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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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511f838945
Previously tile was rolling its own method of capturing backtrace data in the NMI handlers, but it was relying on running printk() from the NMI handler, which is not always safe. So adopt the nmi_backtrace model (with the new cpumask extension) instead. So we can call the nmi_backtrace code directly from the nmi handler, move the nmi_enter()/exit() into the top-level tile NMI handler. The semantics of the routine change slightly since it is now synchronous with the remote cores completing the backtraces. Previously it was asynchronous, but with protection to avoid starting a new remote backtrace if the old one was still in progress. Link: http://lkml.kernel.org/r/1472487169-14923-4-git-send-email-cmetcalf@mellanox.com Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> [arm] Cc: Petr Mladek <pmladek@suse.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
119 lines
3.1 KiB
C
119 lines
3.1 KiB
C
/*
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* Copyright 2014 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/errno.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <linux/atomic.h>
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#include <asm/processor.h>
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#include <asm/pmc.h>
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perf_irq_t perf_irq = NULL;
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int handle_perf_interrupt(struct pt_regs *regs, int fault)
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{
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int retval;
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if (!perf_irq)
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panic("Unexpected PERF_COUNT interrupt %d\n", fault);
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retval = perf_irq(regs, fault);
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return retval;
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}
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/* Reserve PMC hardware if it is available. */
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perf_irq_t reserve_pmc_hardware(perf_irq_t new_perf_irq)
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{
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return cmpxchg(&perf_irq, NULL, new_perf_irq);
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}
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EXPORT_SYMBOL(reserve_pmc_hardware);
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/* Release PMC hardware. */
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void release_pmc_hardware(void)
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{
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perf_irq = NULL;
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}
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EXPORT_SYMBOL(release_pmc_hardware);
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/*
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* Get current overflow status of each performance counter,
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* and auxiliary performance counter.
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*/
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unsigned long
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pmc_get_overflow(void)
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{
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unsigned long status;
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/*
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* merge base+aux into a single vector
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*/
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status = __insn_mfspr(SPR_PERF_COUNT_STS);
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status |= __insn_mfspr(SPR_AUX_PERF_COUNT_STS) << TILE_BASE_COUNTERS;
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return status;
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}
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/*
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* Clear the status bit for the corresponding counter, if written
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* with a one.
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*/
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void
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pmc_ack_overflow(unsigned long status)
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{
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/*
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* clear overflow status by writing ones
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*/
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__insn_mtspr(SPR_PERF_COUNT_STS, status);
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__insn_mtspr(SPR_AUX_PERF_COUNT_STS, status >> TILE_BASE_COUNTERS);
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}
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/*
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* The perf count interrupts are masked and unmasked explicitly,
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* and only here. The normal irq_enable() does not enable them,
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* and irq_disable() does not disable them. That lets these
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* routines drive the perf count interrupts orthogonally.
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*
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* We also mask the perf count interrupts on entry to the perf count
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* interrupt handler in assembly code, and by default unmask them
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* again (with interrupt critical section protection) just before
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* returning from the interrupt. If the perf count handler returns
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* a non-zero error code, then we don't re-enable them before returning.
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*
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* For Pro, we rely on both interrupts being in the same word to update
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* them atomically so we never have one enabled and one disabled.
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*/
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#if CHIP_HAS_SPLIT_INTR_MASK()
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# if INT_PERF_COUNT < 32 || INT_AUX_PERF_COUNT < 32
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# error Fix assumptions about which word PERF_COUNT interrupts are in
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# endif
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#endif
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static inline unsigned long long pmc_mask(void)
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{
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unsigned long long mask = 1ULL << INT_PERF_COUNT;
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mask |= 1ULL << INT_AUX_PERF_COUNT;
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return mask;
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}
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void unmask_pmc_interrupts(void)
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{
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interrupt_mask_reset_mask(pmc_mask());
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}
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void mask_pmc_interrupts(void)
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{
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interrupt_mask_set_mask(pmc_mask());
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}
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