2 files changed, 168 insertions, 15 deletions

diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 71c101601e3e..ab9682f8b044 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -11,7 +11,7 @@
  * Version Perfmon-2.x is a rewrite of perfmon-1.x
  * by Stephane Eranian, Hewlett Packard Co.
  *
- * Copyright (C) 1999-2003, 2005  Hewlett Packard Co
+ * Copyright (C) 1999-2005  Hewlett Packard Co
  *               Stephane Eranian <eranian@hpl.hp.com>
  *               David Mosberger-Tang <davidm@hpl.hp.com>
  *
@@ -497,6 +497,9 @@ typedef struct {
 static pfm_stats_t              pfm_stats[NR_CPUS];
 static pfm_session_t            pfm_sessions;   /* global sessions information */
 
+static spinlock_t pfm_alt_install_check;
+static pfm_intr_handler_desc_t  *pfm_alt_intr_handler;
+
 static struct proc_dir_entry    *perfmon_dir;
 static pfm_uuid_t               pfm_null_uuid = {0,};
 
@@ -606,6 +609,7 @@ DEFINE_PER_CPU(unsigned long, pfm_syst_info);
 DEFINE_PER_CPU(struct task_struct *, pmu_owner);
 DEFINE_PER_CPU(pfm_context_t  *, pmu_ctx);
 DEFINE_PER_CPU(unsigned long, pmu_activation_number);
+EXPORT_SYMBOL_GPL(per_cpu__pfm_syst_info);
 
 
 /* forward declaration */
@@ -1325,7 +1329,7 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
 error_conflict:
         DPRINT(("system wide not possible, conflicting session [%d] on CPU%d\n",
                 pfm_sessions.pfs_sys_session[cpu]->pid,
-                smp_processor_id()));
+                cpu));
 abort:
         UNLOCK_PFS(flags);
 
@@ -5555,26 +5559,32 @@ pfm_interrupt_handler(int irq, void *arg, struct pt_regs *regs)
         int ret;
 
         this_cpu = get_cpu();
-        min      = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min;
-        max      = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max;
+        if (likely(!pfm_alt_intr_handler)) {
+                min = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min;
+                max = pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max;
 
-        start_cycles = ia64_get_itc();
+                start_cycles = ia64_get_itc();
 
-        ret = pfm_do_interrupt_handler(irq, arg, regs);
+                ret = pfm_do_interrupt_handler(irq, arg, regs);
 
-        total_cycles = ia64_get_itc();
+                total_cycles = ia64_get_itc();
 
-        /*
-         * don't measure spurious interrupts
-         */
-        if (likely(ret == 0)) {
-                total_cycles -= start_cycles;
+                /*
+                 * don't measure spurious interrupts
+                 */
+                if (likely(ret == 0)) {
+                        total_cycles -= start_cycles;
 
-                if (total_cycles < min) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min = total_cycles;
-                if (total_cycles > max) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max = total_cycles;
+                        if (total_cycles < min) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_min = total_cycles;
+                        if (total_cycles > max) pfm_stats[this_cpu].pfm_ovfl_intr_cycles_max = total_cycles;
 
-                pfm_stats[this_cpu].pfm_ovfl_intr_cycles += total_cycles;
+                        pfm_stats[this_cpu].pfm_ovfl_intr_cycles += total_cycles;
+                }
+        }
+        else {
+                (*pfm_alt_intr_handler->handler)(irq, arg, regs);
         }
+
         put_cpu_no_resched();
         return IRQ_HANDLED;
 }
@@ -6425,6 +6435,141 @@ static struct irqaction perfmon_irqaction = {
         .name    = "perfmon"
 };
 
