From ec0895f08f99515194e9fcfe1338becf6f759d38 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 2 Dec 2019 07:57:30 +0000 Subject: 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 Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/c39ef7f3dfa25356b01e211d539671f279086c09.1575273217.git.christophe.leroy@c-s.fr --- arch/powerpc/include/asm/vdso_datapage.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/powerpc/include/asm/vdso_datapage.h') diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h index 40f13f3626d3..ee5319a6f4e3 100644 --- a/arch/powerpc/include/asm/vdso_datapage.h +++ b/arch/powerpc/include/asm/vdso_datapage.h @@ -118,6 +118,16 @@ struct vdso_data { extern struct vdso_data *vdso_data; +#else /* __ASSEMBLY__ */ + +.macro get_datapage ptr, tmp + bcl 20, 31, .+4 + mflr \ptr + addi \ptr, \ptr, (__kernel_datapage_offset - (.-4))@l + lwz \tmp, 0(\ptr) + add \ptr, \tmp, \ptr +.endm + #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ -- cgit v1.2.3