__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.le...@c-s.fr> --- arch/powerpc/kernel/vdso32/cacheflush.S | 10 +++++----- arch/powerpc/kernel/vdso32/datapage.S | 29 ++++------------------------- arch/powerpc/kernel/vdso32/datapage.h | 12 ++++++++++++ arch/powerpc/kernel/vdso32/gettimeofday.S | 11 +++++------ 4 files changed, 26 insertions(+), 36 deletions(-) create mode 100644 arch/powerpc/kernel/vdso32/datapage.h 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..ad96256be090 --- /dev/null +++ b/arch/powerpc/kernel/vdso32/datapage.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +.macro get_datapage ptr, tmp + bcl 20,31,888f +888: + mflr \ptr + addi \ptr, \ptr, __kernel_datapage_offset - 888b + 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 e10098cde89c..91a58f01dcd5 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 cr5,70f @@ -235,8 +235,7 @@ 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