kernel.git/arch/powerpc/kernel/time.c, branch linux-4.19.y

Revert "powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled"

2020-04-29T14:31:14Z

[ Upstream commit abc3fce76adbdfa8f87272c784b388cd20b46049 ] This reverts commit ebb37cf3ffd39fdb6ec5b07111f8bb2f11d92c5f. That commit does not play well with soft-masked irq state manipulations in idle, interrupt replay, and possibly others due to tracing code sometimes using irq_work_queue (e.g., in trace_hardirqs_on()). That can cause PACA_IRQ_DEC to become set when it is not expected, and be ignored or cleared or cause warnings. The net result seems to be missing an irq_work until the next timer interrupt in the worst case which is usually not going to be noticed, however it could be a long time if the tick is disabled, which is against the spirit of irq_work and might cause real problems. The idea is still solid, but it would need more work. It's not really clear if it would be worth added complexity, so revert this for now (not a straight revert, but replace with a comment explaining why we might see interrupts happening, and gives git blame something to find). Fixes: ebb37cf3ffd3 ("powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200402120401.1115883-1-npiggin@gmail.com Signed-off-by: Sasha Levin

powerpc/pseries: Mark accumulate_stolen_time() as notrace

2020-01-04T18:12:41Z

[ Upstream commit eb8e20f89093b64f48975c74ccb114e6775cee22 ] accumulate_stolen_time() is called prior to interrupt state being reconciled, which can trip the warning in arch_local_irq_restore(): WARNING: CPU: 5 PID: 1017 at arch/powerpc/kernel/irq.c:258 .arch_local_irq_restore+0x9c/0x130 ... NIP .arch_local_irq_restore+0x9c/0x130 LR .rb_start_commit+0x38/0x80 Call Trace: .ring_buffer_lock_reserve+0xe4/0x620 .trace_function+0x44/0x210 .function_trace_call+0x148/0x170 .ftrace_ops_no_ops+0x180/0x1d0 ftrace_call+0x4/0x8 .accumulate_stolen_time+0x1c/0xb0 decrementer_common+0x124/0x160 For now just mark it as notrace. We may change the ordering to call it after interrupt state has been reconciled, but that is a larger change. Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191024055932.27940-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc: Fix vDSO clock_getres()

2019-12-17T19:35:40Z

[ Upstream commit 552263456215ada7ee8700ce022d12b0cffe4802 ] clock_getres in the vDSO library has to preserve the same behaviour of posix_get_hrtimer_res(). In particular, posix_get_hrtimer_res() does: sec = 0; ns = hrtimer_resolution; and hrtimer_resolution depends on the enablement of the high resolution timers that can happen either at compile or at run time. Fix the powerpc vdso implementation of clock_getres keeping a copy of hrtimer_resolution in vdso data and using that directly. Fixes: a7f290dad32e ("[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel") Cc: stable@vger.kernel.org Signed-off-by: Vincenzo Frascino Reviewed-by: Christophe Leroy Acked-by: Shuah Khan [chleroy: changed CLOCK_REALTIME_RES to CLOCK_HRTIMER_RES] Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/a55eca3a5e85233838c2349783bcb5164dae1d09.1575273217.git.christophe.leroy@c-s.fr Signed-off-by: Sasha Levin

powerpc/time: Fix clockevent_decrementer initalisation for PR KVM

2019-11-24T07:21:08Z

[ Upstream commit b4d16ab58c41ff0125822464bdff074cebd0fe47 ] In the recent commit 8b78fdb045de ("powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer") we changed the way we initialise the decrementer clockevent(s). We no longer initialise the mult & shift values of decrementer_clockevent itself. This has the effect of breaking PR KVM, because it uses those values in kvmppc_emulate_dec(). The symptom is guest kernels spin forever mid-way through boot. For now fix it by assigning back to decrementer_clockevent the mult and shift values. Fixes: 8b78fdb045de ("powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer") Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer

2019-11-24T07:20:09Z

[ Upstream commit 8b78fdb045de60a4eb35460092bbd3cffa925353 ] We currently cap the decrementer clockevent at 4 seconds, even on systems with large decrementer support. Fix this by converting the code to use clockevents_register_device() which calculates the upper bound based on the max_delta passed in. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/time: inline arch_vtime_task_switch()

2018-06-03T14:39:20Z

arch_vtime_task_switch() is a small function which is called only from vtime_common_task_switch(), so it is worth inlining Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc: remove unused to_tm() helper

2018-06-03T10:43:34Z

to_tm() is now completely unused, the only reference being in the _dump_time() helper that is also unused. This removes both, leaving the rest of the powerpc RTC code y2038 safe to as far as the hardware supports. Signed-off-by: Arnd Bergmann Signed-off-by: Michael Ellerman

powerpc: use time64_t in update_persistent_clock

2018-06-03T10:43:34Z

update_persistent_clock() is deprecated because it suffers from overflow in 2038 on 32-bit architectures. This changes powerpc to use the update_persistent_clock64() replacement, and to pass down 64-bit timestamps consistently. This is now simpler, as we no longer have to worry about the offset numbers in tm_year and tm_mon that are different between the Linux conventions and RTAS. Signed-off-by: Arnd Bergmann Signed-off-by: Michael Ellerman

powerpc: use time64_t in read_persistent_clock

2018-06-03T10:43:33Z

Looking through the remaining users of the deprecated mktime() function, I found the powerpc rtc handlers, which use it in place of rtc_tm_to_time64(). To clean this up, I'm changing over the read_persistent_clock() function to the read_persistent_clock64() variant, and change all the platform specific handlers along with it. Signed-off-by: Arnd Bergmann Signed-off-by: Michael Ellerman

powerpc/time: account broadcast timer event interrupts separately

2018-06-03T10:40:29Z

These are not local timer interrupts but IPIs. It's good to be able to see how timer offloading is behaving, so split these out into their own category. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman