Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 390 insertions, 0 deletions

diff --git a/arch/riscv/kernel/kgdb.c b/arch/riscv/kernel/kgdb.c
new file mode 100644
index 000000000..963ed7edc
--- /dev/null
+++ b/arch/riscv/kernel/kgdb.c
@@ -0,0 +1,390 @@
+// 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>
+#include <asm/gdb_xml.h>
+#include <asm/parse_asm.h>
+
+enum {
+	NOT_KGDB_BREAK = 0,
+	KGDB_SW_BREAK,
+	KGDB_COMPILED_BREAK,
+	KGDB_SW_SINGLE_STEP
+};
+
+static unsigned long stepped_address;
+static unsigned int stepped_opcode;
+
+#if __riscv_xlen == 32
+/* C.JAL is an RV32C-only instruction */
+DECLARE_INSN(c_jal, MATCH_C_JAL, MASK_C_JAL)
+#else
+#define is_c_jal_insn(opcode) 0
+#endif
+DECLARE_INSN(jalr, MATCH_JALR, MASK_JALR)
+DECLARE_INSN(jal, MATCH_JAL, MASK_JAL)
+DECLARE_INSN(c_jr, MATCH_C_JR, MASK_C_JR)
+DECLARE_INSN(c_jalr, MATCH_C_JALR, MASK_C_JALR)
+DECLARE_INSN(c_j, MATCH_C_J, MASK_C_J)
+DECLARE_INSN(beq, MATCH_BEQ, MASK_BEQ)
+DECLARE_INSN(bne, MATCH_BNE, MASK_BNE)
+DECLARE_INSN(blt, MATCH_BLT, MASK_BLT)
+DECLARE_INSN(bge, MATCH_BGE, MASK_BGE)
+DECLARE_INSN(bltu, MATCH_BLTU, MASK_BLTU)
+DECLARE_INSN(bgeu, MATCH_BGEU, MASK_BGEU)
+DECLARE_INSN(c_beqz, MATCH_C_BEQZ, MASK_C_BEQZ)
+DECLARE_INSN(c_bnez, MATCH_C_BNEZ, MASK_C_BNEZ)
+DECLARE_INSN(sret, MATCH_SRET, MASK_SRET)
+
+static int decode_register_index(unsigned long opcode, int offset)
+{
+	return (opcode >> offset) & 0x1F;
+}
+
+static int decode_register_index_short(unsigned long opcode, int offset)
+{
+	return ((opcode >> offset) & 0x7) + 8;
+}
+
+/* Calculate the new address for after a step */
+static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
+{
+	unsigned long pc = regs->epc;
+	unsigned long *regs_ptr = (unsigned long *)regs;
+	unsigned int rs1_num, rs2_num;
+	int op_code;
+
+	if (get_kernel_nofault(op_code, (void *)pc))
+		return -EINVAL;
+	if ((op_code & __INSN_LENGTH_MASK) != __INSN_LENGTH_GE_32) {
+		if (is_c_jalr_insn(op_code) || is_c_jr_insn(op_code)) {
+			rs1_num = decode_register_index(op_code, RVC_C2_RS1_OPOFF);
+			*next_addr = regs_ptr[rs1_num];
+		} else if (is_c_j_insn(op_code) || is_c_jal_insn(op_code)) {
+			*next_addr = EXTRACT_RVC_J_IMM(op_code) + pc;
+		} else if (is_c_beqz_insn(op_code)) {
+			rs1_num = decode_register_index_short(op_code,
+							      RVC_C1_RS1_OPOFF);
+			if (!rs1_num || regs_ptr[rs1_num] == 0)
+				*next_addr = EXTRACT_RVC_B_IMM(op_code) + pc;
+			else
+				*next_addr = pc + 2;
+		} else if (is_c_bnez_insn(op_code)) {
+			rs1_num =
+			    decode_register_index_short(op_code, RVC_C1_RS1_OPOFF);
+			if (rs1_num && regs_ptr[rs1_num] != 0)
+				*next_addr = EXTRACT_RVC_B_IMM(op_code) + pc;
+			else
+				*next_addr = pc + 2;
+		} else {
+			*next_addr = pc + 2;
+		}
+	} else {
+		if ((op_code & __INSN_OPCODE_MASK) == __INSN_BRANCH_OPCODE) {
+			bool result = false;
+			long imm = EXTRACT_BTYPE_IMM(op_code);
+			unsigned long rs1_val = 0, rs2_val = 0;
+
+			rs1_num = decode_register_index(op_code, RVG_RS1_OPOFF);
+			rs2_num = decode_register_index(op_code, RVG_RS2_OPOFF);
+			if (rs1_num)
+				rs1_val = regs_ptr[rs1_num];
+			if (rs2_num)
+				rs2_val = regs_ptr[rs2_num];
+
+			if (is_beq_insn(op_code))
+				result = (rs1_val == rs2_val) ? true : false;
+			else if (is_bne_insn(op_code))
+				result = (rs1_val != rs2_val) ? true : false;
+			else if (is_blt_insn(op_code))
+				result =
+				    ((long)rs1_val <
