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Subject[PATCH 5.10 250/563] powerpc/perf: MMCR0 control for PMU registers under PMCC=00
Date
From: Athira Rajeev <atrajeev@linux.vnet.ibm.com>

[ Upstream commit 91668ab7db4bcfae332e561df1de2401f3f18553 ]

PowerISA v3.1 introduces new control bit (PMCCEXT) for restricting
access to group B PMU registers in problem state when
MMCR0 PMCC=0b00. In problem state and when MMCR0 PMCC=0b00,
setting the Monitor Mode Control Register bit 54 (MMCR0 PMCCEXT),
will restrict read permission on Group B Performance Monitor
Registers (SIER, SIAR, SDAR and MMCR1). When this bit is set to zero,
group B registers will be readable. In other platforms (like power9),
the older behaviour is retained where group B PMU SPRs are readable.

Patch adds support for MMCR0 PMCCEXT bit in power10 by enabling
this bit during boot and during the PMU event enable/disable callback
functions.

Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1606409684-1589-8-git-send-email-atrajeev@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/include/asm/reg.h | 1 +
arch/powerpc/kernel/cpu_setup_power.c | 1 +
arch/powerpc/kernel/dt_cpu_ftrs.c | 1 +
arch/powerpc/perf/core-book3s.c | 4 ++++
arch/powerpc/perf/isa207-common.c | 8 ++++++++
5 files changed, 15 insertions(+)

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index f4b98903064f5..6afb14b6bbc26 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -865,6 +865,7 @@
#define MMCR0_BHRBA 0x00200000UL /* BHRB Access allowed in userspace */
#define MMCR0_EBE 0x00100000UL /* Event based branch enable */
#define MMCR0_PMCC 0x000c0000UL /* PMC control */
+#define MMCR0_PMCCEXT ASM_CONST(0x00000200) /* PMCCEXT control */
#define MMCR0_PMCC_U6 0x00080000UL /* PMC1-6 are R/W by user (PR) */
#define MMCR0_PMC1CE 0x00008000UL /* PMC1 count enable*/
#define MMCR0_PMCjCE ASM_CONST(0x00004000) /* PMCj count enable*/
diff --git a/arch/powerpc/kernel/cpu_setup_power.c b/arch/powerpc/kernel/cpu_setup_power.c
index 0c2191ee139ec..3cca88ee96d71 100644
--- a/arch/powerpc/kernel/cpu_setup_power.c
+++ b/arch/powerpc/kernel/cpu_setup_power.c
@@ -123,6 +123,7 @@ static void init_PMU_ISA31(void)
{
mtspr(SPRN_MMCR3, 0);
mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
+ mtspr(SPRN_MMCR0, MMCR0_PMCCEXT);
}

/*
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 1098863e17ee8..9d079659b24d3 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -454,6 +454,7 @@ static void init_pmu_power10(void)

mtspr(SPRN_MMCR3, 0);
mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
+ mtspr(SPRN_MMCR0, MMCR0_PMCCEXT);
}

static int __init feat_enable_pmu_power10(struct dt_cpu_feature *f)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 91452313489f1..7bda7499d0401 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -95,6 +95,7 @@ static unsigned int freeze_events_kernel = MMCR0_FCS;
#define SPRN_SIER3 0
#define MMCRA_SAMPLE_ENABLE 0
#define MMCRA_BHRB_DISABLE 0
+#define MMCR0_PMCCEXT 0

static inline unsigned long perf_ip_adjust(struct pt_regs *regs)
{
@@ -1245,6 +1246,9 @@ static void power_pmu_disable(struct pmu *pmu)
val |= MMCR0_FC;
val &= ~(MMCR0_EBE | MMCR0_BHRBA | MMCR0_PMCC | MMCR0_PMAO |
MMCR0_FC56);
+ /* Set mmcr0 PMCCEXT for p10 */
+ if (ppmu->flags & PPMU_ARCH_31)
+ val |= MMCR0_PMCCEXT;

/*
* The barrier is to make sure the mtspr has been
diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index 5e8eedda45d39..58448f0e47213 100644
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c
@@ -561,6 +561,14 @@ int isa207_compute_mmcr(u64 event[], int n_ev,
if (!(pmc_inuse & 0x60))
mmcr->mmcr0 |= MMCR0_FC56;

+ /*
+ * Set mmcr0 (PMCCEXT) for p10 which
+ * will restrict access to group B registers
+ * when MMCR0 PMCC=0b00.
+ */
+ if (cpu_has_feature(CPU_FTR_ARCH_31))
+ mmcr->mmcr0 |= MMCR0_PMCCEXT;
+
mmcr->mmcr1 = mmcr1;
mmcr->mmcra = mmcra;
mmcr->mmcr2 = mmcr2;
--
2.34.1


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