[PATCH 03/17] kgdb,kdb: individual register set and and get API

From: Jason Wessel
Date: Thu Aug 05 2010 - 10:45:13 EST

The kdb shell specification includes the ability to get and set
architecture specific registers by name.

For the time being individual register get and set will be implemented
on a per architecture basis. If an architecture defines
DBG_MAX_REG_NUM > 0 then kdb and the gdbstub will use the capability
for individually getting and setting architecture specific registers.

Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
---
include/linux/kgdb.h | 13 ++++
kernel/debug/gdbstub.c | 26 +++++++++
kernel/debug/kdb/kdb_main.c | 132 +++++++++++++++++++++++++++++++++++++++----
3 files changed, 159 insertions(+), 12 deletions(-)

diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index 9340f34..d5eb882 100644
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -90,6 +90,19 @@ struct kgdb_bkpt {
enum kgdb_bpstate state;
};

+struct dbg_reg_def_t {
+ char *name;
+ int size;
+ int offset;
+};
+
+#ifndef DBG_MAX_REG_NUM
+#define DBG_MAX_REG_NUM 0
+#else
+extern struct dbg_reg_def_t dbg_reg_def[];
+extern char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs);
+extern int dbg_set_reg(int regno, void *mem, struct pt_regs *regs);
+#endif
#ifndef KGDB_MAX_BREAKPOINTS
# define KGDB_MAX_BREAKPOINTS 1000
#endif
diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
index e117cfd..006bad8 100644
--- a/kernel/debug/gdbstub.c
+++ b/kernel/debug/gdbstub.c
@@ -328,6 +328,32 @@ static int kgdb_ebin2mem(char *buf, char *mem, int count)
return probe_kernel_write(mem, c, size);
}

+#if DBG_MAX_REG_NUM > 0
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ int i;
+ int idx = 0;
+ char *ptr = (char *)gdb_regs;
+
+ for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+ dbg_get_reg(i, ptr + idx, regs);
+ idx += dbg_reg_def[i].size;
+ }
+}
+
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ int i;
+ int idx = 0;
+ char *ptr = (char *)gdb_regs;
+
+ for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+ dbg_set_reg(i, ptr + idx, regs);
+ idx += dbg_reg_def[i].size;
+ }
+}
+#endif /* DBG_MAX_REG_NUM > 0 */
+
/* Write memory due to an 'M' or 'X' packet. */
static int write_mem_msg(int binary)
{
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index ebe4a28..8577e45 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -312,7 +312,7 @@ int kdbgetularg(const char *arg, unsigned long *value)

if (endp == arg) {
/*
- * Try base 16, for us folks too lazy to type the
+ * Also try base 16, for us folks too lazy to type the
* leading 0x...
*/
val = simple_strtoul(arg, &endp, 16);
@@ -325,6 +325,25 @@ int kdbgetularg(const char *arg, unsigned long *value)
return 0;
}

+int kdbgetu64arg(const char *arg, u64 *value)
+{
+ char *endp;
+ u64 val;
+
+ val = simple_strtoull(arg, &endp, 0);
+
+ if (endp == arg) {
+
+ val = simple_strtoull(arg, &endp, 16);
+ if (endp == arg)
+ return KDB_BADINT;
+ }
+
+ *value = val;
+
+ return 0;
+}
+
/*
* kdb_set - This function implements the 'set' command. Alter an
* existing environment variable or create a new one.
@@ -1770,11 +1789,65 @@ static int kdb_go(int argc, const char **argv)
*/
static int kdb_rd(int argc, const char **argv)
{
- int diag = kdb_check_regs();
- if (diag)
- return diag;
+ int len = kdb_check_regs();
+#if DBG_MAX_REG_NUM > 0
+ int i;
+ char *rname;
+ int rsize;
+ u64 reg64;
+ u32 reg32;
+ u16 reg16;
+ u8 reg8;
+
+ if (len)
+ return len;
+
+ for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+ rsize = dbg_reg_def[i].size * 2;
+ if (rsize > 16)
+ rsize = 2;
+ if (len + strlen(dbg_reg_def[i].name) + 4 + rsize > 80) {
+ len = 0;
+ kdb_printf("\n");
+ }
+ if (len)
+ len += kdb_printf(" ");
+ switch(dbg_reg_def[i].size * 8) {
+ case 8:
+ rname = dbg_get_reg(i, &reg8, kdb_current_regs);
+ if (!rname)
+ break;
+ len += kdb_printf("%s: %02x", rname, reg8);
+ break;
+ case 16:
+ rname = dbg_get_reg(i, &reg16, kdb_current_regs);
+ if (!rname)
+ break;
+ len += kdb_printf("%s: %04x", rname, reg16);
+ break;
+ case 32:
+ rname = dbg_get_reg(i, &reg32, kdb_current_regs);
+ if (!rname)
+ break;
+ len += kdb_printf("%s: %08x", rname, reg32);
+ break;
+ case 64:
+ rname = dbg_get_reg(i, &reg64, kdb_current_regs);
+ if (!rname)
+ break;
+ len += kdb_printf("%s: %016llx", rname, reg64);
+ break;
+ default:
+ len += kdb_printf("%s: ??", dbg_reg_def[i].name);
+ }
+ }
+ kdb_printf("\n");
+#else
+ if (len)
+ return len;

kdb_dumpregs(kdb_current_regs);
+#endif
return 0;
}

@@ -1782,32 +1855,67 @@ static int kdb_rd(int argc, const char **argv)
* kdb_rm - This function implements the 'rm' (register modify) command.
* rm register-name new-contents
* Remarks:
- * Currently doesn't allow modification of control or
- * debug registers.
+ * Allows register modification with the same restrictions as gdb
*/
static int kdb_rm(int argc, const char **argv)
{
+#if DBG_MAX_REG_NUM > 0
int diag;
- int ind = 0;
- unsigned long contents;
+ const char *rname;
+ int i;
+ u64 reg64;
+ u32 reg32;
+ u16 reg16;
+ u8 reg8;

if (argc != 2)
return KDB_ARGCOUNT;
/*
* Allow presence or absence of leading '%' symbol.
*/
- if (argv[1][0] == '%')
- ind = 1;
+ rname = argv[1];
+ if (*rname == '%')
+ rname++;

- diag = kdbgetularg(argv[2], &contents);
+ diag = kdbgetu64arg(argv[2], &reg64);
if (diag)
return diag;

diag = kdb_check_regs();
if (diag)
return diag;
+
+ diag = KDB_BADREG;
+ for (i = 0; i < DBG_MAX_REG_NUM; i++) {
+ if (strcmp(rname, dbg_reg_def[i].name) == 0) {
+ diag = 0;
+ break;
+ }
+ }
+ if (!diag) {
+ switch(dbg_reg_def[i].size * 8) {
+ case 8:
+ reg8 = reg64;
+ dbg_set_reg(i, &reg8, kdb_current_regs);
+ break;
+ case 16:
+ reg16 = reg64;
+ dbg_set_reg(i, &reg16, kdb_current_regs);
+ break;
+ case 32:
+ reg32 = reg64;
+ dbg_set_reg(i, &reg32, kdb_current_regs);
+ break;
+ case 64:
+ dbg_set_reg(i, &reg64, kdb_current_regs);
+ break;
+ }
+ }
+ return diag;
+#else
kdb_printf("ERROR: Register set currently not implemented\n");
- return 0;
+ return 0;
+#endif
}

#if defined(CONFIG_MAGIC_SYSRQ)
--
1.6.3.3

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