diff --git a/Documentation/features/debug/kgdb/arch-support.txt b/Documentation/features/debug/kgdb/arch-support.txt
index 958498f9f2a41f2b6c56f2bd3ead11d88b5ef5ae..5e91ec78c80b759cd3af62c696817e7a607e8b93 100644
--- a/Documentation/features/debug/kgdb/arch-support.txt
+++ b/Documentation/features/debug/kgdb/arch-support.txt
@@ -13,7 +13,7 @@
| csky: | TODO |
| hexagon: | ok |
| ia64: | TODO |
- | loongarch: | TODO |
+ | loongarch: | ok |
| m68k: | TODO |
| microblaze: | ok |
| mips: | ok |
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 21cc2e2d1f27db4650df7659b6b0e6679e99f781..b02e399b1cd72b82ab113a57db40ce9ab3882bf4 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -91,6 +91,7 @@ config LOONGARCH
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
+ select HAVE_ARCH_KGDB if PERF_EVENTS
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
diff --git a/arch/loongarch/include/asm/kgdb.h b/arch/loongarch/include/asm/kgdb.h
new file mode 100644
index 0000000000000000000000000000000000000000..2041ae58b161576d8d9bf5e715f8331b8c93c243
--- /dev/null
+++ b/arch/loongarch/include/asm/kgdb.h
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Loongson Technology Corporation Limited
+ */
+
+#ifndef _ASM_LOONGARCH_KGDB_H
+#define _ASM_LOONGARCH_KGDB_H
+
+#define GDB_SIZEOF_REG sizeof(u64)
+
+/* gdb remote procotol expects the following register layout. */
+
+/*
+ * General purpose registers:
+ * r0-r31: 64 bit
+ * orig_a0: 64 bit
+ * pc : 64 bit
+ * csr_badvaddr: 64 bit
+ */
+#define DBG_PT_REGS_BASE 0
+#define DBG_PT_REGS_NUM 35
+#define DBG_PT_REGS_END (DBG_PT_REGS_BASE + DBG_PT_REGS_NUM - 1)
+
+/*
+ * Floating point registers:
+ * f0-f31: 64 bit
+ */
+#define DBG_FPR_BASE (DBG_PT_REGS_END + 1)
+#define DBG_FPR_NUM 32
+#define DBG_FPR_END (DBG_FPR_BASE + DBG_FPR_NUM - 1)
+
+/*
+ * Condition Flag registers:
+ * fcc0-fcc8: 8 bit
+ */
+#define DBG_FCC_BASE (DBG_FPR_END + 1)
+#define DBG_FCC_NUM 8
+#define DBG_FCC_END (DBG_FCC_BASE + DBG_FCC_NUM - 1)
+
+/*
+ * Floating-point Control and Status registers:
+ * fcsr: 32 bit
+ */
+#define DBG_FCSR_NUM 1
+#define DBG_FCSR (DBG_FCC_END + 1)
+
+#define DBG_MAX_REG_NUM (DBG_FCSR + 1)
+
+/*
+ * Size of I/O buffer for gdb packet.
+ * considering to hold all register contents, size is set
+ */
+#define BUFMAX 2048
+
+/*
+ * Number of bytes required for gdb_regs buffer.
+ * PT_REGS and FPR: 8 bytes; FCSR: 4 bytes; FCC: 1 bytes.
