Messages in this thread | | | Subject | Re: [PATCH v2 4/8] powerpc/vdso32: inline __get_datapage() | From | Christophe Leroy <> | Date | Tue, 29 Oct 2019 17:12:52 +0100 |
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Hi Santosh,
Le 26/08/2019 à 07:44, Santosh Sivaraj a écrit : > Hi Christophe, > > Christophe Leroy <christophe.leroy@c-s.fr> writes: > >> __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> >> --- >> arch/powerpc/kernel/vdso32/cacheflush.S | 10 +++++----- >> arch/powerpc/kernel/vdso32/datapage.S | 29 ++++------------------------- >> arch/powerpc/kernel/vdso32/datapage.h | 11 +++++++++++ >> arch/powerpc/kernel/vdso32/gettimeofday.S | 13 ++++++------- >> 4 files changed, 26 insertions(+), 37 deletions(-) >> create mode 100644 arch/powerpc/kernel/vdso32/datapage.h > > The datapage.h file should ideally be moved under include/asm, then we can use > the same for powerpc64 too.
Finally, I added the get_datapage macro to the existing asm/vdso_datapage.h
Christophe
> > Santosh > >> >> diff --git a/arch/powerpc/kernel/vdso32/cacheflush.S b/arch/powerpc/kernel/vdso32/cacheflush.S >> index 7f882e7b9f43..e9453837e4ee 100644 >> --- a/arch/powerpc/kernel/vdso32/cacheflush.S >> +++ b/arch/powerpc/kernel/vdso32/cacheflush.S >> @@ -10,6 +10,8 @@ >> #include <asm/vdso.h> >> #include <asm/asm-offsets.h> >> >> +#include "datapage.h" >> + >> .text >> >> /* >> @@ -24,14 +26,12 @@ V_FUNCTION_BEGIN(__kernel_sync_dicache) >> .cfi_startproc >> mflr r12 >> .cfi_register lr,r12 >> - mr r11,r3 >> - bl __get_datapage@local >> + get_datapage r10, r0 >> mtlr r12 >> - mr r10,r3 >> >> lwz r7,CFG_DCACHE_BLOCKSZ(r10) >> addi r5,r7,-1 >> - andc r6,r11,r5 /* round low to line bdy */ >> + andc r6,r3,r5 /* round low to line bdy */ >> subf r8,r6,r4 /* compute length */ >> add r8,r8,r5 /* ensure we get enough */ >> lwz r9,CFG_DCACHE_LOGBLOCKSZ(r10) >> @@ -48,7 +48,7 @@ V_FUNCTION_BEGIN(__kernel_sync_dicache) >> >> lwz r7,CFG_ICACHE_BLOCKSZ(r10) >> addi r5,r7,-1 >> - andc r6,r11,r5 /* round low to line bdy */ >> + andc r6,r3,r5 /* round low to line bdy */ >> subf r8,r6,r4 /* compute length */ >> add r8,r8,r5 >> lwz r9,CFG_ICACHE_LOGBLOCKSZ(r10) >> diff --git a/arch/powerpc/kernel/vdso32/datapage.S b/arch/powerpc/kernel/vdso32/datapage.S >> index 6984125b9fc0..d480d2d4a3fe 100644 >> --- a/arch/powerpc/kernel/vdso32/datapage.S >> +++ b/arch/powerpc/kernel/vdso32/datapage.S >> @@ -11,34 +11,13 @@ >> #include <asm/unistd.h> >> #include <asm/vdso.h> >> >> +#include "datapage.h" >> + >> .text >> .global __kernel_datapage_offset; >> __kernel_datapage_offset: >> .long 0 >> >> -V_FUNCTION_BEGIN(__get_datapage) >> - .cfi_startproc >> - /* We don't want that exposed or overridable as we want other objects >> - * to be able to bl directly to here >> - */ >> - .protected __get_datapage >> - .hidden __get_datapage >> - >> - mflr r0 >> - .cfi_register lr,r0 >> - >> - bcl 20,31,data_page_branch >> -data_page_branch: >> - mflr r3 >> - mtlr r0 >> - addi r3, r3, __kernel_datapage_offset-data_page_branch >> - lwz r0,0(r3) >> - .cfi_restore lr >> - add r3,r0,r3 >> - blr >> - .cfi_endproc >> -V_FUNCTION_END(__get_datapage) >> - >> /* >> * void *__kernel_get_syscall_map(unsigned int *syscall_count) ; >> * >> @@ -53,7 +32,7 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map) >> mflr r12 >> .cfi_register lr,r12 >> mr r4,r3 >> - bl __get_datapage@local >> + get_datapage r3, r0 >> mtlr r12 >> addi r3,r3,CFG_SYSCALL_MAP32 >> cmpli cr0,r4,0 >> @@ -74,7 +53,7 @@ V_FUNCTION_BEGIN(__kernel_get_tbfreq) >> .cfi_startproc >> mflr r12 >> .cfi_register lr,r12 >> - bl __get_datapage@local >> + get_datapage r3, r0 >> lwz r4,(CFG_TB_TICKS_PER_SEC + 4)(r3) >> lwz r3,CFG_TB_TICKS_PER_SEC(r3) >> mtlr r12 >> diff --git a/arch/powerpc/kernel/vdso32/datapage.h b/arch/powerpc/kernel/vdso32/datapage.h >> new file mode 100644 >> index 000000000000..74f4f57c2da8 >> --- /dev/null >> +++ b/arch/powerpc/kernel/vdso32/datapage.h >> @@ -0,0 +1,11 @@ >> +/* SPDX-License-Identifier: GPL-2.0-or-later */ >> + >> +.macro get_datapage ptr, tmp >> + bcl 20,31,.+4 >> + mflr \ptr >> + addi \ptr, \ptr, __kernel_datapage_offset - (.-4) >> + lwz \tmp, 0(\ptr) >> + add \ptr, \tmp, \ptr >> +.endm >> + >> + >> diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S >> index 355b537d327a..3e55cba19f44 100644 >> --- a/arch/powerpc/kernel/vdso32/gettimeofday.S >> +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S >> @@ -12,6 +12,8 @@ >> #include <asm/asm-offsets.h> >> #include <asm/unistd.h> >> >> +#include "datapage.h" >> + >> /* Offset for the low 32-bit part of a field of long type */ >> #ifdef CONFIG_PPC64 >> #define LOPART 4 >> @@ -35,8 +37,7 @@ 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 */ >> @@ -82,8 +83,7 @@ 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 >> @@ -208,7 +208,7 @@ 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 >> @@ -242,8 +242,7 @@ 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+TSPEC_TV_SEC(r9) >> >> -- >> 2.13.3
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