Christophe Leroy <christophe.le...@c-s.fr> writes: > Le 22/11/2019 à 07:38, Michael Ellerman a écrit : >> Michael Ellerman <m...@ellerman.id.au> writes: >>> Christophe Leroy <christophe.le...@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.le...@c-s.fr> >>> >>> This doesn't build with gcc 4.6.3: >>> >>> /linux/arch/powerpc/kernel/vdso32/gettimeofday.S: Assembler messages: >>> /linux/arch/powerpc/kernel/vdso32/gettimeofday.S:41: Error: unsupported >>> relocation against __kernel_datapage_offset >>> /linux/arch/powerpc/kernel/vdso32/gettimeofday.S:86: Error: unsupported >>> relocation against __kernel_datapage_offset >>> /linux/arch/powerpc/kernel/vdso32/gettimeofday.S:213: Error: unsupported >>> relocation against __kernel_datapage_offset >>> /linux/arch/powerpc/kernel/vdso32/gettimeofday.S:247: Error: unsupported >>> relocation against __kernel_datapage_offset >>> make[4]: *** [arch/powerpc/kernel/vdso32/gettimeofday.o] Error 1 >> >> Actually I guess it's binutils, which is v2.22 in this case. >> >> Needed this: >> >> diff --git a/arch/powerpc/include/asm/vdso_datapage.h >> b/arch/powerpc/include/asm/vdso_datapage.h >> index 12785f72f17d..0048db347ddf 100644 >> --- a/arch/powerpc/include/asm/vdso_datapage.h >> +++ b/arch/powerpc/include/asm/vdso_datapage.h >> @@ -117,7 +117,7 @@ extern struct vdso_data *vdso_data; >> .macro get_datapage ptr, tmp >> bcl 20, 31, .+4 >> mflr \ptr >> - addi \ptr, \ptr, __kernel_datapage_offset - (.-4) >> + addi \ptr, \ptr, (__kernel_datapage_offset - (.-4))@l >> lwz \tmp, 0(\ptr) >> add \ptr, \tmp, \ptr >> .endm >> > > Are you still planning to getting this series merged ? Do you need any > help / rebase / re-spin ?
Not sure. I'll possibly send a 2nd pull request next week with it included. cheers
