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| author | Adrian Hunter <adrian.hunter@intel.com> | 2024-03-25 08:40:10 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-04-08 15:03:07 +0200 |
| commit | d2e58ab5cda2a225c406ac10d0a8b960bc5a39b6 (patch) | |
| tree | 18d081c1c8b2e1da02f17161a8edb4912040f4aa | |
| parent | 1beb35ec615f676d49d68b6dc23c7418ba8ff145 (diff) | |
| download | linux-stable-d2e58ab5cda2a225c406ac10d0a8b960bc5a39b6.tar.gz linux-stable-d2e58ab5cda2a225c406ac10d0a8b960bc5a39b6.tar.bz2 linux-stable-d2e58ab5cda2a225c406ac10d0a8b960bc5a39b6.zip | |
vdso: Add vdso_data:: Max_cycles
Add vdso_data::max_cycles in preparation to use it to detect potential
multiplication overflow.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240325064023.2997-7-adrian.hunter@intel.com
| -rw-r--r-- | include/vdso/datapage.h | 4 | ||||
| -rw-r--r-- | kernel/time/vsyscall.c | 6 |
2 files changed, 10 insertions, 0 deletions
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h index c71ddb6d4691..d04d394db064 100644 --- a/include/vdso/datapage.h +++ b/include/vdso/datapage.h @@ -61,6 +61,7 @@ struct vdso_timestamp { * @seq: timebase sequence counter * @clock_mode: clock mode * @cycle_last: timebase at clocksource init + * @max_cycles: maximum cycles which won't overflow 64bit multiplication * @mask: clocksource mask * @mult: clocksource multiplier * @shift: clocksource shift @@ -92,6 +93,9 @@ struct vdso_data { s32 clock_mode; u64 cycle_last; +#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT + u64 max_cycles; +#endif u64 mask; u32 mult; u32 shift; diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c index f0d5062d9cbc..9193d6133e5d 100644 --- a/kernel/time/vsyscall.c +++ b/kernel/time/vsyscall.c @@ -22,10 +22,16 @@ static inline void update_vdso_data(struct vdso_data *vdata, u64 nsec, sec; vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last; +#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT + vdata[CS_HRES_COARSE].max_cycles = tk->tkr_mono.clock->max_cycles; +#endif vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask; vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult; vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift; vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last; +#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT + vdata[CS_RAW].max_cycles = tk->tkr_raw.clock->max_cycles; +#endif vdata[CS_RAW].mask = tk->tkr_raw.mask; vdata[CS_RAW].mult = tk->tkr_raw.mult; vdata[CS_RAW].shift = tk->tkr_raw.shift; |