This patch extends the current KGDB logic to handle 'Z' and 'z' GDB packets for setting or removing breakpoints.
Two weak functions have been added to the kgdb_stub.c: arch_kgdb_set_sw_break() and arch_kgdb_remove_sw_break() could be overrode by the arch implementations.
Please note, after applying this patch, those architectures, which already enabled KGDB support, have to create a new asm/kgdb.h and define the length of the break instruction (BREAK_INSTR_SIZE) in that file.
Signed-off-by: Tonny Tzeng tonny.tzeng@gmail.com --- common/kgdb.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++ common/kgdb_stubs.c | 12 +++++++ include/kgdb.h | 31 ++++++++++++++++++ 3 files changed, 128 insertions(+), 0 deletions(-)
diff --git a/common/kgdb.c b/common/kgdb.c index 0531452..66378e5 100644 --- a/common/kgdb.c +++ b/common/kgdb.c @@ -220,6 +220,85 @@ hexToInt(char **ptr, int *intValue) return (numChars); }
+/* + * Holds information about breakpoints in a kernel. These breakpoints are + * added and removed by gdb. + */ +static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS]; + +static int kgdb_set_sw_break(int addr) +{ + int i, breakno = -1; + struct kgdb_bkpt *bkpt; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_SET) && + (kgdb_break[i].bpt_addr == addr)) + return -KGDBERR_BPEXIST; + if ((kgdb_break[i].state == BP_REMOVED) && + (kgdb_break[i].bpt_addr == addr)) { + breakno = i; + break; + } + } + if (breakno == -1) + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state == BP_UNDEFINED) { + breakno = i; + break; + } + } + if (breakno == -1) + return -KGDBERR_BPNOENT; + + bkpt = kgdb_break + breakno; + bkpt->state = BP_SET; + bkpt->type = BP_BREAKPOINT; + bkpt->bpt_addr = addr; + arch_kgdb_set_sw_break(bkpt); + + return 0; +} + +static int kgdb_remove_sw_break(int addr) +{ + int i; + struct kgdb_bkpt *bkpt; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + bkpt = kgdb_break + i; + if ((bkpt->state == BP_SET) && (bkpt->bpt_addr == addr)) { + bkpt->state = BP_REMOVED; + arch_kgdb_remove_sw_break(bkpt); + return 0; + } + } + return -KGDBERR_BPNOENT; +} + +/* Handle the 'z' or 'Z' breakpoint remove or set packets */ +static void gdb_cmd_break(kgdb_data *kdp) +{ + /* + * Since GDB-5.3, it's been drafted that '0' is a software + * breakpoint, '1' is a hardware breakpoint, so let's do that. + */ + char *bpt_type = &remcomInBuffer[1]; + char *ptr = &remcomInBuffer[2]; + int addr, length; + + if (*bpt_type != '0') + return; /* Unsupported. */ + if (*ptr++ != ',' || !hexToInt(&ptr, &addr) || + *ptr++ != ',' || !hexToInt(&ptr, &length)) { + kgdb_error(KGDBERR_BADPARAMS); + } + + if ((remcomInBuffer[0] == 'Z' && kgdb_set_sw_break(addr) == 0) || + (remcomInBuffer[0] == 'z' && kgdb_remove_sw_break(addr) == 0)) + strcpy(remcomOutBuffer, "OK"); +} + /* scan for the sequence $<data>#<checksum> */ static void getpacket(char *buffer) @@ -341,7 +420,9 @@ handle_exception (struct pt_regs *regs)
kgdb_interruptible(0);
+#ifdef KGDB_DEBUG printf("kgdb: handle_exception; trap [0x%x]\n", kgdb_trap(regs)); +#endif
if (kgdb_setjmp(error_jmp_buf) != 0) panic("kgdb: error or fault in entry init!\n"); @@ -516,6 +597,10 @@ handle_exception (struct pt_regs *regs) kgdb_error(KGDBERR_BADPARAMS); } break; + case 'Z': /* [Z|z]N,AA..AA,LLLL Set/Remove breakpoint type N */ + case 'z': /* LLLL bytes at address AA.AA return OK */ + gdb_cmd_break(&kd); + break; } /* switch */
if (errnum != 0) diff --git a/common/kgdb_stubs.c b/common/kgdb_stubs.c index 19b0c18..2b3f424 100644 --- a/common/kgdb_stubs.c +++ b/common/kgdb_stubs.c @@ -45,6 +45,18 @@ void kgdb_interruptible(int yes) }
__attribute__((weak)) +void arch_kgdb_set_sw_break(struct kgdb_bkpt *bkpt) +{ + return; +} + +__attribute__((weak)) +void arch_kgdb_remove_sw_break(struct kgdb_bkpt *bkpt) +{ + return; +} + +__attribute__((weak)) void kgdb_flush_cache_range(void *from, void *to) { flush_cache((unsigned long)from, (unsigned long)(to - from)); diff --git a/include/kgdb.h b/include/kgdb.h index f543cd6..82ae8ab 100644 --- a/include/kgdb.h +++ b/include/kgdb.h @@ -2,12 +2,41 @@ #define __KGDB_H__
#include <asm/ptrace.h> +#include <asm/kgdb.h>
#define KGDBERR_BADPARAMS 1 #define KGDBERR_NOTHEXDIG 2 #define KGDBERR_MEMFAULT 3 #define KGDBERR_NOSPACE 4 #define KGDBERR_ALIGNFAULT 5 +#define KGDBERR_BPEXIST 6 +#define KGDBERR_BPNOENT 7 + +#ifndef KGDB_MAX_BREAKPOINTS +#define KGDB_MAX_BREAKPOINTS 1000 +#endif + +enum kgdb_bptype { + BP_BREAKPOINT = 0, + BP_HARDWARE_BREAKPOINT, + BP_WRITE_WATCHPOINT, + BP_READ_WATCHPOINT, + BP_ACCESS_WATCHPOINT +}; + +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; +};
#define KGDBDATA_MAXREGS 8 #define KGDBDATA_MAXPRIV 8 @@ -56,6 +85,8 @@ extern void kgdb_putreg(struct pt_regs *, int, char *, int); extern void kgdb_putregs(struct pt_regs *, char *, int); extern int kgdb_trap(struct pt_regs *); extern void kgdb_breakpoint(int argc, char *argv[]); +extern void arch_kgdb_set_sw_break(struct kgdb_bkpt *); +extern void arch_kgdb_remove_sw_break(struct kgdb_bkpt *);
/* these functions are provided by the platform serial driver */ extern void kgdb_serial_init(void);