Add Z/z protocal support for breakpoint set/remove.
Signed-off-by: Peng Fan Peng.Fan@freescale.com --- common/kgdb.c | 273 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ include/kgdb.h | 35 ++++++++ 2 files changed, 308 insertions(+)
diff --git a/common/kgdb.c b/common/kgdb.c index d357463..fd83ccd 100644 --- a/common/kgdb.c +++ b/common/kgdb.c @@ -92,6 +92,8 @@ #include <kgdb.h> #include <command.h>
+#include <asm-generic/errno.h> + #undef KGDB_DEBUG
/* @@ -111,6 +113,17 @@ static int longjmp_on_fault = 0; static int kdebug = 1; #endif
+struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { + [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } +}; + +#ifdef CONFIG_ARM +unsigned char gdb_bpt_instr[4] = {0xfe, 0xde, 0xff, 0xe7}; +#else +#error "Please implement gdb_bpt_instr!" +#endif + + static const char hexchars[]="0123456789abcdef";
/* Convert ch from a hex digit to an int */ @@ -309,6 +322,200 @@ putpacket(unsigned char *buffer) } while ((recv & 0x7f) != '+'); }
+int kgdb_validate_break_address(unsigned addr) +{ + /* Need More */ + return 0; +} + +static int probe_kernel_read(unsigned char *dst, void *src, size_t size) +{ + int i; + unsigned char *dst_ptr = dst; + unsigned char *src_ptr = src; + + for (i = 0; i < size; i++) + *dst_ptr++ = *src_ptr++; + + return 0; +} + +static int probe_kernel_write(char *dst, void *src, size_t size) +{ + int i; + char *dst_ptr = dst; + char *src_ptr = src; + + for (i = 0; i < size; i++) + *dst_ptr++ = *src_ptr++; + + return 0; +} + +__weak int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) +{ + int err; + + err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, + BREAK_INSTR_SIZE); + if (err) + return err; + + err = probe_kernel_write((char *)bpt->bpt_addr, gdb_bpt_instr, + BREAK_INSTR_SIZE); + + return err; +} + +/* + * Set the breakpoints whose state is BP_SET to BP_ACTIVE + */ +int kgdb_active_sw_breakpoints(void) +{ + int err; + int ret = 0; + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_SET) + continue; + + err = kgdb_arch_set_breakpoint(&kgdb_break[i]); + if (err) { + ret = err; + printf("KGDB: BP install failed: %lx\n", + kgdb_break[i].bpt_addr); + continue; + } + + kgdb_break[i].state = BP_ACTIVE; + + /* + * kgdb_arch_set_breakpoint touched dcache and memory. + * cache should be flushed to let icache can see the updated + * inst. + */ + /* flush work is done in do_exit */ + kgdb_flush_cache_all(); + } + + return ret; +} + +/* + * Set state from BP_SET to BP_REMOVED + */ +int kgdb_remove_sw_breakpoint(unsigned int addr) +{ + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_SET) && + (kgdb_break[i].bpt_addr == addr)) { + kgdb_break[i].state = BP_REMOVED; + return 0; + } + } + + return -ENOENT; +} + +int kgdb_set_sw_breakpoint(unsigned int addr) +{ + int err = kgdb_validate_break_address(addr); + int breakno = -1; + int i; + + if (err) + return err; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_SET) && + (kgdb_break[i].bpt_addr == addr)) + return -EEXIST; + } + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + /* removed or unused, use it */ + if ((kgdb_break[i].state == BP_REMOVED) || + (kgdb_break[i].state == BP_UNDEFINED)) { + breakno = i; + break; + } + } + + if (breakno == -1) + return -E2BIG; + + kgdb_break[breakno].state = BP_SET; + kgdb_break[breakno].type = BP_BREAKPOINT; + kgdb_break[breakno].bpt_addr = addr; + + return 0; +} + +__weak int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) +{ + return probe_kernel_write((char *)bpt->bpt_addr, + (char *)bpt->saved_instr, BREAK_INSTR_SIZE); +} + +/* + * set breakpoints whose state is BP_ACTIVE to BP_SET + */ +int kgdb_deactivate_sw_breakpoints(void) +{ + int err; + int ret = 0; + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_ACTIVE) + continue; + + err = kgdb_arch_remove_breakpoint(&kgdb_break[i]); + if (err) { + printf("KGDB: BP remove failed: %lx\n", + kgdb_break[i].bpt_addr); + ret = err; + } + + kgdb_break[i].state = BP_SET; + + /* + * kgdb_arch_remove_breakpoint touched dcache and memory. + * cache should be flushed to let icache can see the updated + * inst. + */ + kgdb_flush_cache_all(); + } + + return ret; +} + +static int kgdb_remove_all_break(void) +{ + int err; + int i; + + /* Clear memory breakpoints. */ + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_ACTIVE) + goto setundefined; + err = kgdb_arch_remove_breakpoint(&kgdb_break[i]); + if (err) + printf("KGDB: breakpoint remove failed: %lx\n", + kgdb_break[i].bpt_addr); +setundefined: + kgdb_break[i].state = BP_UNDEFINED; + } + + /* clear hardware breakpoints. */ + /* ToDo in future. */ + + return 0; +} + /* * This function does all command processing for interfacing to gdb. */ @@ -318,6 +525,7 @@ handle_exception (struct pt_regs *regs) int addr; int length; char *ptr; + char *bpt_type; kgdb_data kd; int i;
