| Message ID | 20181012131406.18601-1-vincent.whitchurch@axis.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ARM: Optimise copy_{from/to}_user for !CPU_USE_DOMAINS | expand |
On Fri, 12 Oct 2018, Vincent Whitchurch wrote: > 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 > > Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> > --- > v2: Group *_SHIFT #defines with respective .macro implementations Reviewed-by: Nicolas Pitre <nico@linaro.org> Please submit your patch here: http://www.arm.linux.org.uk/developer/patches/ > arch/arm/include/asm/assembler.h | 6 ++++-- > arch/arm/lib/copy_from_user.S | 27 ++++++++++++++++++++++++++- > arch/arm/lib/copy_to_user.S | 31 ++++++++++++++++++++++++++----- > 3 files changed, 56 insertions(+), 8 deletions(-) > > diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h > index b17ee03d280b..da16d31c7ef9 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 a826df3d3814..fca3a7037725 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 > @@ -61,6 +62,30 @@ > ldrusr \reg, \ptr, 1, \cond, abort=\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 > + > + .macro ldr1b ptr reg cond=al abort > + USERL(\abort, ldr\cond\()b \reg, [\ptr], #1) > + .endm > + > +#endif /* CONFIG_CPU_USE_DOMAINS */ > + > +#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 caf5019d8161..d6fe31fb9bc4 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 > @@ -76,6 +79,24 @@ > strusr \reg, \ptr, 1, \cond, abort=\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 > + > + .macro str1b ptr reg cond=al abort > + USERL(\abort, str\cond\()b \reg, [\ptr], #1) > + .endm > + > +#endif /* CONFIG_CPU_USE_DOMAINS */ > + > .macro enter reg1 reg2 > mov r3, #0 > stmdb sp!, {r0, r2, r3, \reg1, \reg2} > -- > 2.11.0 > >
On Fri, Oct 12, 2018 at 03:14:06PM +0200, Vincent Whitchurch wrote: > + .macro ldr1b ptr reg cond=al abort > + USERL(\abort, ldr\cond\()b \reg, [\ptr], #1) > + .endm This is broken on Thumb-2 since the fault handler is installed on the implicitly-inserted IT instead of the LDR. I will send a v3.
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index b17ee03d280b..da16d31c7ef9 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 a826df3d3814..fca3a7037725 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 @@ -61,6 +62,30 @@ ldrusr \reg, \ptr, 1, \cond, abort=\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 + + .macro ldr1b ptr reg cond=al abort + USERL(\abort, ldr\cond\()b \reg, [\ptr], #1) + .endm + +#endif /* CONFIG_CPU_USE_DOMAINS */ + +#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 caf5019d8161..d6fe31fb9bc4 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 @@ -76,6 +79,24 @@ strusr \reg, \ptr, 1, \cond, abort=\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 + + .macro str1b ptr reg cond=al abort + USERL(\abort, str\cond\()b \reg, [\ptr], #1) + .endm + +#endif /* CONFIG_CPU_USE_DOMAINS */ + .macro enter reg1 reg2 mov r3, #0 stmdb sp!, {r0, r2, r3, \reg1, \reg2}
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 Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> --- v2: Group *_SHIFT #defines with respective .macro implementations arch/arm/include/asm/assembler.h | 6 ++++-- arch/arm/lib/copy_from_user.S | 27 ++++++++++++++++++++++++++- arch/arm/lib/copy_to_user.S | 31 ++++++++++++++++++++++++++----- 3 files changed, 56 insertions(+), 8 deletions(-)