+				     (long)rs2_val) ? true : false;
+			else if (is_bge_insn(op_code))
+				result =
+				    ((long)rs1_val >=
+				     (long)rs2_val) ? true : false;
+			else if (is_bltu_insn(op_code))
+				result = (rs1_val < rs2_val) ? true : false;
+			else if (is_bgeu_insn(op_code))
+				result = (rs1_val >= rs2_val) ? true : false;
+			if (result)
+				*next_addr = imm + pc;
+			else
+				*next_addr = pc + 4;
+		} else if (is_jal_insn(op_code)) {
+			*next_addr = EXTRACT_JTYPE_IMM(op_code) + pc;
+		} else if (is_jalr_insn(op_code)) {
+			rs1_num = decode_register_index(op_code, RVG_RS1_OPOFF);
+			if (rs1_num)
+				*next_addr = ((unsigned long *)regs)[rs1_num];
+			*next_addr += EXTRACT_ITYPE_IMM(op_code);
+		} else if (is_sret_insn(op_code)) {
+			*next_addr = pc;
+		} else {
+			*next_addr = pc + 4;
+		}
+	}
+	return 0;
+}
+
+static int do_single_step(struct pt_regs *regs)
+{
+	/* Determine where the target instruction will send us to */
+	unsigned long addr = 0;
+	int error = get_step_address(regs, &addr);
+
+	if (error)
+		return error;
+
+	/* Store the op code in the stepped address */
+	error = get_kernel_nofault(stepped_opcode, (void *)addr);
+	if (error)
+		return error;
+
+	stepped_address = addr;
+
+	/* Replace the op code with the break instruction */
+	error = copy_to_kernel_nofault((void *)stepped_address,
+				   arch_kgdb_ops.gdb_bpt_instr,
+				   BREAK_INSTR_SIZE);
+	/* Flush and return */
+	if (!error) {
+		flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+		kgdb_single_step = 1;
+		atomic_set(&kgdb_cpu_doing_single_step,
+			   raw_smp_processor_id());
+	} else {
+		stepped_address = 0;
+		stepped_opcode = 0;
+	}
+	return error;
+}
+
+/* Undo a single step */
+static void undo_single_step(struct pt_regs *regs)
+{
+	if (stepped_opcode != 0) {
+		copy_to_kernel_nofault((void *)stepped_address,
+				   (void *)&stepped_opcode, BREAK_INSTR_SIZE);
+		flush_icache_range(stepped_address,
+				   stepped_address + BREAK_INSTR_SIZE);
+	}
+	stepped_address = 0;
+	stepped_opcode = 0;
+	kgdb_single_step = 0;
+	atomic_set(&kgdb_cpu_doing_single_step, -1);
+}
+
+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)},
+	{DBG_REG_STATUS, GDB_SIZEOF_REG, offsetof(struct pt_regs, status)},
+	{DBG_REG_BADADDR, GDB_SIZEOF_REG, offsetof(struct pt_regs, badaddr)},
+	{DBG_REG_CAUSE, GDB_SIZEOF_REG, offsetof(struct pt_regs, cause)},
+};
+
+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;
+}
+
+void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer,
+				char *remcom_out_buffer)
+{
+	if (!strncmp(remcom_in_buffer, gdb_xfer_read_target,
+		     sizeof(gdb_xfer_read_target)))
+		strcpy(remcom_out_buffer, riscv_gdb_stub_target_desc);
+	else if (!strncmp(remcom_in_buffer, gdb_xfer_read_cpuxml,
+			  sizeof(gdb_xfer_read_cpuxml)))
+		strcpy(remcom_out_buffer, riscv_gdb_stub_cpuxml);
+}
+
+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;
+
+	undo_single_step(regs);
+
+	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;
+	case 's':
+		kgdb_arch_update_addr(regs, remcom_in_buffer);
+		err = do_single_step(regs);
+		break;
+	default:
+		err = -1;
+	}
+	return err;
+}
+
+static int kgdb_riscv_kgdbbreak(unsigned long addr)
+{
+	if (stepped_address == addr)
+		return KGDB_SW_SINGLE_STEP;
+	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(type == KGDB_SW_SINGLE_STEP ? 0 : 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