OpenCloudOS-Kernel/arch/powerpc/include/asm/pmc.h

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* pmc.h
* Copyright (C) 2004 David Gibson, IBM Corporation
*/
#ifndef _POWERPC_PMC_H
#define _POWERPC_PMC_H
#ifdef __KERNEL__
#include <asm/ptrace.h>
typedef void (*perf_irq_t)(struct pt_regs *);
extern perf_irq_t perf_irq;
int reserve_pmc_hardware(perf_irq_t new_perf_irq);
void release_pmc_hardware(void);
powerpc: Fix bug where perf_counters breaks oprofile Currently there is a bug where if you use oprofile on a pSeries machine, then use perf_counters, then use oprofile again, oprofile will not work correctly; it will lose the PMU configuration the next time the hypervisor does a partition context switch, and thereafter won't count anything. Maynard Johnson identified the sequence causing the problem: - oprofile setup calls ppc_enable_pmcs(), which calls pseries_lpar_enable_pmcs, which tells the hypervisor that we want to use the PMU, and sets the "PMU in use" flag in the lppaca. This flag tells the hypervisor whether it needs to save and restore the PMU config. - The perf_counter code sets and clears the "PMU in use" flag directly as it context-switches the PMU between tasks, and leaves it clear when it finishes. - oprofile setup, called for a new oprofile run, calls ppc_enable_pmcs, which does nothing because it has already been called. In particular it doesn't set the "PMU in use" flag. This fixes the problem by arranging for ppc_enable_pmcs to always set the "PMU in use" flag. It makes the perf_counter code call ppc_enable_pmcs also rather than calling the lower-level function directly, and removes the setting of the "PMU in use" flag from pseries_lpar_enable_pmcs, since that is now done in its caller. This also removes the declaration of pasemi_enable_pmcs because it isn't defined anywhere. Reported-by: Maynard Johnson <mpjohn@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: <stable@kernel.org) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-09-09 09:26:03 +08:00
void ppc_enable_pmcs(void);
#ifdef CONFIG_PPC_BOOK3S_64
powerpc: Fix bug where perf_counters breaks oprofile Currently there is a bug where if you use oprofile on a pSeries machine, then use perf_counters, then use oprofile again, oprofile will not work correctly; it will lose the PMU configuration the next time the hypervisor does a partition context switch, and thereafter won't count anything. Maynard Johnson identified the sequence causing the problem: - oprofile setup calls ppc_enable_pmcs(), which calls pseries_lpar_enable_pmcs, which tells the hypervisor that we want to use the PMU, and sets the "PMU in use" flag in the lppaca. This flag tells the hypervisor whether it needs to save and restore the PMU config. - The perf_counter code sets and clears the "PMU in use" flag directly as it context-switches the PMU between tasks, and leaves it clear when it finishes. - oprofile setup, called for a new oprofile run, calls ppc_enable_pmcs, which does nothing because it has already been called. In particular it doesn't set the "PMU in use" flag. This fixes the problem by arranging for ppc_enable_pmcs to always set the "PMU in use" flag. It makes the perf_counter code call ppc_enable_pmcs also rather than calling the lower-level function directly, and removes the setting of the "PMU in use" flag from pseries_lpar_enable_pmcs, since that is now done in its caller. This also removes the declaration of pasemi_enable_pmcs because it isn't defined anywhere. Reported-by: Maynard Johnson <mpjohn@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: <stable@kernel.org) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-09-09 09:26:03 +08:00
#include <asm/lppaca.h>
#include <asm/firmware.h>
powerpc: Fix bug where perf_counters breaks oprofile Currently there is a bug where if you use oprofile on a pSeries machine, then use perf_counters, then use oprofile again, oprofile will not work correctly; it will lose the PMU configuration the next time the hypervisor does a partition context switch, and thereafter won't count anything. Maynard Johnson identified the sequence causing the problem: - oprofile setup calls ppc_enable_pmcs(), which calls pseries_lpar_enable_pmcs, which tells the hypervisor that we want to use the PMU, and sets the "PMU in use" flag in the lppaca. This flag tells the hypervisor whether it needs to save and restore the PMU config. - The perf_counter code sets and clears the "PMU in use" flag directly as it context-switches the PMU between tasks, and leaves it clear when it finishes. - oprofile setup, called for a new oprofile run, calls ppc_enable_pmcs, which does nothing because it has already been called. In particular it doesn't set the "PMU in use" flag. This fixes the problem by arranging for ppc_enable_pmcs to always set the "PMU in use" flag. It makes the perf_counter code call ppc_enable_pmcs also rather than calling the lower-level function directly, and removes the setting of the "PMU in use" flag from pseries_lpar_enable_pmcs, since that is now done in its caller. This also removes the declaration of pasemi_enable_pmcs because it isn't defined anywhere. Reported-by: Maynard Johnson <mpjohn@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: <stable@kernel.org) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-09-09 09:26:03 +08:00
