hwpmc: consistently validate PMC class in allocation method

It is always a good idea. In one case, attempting to allocate N+1 PMCs
from a class with N hardware counters would incorrectly attempt to
allocate from the next class in the list. Without this validation, this
can lead to all kinds of strange behaviour.

Since powerpc_allocate_pmc() is used by both the mpc7xxx and ppc970
classes, add a new global to track which is active (it will never be
both).

Reviewed by:	luporl, ray
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D31387

(cherry picked from commit 315cd55dba61416495a847f0eed6e522421e2347)

7 files changed, 16 insertions, 0 deletions

diff --git a/sys/dev/hwpmc/hwpmc_core.c b/sys/dev/hwpmc/hwpmc_core.c
index 692d7fcd52d9..c9a040f44ffd 100644
--- a/sys/dev/hwpmc/hwpmc_core.c
+++ b/sys/dev/hwpmc/hwpmc_core.c
@@ -744,6 +744,9 @@ iap_allocate_pmc(int cpu, int ri, struct pmc *pm,
 	KASSERT(ri >= 0 && ri < core_iap_npmc,
 	    ("[core,%d] illegal row-index value %d", __LINE__, ri));
 
+	if (a->pm_class != PMC_CLASS_IAP)
+		return (EINVAL);
+
 	/* check requested capabilities */
 	caps = a->pm_caps;
 	if ((IAP_PMC_CAPS & caps) != caps)
diff --git a/sys/dev/hwpmc/hwpmc_e500.c b/sys/dev/hwpmc/hwpmc_e500.c
index 72c0868f08b5..b82bada95fe3 100644
--- a/sys/dev/hwpmc/hwpmc_e500.c
+++ b/sys/dev/hwpmc/hwpmc_e500.c
@@ -376,6 +376,9 @@ e500_allocate_pmc(int cpu, int ri, struct pmc *pm,
 	KASSERT(ri >= 0 && ri < E500_MAX_PMCS,
 	    ("[powerpc,%d] illegal row index %d", __LINE__, ri));
 
+	if (a->pm_class != PMC_CLASS_E500)
+		return (EINVAL);
+
 	caps = a->pm_caps;
 
 	pe = a->pm_ev;
diff --git a/sys/dev/hwpmc/hwpmc_mpc7xxx.c b/sys/dev/hwpmc/hwpmc_mpc7xxx.c
index 987480e89efd..c62c0791af01 100644
--- a/sys/dev/hwpmc/hwpmc_mpc7xxx.c
+++ b/sys/dev/hwpmc/hwpmc_mpc7xxx.c
@@ -471,6 +471,7 @@ pmc_mpc7xxx_initialize(struct pmc_mdep *pmc_mdep)
 	ppc_event_first = PMC_EV_PPC7450_FIRST;
 	ppc_event_last = PMC_EV_PPC7450_LAST;
 	ppc_max_pmcs = MPC7XXX_MAX_PMCS;
+	ppc_class = pcd->pcd_class;
 
 	powerpc_set_pmc = mpc7xxx_set_pmc;
 	powerpc_pmcn_read = mpc7xxx_pmcn_read;
diff --git a/sys/dev/hwpmc/hwpmc_powerpc.c b/sys/dev/hwpmc/hwpmc_powerpc.c
index 537e263d4c15..aa18d2659d7d 100644
--- a/sys/dev/hwpmc/hwpmc_powerpc.c
+++ b/sys/dev/hwpmc/hwpmc_powerpc.c
@@ -59,6 +59,7 @@ size_t ppc_event_codes_size;
 int ppc_event_first;
 int ppc_event_last;
 int ppc_max_pmcs;
+enum pmc_class ppc_class;
 
 void (*powerpc_set_pmc)(int cpu, int ri, int config);
 pmc_value_t (*powerpc_pmcn_read)(unsigned int pmc);
@@ -209,6 +210,9 @@ powerpc_allocate_pmc(int cpu, int ri, struct pmc *pm,
 	KASSERT(ri >= 0 && ri < ppc_max_pmcs,
 	    ("[powerpc,%d] illegal row index %d", __LINE__, ri));
 
+	if (a->pm_class != ppc_class)
+		return (EINVAL);
+
 	caps = a->pm_caps;
 
 	pe = a->pm_ev;
diff --git a/sys/dev/hwpmc/hwpmc_powerpc.h b/sys/dev/hwpmc/hwpmc_powerpc.h
index 551f59b60528..25b041327b84 100644
--- a/sys/dev/hwpmc/hwpmc_powerpc.h
+++ b/sys/dev/hwpmc/hwpmc_powerpc.h
@@ -82,6 +82,7 @@ extern size_t ppc_event_codes_size;
 extern int ppc_event_first;
 extern int ppc_event_last;
 extern int ppc_max_pmcs;
+extern enum pmc_class ppc_class;
 
 extern void (*powerpc_set_pmc)(int cpu, int ri, int config);
 extern pmc_value_t (*powerpc_pmcn_read)(unsigned int pmc);
diff --git a/sys/dev/hwpmc/hwpmc_ppc970.c b/sys/dev/hwpmc/hwpmc_ppc970.c
index 39dc4efb290a..3e92c4dc6aa2 100644
--- a/sys/dev/hwpmc/hwpmc_ppc970.c
+++ b/sys/dev/hwpmc/hwpmc_ppc970.c
@@ -380,6 +380,7 @@ pmc_ppc970_initialize(struct pmc_mdep *pmc_mdep)
 	ppc_event_first = PMC_EV_PPC970_FIRST;
 	ppc_event_last = PMC_EV_PPC970_LAST;
 	ppc_max_pmcs = PPC970_MAX_PMCS;
+	ppc_class = pcd->pcd_class;
 
 	powerpc_set_pmc = ppc970_set_pmc;
 	powerpc_pmcn_read = powerpc_pmcn_read_default;
diff --git a/sys/dev/hwpmc/hwpmc_uncore.c b/sys/dev/hwpmc/hwpmc_uncore.c
index f87b36616d18..85ef0f441b5c 100644
--- a/sys/dev/hwpmc/hwpmc_uncore.c
+++ b/sys/dev/hwpmc/hwpmc_uncore.c
@@ -526,6 +526,9 @@ ucp_allocate_pmc(int cpu, int ri, struct pmc *pm,
 	KASSERT(ri >= 0 && ri < uncore_ucp_npmc,
 	    ("[uncore,%d] illegal row-index value %d", __LINE__, ri));
 
+	if (a->pm_class != PMC_CLASS_UCP)
+		return (EINVAL);
+
 	/* check requested capabilities */
 	caps = a->pm_caps;
 	if ((UCP_PMC_CAPS & caps) != caps)