+static void
+pfm_alt_save_pmu_state(void *data)
+{
+        struct pt_regs *regs;
+
+        regs = ia64_task_regs(current);
+
+        DPRINT(("called\n"));
+
+        /*
+         * should not be necessary but
+         * let's take not risk
+         */
+        pfm_clear_psr_up();
+        pfm_clear_psr_pp();
+        ia64_psr(regs)->pp = 0;
+
+        /*
+         * This call is required
+         * May cause a spurious interrupt on some processors
+         */
+        pfm_freeze_pmu();
+
+        ia64_srlz_d();
+}
+
+void
+pfm_alt_restore_pmu_state(void *data)
+{
+        struct pt_regs *regs;
+
+        regs = ia64_task_regs(current);
+
+        DPRINT(("called\n"));
+
+        /*
+         * put PMU back in state expected
+         * by perfmon
+         */
+        pfm_clear_psr_up();
+        pfm_clear_psr_pp();
+        ia64_psr(regs)->pp = 0;
+
+        /*
+         * perfmon runs with PMU unfrozen at all times
+         */
+        pfm_unfreeze_pmu();
+
+        ia64_srlz_d();
+}
+
+int
+pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
+{
+        int ret, i;
+        int reserve_cpu;
+
+        /* some sanity checks */
+        if (hdl == NULL || hdl->handler == NULL) return -EINVAL;
+
+        /* do the easy test first */
+        if (pfm_alt_intr_handler) return -EBUSY;
+
+        /* one at a time in the install or remove, just fail the others */
+        if (!spin_trylock(&pfm_alt_install_check)) {
+                return -EBUSY;
+        }
+
+        /* reserve our session */
+        for_each_online_cpu(reserve_cpu) {
+                ret = pfm_reserve_session(NULL, 1, reserve_cpu);
+                if (ret) goto cleanup_reserve;
+        }
+
+        /* save the current system wide pmu states */
+        ret = on_each_cpu(pfm_alt_save_pmu_state, NULL, 0, 1);
+        if (ret) {
+                DPRINT(("on_each_cpu() failed: %d\n", ret));
+                goto cleanup_reserve;
+        }
+
+        /* officially change to the alternate interrupt handler */
+        pfm_alt_intr_handler = hdl;
+
+        spin_unlock(&pfm_alt_install_check);
+
+        return 0;
+
+cleanup_reserve:
+        for_each_online_cpu(i) {
+                /* don't unreserve more than we reserved */
+                if (i >= reserve_cpu) break;
+
+                pfm_unreserve_session(NULL, 1, i);
+        }
+
+        spin_unlock(&pfm_alt_install_check);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(pfm_install_alt_pmu_interrupt);
+
+int
+pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
+{
+        int i;
+        int ret;
+
+        if (hdl == NULL) return -EINVAL;
+
+        /* cannot remove someone else's handler! */
+        if (pfm_alt_intr_handler != hdl) return -EINVAL;
+
+        /* one at a time in the install or remove, just fail the others */
+        if (!spin_trylock(&pfm_alt_install_check)) {
+                return -EBUSY;
+        }
+
+        pfm_alt_intr_handler = NULL;
+
+        ret = on_each_cpu(pfm_alt_restore_pmu_state, NULL, 0, 1);
+        if (ret) {
+                DPRINT(("on_each_cpu() failed: %d\n", ret));
+        }
+
+        for_each_online_cpu(i) {
+                pfm_unreserve_session(NULL, 1, i);
+        }
+
+        spin_unlock(&pfm_alt_install_check);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(pfm_remove_alt_pmu_interrupt);
+
 /*
  * perfmon initialization routine, called from the initcall() table
  */
diff --git a/include/asm-ia64/perfmon.h b/include/asm-ia64/perfmon.h
index ed5416c5b1ac..7f3333dd00e4 100644
--- a/include/asm-ia64/perfmon.h
+++ b/include/asm-ia64/perfmon.h
@@ -177,6 +177,10 @@ typedef union {
 
 extern long perfmonctl(int fd, int cmd, void *arg, int narg);
 
+typedef struct {
+        void (*handler)(int irq, void *arg, struct pt_regs *regs);
+} pfm_intr_handler_desc_t;
+
 extern void pfm_save_regs (struct task_struct *);
 extern void pfm_load_regs (struct task_struct *);
 
@@ -187,6 +191,10 @@ extern void pfm_syst_wide_update_task(struct task_struct *, unsigned long info,
 extern void pfm_inherit(struct task_struct *task, struct pt_regs *regs);
 extern void pfm_init_percpu(void);
 extern void pfm_handle_work(void);
+extern int  pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t *h);
+extern int  pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *h);
+
+
 
 /*
  * Reset PMD register flags