diff options
Diffstat (limited to 'arch/mn10300/kernel')
| -rw-r--r-- | arch/mn10300/kernel/kgdb.c | 322 | ||||
| -rw-r--r-- | arch/mn10300/kernel/switch_to.S | 111 |
2 files changed, 421 insertions, 12 deletions
diff --git a/arch/mn10300/kernel/kgdb.c b/arch/mn10300/kernel/kgdb.c index 7d575f55309..f6c981db2a3 100644 --- a/arch/mn10300/kernel/kgdb.c +++ b/arch/mn10300/kernel/kgdb.c @@ -9,6 +9,7 @@ * 2 of the Licence, or (at your option) any later version. */ +#include <linux/slab.h> #include <linux/ptrace.h> #include <linux/kgdb.h> #include <linux/uaccess.h> @@ -19,6 +20,13 @@ #include "internal.h" /* + * Software single-stepping breakpoint save (used by __switch_to()) + */ +static struct thread_info *kgdb_sstep_thread; +u8 *kgdb_sstep_bp_addr[2]; +u8 kgdb_sstep_bp[2]; + +/* * Copy kernel exception frame registers to the GDB register file */ void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) @@ -118,8 +126,293 @@ struct kgdb_arch arch_kgdb_ops = { .flags = KGDB_HW_BREAKPOINT, }; +static const unsigned char mn10300_kgdb_insn_sizes[256] = +{ + /* 1 2 3 4 5 6 7 8 9 a b c d e f */ + 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */ + 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */ + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */ + 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */ + 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */ + 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */ + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */ + 0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1 /* f */ +}; + /* - * Handle unknown packets and [Ccs] packets + * Attempt to emulate single stepping by means of breakpoint instructions. + * Although there is a single-step trace flag in EPSW, its use is not + * sufficiently documented and is only intended for use with the JTAG debugger. + */ +static int kgdb_arch_do_singlestep(struct pt_regs *regs) +{ + unsigned long arg; + unsigned size; + u8 *pc = (u8 *)regs->pc, *sp = (u8 *)(regs + 1), cur; + u8 *x = NULL, *y = NULL; + int ret; + + ret = probe_kernel_read(&cur, pc, 1); + if (ret < 0) + return ret; + + size = mn10300_kgdb_insn_sizes[cur]; + if (size > 0) { + x = pc + size; + goto set_x; + } + + switch (cur) { + /* Bxx (d8,PC) */ + case 0xc0 ... 0xca: + ret = probe_kernel_read(&arg, pc + 1, 1); + if (ret < 0) + return ret; + x = pc + 2; + if (arg >= 0 && arg <= 2) + goto set_x; + y = pc + (s8)arg; + goto set_x_and_y; + + /* LXX (d8,PC) */ + case 0xd0 ... 0xda: + x = pc + 1; + if (regs->pc == regs->lar) + goto set_x; + y = (u8 *)regs->lar; + goto set_x_and_y; + + /* SETLB - loads the next four bytes into the LIR register + * (which mustn't include a breakpoint instruction) */ + case 0xdb: + x = pc + 5; + goto set_x; + + /* JMP (d16,PC) or CALL (d16,PC) */ + case 0xcc: + case 0xcd: + ret = probe_kernel_read(&arg, pc + 1, 2); + if (ret < 0) + return ret; + x = pc + (s16)arg; + goto set_x; + + /* JMP (d32,PC) or CALL (d32,PC) */ + case 0xdc: + case 0xdd: + ret = probe_kernel_read(&arg, pc + 1, 4); + if (ret < 0) + return ret; + x = pc + (s32)arg; + goto set_x; + + /* RETF */ + case 0xde: + x = (u8 *)regs->mdr; + goto set_x; + + /* RET */ + case 0xdf: + ret = probe_kernel_read(&arg, pc + 2, 1); + if (ret < 0) + return ret; + ret = probe_kernel_read(&x, sp + (s8)arg, 4); + if (ret < 0) + return ret; + goto set_x; + + case 0xf0: + ret = probe_kernel_read(&cur, pc + 1, 1); + if (ret < 0) + return ret; + + if (cur >= 0xf0 && cur <= 0xf7) { + /* JMP (An) / CALLS (An) */ + switch (cur & 3) { + case 0: x = (u8 *)regs->a0; break; + case 1: x = (u8 *)regs->a1; break; + case 2: x = (u8 *)regs->a2; break; + case 3: x = (u8 *)regs->a3; break; + } + goto set_x; + } else if (cur == 0xfc) { + /* RETS */ + ret = probe_kernel_read(&x, sp, 