AuxXxilium/linux_dsm_epyc7002
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linux_dsm_epyc7002/arch/riscv/kernel/kgdb.c
Christoph Hellwig 25f12ae45f 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>
2020-06-18 11:14:40 -07:00

391 lines
11 KiB
C
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// 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)
int decode_register_index(unsigned long opcode, int offset)
{
return (opcode >> offset) & 0x1F;
}
int decode_register_index_short(unsigned long opcode, int offset)
{
return ((opcode >> offset) & 0x7) + 8;
}
/* Calculate the new address for after a step */
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;
}
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;
}
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
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