hwpmc: simplify calling convention for hwpmc interrupt handling

pmc_process_interrupt takes 5 arguments when only 3 are needed.
cpu is always available in curcpu and inuserspace can always be
derived from the passed trapframe.

While facially a reasonable cleanup this change was motivated
by the need to workaround a compiler bug.

core2_intr(cpu, tf) ->
  pmc_process_interrupt(cpu, ring, pmc, tf, inuserspace) ->
    pmc_add_sample(cpu, ring, pm, tf, inuserspace)

In the process of optimizing the tail call the tf pointer was getting
clobbered:

(kgdb) up
    at /storage/mmacy/devel/freebsd/sys/dev/hwpmc/hwpmc_mod.c:4709
4709                                pmc_save_kernel_callchain(ps->ps_pc,
(kgdb) up
1205                    error = pmc_process_interrupt(cpu, PMC_HR, pm, tf,

resulting in a crash in pmc_save_kernel_callchain.

1 files changed, 4 insertions, 4 deletions

diff --git a/sys/dev/hwpmc/hwpmc_arm64.c b/sys/dev/hwpmc/hwpmc_arm64.c
index 2e54e3870ba2..6fa319f99e82 100644
--- a/sys/dev/hwpmc/hwpmc_arm64.c
+++ b/sys/dev/hwpmc/hwpmc_arm64.c
@@ -323,18 +323,19 @@ arm64_release_pmc(int cpu, int ri, struct pmc *pmc)
 }
 
 static int
-arm64_intr(int cpu, struct trapframe *tf)
+arm64_intr(struct trapframe *tf)
 {
 	struct arm64_cpu *pc;
 	int retval, ri;
 	struct pmc *pm;
 	int error;
-	int reg;
+	int reg, cpu;
 
 	KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 	    ("[arm64,%d] CPU %d out of range", __LINE__, cpu));
 
 	retval = 0;
+	cpu = curcpu;
 	pc = arm64_pcpu[cpu];
 
 	for (ri = 0; ri < arm64_npmcs; ri++) {
@@ -357,8 +358,7 @@ arm64_intr(int cpu, struct trapframe *tf)
 		if (pm->pm_state != PMC_STATE_RUNNING)
 			continue;
 
-		error = pmc_process_interrupt(cpu, PMC_HR, pm, tf,
-		    TRAPF_USERMODE(tf));
+		error = pmc_process_interrupt(PMC_HR, pm, tf);
 		if (error)
 			arm64_stop_pmc(cpu, ri);