diff options
| -rw-r--r-- | Documentation/features/debug/kgdb/arch-support.txt | 2 | ||||
| -rw-r--r-- | arch/loongarch/Kconfig | 1 | ||||
| -rw-r--r-- | arch/loongarch/include/asm/kgdb.h | 97 | ||||
| -rw-r--r-- | arch/loongarch/include/asm/stackframe.h | 4 | ||||
| -rw-r--r-- | arch/loongarch/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/loongarch/kernel/entry.S | 5 | ||||
| -rw-r--r-- | arch/loongarch/kernel/kgdb.c | 727 | ||||
| -rw-r--r-- | arch/loongarch/kernel/traps.c | 9 |
8 files changed, 845 insertions, 1 deletions
diff --git a/Documentation/features/debug/kgdb/arch-support.txt b/Documentation/features/debug/kgdb/arch-support.txt index 958498f9f2a4..5e91ec78c80b 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 21cc2e2d1f27..b02e399b1cd7 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 000000000000..2041ae58b161 --- /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 7df80e6ae9d2..4fb1e6408b98 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 5341dcf15a17..c0b88528cb81 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 d737e3cf42d3..65518bb8f472 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 000000000000..445c452d72a7 --- /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 7ed01a7b2542..65214774ef7c 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); |