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authorWill Deacon <will.deacon@arm.com>2012-11-29 22:19:01 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2012-12-05 11:20:03 +0000
commitd91fb5c2677db90460611fce72e6a0af8f6c2a73 (patch)
tree408562a6274dacea273c2df11f5513d2ad6b8938 /arch/arm64
parentf84a935db47d7f261c025ba9eaa7700261257469 (diff)
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>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/kernel/vdso/gettimeofday.S88
1 files changed, 44 insertions, 44 deletions
diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S
index 3a7bdcd55ab6..99b7d405767c 100644
--- a/arch/arm64/kernel/vdso/gettimeofday.S
+++ b/arch/arm64/kernel/vdso/gettimeofday.S
@@ -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