static inline void ppc_set_pmu_inuse(int inuse)
{
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)
if (firmware_has_feature(FW_FEATURE_LPAR)) {
#ifdef CONFIG_PPC_PSERIES
get_lppaca()->pmcregs_in_use = inuse;
#endif
powerpc/pmu: Set pmcregs_in_use in paca when running as LPAR The ability to run nested guests under KVM means that a guest can also act as a hypervisor for it's own nested guest. Currently ppc_set_pmu_inuse() assumes that either FW_FEATURE_LPAR is set, indicating a guest environment, and so sets the pmcregs_in_use flag in the lppaca, or that it isn't set, indicating a hypervisor environment, and so sets the pmcregs_in_use flag in the paca. The pmcregs_in_use flag in the lppaca is used to communicate this information to a hypervisor and so must be set in a guest environment. The pmcregs_in_use flag in the paca is used by KVM code to determine whether the host state of the performance monitoring unit (PMU) must be saved and restored when running a guest. Thus when a guest also acts as a hypervisor it must set this bit in both places since it needs to ensure both that the real hypervisor saves it's PMU registers when it runs (requires pmcregs_in_use flag in lppaca), and that it saves it's own PMU registers when running a nested guest (requires pmcregs_in_use flag in paca). Modify ppc_set_pmu_inuse() so that the pmcregs_in_use bit is set in both the lppaca and the paca when a guest (LPAR) is running with the capability of running it's own guests (CONFIG_KVM_BOOK3S_HV_POSSIBLE). Fixes: 95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190703012022.15644-2-sjitindarsingh@gmail.com
2019-07-03 09:20:21 +08:00
}
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
powerpc/pmu: Set pmcregs_in_use in paca when running as LPAR The ability to run nested guests under KVM means that a guest can also act as a hypervisor for it's own nested guest. Currently ppc_set_pmu_inuse() assumes that either FW_FEATURE_LPAR is set, indicating a guest environment, and so sets the pmcregs_in_use flag in the lppaca, or that it isn't set, indicating a hypervisor environment, and so sets the pmcregs_in_use flag in the paca. The pmcregs_in_use flag in the lppaca is used to communicate this information to a hypervisor and so must be set in a guest environment. The pmcregs_in_use flag in the paca is used by KVM code to determine whether the host state of the performance monitoring unit (PMU) must be saved and restored when running a guest. Thus when a guest also acts as a hypervisor it must set this bit in both places since it needs to ensure both that the real hypervisor saves it's PMU registers when it runs (requires pmcregs_in_use flag in lppaca), and that it saves it's own PMU registers when running a nested guest (requires pmcregs_in_use flag in paca). Modify ppc_set_pmu_inuse() so that the pmcregs_in_use bit is set in both the lppaca and the paca when a guest (LPAR) is running with the capability of running it's own guests (CONFIG_KVM_BOOK3S_HV_POSSIBLE). Fixes: 95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190703012022.15644-2-sjitindarsingh@gmail.com
2019-07-03 09:20:21 +08:00
get_paca()->pmcregs_in_use = inuse;
#endif
#endif
powerpc: Fix bug where perf_counters breaks oprofile Currently there is a bug where if you use oprofile on a pSeries machine, then use perf_counters, then use oprofile again, oprofile will not work correctly; it will lose the PMU configuration the next time the hypervisor does a partition context switch, and thereafter won't count anything. Maynard Johnson identified the sequence causing the problem: - oprofile setup calls ppc_enable_pmcs(), which calls pseries_lpar_enable_pmcs, which tells the hypervisor that we want to use the PMU, and sets the "PMU in use" flag in the lppaca. This flag tells the hypervisor whether it needs to save and restore the PMU config. - The perf_counter code sets and clears the "PMU in use" flag directly as it context-switches the PMU between tasks, and leaves it clear when it finishes. - oprofile setup, called for a new oprofile run, calls ppc_enable_pmcs, which does nothing because it has already been called. In particular it doesn't set the "PMU in use" flag. This fixes the problem by arranging for ppc_enable_pmcs to always set the "PMU in use" flag. It makes the perf_counter code call ppc_enable_pmcs also rather than calling the lower-level function directly, and removes the setting of the "PMU in use" flag from pseries_lpar_enable_pmcs, since that is now done in its caller. This also removes the declaration of pasemi_enable_pmcs because it isn't defined anywhere. Reported-by: Maynard Johnson <mpjohn@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: <stable@kernel.org) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-09-09 09:26:03 +08:00
}
extern void power4_enable_pmcs(void);
#else /* CONFIG_PPC64 */
static inline void ppc_set_pmu_inuse(int inuse) { }
#endif
#endif /* __KERNEL__ */
#endif /* _POWERPC_PMC_H */