| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* |
| * Userland implementation of gettimeofday() for 32 bits processes in a |
| * ppc64 kernel for use in the vDSO |
| * |
| * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org, |
| * IBM Corp. |
| */ |
| #include <asm/processor.h> |
| #include <asm/ppc_asm.h> |
| #include <asm/vdso.h> |
| #include <asm/vdso_datapage.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/unistd.h> |
| |
| /* Offset for the low 32-bit part of a field of long type */ |
| #ifdef CONFIG_PPC64 |
| #define LOPART 4 |
| #else |
| #define LOPART 0 |
| #endif |
| |
| .text |
| /* |
| * Exact prototype of gettimeofday |
| * |
| * int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); |
| * |
| */ |
| V_FUNCTION_BEGIN(__kernel_gettimeofday) |
| .cfi_startproc |
| mflr r12 |
| .cfi_register lr,r12 |
| |
| mr. r10,r3 /* r10 saves tv */ |
| mr r11,r4 /* r11 saves tz */ |
| get_datapage r9, r0 |
| beq 3f |
| LOAD_REG_IMMEDIATE(r7, 1000000) /* load up USEC_PER_SEC */ |
| bl __do_get_tspec@local /* get sec/usec from tb & kernel */ |
| stw r3,TVAL32_TV_SEC(r10) |
| stw r4,TVAL32_TV_USEC(r10) |
| |
| 3: cmplwi r11,0 /* check if tz is NULL */ |
| mtlr r12 |
| crclr cr0*4+so |
| li r3,0 |
| beqlr |
| |
| lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */ |
| lwz r5,CFG_TZ_DSTTIME(r9) |
| stw r4,TZONE_TZ_MINWEST(r11) |
| stw r5,TZONE_TZ_DSTTIME(r11) |
| |
| blr |
| .cfi_endproc |
| V_FUNCTION_END(__kernel_gettimeofday) |
| |
| /* |
| * Exact prototype of clock_gettime() |
| * |
| * int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); |
| * |
| */ |
| V_FUNCTION_BEGIN(__kernel_clock_gettime) |
| .cfi_startproc |
| /* Check for supported clock IDs */ |
| cmpli cr0,r3,CLOCK_REALTIME |
| cmpli cr1,r3,CLOCK_MONOTONIC |
| cror cr0*4+eq,cr0*4+eq,cr1*4+eq |
| |
| cmpli cr5,r3,CLOCK_REALTIME_COARSE |
| cmpli cr6,r3,CLOCK_MONOTONIC_COARSE |
| cror cr5*4+eq,cr5*4+eq,cr6*4+eq |
| |
| cror cr0*4+eq,cr0*4+eq,cr5*4+eq |
| bne cr0, .Lgettime_fallback |
| |
| mflr r12 /* r12 saves lr */ |
| .cfi_register lr,r12 |
| mr r11,r4 /* r11 saves tp */ |
| get_datapage r9, r0 |
| LOAD_REG_IMMEDIATE(r7, NSEC_PER_SEC) /* load up NSEC_PER_SEC */ |
| beq cr5, .Lcoarse_clocks |
| .Lprecise_clocks: |
| bl __do_get_tspec@local /* get sec/nsec from tb & kernel */ |
| bne cr1, .Lfinish /* not monotonic -> all done */ |
| |
| /* |
| * CLOCK_MONOTONIC |
| */ |
| |
| /* 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, r3,r4 contain our sec/nsec values, r5 and r6 |
| * can be used, r7 contains NSEC_PER_SEC. |
| */ |
| |
| lwz r5,(WTOM_CLOCK_SEC+LOPART)(r9) |
| lwz r6,WTOM_CLOCK_NSEC(r9) |
| |
| /* We now have our offset in r5,r6. We create a fake dependency |
| * on that value and re-check the counter |
| */ |
| or r0,r6,r5 |
| xor r0,r0,r0 |
| add r9,r9,r0 |
| lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9) |
| cmpl cr0,r8,r0 /* check if updated */ |
