetch resources for the next process. Based on patch from Milton Miller. Signed-off-by: Michael Neuling Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/ppc_asm.h | 11 +++++++++++ arch/powerpc/kernel/entry_64.S | 7 +++++++ 2 files changed, 18 insertions(+) diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h index cea8496091ff..2f1b6c5f8174 100644 --- a/arch/powerpc/include/asm/ppc_asm.h +++ b/arch/powerpc/include/asm/ppc_asm.h @@ -523,6 +523,17 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,946) #define PPC440EP_ERR42 #endif +/* The following stops all load and store data streams associated with stream + * ID (ie. streams created explicitly). The embedded and server mnemonics for + * dcbt are different so we use machine "power4" here explicitly. + */ +#define DCBT_STOP_ALL_STREAM_IDS(scratch) \ +.machine push ; \ +.machine "power4" ; \ + lis scratch,0x60000000@h; \ + dcbt r0,scratch,0b01010; \ +.machine pop + /* * toreal/fromreal/tophys/tovirt macros. 32-bit BookE makes them * keep the address intact to be compatible with code shared with diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 0e9095e47b5b..246b11c4fe7e 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -501,6 +501,13 @@ BEGIN_FTR_SECTION ldarx r6,0,r1 END_FTR_SECTION_IFSET(CPU_FTR_STCX_CHECKS_ADDRESS) +#ifdef CONFIG_PPC_BOOK3S +/* Cancel all explict user streams as they will have no use after context + * switch and will stop the HW from creating streams itself + */ + DCBT_STOP_ALL_STREAM_IDS(r6) +#endif + addi r6,r4,-THREAD /* Convert THREAD to 'current' */ std r6,PACACURRENT(r13) /* Set new 'current' */