+ * GDB fails to connect for size beyond this with error
+ * "'g' packet reply is too long"
+ */
+#define NUMREGBYTES ((DBG_PT_REGS_NUM + DBG_FPR_NUM) * GDB_SIZEOF_REG + DBG_FCC_NUM * 1 + DBG_FCSR_NUM * 4)
+
+#define BREAK_INSTR_SIZE 4
+#define CACHE_FLUSH_IS_SAFE 0
+
+/* Register numbers of various important registers. */
+enum dbg_loongarch_regnum {
+ DBG_LOONGARCH_ZERO = 0,
+ DBG_LOONGARCH_RA,
+ DBG_LOONGARCH_TP,
+ DBG_LOONGARCH_SP,
+ DBG_LOONGARCH_A0,
+ DBG_LOONGARCH_FP = 22,
+ DBG_LOONGARCH_S0,
+ DBG_LOONGARCH_S1,
+ DBG_LOONGARCH_S2,
+ DBG_LOONGARCH_S3,
+ DBG_LOONGARCH_S4,
+ DBG_LOONGARCH_S5,
+ DBG_LOONGARCH_S6,
+ DBG_LOONGARCH_S7,
+ DBG_LOONGARCH_S8,
+ DBG_LOONGARCH_ORIG_A0,
+ DBG_LOONGARCH_PC,
+ DBG_LOONGARCH_BADV
+};
+
+void kgdb_breakinst(void);
+void arch_kgdb_breakpoint(void);
+
+#ifdef CONFIG_KGDB
+bool kgdb_breakpoint_handler(struct pt_regs *regs);
+#else /* !CONFIG_KGDB */
+static inline bool kgdb_breakpoint_handler(struct pt_regs *regs) { return false; }
+#endif /* CONFIG_KGDB */
+
+#endif /* __ASM_KGDB_H_ */
diff --git a/arch/loongarch/include/asm/stackframe.h b/arch/loongarch/include/asm/stackframe.h
index 7df80e6ae9d2c8d76af305b7478bd52776ed380a..4fb1e6408b982aec130c75413e04bb6d2fb6c52c 100644
--- a/arch/loongarch/include/asm/stackframe.h
+++ b/arch/loongarch/include/asm/stackframe.h
@@ -158,6 +158,10 @@
cfi_st u0, PT_R21, \docfi
csrrd u0, PERCPU_BASE_KS
9:
+#ifdef CONFIG_KGDB
+ li.w t0, CSR_CRMD_WE
+ csrxchg t0, t0, LOONGARCH_CSR_CRMD
+#endif
.endm
.macro SAVE_ALL docfi=0
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 5341dcf15a171f04d601d7c6967a6d457dfad200..c0b88528cb81c4bc25cdb3ce04ddc17356b010b0 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
+obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_RETHOOK) += rethook.o rethook_trampoline.o
obj-$(CONFIG_UPROBES) += uprobes.o
diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S
index d737e3cf42d3fd8ca882e08113d58d2887db32c1..65518bb8f47285e406b95f8ba4c63a29e2c23a4a 100644
--- a/arch/loongarch/kernel/entry.S
+++ b/arch/loongarch/kernel/entry.S
@@ -58,6 +58,11 @@ SYM_FUNC_START(handle_syscall)
SAVE_STATIC
+#ifdef CONFIG_KGDB
+ li.w t1, CSR_CRMD_WE
+ csrxchg t1, t1, LOONGARCH_CSR_CRMD
+#endif
+
move u0, t0
li.d tp, ~_THREAD_MASK
and tp, tp, sp
diff --git a/arch/loongarch/kernel/kgdb.c b/arch/loongarch/kernel/kgdb.c
new file mode 100644
index 0000000000000000000000000000000000000000..445c452d72a79cac7f2527319301b7f430258c09
--- /dev/null
+++ b/arch/loongarch/kernel/kgdb.c
@@ -0,0 +1,727 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LoongArch KGDB support
+ *
+ * Copyright (C) 2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/hw_breakpoint.h>
+#include <linux/kdebug.h>
+#include <linux/kgdb.h>
+#include <linux/processor.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+
+#include <asm/cacheflush.h>
+#include <asm/fpu.h>
+#include <asm/hw_breakpoint.h>
+#include <asm/inst.h>
+#include <asm/irq_regs.h>
+#include <asm/ptrace.h>
+#include <asm/sigcontext.h>
+
+int kgdb_watch_activated;
+static unsigned int stepped_opcode;
+static unsigned long stepped_address;
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
+ { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) },
+ { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) },
+ { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) },
+ { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) },
+ { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) },
+ { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) },
+ { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) },
+ { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) },
+ { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) },
+ { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) },
+ { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) },
+ { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) },
+ { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) },
+ { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) },
+ { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) },
+ { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) },
+ { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) },
+ { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) },
+ { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) },
+ { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) },
+ { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) },
+ { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) },
+ { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) },
+ { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) },
+ { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) },
+ { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) },
+ { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) },
+ { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) },
+ { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) },
+ { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) },
+ { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) },
+ { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) },
+ { "orig_a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, orig_a0) },
+ { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, csr_era) },
+ { "badv", GDB_SIZEOF_REG, offsetof(struct pt_regs, csr_badvaddr) },
+ { "f0", GDB_SIZEOF_REG, 0 },
+ { "f1", GDB_SIZEOF_REG, 1 },
+ { "f2", GDB_SIZEOF_REG, 2 },
+ { "f3", GDB_SIZEOF_REG, 3 },
+ { "f4", GDB_SIZEOF_REG, 4 },
+ { "f5", GDB_SIZEOF_REG, 5 },
+ { "f6", GDB_SIZEOF_REG, 6 },
+ { "f7", GDB_SIZEOF_REG, 7 },
+ { "f8", GDB_SIZEOF_REG, 8 },
+ { "f9", GDB_SIZEOF_REG, 9 },
+ { "f10", GDB_SIZEOF_REG, 10 },
+ { "f11", GDB_SIZEOF_REG, 11 },
+ { "f12", GDB_SIZEOF_REG, 12 },
+ { "f13", GDB_SIZEOF_REG, 13 },
+ { "f14", GDB_SIZEOF_REG, 14 },
+ { "f15", GDB_SIZEOF_REG, 15 },
+ { "f16", GDB_SIZEOF_REG, 16 },
+ { "f17", GDB_SIZEOF_REG, 17 },
+ { "f18", GDB_SIZEOF_REG, 18 },
+ { "f19", GDB_SIZEOF_REG, 19 },
+ { "f20", GDB_SIZEOF_REG, 20 },
+ { "f21", GDB_SIZEOF_REG, 21 },
+ { "f22", GDB_SIZEOF_REG, 22 },
+ { "f23", GDB_SIZEOF_REG, 23 },
+ { "f24", GDB_SIZEOF_REG, 24 },
+ { "f25", GDB_SIZEOF_REG, 25 },
+ { "f26", GDB_SIZEOF_REG, 26 },
+ { "f27", GDB_SIZEOF_REG, 27 },
+ { "f28", GDB_SIZEOF_REG, 28 },
+ { "f29", GDB_SIZEOF_REG, 29 },
+ { "f30", GDB_SIZEOF_REG, 30 },
+ { "f31", GDB_SIZEOF_REG, 31 },
+ { "fcc0", 1, 0 },
+ { "fcc1", 1, 1 },
+ { "fcc2", 1, 2 },
+ { "fcc3", 1, 3 },
+ { "fcc4", 1, 4 },
+ { "fcc5", 1, 5 },
