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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-11-27 12:11:00 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-11-27 12:11:00 -0800 |
| commit | 715d2d960871c238e5860d121ba9735e7f6a7ff1 (patch) | |
| tree | 00083a7ba0a27e4ea2eede1faa031dd42a22c374 | |
| parent | b465cf177377033f939224d8f16b5b1dddcd9709 (diff) | |
| parent | 839a973988a94c15002cbd81536e4af6ced2bd30 (diff) | |
| download | linux-715d2d960871c238e5860d121ba9735e7f6a7ff1.tar.bz2 | |
Merge tag 'timers_urgent_for_v6.1_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Borislav Petkov:
- Return the proper timer register width (31 bits) for a 32-bit signed
register in order to avoid a timer interrupt storm on ARM XGene-1
hardware running in NO_HZ mode
* tag 'timers_urgent_for_v6.1_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/arm_arch_timer: Fix XGene-1 TVAL register math error
| -rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index a7ff77550e17..933bb960490d 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -806,6 +806,9 @@ static u64 __arch_timer_check_delta(void) /* * XGene-1 implements CVAL in terms of TVAL, meaning * that the maximum timer range is 32bit. Shame on them. + * + * Note that TVAL is signed, thus has only 31 of its + * 32 bits to express magnitude. */ MIDR_ALL_VERSIONS(MIDR_CPU_MODEL(ARM_CPU_IMP_APM, APM_CPU_PART_POTENZA)), @@ -813,8 +816,8 @@ static u64 __arch_timer_check_delta(void) }; if (is_midr_in_range_list(read_cpuid_id(), broken_cval_midrs)) { - pr_warn_once("Broken CNTx_CVAL_EL1, limiting width to 32bits"); - return CLOCKSOURCE_MASK(32); + pr_warn_once("Broken CNTx_CVAL_EL1, using 31 bit TVAL instead.\n"); + return CLOCKSOURCE_MASK(31); } #endif return CLOCKSOURCE_MASK(arch_counter_get_width()); |