diff options
Diffstat (limited to 'arch/powerpc/kernel/vdso64/gettimeofday.S')
| -rw-r--r-- | arch/powerpc/kernel/vdso64/gettimeofday.S | 141 |
1 files changed, 76 insertions, 65 deletions
diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S index c6401f9e37f..262cd5857a5 100644 --- a/arch/powerpc/kernel/vdso64/gettimeofday.S +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S @@ -75,90 +75,49 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime) mflr r12 /* r12 saves lr */ .cfi_register lr,r12 - mr r10,r3 /* r10 saves id */ mr r11,r4 /* r11 saves tp */ bl V_LOCAL_FUNC(__get_datapage) /* get data page */ - beq cr1,50f /* if monotonic -> jump there */ - - /* - * CLOCK_REALTIME - */ - - bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ - - lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */ - ori r7,r7,16960 - rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ - rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ - std r5,TSPC64_TV_SEC(r11) /* store sec in tv */ - subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ - mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) / - * XSEC_PER_SEC - */ - rldicl r0,r0,44,20 - mulli r0,r0,1000 /* nsec = usec * 1000 */ - std r0,TSPC64_TV_NSEC(r11) /* store nsec in tp */ - - mtlr r12 - crclr cr0*4+so - li r3,0 - blr +50: bl V_LOCAL_FUNC(__do_get_tspec) /* get time from tb & kernel */ + bne cr1,80f /* if not monotonic, all done */ /* * CLOCK_MONOTONIC */ -50: bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */ - - lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */ - ori r7,r7,16960 - rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */ - rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */ - subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */ - mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) / - * XSEC_PER_SEC - */ - rldicl r6,r0,44,20 - mulli r6,r6,1000 /* nsec = usec * 1000 */ - /* now we must fixup using wall to monotonic. We need to snapshot * that value and do the counter trick again. Fortunately, we still - * have the counter value in r8 that was returned by __do_get_xsec. - * At this point, r5,r6 contain our sec/nsec values. - * can be used + * have the counter value in r8 that was returned by __do_get_tspec. + * At this point, r4,r5 contain our sec/nsec values. */ - lwa r4,WTOM_CLOCK_SEC(r3) - lwa r7,WTOM_CLOCK_NSEC(r3) + lwa r6,WTOM_CLOCK_SEC(r3) + lwa r9,WTOM_CLOCK_NSEC(r3) - /* We now have our result in r4,r7. We create a fake dependency + /* We now have our result in r6,r9. We create a fake dependency * on that result and re-check the counter */ - or r9,r4,r7 - xor r0,r9,r9 + or r0,r6,r9 + xor r0,r0,r0 add r3,r3,r0 ld r0,CFG_TB_UPDATE_COUNT(r3) cmpld cr0,r0,r8 /* check if updated */ bne- 50b - /* Calculate and store result. Note that this mimmics the C code, - * which may cause funny results if nsec goes negative... is that - * possible at all ? + /* Add wall->monotonic offset and check for overflow or underflow. */ - add r4,r4,r5 - add r7,r7,r6 - lis r9,NSEC_PER_SEC@h - ori r9,r9,NSEC_PER_SEC@l - cmpl cr0,r7,r9 - cmpli cr1,r7,0 + add r4,r4,r6 + add r5,r5,r9 + cmpd cr0,r5,r7 + cmpdi cr1,r5,0 blt 1f - subf r7,r9,r7 + subf r5,r7,r5 addi r4,r4,1 -1: bge cr1,1f +1: bge cr1,80f addi r4,r4,-1 - add r7,r7,r9 -1: std r4,TSPC64_TV_SEC(r11) - std r7,TSPC64_TV_NSEC(r11) + add r5,r5,r7 + +80: std r4,TSPC64_TV_SEC(r11) + std r5,TSPC64_TV_NSEC(r11) mtlr r12 crclr cr0*4+so @@ -168,10 +127,6 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime) /* * syscall fallback */ -98: - mtlr r12 - mr r3,r10 - mr r4,r11 99: li r0,__NR_clock_gettime sc @@ -253,3 +208,59 @@ V_FUNCTION_BEGIN(__do_get_xsec) blr .cfi_endproc V_FUNCTION_END(__do_get_xsec) + +/* + * This is the core of clock_gettime(), it returns the current + * time in seconds and nanoseconds in r4 and r5. + * It expects the datapage ptr in r3 and doesn't clobber it. + * It clobbers r0 and r6 and returns NSEC_PER_SEC in r7. + * On return, r8 contains the counter value that can be reused. + * This clobbers cr0 but not any other cr field. + */ +V_FUNCTION_BEGIN(__do_get_tspec) + .cfi_startproc + /* check for update count & load values */ +1: ld r8,CFG_TB_UPDATE_COUNT(r3) + andi. r0,r8,1 /* pending update ? loop */ + bne- 1b + xor r0,r8,r8 /* create dependency */ + add r3,r3,r0 + + /* Get TB & offset it. We use the MFTB macro which will generate + * workaround code for Cell. + */ + MFTB(r7) + ld r9,CFG_TB_ORIG_STAMP(r3) + subf r7,r9,r7 + + /* Scale result */ + ld r5,CFG_TB_TO_XS(r3) + sldi r7,r7,12 /* compute time since stamp_xtime */ + mulhdu r6,r7,r5 /* in units of 2^-32 seconds */ + + /* Add stamp since epoch */ + ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3) + ld r5,STAMP_XTIME+TSPC64_TV_NSEC(r3) + or r0,r4,r5 + or r0,r0,r6 + xor r0,r0,r0 + add r3,r3,r0 + ld r0,CFG_TB_UPDATE_COUNT(r3) + cmpld r0,r8 /* check if updated */ + bne- 1b /* reload if so */ + + /* convert to seconds & nanoseconds and add to stamp */ + lis r7,NSEC_PER_SEC@h + ori r7,r7,NSEC_PER_SEC@l + mulhwu r0,r6,r7 /* compute nanoseconds and */ + srdi r6,r6,32 /* seconds since stamp_xtime */ + clrldi r0,r0,32 + add r5,r5,r0 /* add nanoseconds together */ + cmpd r5,r7 /* overflow? */ + add r4,r4,r6 + bltlr /* all done if no overflow */ + subf r5,r7,r5 /* if overflow, adjust */ + addi r4,r4,1 + blr + .cfi_endproc +V_FUNCTION_END(__do_get_tspec) |