+ { "fcc6", 1, 6 },
+ { "fcc7", 1, 7 },
+ { "fcsr", 4, 0 },
+};
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ int reg_offset, reg_size;
+
+ if (regno < 0 || regno >= DBG_MAX_REG_NUM)
+ return NULL;
+
+ reg_offset = dbg_reg_def[regno].offset;
+ reg_size = dbg_reg_def[regno].size;
+
+ if (reg_offset == -1)
+ goto out;
+
+ /* Handle general-purpose/orig_a0/pc/badv registers */
+ if (regno <= DBG_PT_REGS_END) {
+ memcpy(mem, (void *)regs + reg_offset, reg_size);
+ goto out;
+ }
+
+ if (!(regs->csr_euen & CSR_EUEN_FPEN))
+ goto out;
+
+ save_fp(current);
+
+ /* Handle FP registers */
+ switch (regno) {
+ case DBG_FCSR: /* Process the fcsr */
+ memcpy(mem, (void *)¤t->thread.fpu.fcsr, reg_size);
+ break;
+ case DBG_FCC_BASE ... DBG_FCC_END: /* Process the fcc */
+ memcpy(mem, (void *)¤t->thread.fpu.fcc + reg_offset, reg_size);
+ break;
+ case DBG_FPR_BASE ... DBG_FPR_END: /* Process the fpr */
+ memcpy(mem, (void *)¤t->thread.fpu.fpr[reg_offset], reg_size);
+ break;
+ default:
+ break;
+ }
+
+out:
+ return dbg_reg_def[regno].name;
+}
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ int reg_offset, reg_size;
+
+ if (regno < 0 || regno >= DBG_MAX_REG_NUM)
+ return -EINVAL;
+
+ reg_offset = dbg_reg_def[regno].offset;
+ reg_size = dbg_reg_def[regno].size;
+
+ if (reg_offset == -1)
+ return 0;
+
+ /* Handle general-purpose/orig_a0/pc/badv registers */
+ if (regno <= DBG_PT_REGS_END) {
+ memcpy((void *)regs + reg_offset, mem, reg_size);
+ return 0;
+ }
+
+ if (!(regs->csr_euen & CSR_EUEN_FPEN))
+ return 0;
+
+ /* Handle FP registers */
+ switch (regno) {
+ case DBG_FCSR: /* Process the fcsr */
+ memcpy((void *)¤t->thread.fpu.fcsr, mem, reg_size);
+ break;
+ case DBG_FCC_BASE ... DBG_FCC_END: /* Process the fcc */
+ memcpy((void *)¤t->thread.fpu.fcc + reg_offset, mem, reg_size);
+ break;
+ case DBG_FPR_BASE ... DBG_FPR_END: /* Process the fpr */
+ memcpy((void *)¤t->thread.fpu.fpr[reg_offset], mem, reg_size);
+ break;
+ default:
+ break;
+ }
+
+ restore_fp(current);
+
+ return 0;
+}
+
+/*
+ * Similar to regs_to_gdb_regs() except that process is sleeping and so
+ * we may not be able to get all the info.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+ /* Initialize to zero */
+ memset((char *)gdb_regs, 0, NUMREGBYTES);
+
+ gdb_regs[DBG_LOONGARCH_RA] = p->thread.reg01;
+ gdb_regs[DBG_LOONGARCH_TP] = (long)p;
+ gdb_regs[DBG_LOONGARCH_SP] = p->thread.reg03;
+
+ /* S0 - S8 */
+ gdb_regs[DBG_LOONGARCH_S0] = p->thread.reg23;
+ gdb_regs[DBG_LOONGARCH_S1] = p->thread.reg24;
+ gdb_regs[DBG_LOONGARCH_S2] = p->thread.reg25;
+ gdb_regs[DBG_LOONGARCH_S3] = p->thread.reg26;
+ gdb_regs[DBG_LOONGARCH_S4] = p->thread.reg27;
+ gdb_regs[DBG_LOONGARCH_S5] = p->thread.reg28;
+ gdb_regs[DBG_LOONGARCH_S6] = p->thread.reg29;
+ gdb_regs[DBG_LOONGARCH_S7] = p->thread.reg30;
+ gdb_regs[DBG_LOONGARCH_S8] = p->thread.reg31;
+
+ /*
+ * PC use return address (RA), i.e. the moment after return from __switch_to()
+ */
+ gdb_regs[DBG_LOONGARCH_PC] = p->thread.reg01;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+ regs->csr_era = pc;
+}
+
+void arch_kgdb_breakpoint(void)
+{
+ __asm__ __volatile__ ( \
+ ".globl kgdb_breakinst\n\t" \
+ "nop\n" \
+ "kgdb_breakinst:\tbreak 2\n\t"); /* BRK_KDB = 2 */
+}
+
+/*
+ * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
+ * then try to fall into the debugger
+ */
+static int kgdb_loongarch_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+ struct die_args *args = (struct die_args *)ptr;
+ struct pt_regs *regs = args->regs;
+
+ /* Userspace events, ignore. */
+ if (user_mode(regs))
+ return NOTIFY_DONE;
+
+ if (!kgdb_io_module_registered)
+ return NOTIFY_DONE;
+
+ if (atomic_read(&kgdb_active) != -1)
+ kgdb_nmicallback(smp_processor_id(), regs);
+
+ if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs))
+ return NOTIFY_DONE;
+
+ if (atomic_read(&kgdb_setting_breakpoint))
+ if (regs->csr_era == (unsigned long)&kgdb_breakinst)
+ regs->csr_era += LOONGARCH_INSN_SIZE;
+
+ return NOTIFY_STOP;
+}
+
+bool kgdb_breakpoint_handler(struct pt_regs *regs)
+{
+ struct die_args args = {
+ .regs = regs,
+ .str = "Break",
+ .err = BRK_KDB,
+ .trapnr = read_csr_excode(),
+ .signr = SIGTRAP,
+
+ };
+
+ return (kgdb_loongarch_notify(NULL, DIE_TRAP, &args) == NOTIFY_STOP) ? true : false;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_loongarch_notify,
+};
+
+static inline void kgdb_arch_update_addr(struct pt_regs *regs,
+ char *remcom_in_buffer)
+{
+ unsigned long addr;
+ char *ptr;
+
+ ptr = &remcom_in_buffer[1];
+ if (kgdb_hex2long(&ptr, &addr))
+ regs->csr_era = addr;
+}
+
+/* Calculate the new address for after a step */
+static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
+{
+ char cj_val;
+ unsigned int si, si_l, si_h, rd, rj, cj;
+ unsigned long pc = instruction_pointer(regs);
+ union loongarch_instruction *ip = (union loongarch_instruction *)pc;
+
+ if (pc & 3) {
+ pr_warn("%s: invalid pc 0x%lx\n", __func__, pc);
+ return -EINVAL;
+ }
+
+ *next_addr = pc + LOONGARCH_INSN_SIZE;
+
+ si_h = ip->reg0i26_format.immediate_h;
+ si_l = ip->reg0i26_format.immediate_l;
+ switch (ip->reg0i26_format.opcode) {
+ case b_op:
+ *next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
+ return 0;
+ case bl_op:
+ *next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
+ regs->regs[1] = pc + LOONGARCH_INSN_SIZE;
+ return 0;
+ }
+
+ rj = ip->reg1i21_format.rj;
+ cj = (rj & 0x07) + DBG_FCC_BASE;
+ si_l = ip->reg1i21_format.immediate_l;
+ si_h = ip->reg1i21_format.immediate_h;
+ dbg_get_reg(cj, &cj_val, regs);
+ switch (ip->reg1i21_format.opcode) {
+ case beqz_op:
+ if (regs->regs[rj] == 0)
+ *next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
+ return 0;
+ case bnez_op:
+ if (regs->regs[rj] != 0)
+ *next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
+ return 0;
+ case bceqz_op: /* bceqz_op = bcnez_op */
+ if (((rj & 0x18) == 0x00) && !cj_val) /* bceqz */
+ *next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
+ if (((rj & 0x18) == 0x08) && cj_val) /* bcnez */
+ *next_addr = pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
+ return 0;
+ }
+
+ rj = ip->reg2i16_format.rj;
+ rd = ip->reg2i16_format.rd;
+ si = ip->reg2i16_format.immediate;
+ switch (ip->reg2i16_format.opcode) {
+ case beq_op:
+ if (regs->regs[rj] == regs->regs[rd])
+ *next_addr = pc + sign_extend64(si << 2, 17);
+ return 0;
+ case bne_op:
+ if (regs->regs[rj] != regs->regs[rd])
+ *next_addr = pc + sign_extend64(si << 2, 17);
+ return 0;
+ case blt_op:
