Hi Sandeepa,
This is getting there, thanks for persevering with it. I still have a few minor comments though.
On Thu, Oct 17, 2013 at 12:17:46PM +0100, Sandeepa Prabhu wrote:
AArch64 Single Steping and Breakpoint debug exceptions will be used by multiple debug framworks like kprobes & kgdb.
This patch implements the hooks for those frameworks to register their own handlers for handling breakpoint and single step events.
Reworked the debug exception handler in entry.S: do_dbg to route software breakpoint (BRK64) exception to do_debug_exception()
Signed-off-by: Sandeepa Prabhu sandeepa.prabhu@linaro.org Signed-off-by: Deepak Saxena dsaxena@linaro.org
arch/arm64/include/asm/debug-monitors.h | 21 ++++++++ arch/arm64/kernel/debug-monitors.c | 86 ++++++++++++++++++++++++++++++++- arch/arm64/kernel/entry.S | 2 + 3 files changed, 108 insertions(+), 1 deletion(-)
[...]
@@ -215,7 +257,10 @@ static int single_step_handler(unsigned long addr, unsigned int esr, */ user_rewind_single_step(current); } else {
/* TODO: route to KGDB */
/* call registered single step handlers */
Don't bother with this comment (it's crystal clear from the code).
if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)return 0;- pr_warning("Unexpected kernel single-step exception at EL1\n"); /*
- Re-enable stepping since we know that we will be
@@ -227,11 +272,50 @@ static int single_step_handler(unsigned long addr, unsigned int esr, return 0; }
+static LIST_HEAD(break_hook); +DEFINE_RWLOCK(break_hook_lock);
This guy can be a plain old spinlock. That way, the readers have less overhead but things still work because we only call a single hook function.
Will