arm: vdso: Add support for CLOCK_MONOTONIC_RAW
PATCH v5 5/12 arm: vdso: Add support for CLOCK_MONOTONIC_RAW
Take an effort to recode the arm64 vdso code from assembler to C previously submitted by Andrew Pinski <[email protected]>, rework it for use in both arm and arm64, overlapping any optimizations for each architecture. But instead of landing it in arm64, land the result into lib/vdso and unify both implementations to simplify future maintenance.
Add a case for CLOCK_MONOTONIC_RAW to match up with support that is available in arm64's vdso.
v2:
- split first CL into 6 of 7 pieces
v4:
- Move out ARCH_CLOCK_FIXED_MASK to later adjustment.
- update commit message to reflect overall reasoning.
- replace typeof() with type vdso_raw_time_sec_t.
v5:
- replace erroneous tk->raw_time.shift with tk->tkr_raw.shift
--- arch/arm/include/asm/vdso_datapage.h | 11 +++++++++ arch/arm/kernel/vdso.c | 5 ++++ arch/arm/vdso/vgettimeofday.c | 44 ++++++++++++++++++++++++++++++++++++ 3 files changed, 60 insertions(+)
arch/arm/include/asm/vdso_datapage.h +11 -0
@@ -34,6 +34,11 @@ typedef u32 vdso_wtm_clock_nsec_t;typedef u32 vdso_xtime_clock_sec_t ;#endif +#ifndef _VDSO_RAW_TIME_SEC_T +#define _VDSO_RAW_TIME_SEC_T +typedef u32 vdso_raw_time_sec_t ; +#endif +/* Try to be cache-friendly on systems that don't implement the * generic timer: fit the unconditionally updated fields in the first * 32 bytes.
@@ -58,6 +63,12 @@ struct vdso_data {u64 xtime_clock_snsec;/* CLOCK_REALTIME sub-ns base */ u32 tz_minuteswest;/* timezone info for gettimeofday(2) */ u32 tz_dsttime; + +/* Raw clocksource multipler */ +u32 cs_raw_mult; +/* Raw time */ +vdso_raw_time_sec_t raw_time_sec; +u32 raw_time_nsec; };union vdso_data_store {
arch/arm/kernel/vdso.c +5 -0
@@ -335,9 +335,14 @@ void update_vsyscall(struct timekeeper *tk)if (!vdso_data->use_syscall) { vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; + vdso_data->raw_time_sec = tk->raw_time.tv_sec; + vdso_data->raw_time_nsec = (tk->raw_time.tv_nsec << + tk->tkr_raw.shift) + + tk->tkr_raw.xtime_nsec; vdso_data->xtime_clock_sec = tk->xtime_sec; vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec; vdso_data->cs_mono_mult = tk->tkr_mono.mult; + vdso_data->cs_raw_mult = tk->tkr_raw.mult;/* tkr_mono.shift == tkr_raw.shift */ vdso_data->cs_shift = tk->tkr_mono.shift; vdso_data->cs_mask = tk->tkr_mono.mask;
arch/arm/vdso/vgettimeofday.c +44 -0
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Signature · 1 line
2.15.0.403.gc27cc4dac6-goog
kbuild test robot
build botThank you for the patch! Yet something to improve:
Hi Mark,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc8]
[cannot apply to next-20171109]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Mark-Salyzyn/arm-vdso-rename-vdso_datapage-variables/20171109-160311
config: arm-sunxi_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=arm
All errors (new ones prefixed by >>):
arch/arm/kernel/vdso.c: In function 'update_vsyscall':
>> arch/arm/kernel/vdso.c:338:32: error: 'struct timekeeper' has no member named 'raw_time'; did you mean 'raw_sec'?
vdso_data->raw_time_sec = tk->raw_time.tv_sec;
^~
arch/arm/kernel/vdso.c:339:33: error: 'struct timekeeper' has no member named 'raw_time'; did you mean 'raw_sec'?
vdso_data->raw_time_nsec = (tk->raw_time.tv_nsec <<
^~vim +338 arch/arm/kernel/vdso.c
297
298 /**
299 * update_vsyscall - update the vdso data page
300 *
301 * Increment the sequence counter, making it odd, indicating to
302 * userspace that an update is in progress. Update the fields used
303 * for coarse clocks and, if the architected system timer is in use,
304 * the fields used for high precision clocks. Increment the sequence
305 * counter again, making it even, indicating to userspace that the
306 * update is finished.
307 *
308 * Userspace is expected to sample tb_seq_count before reading any other
309 * fields from the data page. If tb_seq_count is odd, userspace is
310 * expected to wait until it becomes even. After copying data from
311 * the page, userspace must sample tb_seq_count again; if it has changed
312 * from its previous value, userspace must retry the whole sequence.
313 *
314 * Calls to update_vsyscall are serialized by the timekeeping core.
315 */
316 void update_vsyscall(struct timekeeper *tk)
317 {
318 struct timespec64 *wtm = &tk->wall_to_monotonic;
319
320 if (!cntvct_ok) {
321 /* The entry points have been zeroed, so there is no
322 * point in updating the data page.
323 */
324 return;
325 }
326
327 vdso_write_begin(vdso_data);
328
329 vdso_data->use_syscall = !tk_is_cntvct(tk);
330 vdso_data->xtime_coarse_sec = tk->xtime_sec;
331 vdso_data->xtime_coarse_nsec = (u32)(tk->tkr_mono.xtime_nsec >>
332 tk->tkr_mono.shift);
333 vdso_data->wtm_clock_sec = wtm->tv_sec;
334 vdso_data->wtm_clock_nsec = wtm->tv_nsec;
335
336 if (!vdso_data->use_syscall) {
337 vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
> 338 vdso_data->raw_time_sec = tk->raw_time.tv_sec;
339 vdso_data->raw_time_nsec = (tk->raw_time.tv_nsec <<
340 tk->tkr_raw.shift) +
341 tk->tkr_raw.xtime_nsec;
342 vdso_data->xtime_clock_sec = tk->xtime_sec;
343 vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec;
344 vdso_data->cs_mono_mult = tk->tkr_mono.mult;
345 vdso_data->cs_raw_mult = tk->tkr_raw.mult;
346 /* tkr_mono.shift == tkr_raw.shift */
347 vdso_data->cs_shift = tk->tkr_mono.shift;
348 vdso_data->cs_mask = tk->tkr_mono.mask;
349 }
350
351 vdso_write_end(vdso_data);
352
353 flush_dcache_page(virt_to_page(vdso_data));
354 }
355
---
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