From: Vincent Chen <vincent.chen@sifive.com>
To: paul.walmsley@sifive.com, palmer@dabbelt.com, daniel.thompson@linaro.org
Cc: kgdb-bugreport@lists.sourceforge.net,
linux-riscv@lists.infradead.org,
Vincent Chen <vincent.chen@sifive.com>
Subject: [V5 patch 2/6] riscv: Add KGDB support
Date: Mon, 1 Jun 2020 11:39:07 +0800 [thread overview]
Message-ID: <1590982751-13401-3-git-send-email-vincent.chen@sifive.com> (raw)
In-Reply-To: <1590982751-13401-1-git-send-email-vincent.chen@sifive.com>
The skeleton of RISC-V KGDB port.
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/kdebug.h | 12 +++
arch/riscv/include/asm/kgdb.h | 105 +++++++++++++++++++++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/kgdb.c | 200 ++++++++++++++++++++++++++++++++++++++++
arch/riscv/kernel/traps.c | 5 +
6 files changed, 324 insertions(+)
create mode 100644 arch/riscv/include/asm/kdebug.h
create mode 100644 arch/riscv/include/asm/kgdb.h
create mode 100644 arch/riscv/kernel/kgdb.c
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index a31e1a41913a..85c5c1829cc4 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -68,6 +68,7 @@ config RISCV
select ARCH_HAS_GCOV_PROFILE_ALL
select HAVE_COPY_THREAD_TLS
select HAVE_ARCH_KASAN if MMU && 64BIT
+ select HAVE_ARCH_KGDB
config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
diff --git a/arch/riscv/include/asm/kdebug.h b/arch/riscv/include/asm/kdebug.h
new file mode 100644
index 000000000000..85ac00411f6e
--- /dev/null
+++ b/arch/riscv/include/asm/kdebug.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ASM_ARC_KDEBUG_H
+#define _ASM_ARC_KDEBUG_H
+
+enum die_val {
+ DIE_UNUSED,
+ DIE_TRAP,
+ DIE_OOPS
+};
+
+#endif
diff --git a/arch/riscv/include/asm/kgdb.h b/arch/riscv/include/asm/kgdb.h
new file mode 100644
index 000000000000..a348efbf04d1
--- /dev/null
+++ b/arch/riscv/include/asm/kgdb.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ASM_KGDB_H_
+#define __ASM_KGDB_H_
+
+#ifdef __KERNEL__
+
+#define GDB_SIZEOF_REG sizeof(unsigned long)
+
+#define DBG_MAX_REG_NUM (33)
+#define NUMREGBYTES ((DBG_MAX_REG_NUM) * GDB_SIZEOF_REG)
+#define CACHE_FLUSH_IS_SAFE 1
+#define BUFMAX 2048
+#ifdef CONFIG_RISCV_ISA_C
+#define BREAK_INSTR_SIZE 2
+#else
+#define BREAK_INSTR_SIZE 4
+#endif
+
+#ifndef __ASSEMBLY__
+
+extern unsigned long kgdb_compiled_break;
+
+static inline void arch_kgdb_breakpoint(void)
+{
+ asm(".global kgdb_compiled_break\n"
+ ".option norvc\n"
+ "kgdb_compiled_break: ebreak\n"
+ ".option rvc\n");
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#define DBG_REG_ZERO "zero"
+#define DBG_REG_RA "ra"
+#define DBG_REG_SP "sp"
+#define DBG_REG_GP "gp"
+#define DBG_REG_TP "tp"
+#define DBG_REG_T0 "t0"
+#define DBG_REG_T1 "t1"
+#define DBG_REG_T2 "t2"
+#define DBG_REG_FP "fp"
+#define DBG_REG_S1 "s1"
+#define DBG_REG_A0 "a0"
+#define DBG_REG_A1 "a1"
+#define DBG_REG_A2 "a2"
+#define DBG_REG_A3 "a3"
