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Commit a515348f authored May 29, 2013 by Michael Neuling Committed by Benjamin Herrenschmidt Jun 01, 2013

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 <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

parent 2ac6f427

arch/powerpc/include/asm/ppc_asm.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -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

arch/powerpc/kernel/entry_64.S

+7 −0

Original line number	Diff line number	Diff line
		@@ -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' */