@@ -376,6 +584,12 @@ handle_exception (struct pt_regs *regs)
putpacket((unsigned char *)&remcomOutBuffer);
+ /* + * Each time trigger a kgdb break, first deactive all active + * breakpoints. + */ + kgdb_deactivate_sw_breakpoints(); + while (1) { volatile int errnum;
@@ -394,6 +608,8 @@ handle_exception (struct pt_regs *regs) if (errnum == 0) switch (remcomInBuffer[0]) {
case '?': /* report most recent signal */ + kgdb_remove_all_break(); + remcomOutBuffer[0] = 'S'; remcomOutBuffer[1] = hexchars[kd.sigval >> 4]; remcomOutBuffer[2] = hexchars[kd.sigval & 0xf]; @@ -465,6 +681,8 @@ handle_exception (struct pt_regs *regs) kd.extype |= KGDBEXIT_WITHADDR; }
+ kgdb_active_sw_breakpoints(); + goto doexit;
case 'S': /* SSS single step with signal SS */ @@ -479,6 +697,8 @@ handle_exception (struct pt_regs *regs) kd.extype |= KGDBEXIT_WITHADDR; }
+ kgdb_active_sw_breakpoints(); + doexit: /* Need to flush the instruction cache here, as we may have deposited a * breakpoint, and the icache probably has no way of knowing that a data ref to @@ -506,6 +726,59 @@ handle_exception (struct pt_regs *regs) kgdb_error(KGDBERR_BADPARAMS); } break; + case 'z': + /* + * Break point remove + * packet: zt,addr,length + */ + case 'Z': + /* + * Break point set + * packet: Zt,addr,length + * + * t is type: `0' - software breakpoint, + * `1' - hardware breakpoint, `2' - write watchpoint, + * `3' - read watchpoint, `4' - access watchpoint; + * addr is address; length is in bytes. For a software + * breakpoint, length specifies the size of the + * instruction to be patched. For hardware breakpoints + * and watchpoints length specifies the memory region + * to be monitored. To avoid potential problems with + * duplicate packets, the operations should be + * implemented in an idempotent way. + */ + bpt_type = &remcomInBuffer[1]; + ptr = &remcomInBuffer[2]; + + if (*(ptr++) != ',') { + errnum = -EINVAL; + break; + } + + if (!hexToInt(&ptr, &addr)) { + errnum = -EINVAL; + break; + } + + if (*ptr++ != ',') { + errnum = -EINVAL; + break; + } + + /* only software breakpoint is implemented */ + if ((remcomInBuffer[0] == 'Z') && (*bpt_type == '0')) { + errnum = kgdb_set_sw_breakpoint(addr); + } else if ((remcomInBuffer[0] == 'z') && + (*bpt_type == '0')) { + errnum = kgdb_remove_sw_breakpoint(addr); + } else { + /* Unsupported */ + errnum = -EINVAL; + } + + if (errnum == 0) + strcpy(remcomOutBuffer, "OK"); + break; } /* switch */
if (errnum != 0) diff --git a/include/kgdb.h b/include/kgdb.h index b6ba742..f9152b5 100644 --- a/include/kgdb.h +++ b/include/kgdb.h @@ -20,6 +20,12 @@
#define KGDBEXIT_WITHADDR 0x100
+#if defined(CONFIG_ARM) +#define BREAK_INSTR_SIZE 4 +#else +#error "BREAK_INSTR_SIZE not set" +#endif + typedef struct { int num; @@ -38,6 +44,29 @@ typedef } kgdb_data;
+enum kgdb_bptype { + BP_BREAKPOINT = 0, + BP_HARDWARE_BREAKPOINT, + BP_WRITE_WATCHPOINT, + BP_READ_WATCHPOINT, + BP_ACCESS_WATCHPOINT, + BP_POKE_BREAKPOINT, +}; + +enum kgdb_bpstate { + BP_UNDEFINED = 0, + BP_REMOVED, + BP_SET, + BP_ACTIVE +}; + +struct kgdb_bkpt { + unsigned long bpt_addr; + unsigned char saved_instr[BREAK_INSTR_SIZE]; + enum kgdb_bptype type; + enum kgdb_bpstate state; +}; + /* these functions are provided by the generic kgdb support */ extern void kgdb_init(void); extern void kgdb_error(int); @@ -67,4 +96,10 @@ extern void kgdb_interruptible(int); /* this is referenced in the trap handler for the platform */ extern int (*debugger_exception_handler)(struct pt_regs *);
+int kgdb_set_sw_break(unsigned int addr); +int kgdb_remove_sw_break(unsigned int addr); +int kgdb_validate_break_address(unsigned int addr); + +#define KGDB_MAX_BREAKPOINTS 32 + #endif /* __KGDB_H__ */