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authorMichael Neuling <mikey@neuling.org>2013-05-29 19:34:27 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-06-01 08:29:25 +1000
commita515348fc69fd1d9e8ebd34a16f1026d7fe32048 (patch)
treeb51f9766922a1050e376df6680bfae4cec82014f
parent2ac6f427ad837a69561160b282eff80d9f0c2466 (diff)
downloadlinux-a515348fc69fd1d9e8ebd34a16f1026d7fe32048.tar.gz
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>
-rw-r--r--arch/powerpc/include/asm/ppc_asm.h11
-rw-r--r--arch/powerpc/kernel/entry_64.S7
2 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index cea8496091f..2f1b6c5f817 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 0e9095e47b5..246b11c4fe7 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' */