+ if ((long)regs->regs[rj] < (long)regs->regs[rd])
+ *next_addr = pc + sign_extend64(si << 2, 17);
+ return 0;
+ case bge_op:
+ if ((long)regs->regs[rj] >= (long)regs->regs[rd])
+ *next_addr = pc + sign_extend64(si << 2, 17);
+ return 0;
+ case bltu_op:
+ if (regs->regs[rj] < regs->regs[rd])
+ *next_addr = pc + sign_extend64(si << 2, 17);
+ return 0;
+ case bgeu_op:
+ if (regs->regs[rj] >= regs->regs[rd])
+ *next_addr = pc + sign_extend64(si << 2, 17);
+ return 0;
+ case jirl_op:
+ regs->regs[rd] = pc + LOONGARCH_INSN_SIZE;
+ *next_addr = regs->regs[rj] + sign_extend64(si << 2, 17);
+ return 0;
+ }
+
+ return 0;
+}
+
+static int do_single_step(struct pt_regs *regs)
+{
+ int error = 0;
+ unsigned long addr = 0; /* Determine where the target instruction will send us to */
+
+ error = get_step_address(regs, &addr);
+ if (error)
+ return error;
+
+ /* Store the opcode in the stepped address */
+ error = get_kernel_nofault(stepped_opcode, (void *)addr);
+ if (error)
+ return error;
+
+ stepped_address = addr;
+
+ /* Replace the opcode with the break instruction */
+ error = copy_to_kernel_nofault((void *)stepped_address,
+ arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+ flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+
+ if (error) {
+ stepped_opcode = 0;
+ stepped_address = 0;
+ } else {
+ kgdb_single_step = 1;
+ atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
+ }
+
+ return error;
+}
+
+/* Undo a single step */
+static void undo_single_step(struct pt_regs *regs)
+{
+ if (stepped_opcode) {
+ copy_to_kernel_nofault((void *)stepped_address,
+ (void *)&stepped_opcode, BREAK_INSTR_SIZE);
+ flush_icache_range(stepped_address, stepped_address + BREAK_INSTR_SIZE);
+ }
+
+ stepped_opcode = 0;
+ stepped_address = 0;
+ kgdb_single_step = 0;
+ atomic_set(&kgdb_cpu_doing_single_step, -1);
+}
+
+int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+ char *remcom_in_buffer, char *remcom_out_buffer,
+ struct pt_regs *regs)
+{
+ int ret = 0;
+
+ undo_single_step(regs);
+ regs->csr_prmd |= CSR_PRMD_PWE;
+
+ switch (remcom_in_buffer[0]) {
+ case 'D':
+ case 'k':
+ regs->csr_prmd &= ~CSR_PRMD_PWE;
+ fallthrough;
+ case 'c':
+ kgdb_arch_update_addr(regs, remcom_in_buffer);
+ break;
+ case 's':
+ kgdb_arch_update_addr(regs, remcom_in_buffer);
+ ret = do_single_step(regs);
+ break;
+ default:
+ ret = -1;
+ }
+
+ return ret;
+}
+
+static struct hw_breakpoint {
+ unsigned int enabled;
+ unsigned long addr;
+ int len;
+ int type;
+ struct perf_event * __percpu *pev;
+} breakinfo[LOONGARCH_MAX_BRP];
+
+static int hw_break_reserve_slot(int breakno)
+{
+ int cpu, cnt = 0;
+ struct perf_event **pevent;
+
+ for_each_online_cpu(cpu) {
+ cnt++;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_reserve_bp_slot(*pevent))
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ for_each_online_cpu(cpu) {
+ cnt--;
+ if (!cnt)
+ break;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ dbg_release_bp_slot(*pevent);
+ }
+
+ return -1;
+}
+
+static int hw_break_release_slot(int breakno)
+{
+ int cpu;
+ struct perf_event **pevent;
+
+ if (dbg_is_early)
+ return 0;
+
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_release_bp_slot(*pevent))
+ /*
+ * The debugger is responsible for handing the retry on
+ * remove failure.
