| /* |
| * Userspace implementations of gettimeofday() and friends. |
| * |
| * Copyright (C) 2012 ARM Limited |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| * |
| * Author: Will Deacon <will.deacon@arm.com> |
| */ |
| |
| #include <linux/linkage.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/unistd.h> |
| |
| #define NSEC_PER_SEC_LO16 0xca00 |
| #define NSEC_PER_SEC_HI16 0x3b9a |
| |
| vdso_data .req x6 |
| use_syscall .req w7 |
| seqcnt .req w8 |
| |
| .macro seqcnt_acquire |
| 9999: ldr seqcnt, [vdso_data, #VDSO_TB_SEQ_COUNT] |
| tbnz seqcnt, #0, 9999b |
| dmb ishld |
| ldr use_syscall, [vdso_data, #VDSO_USE_SYSCALL] |
| .endm |
| |
| .macro seqcnt_read, cnt |
| dmb ishld |
| ldr \cnt, [vdso_data, #VDSO_TB_SEQ_COUNT] |
| .endm |
| |
| .macro seqcnt_check, cnt, fail |
| cmp \cnt, seqcnt |
| b.ne \fail |
| .endm |
| |
| .text |
| |
| /* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); */ |
| ENTRY(__kernel_gettimeofday) |
| .cfi_startproc |
| mov x2, x30 |
| .cfi_register x30, x2 |
| |
| /* Acquire the sequence counter and get the timespec. */ |
| adr vdso_data, _vdso_data |
| 1: seqcnt_acquire |
| cbnz use_syscall, 4f |
| |
| /* If tv is NULL, skip to the timezone code. */ |
| cbz x0, 2f |
| bl __do_get_tspec |
| seqcnt_check w9, 1b |
| |
| /* Convert ns to us. */ |
| mov x13, #1000 |
| lsl x13, x13, x12 |
| udiv x11, x11, x13 |
| stp x10, x11, [x0, #TVAL_TV_SEC] |
| 2: |
| /* If tz is NULL, return 0. */ |
| cbz x1, 3f |
| ldp w4, w5, [vdso_data, #VDSO_TZ_MINWEST] |
| stp w4, w5, [x1, #TZ_MINWEST] |
| 3: |
| mov x0, xzr |
| ret x2 |
| 4: |
| /* Syscall fallback. */ |
| mov x8, #__NR_gettimeofday |
| svc #0 |
| ret x2 |
| .cfi_endproc |
| ENDPROC(__kernel_gettimeofday) |
| |
| /* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); */ |
| ENTRY(__kernel_clock_gettime) |
| .cfi_startproc |
| cmp w0, #CLOCK_REALTIME |
| ccmp w0, #CLOCK_MONOTONIC, #0x4, ne |
| b.ne 2f |
| |
| mov x2, x30 |
| .cfi_register x30, x2 |
| |
| /* Get kernel timespec. */ |
| adr vdso_data, _vdso_data |
| 1: seqcnt_acquire |
| cbnz use_syscall, 7f |
| |
| bl __do_get_tspec |
| seqcnt_check w9, 1b |
| |
| mov x30, x2 |
| |
| cmp w0, #CLOCK_MONOTONIC |
| b.ne 6f |
| |
| /* Get wtm timespec. */ |
| ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC] |
| |
| /* Check the sequence counter. */ |
| seqcnt_read w9 |
| seqcnt_check w9, 1b |
| b 4f |
| 2: |
| cmp w0, #CLOCK_REALTIME_COARSE |
| ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne |
| b.ne 8f |
| |
| /* xtime_coarse_nsec is already right-shifted */ |
| mov x12, #0 |
| |
| /* Get coarse timespec. */ |
| adr vdso_data, _vdso_data |
| 3: seqcnt_acquire |
| ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC] |
| |
| /* Get wtm timespec. */ |
| ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC] |
| |
| /* Check the sequence counter. */ |
| seqcnt_read w9 |
| seqcnt_check w9, 3b |
| |
| cmp w0, #CLOCK_MONOTONIC_COARSE |
| b.ne 6f |
| 4: |
| /* Add on wtm timespec. */ |
| add x10, x10, x13 |
| lsl x14, x14, x12 |
| add x11, x11, x14 |
| |
| /* Normalise the new timespec. */ |
| mov x15, #NSEC_PER_SEC_LO16 |
| movk x15, #NSEC_PER_SEC_HI16, lsl #16 |
| lsl x15, x15, x12 |
| cmp x11, x15 |
| b.lt 5f |
| sub x11, x11, x15 |
| add x10, x10, #1 |
| 5: |
| cmp x11, #0 |
| b.ge 6f |
| add x11, x11, x15 |
| sub x10, x10, #1 |
| |
| 6: /* Store to the user timespec. */ |
| lsr x11, x11, x12 |
| stp x10, x11, [x1, #TSPEC_TV_SEC] |
| mov x0, xzr |
| ret |
| 7: |
| mov x30, x2 |
| 8: /* Syscall fallback. */ |
| mov x8, #__NR_clock_gettime |
| svc #0 |
| ret |
| .cfi_endproc |
| ENDPROC(__kernel_clock_gettime) |
| |
| /* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res); */ |
| ENTRY(__kernel_clock_getres) |
| .cfi_startproc |
| cbz w1, 3f |
| |
| cmp w0, #CLOCK_REALTIME |
| ccmp w0, #CLOCK_MONOTONIC, #0x4, ne |
| b.ne 1f |
| |
| ldr x2, 5f |
| b 2f |
| 1: |
| cmp w0, #CLOCK_REALTIME_COARSE |
| ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne |
| b.ne 4f |
| ldr x2, 6f |
| 2: |
| stp xzr, x2, [x1] |
| |
| 3: /* res == NULL. */ |
| mov w0, wzr |
| ret |
| |
| 4: /* Syscall fallback. */ |
| mov x8, #__NR_clock_getres |
| svc #0 |
| ret |
| 5: |
| .quad CLOCK_REALTIME_RES |
| 6: |
| .quad CLOCK_COARSE_RES |
| .cfi_endproc |
| ENDPROC(__kernel_clock_getres) |
| |
| /* |
| * Read the current time from the architected counter. |
| * Expects vdso_data to be initialised. |
| * Clobbers the temporary registers (x9 - x15). |
| * Returns: |
| * - w9 = vDSO sequence counter |
| * - (x10, x11) = (ts->tv_sec, shifted ts->tv_nsec) |
| * - w12 = cs_shift |
| */ |
| ENTRY(__do_get_tspec) |
| .cfi_startproc |
| |
| /* Read from the vDSO data page. */ |
| ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST] |
| ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC] |
| ldp w11, w12, [vdso_data, #VDSO_CS_MULT] |
| seqcnt_read w9 |
| |
| /* Read the virtual counter. */ |
| isb |
| mrs x15, cntvct_el0 |
| |
| /* Calculate cycle delta and convert to ns. */ |
| sub x10, x15, x10 |
| /* We can only guarantee 56 bits of precision. */ |
| movn x15, #0xff00, lsl #48 |
| and x10, x15, x10 |
| mul x10, x10, x11 |
| |
| /* Use the kernel time to calculate the new timespec. */ |
| mov x11, #NSEC_PER_SEC_LO16 |
| movk x11, #NSEC_PER_SEC_HI16, lsl #16 |
| lsl x11, x11, x12 |
| add x15, x10, x14 |
| udiv x14, x15, x11 |
| add x10, x13, x14 |
| mul x13, x14, x11 |
| sub x11, x15, x13 |
| |
| ret |
| .cfi_endproc |
| ENDPROC(__do_get_tspec) |
