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Subject[PATCH 5/6] kgdb,debug_core: pass the breakpoint struct instead of address and memory
Date
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>
---
include/linux/kgdb.h | 4 ++--
kernel/debug/debug_core.c | 53 ++++++++++++++++++++-------------------------
2 files changed, 26 insertions(+), 31 deletions(-)
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index fa39183..e5d689c 100644
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -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.
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 3f88a45..a7e52ca 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -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;
}
--
1.7.9.4


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