| bne- .Lprecise_clocks |
| b .Lfinish_monotonic |
| |
| /* |
| * For coarse clocks we get data directly from the vdso data page, so |
| * we don't need to call __do_get_tspec, but we still need to do the |
| * counter trick. |
| */ |
| .Lcoarse_clocks: |
| lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9) |
| andi. r0,r8,1 /* pending update ? loop */ |
| bne- .Lcoarse_clocks |
| add r9,r9,r0 /* r0 is already 0 */ |
| |
| /* |
| * CLOCK_REALTIME_COARSE, below values are needed for MONOTONIC_COARSE |
| * too |
| */ |
| lwz r3,STAMP_XTIME_SEC+LOPART(r9) |
| lwz r4,STAMP_XTIME_NSEC+LOPART(r9) |
| bne cr6,1f |
| |
| /* CLOCK_MONOTONIC_COARSE */ |
| lwz r5,(WTOM_CLOCK_SEC+LOPART)(r9) |
| lwz r6,WTOM_CLOCK_NSEC(r9) |
| |
| /* check if counter has updated */ |
| or r0,r6,r5 |
| 1: or r0,r0,r3 |
| or r0,r0,r4 |
| xor r0,r0,r0 |
| add r3,r3,r0 |
| lwz r0,CFG_TB_UPDATE_COUNT+LOPART(r9) |
| cmpl cr0,r0,r8 /* check if updated */ |
| bne- .Lcoarse_clocks |
| |
| /* Counter has not updated, so continue calculating proper values for |
| * sec and nsec if monotonic coarse, or just return with the proper |
| * values for realtime. |
| */ |
| bne cr6, .Lfinish |
| |
| /* Calculate and store result. Note that this mimics the C code, |
| * which may cause funny results if nsec goes negative... is that |
| * possible at all ? |
| */ |
| .Lfinish_monotonic: |
| add r3,r3,r5 |
| add r4,r4,r6 |
| cmpw cr0,r4,r7 |
| cmpwi cr1,r4,0 |
| blt 1f |
| subf r4,r7,r4 |
| addi r3,r3,1 |
| 1: bge cr1, .Lfinish |
| addi r3,r3,-1 |
| add r4,r4,r7 |
| |
| .Lfinish: |
| stw r3,TSPC32_TV_SEC(r11) |
| stw r4,TSPC32_TV_NSEC(r11) |
| |
| mtlr r12 |
| crclr cr0*4+so |
| li r3,0 |
| blr |
| |
| /* |
| * syscall fallback |
| */ |
| .Lgettime_fallback: |
| li r0,__NR_clock_gettime |
| .cfi_restore lr |
| sc |
| blr |
| .cfi_endproc |
| V_FUNCTION_END(__kernel_clock_gettime) |
| |
| |
| /* |
| * Exact prototype of clock_getres() |
| * |
| * int __kernel_clock_getres(clockid_t clock_id, struct timespec *res); |
| * |
| */ |
| V_FUNCTION_BEGIN(__kernel_clock_getres) |
| .cfi_startproc |
| /* Check for supported clock IDs */ |
| cmplwi cr0, r3, CLOCK_MAX |
| cmpwi cr1, r3, CLOCK_REALTIME_COARSE |
| cmpwi cr7, r3, CLOCK_MONOTONIC_COARSE |
| bgt cr0, 99f |
| LOAD_REG_IMMEDIATE(r5, KTIME_LOW_RES) |
| beq cr1, 1f |
| beq cr7, 1f |
| |
| mflr r12 |
| .cfi_register lr,r12 |
| get_datapage r3, r0 |
| lwz r5, CLOCK_HRTIMER_RES(r3) |
| mtlr r12 |
| 1: li r3,0 |
| cmpli cr0,r4,0 |
| crclr cr0*4+so |
| beqlr |
| stw r3,TSPC32_TV_SEC(r4) |
| stw r5,TSPC32_TV_NSEC(r4) |
| blr |
| |
| /* |
| * syscall fallback |
| */ |
| 99: |
| li r0,__NR_clock_getres |
| sc |
| blr |
| .cfi_endproc |
| V_FUNCTION_END(__kernel_clock_getres) |
| |
| |
| /* |
| * Exact prototype of time() |
| * |
| * time_t time(time *t); |
| * |
| */ |
| V_FUNCTION_BEGIN(__kernel_time) |
| .cfi_startproc |
| mflr r12 |
