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kgdb,debug_core: pass the breakpoint struct instead of address and memory 

There is extra state information that needs to be exposed in the
kgdb_bpt structure for tracking how a breakpoint was installed.  The
debug_core only uses the the probe_kernel_write() to install
breakpoints, but this is not enough for all the archs.  Some arch such
as x86 need to use text_poke() in order to install a breakpoint into a
read only page.

Passing the kgdb_bpt structure to kgdb_arch_set_breakpoint() and
kgdb_arch_remove_breakpoint() allows other archs to set the type
variable which indicates how the breakpoint was installed.

Cc: stable@vger.kernel.org # >= 2.6.36
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
This commit is contained in:
Jason Wessel 2012-03-21 10:17:03 -05:00
parent 23bbd8e346
commit 98b54aa1a2
2 changed files with 26 additions and 31 deletions
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4
include/linux/kgdb.h
View File

@ -207,8 +207,8 @@ extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc);
/* Optional functions. */ /* Optional functions. */
extern int kgdb_validate_break_address(unsigned long addr); extern int kgdb_validate_break_address(unsigned long addr);
extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr); extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);
extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle); extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);
/** /**
* kgdb_arch_late - Perform any architecture specific initalization. * kgdb_arch_late - Perform any architecture specific initalization.

53
kernel/debug/debug_core.c
View File

@ -161,37 +161,39 @@ early_param("nokgdbroundup", opt_nokgdbroundup);
* Weak aliases for breakpoint management, * Weak aliases for breakpoint management,
* can be overriden by architectures when needed: * can be overriden by architectures when needed:
*/ */
int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{ {
int err; int err;
err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE); err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
BREAK_INSTR_SIZE);
if (err) if (err)
return err; return err;
err = probe_kernel_write((char *)bpt->bpt_addr,
return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
BREAK_INSTR_SIZE); return err;
} }
int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{ {
return probe_kernel_write((char *)addr, return probe_kernel_write((char *)bpt->bpt_addr,
(char *)bundle, BREAK_INSTR_SIZE); (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
} }
int __weak kgdb_validate_break_address(unsigned long addr) int __weak kgdb_validate_break_address(unsigned long addr)
{ {
char tmp_variable[BREAK_INSTR_SIZE]; struct kgdb_bkpt tmp;
int err; int err;
/* Validate setting the breakpoint and then removing it. In the /* Validate setting the breakpoint and then removing it. If the
* remove fails, the kernel needs to emit a bad message because we * remove fails, the kernel needs to emit a bad message because we
* are deep trouble not being able to put things back the way we * are deep trouble not being able to put things back the way we
* found them. * found them.
*/ */
err = kgdb_arch_set_breakpoint(addr, tmp_variable); tmp.bpt_addr = addr;
err = kgdb_arch_set_breakpoint(&tmp);
if (err) if (err)
return err; return err;
err = kgdb_arch_remove_breakpoint(addr, tmp_variable); err = kgdb_arch_remove_breakpoint(&tmp);
if (err) if (err)
printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
"memory destroyed at: %lx", addr); "memory destroyed at: %lx", addr);
@ -235,7 +237,6 @@ static void kgdb_flush_swbreak_addr(unsigned long addr)
*/ */
int dbg_activate_sw_breakpoints(void) int dbg_activate_sw_breakpoints(void)
{ {
unsigned long addr;
int error; int error;
int ret = 0; int ret = 0;
int i; int i;
@ -244,16 +245,15 @@ int dbg_activate_sw_breakpoints(void)
if (kgdb_break[i].state != BP_SET) if (kgdb_break[i].state != BP_SET)
continue; continue;
addr = kgdb_break[i].bpt_addr; error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
error = kgdb_arch_set_breakpoint(addr,
kgdb_break[i].saved_instr);
if (error) { if (error) {
ret = error; ret = error;
printk(KERN_INFO "KGDB: BP install failed: %lx", addr); printk(KERN_INFO "KGDB: BP install failed: %lx",
kgdb_break[i].bpt_addr);
continue; continue;
} }
kgdb_flush_swbreak_addr(addr); kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
kgdb_break[i].state = BP_ACTIVE; kgdb_break[i].state = BP_ACTIVE;
} }
return ret; return ret;
@ -302,7 +302,6 @@ int dbg_set_sw_break(unsigned long addr)
int dbg_deactivate_sw_breakpoints(void) int dbg_deactivate_sw_breakpoints(void)
{ {
unsigned long addr;
int error; int error;
int ret = 0; int ret = 0;
int i; int i;
@ -310,15 +309,14 @@ int dbg_deactivate_sw_breakpoints(void)
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
if (kgdb_break[i].state != BP_ACTIVE) if (kgdb_break[i].state != BP_ACTIVE)
continue; continue;
addr = kgdb_break[i].bpt_addr; error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
error = kgdb_arch_remove_breakpoint(addr,
kgdb_break[i].saved_instr);
if (error) { if (error) {
printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr); printk(KERN_INFO "KGDB: BP remove failed: %lx\n",
kgdb_break[i].bpt_addr);
ret = error; ret = error;
} }
kgdb_flush_swbreak_addr(addr); kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
kgdb_break[i].state = BP_SET; kgdb_break[i].state = BP_SET;
} }
return ret; return ret;
@ -352,7 +350,6 @@ int kgdb_isremovedbreak(unsigned long addr)
int dbg_remove_all_break(void) int dbg_remove_all_break(void)
{ {
unsigned long addr;
int error; int error;
int i; int i;
@ -360,12 +357,10 @@ int dbg_remove_all_break(void)
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
if (kgdb_break[i].state != BP_ACTIVE) if (kgdb_break[i].state != BP_ACTIVE)
goto setundefined; goto setundefined;
addr = kgdb_break[i].bpt_addr; error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
error = kgdb_arch_remove_breakpoint(addr,
kgdb_break[i].saved_instr);
if (error) if (error)
printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n", printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
addr); kgdb_break[i].bpt_addr);
setundefined: setundefined:
kgdb_break[i].state = BP_UNDEFINED; kgdb_break[i].state = BP_UNDEFINED;
} }