+#define DBG_REG_A4 "a4"
+#define DBG_REG_A5 "a5"
+#define DBG_REG_A6 "a6"
+#define DBG_REG_A7 "a7"
+#define DBG_REG_S2 "s2"
+#define DBG_REG_S3 "s3"
+#define DBG_REG_S4 "s4"
+#define DBG_REG_S5 "s5"
+#define DBG_REG_S6 "s6"
+#define DBG_REG_S7 "s7"
+#define DBG_REG_S8 "s8"
+#define DBG_REG_S9 "s9"
+#define DBG_REG_S10 "s10"
+#define DBG_REG_S11 "s11"
+#define DBG_REG_T3 "t3"
+#define DBG_REG_T4 "t4"
+#define DBG_REG_T5 "t5"
+#define DBG_REG_T6 "t6"
+#define DBG_REG_EPC "pc"
+
+#define DBG_REG_ZERO_OFF 0
+#define DBG_REG_RA_OFF 1
+#define DBG_REG_SP_OFF 2
+#define DBG_REG_GP_OFF 3
+#define DBG_REG_TP_OFF 4
+#define DBG_REG_T0_OFF 5
+#define DBG_REG_T1_OFF 6
+#define DBG_REG_T2_OFF 7
+#define DBG_REG_FP_OFF 8
+#define DBG_REG_S1_OFF 9
+#define DBG_REG_A0_OFF 10
+#define DBG_REG_A1_OFF 11
+#define DBG_REG_A2_OFF 12
+#define DBG_REG_A3_OFF 13
+#define DBG_REG_A4_OFF 14
+#define DBG_REG_A5_OFF 15
+#define DBG_REG_A6_OFF 16
+#define DBG_REG_A7_OFF 17
+#define DBG_REG_S2_OFF 18
+#define DBG_REG_S3_OFF 19
+#define DBG_REG_S4_OFF 20
+#define DBG_REG_S5_OFF 21
+#define DBG_REG_S6_OFF 22
+#define DBG_REG_S7_OFF 23
+#define DBG_REG_S8_OFF 24
+#define DBG_REG_S9_OFF 25
+#define DBG_REG_S10_OFF 26
+#define DBG_REG_S11_OFF 27
+#define DBG_REG_T3_OFF 28
+#define DBG_REG_T4_OFF 29
+#define DBG_REG_T5_OFF 30
+#define DBG_REG_T6_OFF 31
+#define DBG_REG_EPC_OFF 32
+#define DBG_REG_STATUS_OFF 33
+#define DBG_REG_BADADDR_OFF 34
+#define DBG_REG_CAUSE_OFF 35
+#endif
+#endif
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index d8bbd3207100..b355cf485671 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -51,5 +51,6 @@ ifeq ($(CONFIG_RISCV_SBI), y)
obj-$(CONFIG_SMP) += cpu_ops_sbi.o
endif
obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o
+obj-$(CONFIG_KGDB) += kgdb.o
clean:
diff --git a/arch/riscv/kernel/kgdb.c b/arch/riscv/kernel/kgdb.c
new file mode 100644
index 000000000000..e6b1f989f704
--- /dev/null
+++ b/arch/riscv/kernel/kgdb.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 SiFive
+ */
+
+#include <linux/ptrace.h>
+#include <linux/kdebug.h>
+#include <linux/bug.h>
+#include <linux/kgdb.h>
+#include <linux/irqflags.h>
+#include <linux/string.h>
+#include <asm/cacheflush.h>
+
+enum {
+ NOT_KGDB_BREAK = 0,
+ KGDB_SW_BREAK,
+ KGDB_COMPILED_BREAK,
+};
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
+ {DBG_REG_ZERO, GDB_SIZEOF_REG, -1},
+ {DBG_REG_RA, GDB_SIZEOF_REG, offsetof(struct pt_regs, ra)},
+ {DBG_REG_SP, GDB_SIZEOF_REG, offsetof(struct pt_regs, sp)},
+ {DBG_REG_GP, GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
+ {DBG_REG_TP, GDB_SIZEOF_REG, offsetof(struct pt_regs, tp)},
+ {DBG_REG_T0, GDB_SIZEOF_REG, offsetof(struct pt_regs, t0)},
+ {DBG_REG_T1, GDB_SIZEOF_REG, offsetof(struct pt_regs, t1)},
+ {DBG_REG_T2, GDB_SIZEOF_REG, offsetof(struct pt_regs, t2)},
+ {DBG_REG_FP, GDB_SIZEOF_REG, offsetof(struct pt_regs, s0)},
