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

BugLink: http://bugs.launchpad.net/bugs/983326

commit 98b54aa1a2241b59372468bd1e9c2d207bdba54b upstream.

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.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 24 insertions, 29 deletions

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index bad6786dee8..5ee24d10632 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -157,37 +157,39 @@ 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);
@@ -231,7 +233,6 @@ 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;
@@ -240,16 +241,15 @@ 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;
@@ -298,7 +298,6 @@ int dbg_set_sw_break(unsigned long addr)
 
 int dbg_deactivate_sw_breakpoints(void)
 {
-        unsigned long addr;
         int error;
         int ret = 0;
         int i;
@@ -306,15 +305,14 @@ 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;
@@ -348,7 +346,6 @@ int kgdb_isremovedbreak(unsigned long addr)
 
 int dbg_remove_all_break(void)
 {
-        unsigned long addr;
         int error;
         int i;
 
@@ -356,12 +353,10 @@ 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;
         }