diff options
| -rw-r--r-- | Documentation/DocBook/kgdb.tmpl | 10 | ||||
| -rw-r--r-- | kernel/kgdb.c | 26 |
2 files changed, 29 insertions, 7 deletions
diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl index 54d3b158d080..372dec20c8da 100644 --- a/Documentation/DocBook/kgdb.tmpl +++ b/Documentation/DocBook/kgdb.tmpl @@ -106,6 +106,16 @@ while debugging the kernel. </para> <para> + If the architecture that you are using supports the kernel option + CONFIG_DEBUG_RODATA, you should consider turning it off. This + option will prevent the use of software breakpoints because it + marks certain regions of the kernel's memory space as read-only. + If kgdb supports it for the architecture you are using, you can + use hardware breakpoints if you desire to run with the + CONFIG_DEBUG_RODATA option turned on, else you need to turn off + this option. + </para> + <para> Next you should choose one of more I/O drivers to interconnect debugging host and debugged target. Early boot debugging requires a KGDB I/O driver that supports early debugging and the driver must be diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 3ec23c3ec97f..c0d45b2c4d79 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -166,13 +166,6 @@ early_param("nokgdbroundup", opt_nokgdbroundup); * Weak aliases for breakpoint management, * can be overriden by architectures when needed: */ -int __weak kgdb_validate_break_address(unsigned long addr) -{ - char tmp_variable[BREAK_INSTR_SIZE]; - - return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE); -} - int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) { int err; @@ -191,6 +184,25 @@ int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) (char *)bundle, BREAK_INSTR_SIZE); } +int __weak kgdb_validate_break_address(unsigned long addr) +{ + char tmp_variable[BREAK_INSTR_SIZE]; + int err; + /* Validate setting the breakpoint and then removing it. In 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); + if (err) + return err; + err = kgdb_arch_remove_breakpoint(addr, tmp_variable); + if (err) + printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " + "memory destroyed at: %lx", addr); + return err; +} + unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) { return instruction_pointer(regs); |