+ */
+ return -1;
+ }
+
+ return 0;
+}
+
+static int kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+ int i;
+
+ for (i = 0; i < LOONGARCH_MAX_BRP; i++)
+ if (!breakinfo[i].enabled)
+ break;
+
+ if (i == LOONGARCH_MAX_BRP)
+ return -1;
+
+ switch (bptype) {
+ case BP_HARDWARE_BREAKPOINT:
+ breakinfo[i].type = HW_BREAKPOINT_X;
+ break;
+ case BP_READ_WATCHPOINT:
+ breakinfo[i].type = HW_BREAKPOINT_R;
+ break;
+ case BP_WRITE_WATCHPOINT:
+ breakinfo[i].type = HW_BREAKPOINT_W;
+ break;
+ case BP_ACCESS_WATCHPOINT:
+ breakinfo[i].type = HW_BREAKPOINT_RW;
+ break;
+ default:
+ return -1;
+ }
+
+ switch (len) {
+ case 1:
+ breakinfo[i].len = HW_BREAKPOINT_LEN_1;
+ break;
+ case 2:
+ breakinfo[i].len = HW_BREAKPOINT_LEN_2;
+ break;
+ case 4:
+ breakinfo[i].len = HW_BREAKPOINT_LEN_4;
+ break;
+ case 8:
+ breakinfo[i].len = HW_BREAKPOINT_LEN_8;
+ break;
+ default:
+ return -1;
+ }
+
+ breakinfo[i].addr = addr;
+ if (hw_break_reserve_slot(i)) {
+ breakinfo[i].addr = 0;
+ return -1;
+ }
+ breakinfo[i].enabled = 1;
+
+ return 0;
+}
+
+static int kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+ int i;
+
+ for (i = 0; i < LOONGARCH_MAX_BRP; i++)
+ if (breakinfo[i].addr == addr && breakinfo[i].enabled)
+ break;
+
+ if (i == LOONGARCH_MAX_BRP)
+ return -1;
+
+ if (hw_break_release_slot(i)) {
+ pr_err("Cannot remove hw breakpoint at %lx\n", addr);
+ return -1;
+ }
+ breakinfo[i].enabled = 0;
+
+ return 0;
+}
+
+static void kgdb_disable_hw_break(struct pt_regs *regs)
+{
+ int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
+
+ for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (bp->attr.disabled == 1)
+ continue;
+
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ }
+
+ /* Disable hardware debugging while we are in kgdb */
+ csr_xchg32(0, CSR_CRMD_WE, LOONGARCH_CSR_CRMD);
+}
+
+static void kgdb_remove_all_hw_break(void)
+{
+ int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
+
+ for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (!bp->attr.disabled) {
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ continue;
+ }
+
+ if (hw_break_release_slot(i))
+ pr_err("KGDB: hw bpt remove failed %lx\n", breakinfo[i].addr);
+ breakinfo[i].enabled = 0;
+ }
+
+ csr_xchg32(0, CSR_CRMD_WE, LOONGARCH_CSR_CRMD);
+ kgdb_watch_activated = 0;
+}
+
+static void kgdb_correct_hw_break(void)
+{
+ int i, activated = 0;
+
+ for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
+ struct perf_event *bp;
+ int val;
+ int cpu = raw_smp_processor_id();
+
+ if (!breakinfo[i].enabled)
+ continue;
+
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (bp->attr.disabled != 1)
+ continue;
+
+ bp->attr.bp_addr = breakinfo[i].addr;
+ bp->attr.bp_len = breakinfo[i].len;
+ bp->attr.bp_type = breakinfo[i].type;
+