4); + if (ret < 0) + return ret; + goto set_x; + } else if (cur == 0xfd) { + /* RTI */ + ret = probe_kernel_read(&x, sp + 4, 4); + if (ret < 0) + return ret; + goto set_x; + } else { + x = pc + 2; + goto set_x; + } + break; + + /* potential 3-byte conditional branches */ + case 0xf8: + ret = probe_kernel_read(&cur, pc + 1, 1); + if (ret < 0) + return ret; + x = pc + 3; + + if (cur >= 0xe8 && cur <= 0xeb) { + ret = probe_kernel_read(&arg, pc + 2, 1); + if (ret < 0) + return ret; + if (arg >= 0 && arg <= 3) + goto set_x; + y = pc + (s8)arg; + goto set_x_and_y; + } + goto set_x; + + case 0xfa: + ret = probe_kernel_read(&cur, pc + 1, 1); + if (ret < 0) + return ret; + + if (cur == 0xff) { + /* CALLS (d16,PC) */ + ret = probe_kernel_read(&arg, pc + 2, 2); + if (ret < 0) + return ret; + x = pc + (s16)arg; + goto set_x; + } + + x = pc + 4; + goto set_x; + + case 0xfc: + ret = probe_kernel_read(&cur, pc + 1, 1); + if (ret < 0) + return ret; + + if (cur == 0xff) { + /* CALLS (d32,PC) */ + ret = probe_kernel_read(&arg, pc + 2, 4); + if (ret < 0) + return ret; + x = pc + (s32)arg; + goto set_x; + } + + x = pc + 6; + goto set_x; + } + + return 0; + +set_x: + kgdb_sstep_bp_addr[0] = x; + kgdb_sstep_bp_addr[1] = NULL; + ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1); + if (ret < 0) + return ret; + ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1); + if (ret < 0) + return ret; + kgdb_sstep_thread = current_thread_info(); + debugger_local_cache_flushinv_one(x); + return ret; + +set_x_and_y: + kgdb_sstep_bp_addr[0] = x; + kgdb_sstep_bp_addr[1] = y; + ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1); + if (ret < 0) + return ret; + ret = probe_kernel_read(&kgdb_sstep_bp[1], y, 1); + if (ret < 0) + return ret; + ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1); + if (ret < 0) + return ret; + ret = probe_kernel_write(y, &arch_kgdb_ops.gdb_bpt_instr, 1); + if (ret < 0) { + probe_kernel_write(kgdb_sstep_bp_addr[0], + &kgdb_sstep_bp[0], 1); + } else { + kgdb_sstep_thread = current_thread_info(); + } + debugger_local_cache_flushinv_one(x); + debugger_local_cache_flushinv_one(y); + return ret; +} + +/* + * Remove emplaced single-step breakpoints, returning true if we hit one of + * them. + */ +static bool kgdb_arch_undo_singlestep(struct pt_regs *regs) +{ + bool hit = false; + u8 *x = kgdb_sstep_bp_addr[0], *y = kgdb_sstep_bp_addr[1]; + u8 opcode; + + if (kgdb_sstep_thread == current_thread_info()) { + if (x) { + if (x == (u8 *)regs->pc) + hit = true; + if (probe_kernel_read(&opcode, x, + 1) < 0 || + opcode != 0xff) + BUG(); + probe_kernel_write(x, &kgdb_sstep_bp[0], 1); + debugger_local_cache_flushinv_one(x); + } + if (y) { + if (y == (u8 *)regs->pc) + hit = true; + if (probe_kernel_read(&opcode, y, + 1) < 0 || + opcode != 0xff) + BUG(); + probe_kernel_write(y, &kgdb_sstep_bp[1], 1); + debugger_local_cache_flushinv_one(y); + } + } + + kgdb_sstep_bp_addr[0] = NULL; + kgdb_sstep_bp_addr[1] = NULL; + kgdb_sstep_thread = NULL; + return hit; +} + +/* + * Catch a single-step-pending thread being deleted and make sure the global + * single-step state is cleared. At this point the breakpoints should have + * been removed by __switch_to(). + */ +void free_thread_info(struct thread_info *ti) +{ + if (kgdb_sstep_thread == ti) { + kgdb_sstep_thread = NULL; + + /* However, we may now be running in degraded mode, with most + * of the CPUs disabled until such a time as KGDB is reentered, + * so force immediate reentry */ + kgdb_breakpoint(); + } + kfree(ti); +} + +/* + * Handle unknown packets and [CcsDk] packets + * - at this point breakpoints have been installed */ int kgdb_arch_handle_exception(int vector, int signo, int err_code, char *remcom_in_buffer, char *remcom_out_buffer, @@ -130,21 +423,22 