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arm64: gettimeofday change for timer rollover condition

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Adding a check in gettimeofday api for timer rollover
condition.

Change-Id: I50c36e5983f05700e49987f6e24c1b17f38a9e1f
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
This commit is contained in:
Prasad Sodagudi 2017-01-18 10:44:41 -08:00 • committed by Gerrit - the friendly Code Review server
parent 2aa89ab3ff
commit 5dbeb97af8
1 changed files with 13 additions and 4 deletions
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17
arch/arm64/kernel/vdso/gettimeofday.S
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@ -216,16 +216,25 @@ ENDPROC(__kernel_clock_getres)
ENTRY(__do_get_tspec)
.cfi_startproc
/* Read the virtual counter. */
isb
#if IS_ENABLED(CONFIG_MSM_TIMER_LEAP)
#define LEAST_32BITS 0x00000000FFFFFFFF
reread:
mrs x15, cntvct_el0
and x13, x15, #LEAST_32BITS
eor x13, x13, #LEAST_32BITS
cbz x13, reread
#else
mrs x15, cntvct_el0
#endif
/* 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. */