| Message ID | 2e730f4e6ef77be2d5bfc38273d8a622e2cb4f97.1579196675.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Paul Burton |
| Headers | show |
| Series | powerpc: switch VDSO to C implementation. | expand |
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h index 4d7965bf369e..7342cc0c1ae4 100644 --- a/arch/powerpc/include/asm/vdso_datapage.h +++ b/arch/powerpc/include/asm/vdso_datapage.h @@ -105,6 +105,17 @@ struct vdso_arch_data { extern struct vdso_arch_data *vdso_data; +#else /* __ASSEMBLY__ */ + +.macro get_datapage ptr, offset=0 + bcl 20, 31, .+4 + mflr \ptr +#if CONFIG_PPC_PAGE_SHIFT > 14 + addis \ptr, \ptr, (_vdso_datapage + \offset - (.-4))@ha +#endif + addi \ptr, \ptr, (_vdso_datapage + \offset - (.-4))@l +.endm + #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */
__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) With current __get_datapage() function: gettimeofday: vdso: 731 nsec/call clock-gettime-realtime-coarse: vdso: 668 nsec/call clock-gettime-monotonic-coarse: vdso: 745 nsec/call Using the __get_datapage macro provided by this 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/include/asm/vdso_datapage.h | 11 +++++++++++ 1 file changed, 11 insertions(+)