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authorVincent Whitchurch <vincent.whitchurch@axis.com>2018-11-09 10:09:48 +0100
committerRussell King <rmk+kernel@armlinux.org.uk>2018-11-12 10:51:59 +0000
commitf441882a5229ffaef61a47bccd4518f7e2749cbc (patch)
tree551bb462ee92122edfbaf07c35b42791b651abbf /arch
parentbc2eca9a682881f9da3cc7e2d75b752e549a134d (diff)
downloadlinux-f441882a5229ffaef61a47bccd4518f7e2749cbc.tar.bz2
ARM: 8812/1: Optimise copy_{from/to}_user for !CPU_USE_DOMAINS
ARMv6+ processors do not use CONFIG_CPU_USE_DOMAINS and use privileged ldr/str instructions in copy_{from/to}_user. They are currently unnecessarily using single ldr/str instructions and can use ldm/stm instructions instead like memcpy does (but with appropriate fixup tables). This speeds up a "dd if=foo of=bar bs=32k" on a tmpfs filesystem by about 4% on my Cortex-A9. before:134217728 bytes (128.0MB) copied, 0.543848 seconds, 235.4MB/s before:134217728 bytes (128.0MB) copied, 0.538610 seconds, 237.6MB/s before:134217728 bytes (128.0MB) copied, 0.544356 seconds, 235.1MB/s before:134217728 bytes (128.0MB) copied, 0.544364 seconds, 235.1MB/s before:134217728 bytes (128.0MB) copied, 0.537130 seconds, 238.3MB/s before:134217728 bytes (128.0MB) copied, 0.533443 seconds, 240.0MB/s before:134217728 bytes (128.0MB) copied, 0.545691 seconds, 234.6MB/s before:134217728 bytes (128.0MB) copied, 0.534695 seconds, 239.4MB/s before:134217728 bytes (128.0MB) copied, 0.540561 seconds, 236.8MB/s before:134217728 bytes (128.0MB) copied, 0.541025 seconds, 236.6MB/s after:134217728 bytes (128.0MB) copied, 0.520445 seconds, 245.9MB/s after:134217728 bytes (128.0MB) copied, 0.527846 seconds, 242.5MB/s after:134217728 bytes (128.0MB) copied, 0.519510 seconds, 246.4MB/s after:134217728 bytes (128.0MB) copied, 0.527231 seconds, 242.8MB/s after:134217728 bytes (128.0MB) copied, 0.525030 seconds, 243.8MB/s after:134217728 bytes (128.0MB) copied, 0.524236 seconds, 244.2MB/s after:134217728 bytes (128.0MB) copied, 0.523659 seconds, 244.4MB/s after:134217728 bytes (128.0MB) copied, 0.525018 seconds, 243.8MB/s after:134217728 bytes (128.0MB) copied, 0.519249 seconds, 246.5MB/s after:134217728 bytes (128.0MB) copied, 0.518527 seconds, 246.9MB/s Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/assembler.h6
-rw-r--r--arch/arm/lib/copy_from_user.S23
-rw-r--r--arch/arm/lib/copy_to_user.S27
3 files changed, 48 insertions, 8 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 88286dd483ff..28a48e0d4cca 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -243,13 +243,15 @@
.endm
#endif
-#define USER(x...) \
+#define USERL(l, x...) \
9999: x; \
.pushsection __ex_table,"a"; \
.align 3; \
- .long 9999b,9001f; \
+ .long 9999b,l; \
.popsection
+#define USER(x...) USERL(9001f, x)
+
#ifdef CONFIG_SMP
#define ALT_SMP(instr...) \
9998: instr
diff --git a/arch/arm/lib/copy_from_user.S b/arch/arm/lib/copy_from_user.S
index 6709a8d33963..0d4c189c7f4f 100644
--- a/arch/arm/lib/copy_from_user.S
+++ b/arch/arm/lib/copy_from_user.S
@@ -34,12 +34,13 @@
* Number of bytes NOT copied.
*/
+#ifdef CONFIG_CPU_USE_DOMAINS
+
#ifndef CONFIG_THUMB2_KERNEL
#define LDR1W_SHIFT 0
#else
#define LDR1W_SHIFT 1
#endif
-#define STR1W_SHIFT 0
.macro ldr1w ptr reg abort
ldrusr \reg, \ptr, 4, abort=\abort
@@ -57,10 +58,30 @@
ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
.endm
+#else
+
+#define LDR1W_SHIFT 0
+
+ .macro ldr1w ptr reg abort
+ USERL(\abort, W(ldr) \reg, [\ptr], #4)
+ .endm
+
+ .macro ldr4w ptr reg1 reg2 reg3 reg4 abort
+ USERL(\abort, ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4})
+ .endm
+
+ .macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ USERL(\abort, ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8})
+ .endm
+
+#endif /* CONFIG_CPU_USE_DOMAINS */
+
.macro ldr1b ptr reg cond=al abort
ldrusr \reg, \ptr, 1, \cond, abort=\abort
.endm
+#define STR1W_SHIFT 0
+
.macro str1w ptr reg abort
W(str) \reg, [\ptr], #4
.endm
diff --git a/arch/arm/lib/copy_to_user.S b/arch/arm/lib/copy_to_user.S
index 970abe521197..97a6ff4b7e3c 100644
--- a/arch/arm/lib/copy_to_user.S
+++ b/arch/arm/lib/copy_to_user.S
@@ -35,11 +35,6 @@
*/
#define LDR1W_SHIFT 0
-#ifndef CONFIG_THUMB2_KERNEL
-#define STR1W_SHIFT 0
-#else
-#define STR1W_SHIFT 1
-#endif
.macro ldr1w ptr reg abort
W(ldr) \reg, [\ptr], #4
@@ -57,6 +52,14 @@
ldr\cond\()b \reg, [\ptr], #1
.endm
+#ifdef CONFIG_CPU_USE_DOMAINS
+
+#ifndef CONFIG_THUMB2_KERNEL
+#define STR1W_SHIFT 0
+#else
+#define STR1W_SHIFT 1
+#endif
+
.macro str1w ptr reg abort
strusr \reg, \ptr, 4, abort=\abort
.endm
@@ -72,6 +75,20 @@
str1w \ptr, \reg8, \abort
.endm
+#else
+
+#define STR1W_SHIFT 0
+
+ .macro str1w ptr reg abort
+ USERL(\abort, W(str) \reg, [\ptr], #4)
+ .endm
+
+ .macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ USERL(\abort, stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8})
+ .endm
+
+#endif /* CONFIG_CPU_USE_DOMAINS */
+
.macro str1b ptr reg cond=al abort
strusr \reg, \ptr, 1, \cond, abort=\abort
.endm