| .cfi_register lr,r12 |
| |
| mr r11,r3 /* r11 holds t */ |
| get_datapage r9, r0 |
| |
| lwz r3,STAMP_XTIME_SEC+LOPART(r9) |
| |
| cmplwi r11,0 /* check if t is NULL */ |
| mtlr r12 |
| crclr cr0*4+so |
| beqlr |
| stw r3,0(r11) /* store result at *t */ |
| blr |
| .cfi_endproc |
| V_FUNCTION_END(__kernel_time) |
| |
| /* |
| * This is the core of clock_gettime() and gettimeofday(), |
| * it returns the current time in r3 (seconds) and r4. |
| * On entry, r7 gives the resolution of r4, either USEC_PER_SEC |
| * or NSEC_PER_SEC, giving r4 in microseconds or nanoseconds. |
| * It expects the datapage ptr in r9 and doesn't clobber it. |
| * It clobbers r0, r5 and r6. |
| * On return, r8 contains the counter value that can be reused. |
| * This clobbers cr0 but not any other cr field. |
| */ |
| __do_get_tspec: |
| .cfi_startproc |
| /* Check for update count & load values. We use the low |
| * order 32 bits of the update count |
| */ |
| 1: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9) |
| andi. r0,r8,1 /* pending update ? loop */ |
| bne- 1b |
| xor r0,r8,r8 /* create dependency */ |
| add r9,r9,r0 |
| |
| /* Load orig stamp (offset to TB) */ |
| lwz r5,CFG_TB_ORIG_STAMP(r9) |
| lwz r6,(CFG_TB_ORIG_STAMP+4)(r9) |
| |
| /* Get a stable TB value */ |
| 2: MFTBU(r3) |
| MFTBL(r4) |
| MFTBU(r0) |
| cmplw cr0,r3,r0 |
| bne- 2b |
| |
| /* Subtract tb orig stamp and shift left 12 bits. |
| */ |
| subfc r4,r6,r4 |
| subfe r0,r5,r3 |
| slwi r0,r0,12 |
| rlwimi. r0,r4,12,20,31 |
| slwi r4,r4,12 |
| |
| /* |
| * Load scale factor & do multiplication. |
| * We only use the high 32 bits of the tb_to_xs value. |
| * Even with a 1GHz timebase clock, the high 32 bits of |
| * tb_to_xs will be at least 4 million, so the error from |
| * ignoring the low 32 bits will be no more than 0.25ppm. |
| * The error will just make the clock run very very slightly |
| * slow until the next time the kernel updates the VDSO data, |
| * at which point the clock will catch up to the kernel's value, |
| * so there is no long-term error accumulation. |
| */ |
| lwz r5,CFG_TB_TO_XS(r9) /* load values */ |
| mulhwu r4,r4,r5 |
| li r3,0 |
| |
| beq+ 4f /* skip high part computation if 0 */ |
| mulhwu r3,r0,r5 |
| mullw r5,r0,r5 |
| addc r4,r4,r5 |
| addze r3,r3 |
| 4: |
| /* At this point, we have seconds since the xtime stamp |
| * as a 32.32 fixed-point number in r3 and r4. |
| * Load & add the xtime stamp. |
| */ |
| lwz r5,STAMP_XTIME_SEC+LOPART(r9) |
| lwz r6,STAMP_SEC_FRAC(r9) |
| addc r4,r4,r6 |
| adde r3,r3,r5 |
| |
| /* We create a fake dependency on the result in r3/r4 |
| * and re-check the counter |
| */ |
| or r6,r4,r3 |
| xor r0,r6,r6 |
| add r9,r9,r0 |
| lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9) |
| cmplw cr0,r8,r0 /* check if updated */ |
| bne- 1b |
| |
| mulhwu r4,r4,r7 /* convert to micro or nanoseconds */ |
| |
| blr |
| .cfi_endproc |
