bug: Add BUG_FORMAT_ARGS infrastructure

Add BUG_FORMAT_ARGS; when an architecture is able to provide a va_list
given pt_regs, use this to print format arguments.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251110115757.457339417@infradead.org

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 9ee622ae0c9a0fab0d88ee2ca5cc1fcc13334ef7..228873e13b95c48e986b1ea9dd16edcea76f5f93 100644 (file)
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -13,6 +13,7 @@
 #define BUGFLAG_ONCE           (1 << 1)
 #define BUGFLAG_DONE           (1 << 2)
 #define BUGFLAG_NO_CUT_HERE    (1 << 3)        /* CUT_HERE already sent */
+#define BUGFLAG_ARGS           (1 << 4)
 #define BUGFLAG_TAINT(taint)   ((taint) << 8)
 #define BUG_GET_TAINT(bug)     ((bug)->flags >> 8)
 #endif

diff --git a/lib/bug.c b/lib/bug.c
index 6e57199ed1f7fd325e47d7c0559f14200936433b..8100258a200487d719b3bdca8761c9d7debd9886 100644 (file)
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -163,11 +163,23 @@ struct bug_entry *find_bug(unsigned long bugaddr)
        return module_find_bug(bugaddr);
 }
 
-static void __warn_printf(const char *fmt)
+static void __warn_printf(const char *fmt, struct pt_regs *regs)
 {
        if (!fmt)
                return;
 
+#ifdef HAVE_ARCH_BUG_FORMAT_ARGS
+       if (regs) {
+               struct arch_va_list _args;
+               va_list *args = __warn_args(&_args, regs);
+
+               if (args) {
+                       vprintk(fmt, *args);
+                       return;
+               }
+       }
+#endif
+
        printk("%s", fmt);
 }
 
@@ -193,6 +205,7 @@ static enum bug_trap_type __report_bug(unsigned long bugaddr, struct pt_regs *re
        once     = bug->flags & BUGFLAG_ONCE;
        done     = bug->flags & BUGFLAG_DONE;
        no_cut   = bug->flags & BUGFLAG_NO_CUT_HERE;
+       has_args = bug->flags & BUGFLAG_ARGS;
 
        if (warning && once) {
                if (done)
@@ -212,7 +225,7 @@ static enum bug_trap_type __report_bug(unsigned long bugaddr, struct pt_regs *re
         */
        if (!no_cut) {
                printk(KERN_DEFAULT CUT_HERE);
-               __warn_printf(fmt);
+               __warn_printf(fmt, has_args ? regs : NULL);
        }
 
        if (warning) {