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Commit 98b54aa1 authored by Jason Wessel's avatar Jason Wessel
Browse files

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: default avatarJason Wessel <jason.wessel@windriver.com>
parent 23bbd8e3

include/linux/kgdb.h

+2 −2
Original line number Diff line number Diff line
@@ -207,8 +207,8 @@ extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc); 


/* Optional functions. */

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_remove_breakpoint(unsigned long addr, char *bundle);

extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);

extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);



/**

 *	kgdb_arch_late - Perform any architecture specific initalization.

kernel/debug/debug_core.c

+24 −29
Original line number Diff line number Diff line
@@ -161,37 +161,39 @@ early_param("nokgdbroundup", opt_nokgdbroundup); 
 * Weak aliases for breakpoint management,

 * 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;



	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)

		return err;



	return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,

				  BREAK_INSTR_SIZE);

	err = probe_kernel_write((char *)bpt->bpt_addr,

				 arch_kgdb_ops.gdb_bpt_instr, 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,

				  (char *)bundle, BREAK_INSTR_SIZE);

	return probe_kernel_write((char *)bpt->bpt_addr,

				  (char *)bpt->saved_instr, BREAK_INSTR_SIZE);

}



int __weak kgdb_validate_break_address(unsigned long addr)

{

	char tmp_variable[BREAK_INSTR_SIZE];

	struct kgdb_bkpt tmp;

	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

	 * are deep trouble not being able to put things back the way we

	 * found them.

	 */

	err = kgdb_arch_set_breakpoint(addr, tmp_variable);

	tmp.bpt_addr = addr;

	err = kgdb_arch_set_breakpoint(&tmp);

	if (err)

		return err;

	err = kgdb_arch_remove_breakpoint(addr, tmp_variable);

	err = kgdb_arch_remove_breakpoint(&tmp);

	if (err)

		printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "

		   "memory destroyed at: %lx", addr);
@@ -235,7 +237,6 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) 
 */

int dbg_activate_sw_breakpoints(void)

{

	unsigned long addr;

	int error;

	int ret = 0;

	int i;
@@ -244,16 +245,15 @@ int dbg_activate_sw_breakpoints(void) 
		if (kgdb_break[i].state != BP_SET)

			continue;



		addr = kgdb_break[i].bpt_addr;

		error = kgdb_arch_set_breakpoint(addr,

				kgdb_break[i].saved_instr);

		error = kgdb_arch_set_breakpoint(&kgdb_break[i]);

		if (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;

		}



		kgdb_flush_swbreak_addr(addr);

		kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);

		kgdb_break[i].state = BP_ACTIVE;

	}

	return ret;
@@ -302,7 +302,6 @@ int dbg_set_sw_break(unsigned long addr) 


int dbg_deactivate_sw_breakpoints(void)

{

	unsigned long addr;

	int error;

	int ret = 0;

	int i;
@@ -310,15 +309,14 @@ int dbg_deactivate_sw_breakpoints(void) 
	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {

		if (kgdb_break[i].state != BP_ACTIVE)

			continue;

		addr = kgdb_break[i].bpt_addr;

		error = kgdb_arch_remove_breakpoint(addr,

					kgdb_break[i].saved_instr);

		error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);

		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;

		}



		kgdb_flush_swbreak_addr(addr);

		kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);

		kgdb_break[i].state = BP_SET;

	}

	return ret;
@@ -352,7 +350,6 @@ int kgdb_isremovedbreak(unsigned long addr) 


int dbg_remove_all_break(void)

{

	unsigned long addr;

	int error;

	int i;
@@ -360,12 +357,10 @@ int dbg_remove_all_break(void) 
	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {

		if (kgdb_break[i].state != BP_ACTIVE)

			goto setundefined;

		addr = kgdb_break[i].bpt_addr;

		error = kgdb_arch_remove_breakpoint(addr,

				kgdb_break[i].saved_instr);

		error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);

		if (error)

			printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",

			   addr);

			       kgdb_break[i].bpt_addr);

setundefined:

		kgdb_break[i].state = BP_UNDEFINED;

	}