4 files changed, 84 insertions, 12 deletions

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 223edbb8fe84..cc3ba53242b6 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -142,6 +142,14 @@ config CPU_HAS_PREFETCH
 	bool
 	default y
 
+config GENERIC_BUG
+	def_bool y
+	depends on BUG
+
+config GENERIC_BUG_RELATIVE_POINTERS
+	def_bool y
+	depends on GENERIC_BUG
+
 config GENERIC_CALIBRATE_DELAY
 	def_bool y
 
diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
index bda49108a76d..d4ca3ba25418 100644
--- a/arch/loongarch/include/asm/bug.h
+++ b/arch/loongarch/include/asm/bug.h
@@ -2,21 +2,59 @@
 #ifndef __ASM_BUG_H
 #define __ASM_BUG_H
 
-#include <linux/compiler.h>
+#include <asm/break.h>
+#include <linux/stringify.h>
+
+#ifndef CONFIG_DEBUG_BUGVERBOSE
+#define _BUGVERBOSE_LOCATION(file, line)
+#else
+#define __BUGVERBOSE_LOCATION(file, line)			\
+		.pushsection .rodata.str, "aMS", @progbits, 1;	\
+	10002:	.string file;					\
+		.popsection;					\
+								\
+		.long 10002b - .;				\
+		.short line;
+#define _BUGVERBOSE_LOCATION(file, line) __BUGVERBOSE_LOCATION(file, line)
+#endif
 
-#ifdef CONFIG_BUG
+#ifndef CONFIG_GENERIC_BUG
+#define __BUG_ENTRY(flags)
+#else
+#define __BUG_ENTRY(flags) 					\
+		.pushsection __bug_table, "aw";			\
+		.align 2;					\
+	10000:	.long 10001f - .;				\
+		_BUGVERBOSE_LOCATION(__FILE__, __LINE__)	\
+		.short flags; 					\
+		.popsection;					\
+	10001:
+#endif
 
-#include <asm/break.h>
+#define ASM_BUG_FLAGS(flags)					\
+	__BUG_ENTRY(flags)					\
+	break		BRK_BUG
 
-static inline void __noreturn BUG(void)
-{
-	__asm__ __volatile__("break %0" : : "i" (BRK_BUG));
-	unreachable();
-}
+#define ASM_BUG()	ASM_BUG_FLAGS(0)
 
-#define HAVE_ARCH_BUG
+#define __BUG_FLAGS(flags)					\
+	asm_inline volatile (__stringify(ASM_BUG_FLAGS(flags)));
 
-#endif
+#define __WARN_FLAGS(flags)					\
+do {								\
+	instrumentation_begin();				\
+	__BUG_FLAGS(BUGFLAG_WARNING|(flags));			\
+	instrumentation_end();					\
+} while (0)
+
+#define BUG()							\
+do {								\
+	instrumentation_begin();				\
+	__BUG_FLAGS(0);						\
+	unreachable();						\
+} while (0)
+
+#define HAVE_ARCH_BUG
 
 #include <asm-generic/bug.h>
 
diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S
index 0c67c24ce087..d32128f1d3c4 100644
--- a/arch/loongarch/kernel/head.S
+++ b/arch/loongarch/kernel/head.S
@@ -8,6 +8,7 @@
 #include <asm/addrspace.h>
 #include <asm/asm.h>
 #include <asm/asmmacro.h>
+#include <asm/bug.h>
 #include <asm/regdef.h>
 #include <asm/loongarch.h>
 #include <asm/stackframe.h>
@@ -85,6 +86,7 @@ SYM_CODE_START(kernel_entry)			# kernel entry point
 	PTR_ADDI	sp, sp, -4 * SZREG	# init stack pointer
 
 	bl		start_kernel
+	ASM_BUG()
 
 SYM_CODE_END(kernel_entry)
 
@@ -116,6 +118,8 @@ SYM_CODE_START(smpboot_entry)
 	ld.d		tp, t0, CPU_BOOT_TINFO
 
 	bl		start_secondary
+	ASM_BUG()
+
 SYM_CODE_END(smpboot_entry)
 
 #endif /* CONFIG_SMP */
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index a5e8bd5d7948..66c2849b26e5 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -374,6 +374,29 @@ asmlinkage void noinstr do_ale(struct pt_regs *regs)
 	irqentry_exit(regs, state);
 }
 
+#ifdef CONFIG_GENERIC_BUG
+int is_valid_bugaddr(unsigned long addr)
+{
+	return 1;
+}
+#endif /* CONFIG_GENERIC_BUG */
+
+static void bug_handler(struct pt_regs *regs)
+{
+	switch (report_bug(regs->csr_era, regs)) {
+	case BUG_TRAP_TYPE_BUG:
+	case BUG_TRAP_TYPE_NONE:
+		die_if_kernel("Oops - BUG", regs);
+		force_sig(SIGTRAP);
+		break;
+
+	case BUG_TRAP_TYPE_WARN:
+		/* Skip the BUG instruction and continue */
+		regs->csr_era += LOONGARCH_INSN_SIZE;
+		break;
+	}
+}
+
 asmlinkage void noinstr do_bp(struct pt_regs *regs)
 {
 	bool user = user_mode(regs);
@@ -427,8 +450,7 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
 
 	switch (bcode) {
 	case BRK_BUG:
-		die_if_kernel("Kernel bug detected", regs);
-		force_sig(SIGTRAP);
+		bug_handler(regs);
 		break;
 	case BRK_DIVZERO:
 		die_if_kernel("Break instruction in kernel code", regs);