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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-12-02 08:57:30 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-23 11:31:15 +0100 |
| commit | ec0895f08f99515194e9fcfe1338becf6f759d38 (patch) | |
| tree | 7cc3179bddb320ffaac953354f910a27f4bf939f /arch/powerpc/kernel/vdso32/gettimeofday.S | |
| parent | powerpc/vdso32: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE (diff) | |
| download | linux-ec0895f08f99515194e9fcfe1338becf6f759d38.tar.xz linux-ec0895f08f99515194e9fcfe1338becf6f759d38.zip | |
powerpc/vdso32: inline __get_datapage()
__get_datapage() is only a few instructions to retrieve the
address of the page where the kernel stores data to the VDSO.
By inlining this function into its users, a bl/blr pair and
a mflr/mtlr pair is avoided, plus a few reg moves.
The improvement is noticeable (about 55 nsec/call on an 8xx)
vdsotest before the patch:
gettimeofday: vdso: 731 nsec/call
clock-gettime-realtime-coarse: vdso: 668 nsec/call
clock-gettime-monotonic-coarse: vdso: 745 nsec/call
vdsotest after the patch:
gettimeofday: vdso: 677 nsec/call
clock-gettime-realtime-coarse: vdso: 613 nsec/call
clock-gettime-monotonic-coarse: vdso: 690 nsec/call
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c39ef7f3dfa25356b01e211d539671f279086c09.1575273217.git.christophe.leroy@c-s.fr
Diffstat (limited to 'arch/powerpc/kernel/vdso32/gettimeofday.S')
| -rw-r--r-- | arch/powerpc/kernel/vdso32/gettimeofday.S | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S index e9ce8ee56edb..74973548529a 100644 --- a/arch/powerpc/kernel/vdso32/gettimeofday.S +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S @@ -9,6 +9,7 @@ #include <asm/processor.h> #include <asm/ppc_asm.h> #include <asm/vdso.h> +#include <asm/vdso_datapage.h> #include <asm/asm-offsets.h> #include <asm/unistd.h> @@ -33,8 +34,7 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday) mr r10,r3 /* r10 saves tv */ mr r11,r4 /* r11 saves tz */ - bl __get_datapage@local /* get data page */ - mr r9, r3 /* datapage ptr in r9 */ + get_datapage r9, r0 cmplwi r10,0 /* check if tv is NULL */ beq 3f lis r7,1000000@ha /* load up USEC_PER_SEC */ @@ -80,8 +80,7 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime) mflr r12 /* r12 saves lr */ .cfi_register lr,r12 mr r11,r4 /* r11 saves tp */ - bl __get_datapage@local /* get data page */ - mr r9,r3 /* datapage ptr in r9 */ + get_datapage r9, r0 lis r7,NSEC_PER_SEC@h /* want nanoseconds */ ori r7,r7,NSEC_PER_SEC@l beq cr5, .Lcoarse_clocks @@ -206,7 +205,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) mflr r12 .cfi_register lr,r12 - bl __get_datapage@local /* get data page */ + get_datapage r3, r0 lwz r5, CLOCK_HRTIMER_RES(r3) mtlr r12 li r3,0 @@ -240,8 +239,7 @@ V_FUNCTION_BEGIN(__kernel_time) .cfi_register lr,r12 mr r11,r3 /* r11 holds t */ - bl __get_datapage@local - mr r9, r3 /* datapage ptr in r9 */ + get_datapage r9, r0 lwz r3,STAMP_XTIME_SEC+LOPART(r9) |