[PATCH v2 3/4] x86/traps: split code to dump execution state to a separate helper

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Split the code that triggers remote CPUs to dump stacks into a separate
function.  Also introduce a parameter that can be set by the caller of the
newly introduced function to force CPUs to dump the full stack, rather than
just dumping the current function name.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/include/asm/processor.h |  1 +
 xen/arch/x86/traps.c                 | 62 +++++++++++++++++-----------
 2 files changed, 39 insertions(+), 24 deletions(-)

diff --git a/xen/arch/x86/include/asm/processor.h 
b/xen/arch/x86/include/asm/processor.h
index eacd425c5350..10d8078cc1ca 100644
--- a/xen/arch/x86/include/asm/processor.h
+++ b/xen/arch/x86/include/asm/processor.h
@@ -371,6 +371,7 @@ void show_registers(const struct cpu_user_regs *regs);
 #define dump_execution_state() run_in_exception_handler(show_execution_state)
 void show_page_walk(unsigned long addr);
 void noreturn fatal_trap(const struct cpu_user_regs *regs, bool show_remote);
+void show_execution_state_nmi(const cpumask_t *mask, bool show_all);
 
 extern void mtrr_ap_init(void);
 extern void mtrr_bp_init(void);
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 22f20629327d..f6646d505644 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -714,13 +714,15 @@ static cpumask_t show_state_mask;
 static bool opt_show_all;
 boolean_param("async-show-all", opt_show_all);
 
+static bool force_show_all;
+
 static int cf_check nmi_show_execution_state(
     const struct cpu_user_regs *regs, int cpu)
 {
     if ( !cpumask_test_cpu(cpu, &show_state_mask) )
         return 0;
 
-    if ( opt_show_all )
+    if ( opt_show_all || force_show_all )
         show_execution_state(regs);
     else if ( guest_mode(regs) )
         printk(XENLOG_ERR "CPU%d\t%pv\t%04x:%p in guest\n",
@@ -734,6 +736,38 @@ static int cf_check nmi_show_execution_state(
     return 1;
 }
 
+void show_execution_state_nmi(const cpumask_t *mask, bool show_all)
+{
+    unsigned int msecs, pending;
+
+    force_show_all = show_all;
+
+    watchdog_disable();
+    console_start_sync();
+
+    cpumask_copy(&show_state_mask, mask);
+    set_nmi_callback(nmi_show_execution_state);
+    send_IPI_mask(mask, APIC_DM_NMI);
+
+    /* Wait at most 10ms for some other CPU to respond. */
+    msecs = 10;
+    pending = cpumask_weight(&show_state_mask);
+    while ( pending && msecs-- )
+    {
+        unsigned int left;
+
+        mdelay(1);
+        left = cpumask_weight(&show_state_mask);
+        if ( left < pending )
+        {
+            pending = left;
+            msecs = 10;
+        }
+    }
+    if ( pending )
+        printk("Non-responding CPUs: {%*pbl}\n", CPUMASK_PR(&show_state_mask));
+}
+
 const char *vector_name(unsigned int vec)
 {
     static const char names[][4] = {
@@ -780,31 +814,11 @@ void fatal_trap(const struct cpu_user_regs *regs, bool 
show_remote)
 
         if ( show_remote )
         {
-            unsigned int msecs, pending;
+            cpumask_t *scratch = this_cpu(scratch_cpumask);
 
-            cpumask_andnot(&show_state_mask, &cpu_online_map,
+            cpumask_andnot(scratch, &cpu_online_map,
                            cpumask_of(smp_processor_id()));
-            set_nmi_callback(nmi_show_execution_state);
-            smp_send_nmi_allbutself();
-
-            /* Wait at most 10ms for some other CPU to respond. */
-            msecs = 10;
-            pending = cpumask_weight(&show_state_mask);
-            while ( pending && msecs-- )
-            {
-                unsigned int left;
-
-                mdelay(1);
-                left = cpumask_weight(&show_state_mask);
-                if ( left < pending )
-                {
-                    pending = left;
-                    msecs = 10;
-                }
-            }
-            if ( pending )
-                printk("Non-responding CPUs: {%*pbl}\n",
-                       CPUMASK_PR(&show_state_mask));
+            show_execution_state_nmi(scratch, false);
         }
     }
 
-- 
2.49.0