+ {DBG_REG_S1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)},
+ {DBG_REG_A0, GDB_SIZEOF_REG, offsetof(struct pt_regs, a0)},
+ {DBG_REG_A1, GDB_SIZEOF_REG, offsetof(struct pt_regs, a1)},
+ {DBG_REG_A2, GDB_SIZEOF_REG, offsetof(struct pt_regs, a2)},
+ {DBG_REG_A3, GDB_SIZEOF_REG, offsetof(struct pt_regs, a3)},
+ {DBG_REG_A4, GDB_SIZEOF_REG, offsetof(struct pt_regs, a4)},
+ {DBG_REG_A5, GDB_SIZEOF_REG, offsetof(struct pt_regs, a5)},
+ {DBG_REG_A6, GDB_SIZEOF_REG, offsetof(struct pt_regs, a6)},
+ {DBG_REG_A7, GDB_SIZEOF_REG, offsetof(struct pt_regs, a7)},
+ {DBG_REG_S2, GDB_SIZEOF_REG, offsetof(struct pt_regs, s2)},
+ {DBG_REG_S3, GDB_SIZEOF_REG, offsetof(struct pt_regs, s3)},
+ {DBG_REG_S4, GDB_SIZEOF_REG, offsetof(struct pt_regs, s4)},
+ {DBG_REG_S5, GDB_SIZEOF_REG, offsetof(struct pt_regs, s5)},
+ {DBG_REG_S6, GDB_SIZEOF_REG, offsetof(struct pt_regs, s6)},
+ {DBG_REG_S7, GDB_SIZEOF_REG, offsetof(struct pt_regs, s7)},
+ {DBG_REG_S8, GDB_SIZEOF_REG, offsetof(struct pt_regs, s8)},
+ {DBG_REG_S9, GDB_SIZEOF_REG, offsetof(struct pt_regs, s9)},
+ {DBG_REG_S10, GDB_SIZEOF_REG, offsetof(struct pt_regs, s10)},
+ {DBG_REG_S11, GDB_SIZEOF_REG, offsetof(struct pt_regs, s11)},
+ {DBG_REG_T3, GDB_SIZEOF_REG, offsetof(struct pt_regs, t3)},
+ {DBG_REG_T4, GDB_SIZEOF_REG, offsetof(struct pt_regs, t4)},
+ {DBG_REG_T5, GDB_SIZEOF_REG, offsetof(struct pt_regs, t5)},
+ {DBG_REG_T6, GDB_SIZEOF_REG, offsetof(struct pt_regs, t6)},
+ {DBG_REG_EPC, GDB_SIZEOF_REG, offsetof(struct pt_regs, epc)},
+};
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return NULL;
+
+ if (dbg_reg_def[regno].offset != -1)
+ memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
+ dbg_reg_def[regno].size);
+ else
+ memset(mem, 0, dbg_reg_def[regno].size);
+ return dbg_reg_def[regno].name;
+}
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return -EINVAL;
+
+ if (dbg_reg_def[regno].offset != -1)
+ memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
+ dbg_reg_def[regno].size);
+ return 0;
+}
+
+void
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
+{
+ /* Initialize to zero */
+ memset((char *)gdb_regs, 0, NUMREGBYTES);
+
+ gdb_regs[DBG_REG_SP_OFF] = task->thread.sp;
+ gdb_regs[DBG_REG_FP_OFF] = task->thread.s[0];
+ gdb_regs[DBG_REG_S1_OFF] = task->thread.s[1];
+ gdb_regs[DBG_REG_S2_OFF] = task->thread.s[2];
+ gdb_regs[DBG_REG_S3_OFF] = task->thread.s[3];
+ gdb_regs[DBG_REG_S4_OFF] = task->thread.s[4];
+ gdb_regs[DBG_REG_S5_OFF] = task->thread.s[5];
+ gdb_regs[DBG_REG_S6_OFF] = task->thread.s[6];
+ gdb_regs[DBG_REG_S7_OFF] = task->thread.s[7];
+ gdb_regs[DBG_REG_S8_OFF] = task->thread.s[8];
+ gdb_regs[DBG_REG_S9_OFF] = task->thread.s[10];
+ gdb_regs[DBG_REG_S10_OFF] = task->thread.s[11];
+ gdb_regs[DBG_REG_EPC_OFF] = task->thread.ra;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+ regs->epc = pc;
+}
+
+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->epc = addr;