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code, switch (remcom_in_buffer[0]) { case 'c': - if (kgdb_contthread && kgdb_contthread != current) { - strcpy(remcom_out_buffer, "E00"); - break; - } - - kgdb_contthread = NULL; - + case 's': /* try to read optional parameter, pc unchanged if no parm */ ptr = &remcom_in_buffer[1]; if (kgdb_hex2long(&ptr, &addr)) regs->pc = addr; - return 0; + case 'D': + case 'k': + atomic_set(&kgdb_cpu_doing_single_step, -1); - case 's': - break; /* we don't do hardware single stepping */ + if (remcom_in_buffer[0] == 's') { + kgdb_arch_do_singlestep(regs); + kgdb_single_step = 1; + atomic_set(&kgdb_cpu_doing_single_step, + raw_smp_processor_id()); + } + return 0; } return -1; /* this means that we do not want to exit from the handler */ } @@ -158,6 +452,12 @@ int debugger_intercept(enum exception_code excep, int signo, int si_code, { int ret; + if (kgdb_arch_undo_singlestep(regs)) { + excep = EXCEP_TRAP; + signo = SIGTRAP; + si_code = TRAP_TRACE; + } + ret = kgdb_handle_exception(excep, signo, si_code, regs); debugger_local_cache_flushinv(); diff --git a/arch/mn10300/kernel/switch_to.S b/arch/mn10300/kernel/switch_to.S index 9074d0fb878..de3e74fc9ea 100644 --- a/arch/mn10300/kernel/switch_to.S +++ b/arch/mn10300/kernel/switch_to.S @@ -39,11 +39,17 @@ ENTRY(__switch_to) # save prev context mov __switch_back,d0 - mov d0,(THREAD_PC,a0) mov sp,a2 mov a2,(THREAD_SP,a0) mov a3,(THREAD_A3,a0) +#ifdef CONFIG_KGDB + btst 0xff,(kgdb_single_step) + bne __switch_to__lift_sstep_bp +__switch_to__continue: +#endif + mov d0,(THREAD_PC,a0) + mov (THREAD_A3,a1),a3 mov (THREAD_SP,a1),a2 @@ -68,3 +74,106 @@ ENTRY(__switch_to) __switch_back: and ~EPSW_NMID,epsw ret [d2,d3,a2,a3,exreg1],32 + +#ifdef CONFIG_KGDB +############################################################################### +# +# Lift the single-step breakpoints when the task being traced is switched out +# A0 = prev +# A1 = next +# +############################################################################### +__switch_to__lift_sstep_bp: + add -12,sp + mov a0,e4 + mov a1,e5 + + # Clear the single-step flag to prevent us coming this way until we get + # switched back in + bclr 0xff,(kgdb_single_step) + + # Remove first breakpoint + mov (kgdb_sstep_bp_addr),a2 + cmp 0,a2 + beq 1f + movbu (kgdb_sstep_bp),d0 + movbu d0,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +1: + + # Remove second breakpoint + mov (kgdb_sstep_bp_addr+4),a2 + cmp 0,a2 + beq 2f + movbu (kgdb_sstep_bp+1),d0 + movbu d0,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +2: + + # Change the resumption address and return + mov __switch_back__reinstall_sstep_bp,d0 + mov e4,a0 + mov e5,a1 + add 12,sp + bra __switch_to__continue + +############################################################################### +# +# Reinstall the single-step breakpoints when the task being traced is switched +# back in (A1 points to the new thread_struct). +# +############################################################################### +__switch_back__reinstall_sstep_bp: + add -12,sp + mov a0,e4 # save the return value + mov 0xff,d3 + + # Reinstall first breakpoint + mov (kgdb_sstep_bp_addr),a2 + cmp 0,a2 + beq 1f + movbu (a2),d0 + movbu d0,(kgdb_sstep_bp) + movbu d3,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +1: + + # Reinstall second breakpoint + mov (kgdb_sstep_bp_addr+4),a2 + cmp 0,a2 + beq 2f + movbu (a2),d0 + movbu d0,(kgdb_sstep_bp+1) + movbu d3,(a2) +#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) + mov a2,d0 + mov a2,d1 + add 1,d1 + calls flush_icache_range +#endif +2: + + mov d3,(kgdb_single_step) + + # Restore the return value (the previous thread_struct pointer) + mov e4,a0 + mov a0,d0 + add 12,sp + bra __switch_back + +#endif /* CONFIG_KGDB */ |