[xen staging] x86/traps: split code to dump execution state to a separate helper

[patchbot@xxxxxxx]

commit 3368f3d6923216065661af5bed89b54f1ba180c9
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Thu May 22 09:30:15 2025 +0200
Commit:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
CommitDate: Tue May 27 09:11:37 2025 +0200

    x86/traps: split code to dump execution state to a separate helper
    
    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>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/include/asm/processor.h |  1 +
 xen/arch/x86/traps.c                 | 63 +++++++++++++++++++++++-------------
 2 files changed, 41 insertions(+), 23 deletions(-)

diff --git a/xen/arch/x86/include/asm/processor.h 
b/xen/arch/x86/include/asm/processor.h
index 1820e04a32..96b9bf5f5e 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 22f2062932..559bb1d202 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -734,6 +734,43 @@ 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;
+
+    /*
+     * Overwrite the global variable, caller is expected to panic after having
+     * dumped the execution state.
+     */
+    if ( show_all )
+        opt_show_all = true;
+
+    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 +817,11 @@ 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);
         }
     }
 
--
generated by git-patchbot for /home/xen/git/xen.git#staging