+}
+
+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 err = 0;
+
+ switch (remcom_in_buffer[0]) {
+ case 'c':
+ case 'D':
+ case 'k':
+ if (remcom_in_buffer[0] == 'c')
+ kgdb_arch_update_addr(regs, remcom_in_buffer);
+ break;
+ default:
+ err = -1;
+ }
+
+ return err;
+}
+
+static int kgdb_riscv_kgdbbreak(unsigned long addr)
+{
+ if (atomic_read(&kgdb_setting_breakpoint))
+ if (addr == (unsigned long)&kgdb_compiled_break)
+ return KGDB_COMPILED_BREAK;
+
+ return kgdb_has_hit_break(addr);
+}
+
+static int kgdb_riscv_notify(struct notifier_block *self, unsigned long cmd,
+ void *ptr)
+{
+ struct die_args *args = (struct die_args *)ptr;
+ struct pt_regs *regs = args->regs;
+ unsigned long flags;
+ int type;
+
+ if (user_mode(regs))
+ return NOTIFY_DONE;
+
+ type = kgdb_riscv_kgdbbreak(regs->epc);
+ if (type == NOT_KGDB_BREAK && cmd == DIE_TRAP)
+ return NOTIFY_DONE;
+
+ local_irq_save(flags);
+ if (kgdb_handle_exception(1, args->signr, cmd, regs))
+ return NOTIFY_DONE;
+
+ if (type == KGDB_COMPILED_BREAK)
+ regs->epc += 4;
+
+ local_irq_restore(flags);
+
+ return NOTIFY_STOP;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_riscv_notify,
+};
+
+int kgdb_arch_init(void)
+{
+ register_die_notifier(&kgdb_notifier);
+
+ return 0;
+}
+
+void kgdb_arch_exit(void)
+{
+ unregister_die_notifier(&kgdb_notifier);
+}
+
+/*
+ * Global data
+ */
+#ifdef CONFIG_RISCV_ISA_C
+const struct kgdb_arch arch_kgdb_ops = {
+ .gdb_bpt_instr = {0x02, 0x90}, /* c.ebreak */
+};
+#else
+const struct kgdb_arch arch_kgdb_ops = {
+ .gdb_bpt_instr = {0x73, 0x00, 0x10, 0x00}, /* ebreak */
+};
+#endif
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 7f58fa53033f..5080fdf8c296 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -147,6 +147,11 @@ asmlinkage __visible void do_trap_break(struct pt_regs *regs)
{
if (user_mode(regs))
force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc);
+#ifdef CONFIG_KGDB
+ else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP)
+ == NOTIFY_STOP)
+ return;
+#endif
else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN)
regs->epc += get_break_insn_length(regs->epc);
else
--
2.7.4
next prev parent reply other threads:[~2020-06-01 3:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-01 3:39 [V5 patch 0/6] riscv: Add KGDB and KDB support Vincent Chen
2020-06-01 3:39 ` [V5 patch 1/6] kgdb: Add kgdb_has_hit_break function Vincent Chen
2020-06-01 3:39 ` Vincent Chen [this message]
2020-06-01 3:39 ` [V5 patch 3/6] kgdb: enable arch to support XML packet support Vincent Chen
2020-06-01 3:39 ` [V5 patch 4/6] riscv: enable the Kconfig prompt of STRICT_KERNEL_RWX Vincent Chen
2020-06-01 3:39 ` [V5 patch 5/6] riscv: Use the XML target descriptions to report 3 system registers Vincent Chen
2020-06-01 3:39 ` [V5 patch 6/6] riscv: Add SW single-step support for KDB Vincent Chen
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