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linux/arch/riscv/kernel/kgdb.c

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riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
// 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>
riscv: Use the XML target descriptions to report 3 system registers The $status, $badaddr, and $cause registers belong to the thread context, so KGDB can obtain their contents from pt_regs in each trap. However, the sequential number of these registers in the gdb register list is far from the general-purpose registers. If riscv port uses the existing method to report these three registers, many trivial registers with sequence numbers in the middle of them will also be packaged to the reply packets. To solve this problem, the riscv port wants to introduce the GDB target description mechanism to customize the reported register list. By the list, the KGDB can ignore the intermediate registers and just reports the general-purpose registers and these three system registers. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:07 +08:00
#include <asm/gdb_xml.h>
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
#include <asm/parse_asm.h>
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
enum {
NOT_KGDB_BREAK = 0,
KGDB_SW_BREAK,
KGDB_COMPILED_BREAK,
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
KGDB_SW_SINGLE_STEP
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
};
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
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)
riscv: Fix "no previous prototype" compile warning in kgdb.c file Some functions are only used in the kgdb.c file. Add static properities to these functions to avoid "no previous prototype" compile warnings Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-06-23 13:37:10 +08:00
static int decode_register_index(unsigned long opcode, int offset)
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
{
return (opcode >> offset) & 0x1F;
}
riscv: Fix "no previous prototype" compile warning in kgdb.c file Some functions are only used in the kgdb.c file. Add static properities to these functions to avoid "no previous prototype" compile warnings Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-06-23 13:37:10 +08:00
static int decode_register_index_short(unsigned long opcode, int offset)
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
{
return ((opcode >> offset) & 0x7) + 8;
}
/* Calculate the new address for after a step */
riscv: Fix "no previous prototype" compile warning in kgdb.c file Some functions are only used in the kgdb.c file. Add static properities to these functions to avoid "no previous prototype" compile warnings Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-06-23 13:37:10 +08:00
static int get_step_address(struct pt_regs *regs, unsigned long *next_addr)
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
{
unsigned long pc = regs->epc;
unsigned long *regs_ptr = (unsigned long *)regs;
unsigned int rs1_num, rs2_num;
int op_code;
maccess: rename probe_kernel_address to get_kernel_nofault Better describe what this helper does, and match the naming of copy_from_kernel_nofault. Also switch the argument order around, so that it acts and looks like get_user(). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-17 15:37:55 +08:00
if (get_kernel_nofault(op_code, (void *)pc))
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
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;
}
riscv: Fix "no previous prototype" compile warning in kgdb.c file Some functions are only used in the kgdb.c file. Add static properities to these functions to avoid "no previous prototype" compile warnings Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-06-23 13:37:10 +08:00
static int do_single_step(struct pt_regs *regs)
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
{
/* 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 */
maccess: rename probe_kernel_address to get_kernel_nofault Better describe what this helper does, and match the naming of copy_from_kernel_nofault. Also switch the argument order around, so that it acts and looks like get_user(). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-17 15:37:55 +08:00
error = get_kernel_nofault(stepped_opcode, (void *)addr);
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
if (error)
return error;
stepped_address = addr;
/* Replace the op code with the break instruction */
maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault Better describe what these functions do. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-17 15:37:53 +08:00
error = copy_to_kernel_nofault((void *)stepped_address,
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
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) {
maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault Better describe what these functions do. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-17 15:37:53 +08:00
copy_to_kernel_nofault((void *)stepped_address,
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
(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);
}
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
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)},
riscv: Use the XML target descriptions to report 3 system registers The $status, $badaddr, and $cause registers belong to the thread context, so KGDB can obtain their contents from pt_regs in each trap. However, the sequential number of these registers in the gdb register list is far from the general-purpose registers. If riscv port uses the existing method to report these three registers, many trivial registers with sequence numbers in the middle of them will also be packaged to the reply packets. To solve this problem, the riscv port wants to introduce the GDB target description mechanism to customize the reported register list. By the list, the KGDB can ignore the intermediate registers and just reports the general-purpose registers and these three system registers. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:07 +08:00
{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)},
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
};
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;
}
riscv: Use the XML target descriptions to report 3 system registers The $status, $badaddr, and $cause registers belong to the thread context, so KGDB can obtain their contents from pt_regs in each trap. However, the sequential number of these registers in the gdb register list is far from the general-purpose registers. If riscv port uses the existing method to report these three registers, many trivial registers with sequence numbers in the middle of them will also be packaged to the reply packets. To solve this problem, the riscv port wants to introduce the GDB target description mechanism to customize the reported register list. By the list, the KGDB can ignore the intermediate registers and just reports the general-purpose registers and these three system registers. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:07 +08:00
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);
}
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
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;
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
undo_single_step(regs);
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
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;
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
case 's':
kgdb_arch_update_addr(regs, remcom_in_buffer);
err = do_single_step(regs);
break;
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
default:
err = -1;
}
return err;
}
riscv: Fix "no previous prototype" compile warning in kgdb.c file Some functions are only used in the kgdb.c file. Add static properities to these functions to avoid "no previous prototype" compile warnings Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-06-23 13:37:10 +08:00
static int kgdb_riscv_kgdbbreak(unsigned long addr)
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
{
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
if (stepped_address == addr)
return KGDB_SW_SINGLE_STEP;
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
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);
riscv: Add SW single-step support for KDB In KGDB, the GDB in the host is responsible for the single-step operation of the software. In other words, KGDB does not need to derive the next pc address when performing a software single-step operation. KGDB just inserts the break instruction at the indicated address according to the GDB instructions. This approach does not work in KDB because the GDB does not involve the KDB process. Therefore, this patch provides KDB a software single-step mechanism to use. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:08 +08:00
if (kgdb_handle_exception(type == KGDB_SW_SINGLE_STEP ? 0 : 1,
args->signr, cmd, regs))
riscv: Add KGDB support The skeleton of RISC-V KGDB port. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-04-16 10:38:05 +08:00
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