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.tz...@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);
--
1.6.0.6
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