arm64: vdso: rework __do_get_tspec register allocation and return shift
In preparation for sub-ns precision in the vdso timespec maths, change the __do_get_tspec register allocation so that we return the clocksource shift value instead of the unused xtime tspec. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Will Deacon
Catalin Marinas
parent
f84a935db4
commit
d91fb5c267
|
|
@ -62,18 +62,18 @@ ENTRY(__kernel_gettimeofday)
|
|||
/* If tv is NULL, skip to the timezone code. */
|
||||
cbz x0, 2f
|
||||
bl __do_get_tspec
|
||||
seqcnt_check w13, 1b
|
||||
seqcnt_check w9, 1b
|
||||
|
||||
/* Convert ns to us. */
|
||||
mov x11, #1000
|
||||
udiv x10, x10, x11
|
||||
stp x9, x10, [x0, #TVAL_TV_SEC]
|
||||
mov x13, #1000
|
||||
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]
|
||||
seqcnt_read w13
|
||||
seqcnt_check w13, 1b
|
||||
seqcnt_read w9
|
||||
seqcnt_check w9, 1b
|
||||
stp w4, w5, [x1, #TZ_MINWEST]
|
||||
3:
|
||||
mov x0, xzr
|
||||
|
|
@ -102,17 +102,17 @@ ENTRY(__kernel_clock_gettime)
|
|||
cbnz use_syscall, 7f
|
||||
|
||||
bl __do_get_tspec
|
||||
seqcnt_check w13, 1b
|
||||
seqcnt_check w9, 1b
|
||||
|
||||
cmp w0, #CLOCK_MONOTONIC
|
||||
b.ne 6f
|
||||
|
||||
/* Get wtm timespec. */
|
||||
ldp x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC]
|
||||
ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
|
||||
|
||||
/* Check the sequence counter. */
|
||||
seqcnt_read w13
|
||||
seqcnt_check w13, 1b
|
||||
seqcnt_read w9
|
||||
seqcnt_check w9, 1b
|
||||
b 4f
|
||||
2:
|
||||
cmp w0, #CLOCK_REALTIME_COARSE
|
||||
|
|
@ -122,37 +122,37 @@ ENTRY(__kernel_clock_gettime)
|
|||
/* Get coarse timespec. */
|
||||
adr vdso_data, _vdso_data
|
||||
3: seqcnt_acquire
|
||||
ldp x9, x10, [vdso_data, #VDSO_XTIME_CRS_SEC]
|
||||
ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
|
||||
|
||||
/* Get wtm timespec. */
|
||||
ldp x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC]
|
||||
ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
|
||||
|
||||
/* Check the sequence counter. */
|
||||
seqcnt_read w13
|
||||
seqcnt_check w13, 3b
|
||||
seqcnt_read w9
|
||||
seqcnt_check w9, 3b
|
||||
|
||||
cmp w0, #CLOCK_MONOTONIC_COARSE
|
||||
b.ne 6f
|
||||
4:
|
||||
/* Add on wtm timespec. */
|
||||
add x9, x9, x14
|
||||
add x10, x10, x15
|
||||
add x10, x10, x13
|
||||
add x11, x11, x14
|
||||
|
||||
/* Normalise the new timespec. */
|
||||
mov x14, #NSEC_PER_SEC_LO16
|
||||
movk x14, #NSEC_PER_SEC_HI16, lsl #16
|
||||
cmp x10, x14
|
||||
mov x15, #NSEC_PER_SEC_LO16
|
||||
movk x15, #NSEC_PER_SEC_HI16, lsl #16
|
||||
cmp x11, x15
|
||||
b.lt 5f
|
||||
sub x10, x10, x14
|
||||
add x9, x9, #1
|
||||
sub x11, x11, x15
|
||||
add x10, x10, #1
|
||||
5:
|
||||
cmp x10, #0
|
||||
cmp x11, #0
|
||||
b.ge 6f
|
||||
add x10, x10, x14
|
||||
sub x9, x9, #1
|
||||
add x11, x11, x15
|
||||
sub x10, x10, #1
|
||||
|
||||
6: /* Store to the user timespec. */
|
||||
stp x9, x10, [x1, #TSPEC_TV_SEC]
|
||||
stp x10, x11, [x1, #TSPEC_TV_SEC]
|
||||
mov x0, xzr
|
||||
ret x2
|
||||
7:
|
||||
|
|
@ -203,39 +203,39 @@ ENDPROC(__kernel_clock_getres)
|
|||
* Expects vdso_data to be initialised.
|
||||
* Clobbers the temporary registers (x9 - x15).
|
||||
* Returns:
|
||||
* - (x9, x10) = (ts->tv_sec, ts->tv_nsec)
|
||||
* - (x11, x12) = (xtime->tv_sec, xtime->tv_nsec)
|
||||
* - w13 = vDSO sequence counter
|
||||
* - w9 = vDSO sequence counter
|
||||
* - (x10, x11) = (ts->tv_sec, 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 x11, x12, [vdso_data, #VDSO_XTIME_CLK_SEC]
|
||||
ldp w14, w15, [vdso_data, #VDSO_CS_MULT]
|
||||
seqcnt_read w13
|
||||
ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
|
||||
ldp w11, w12, [vdso_data, #VDSO_CS_MULT]
|
||||
seqcnt_read w9
|
||||
|
||||
/* Read the physical counter. */
|
||||
isb
|
||||
mrs x9, cntpct_el0
|
||||
mrs x15, cntpct_el0
|
||||
|
||||
/* Calculate cycle delta and convert to ns. */
|
||||
sub x10, x9, x10
|
||||
sub x10, x15, x10
|
||||
/* We can only guarantee 56 bits of precision. */
|
||||
movn x9, #0xff00, lsl #48
|
||||
and x10, x9, x10
|
||||
mul x10, x10, x14
|
||||
lsr x10, x10, x15
|
||||
movn x15, #0xff00, lsl #48
|
||||
and x10, x15, x10
|
||||
mul x10, x10, x11
|
||||
lsr x10, x10, x12
|
||||
|
||||
/* Use the kernel time to calculate the new timespec. */
|
||||
add x10, x12, x10
|
||||
mov x14, #NSEC_PER_SEC_LO16
|
||||
movk x14, #NSEC_PER_SEC_HI16, lsl #16
|
||||
udiv x15, x10, x14
|
||||
add x9, x15, x11
|
||||
mul x14, x14, x15
|
||||
sub x10, x10, x14
|
||||
mov x11, #NSEC_PER_SEC_LO16
|
||||
movk x11, #NSEC_PER_SEC_HI16, lsl #16
|
||||
add x15, x10, x14
|
||||
udiv x14, x15, x11
|
||||
add x10, x13, x14
|
||||
mul x13, x14, x11
|
||||
sub x11, x15, x13
|
||||
|
||||
ret
|
||||
.cfi_endproc
|
||||
|
|
|
|||
Loading…
Reference in New Issue