diff options
| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-12-02 10:57:30 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-23 13:31:15 +0300 |
| commit | ec0895f08f99515194e9fcfe1338becf6f759d38 (patch) | |
| tree | 7cc3179bddb320ffaac953354f910a27f4bf939f /arch/powerpc/include/asm/vdso_datapage.h | |
| parent | 654abc69ef2e69712e6d4e8a6cb9292b97a4aa39 (diff) | |
| download | linux-ec0895f08f99515194e9fcfe1338becf6f759d38.tar.xz | |
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/include/asm/vdso_datapage.h')
| -rw-r--r-- | arch/powerpc/include/asm/vdso_datapage.h | 10 |
1 files changed, 10 insertions, 0 deletions
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__ */ |