+ val = hw_breakpoint_arch_parse(bp, &bp->attr, counter_arch_bp(bp));
+ if (val)
+ return;
+
+ val = arch_install_hw_breakpoint(bp);
+ if (!val)
+ bp->attr.disabled = 0;
+ activated = 1;
+ }
+
+ csr_xchg32(activated ? CSR_CRMD_WE : 0, CSR_CRMD_WE, LOONGARCH_CSR_CRMD);
+ kgdb_watch_activated = activated;
+}
+
+const struct kgdb_arch arch_kgdb_ops = {
+ .gdb_bpt_instr = {0x02, 0x00, break_op >> 1, 0x00}, /* BRK_KDB = 2 */
+ .flags = KGDB_HW_BREAKPOINT,
+ .set_hw_breakpoint = kgdb_set_hw_break,
+ .remove_hw_breakpoint = kgdb_remove_hw_break,
+ .disable_hw_break = kgdb_disable_hw_break,
+ .remove_all_hw_break = kgdb_remove_all_hw_break,
+ .correct_hw_break = kgdb_correct_hw_break,
+};
+
+int kgdb_arch_init(void)
+{
+ return register_die_notifier(&kgdb_notifier);
+}
+
+void kgdb_arch_late(void)
+{
+ int i, cpu;
+ struct perf_event_attr attr;
+ struct perf_event **pevent;
+
+ hw_breakpoint_init(&attr);
+
+ attr.bp_addr = (unsigned long)kgdb_arch_init;
+ attr.bp_len = HW_BREAKPOINT_LEN_4;
+ attr.bp_type = HW_BREAKPOINT_W;
+ attr.disabled = 1;
+
+ for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
+ if (breakinfo[i].pev)
+ continue;
+
+ breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
+ if (IS_ERR((void * __force)breakinfo[i].pev)) {
+ pr_err("kgdb: Could not allocate hw breakpoints.\n");
+ breakinfo[i].pev = NULL;
+ return;
+ }
+
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (pevent[0]->destroy) {
+ pevent[0]->destroy = NULL;
+ release_bp_slot(*pevent);
+ }
+ }
+ }
+}
+
+void kgdb_arch_exit(void)
+{
+ int i;
+
+ for (i = 0; i < LOONGARCH_MAX_BRP; i++) {
+ if (breakinfo[i].pev) {
+ unregister_wide_hw_breakpoint(breakinfo[i].pev);
+ breakinfo[i].pev = NULL;
+ }
+ }
+
+ unregister_die_notifier(&kgdb_notifier);
+}
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index 7ed01a7b2542548ae9863d8f5d59fe86ecedaf72..65214774ef7c6bade648ccf4f8702cdefc7baac1 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -38,6 +38,7 @@
#include <asm/fpu.h>
#include <asm/lbt.h>
#include <asm/inst.h>
+#include <asm/kgdb.h>
#include <asm/loongarch.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
@@ -703,6 +704,11 @@ asmlinkage void noinstr do_bp(struct pt_regs *regs)
* pertain to them.
*/
switch (bcode) {
+ case BRK_KDB:
+ if (kgdb_breakpoint_handler(regs))
+ goto out;
+ else
+ break;
case BRK_KPROBE_BP:
if (kprobe_breakpoint_handler(regs))
goto out;
@@ -769,6 +775,9 @@ asmlinkage void noinstr do_watch(struct pt_regs *regs)
#ifndef CONFIG_HAVE_HW_BREAKPOINT
pr_warn("Hardware watch point handler not implemented!\n");
#else
+ if (kgdb_breakpoint_handler(regs))
+ goto out;
+
if (test_tsk_thread_flag(current, TIF_SINGLESTEP)) {
int llbit = (csr_read32(LOONGARCH_CSR_LLBCTL) & 0x1);
unsigned long pc = instruction_pointer(regs);