| Message ID | 9737ec351e2f9f2e7472d8d7133568f7915f20aa.1470114993.git.panand@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 02, 2016 at 11:00:08AM +0530, Pratyush Anand wrote: > --- a/arch/arm64/kernel/debug-monitors.c > +++ b/arch/arm64/kernel/debug-monitors.c > @@ -326,16 +326,20 @@ NOKPROBE_SYMBOL(call_break_hook); > static int brk_handler(unsigned long addr, unsigned int esr, > struct pt_regs *regs) > { > - if (user_mode(regs)) { > - send_user_sigtrap(TRAP_BRKPT); > - } > + bool handler_found = false; > + > #ifdef CONFIG_KPROBES > - else if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) { > - if (kprobe_breakpoint_handler(regs, esr) != DBG_HOOK_HANDLED) > - return -EFAULT; > + if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) { > + if (kprobe_breakpoint_handler(regs, esr) == DBG_HOOK_HANDLED) > + handler_found = true; > } > #endif > - else if (call_break_hook(regs, esr) != DBG_HOOK_HANDLED) { > + if (!handler_found && call_break_hook(regs, esr) == DBG_HOOK_HANDLED) > + handler_found = true; > + > + if (!handler_found && user_mode(regs)) { > + send_user_sigtrap(TRAP_BRKPT); > + } else if (!handler_found) { > pr_warn("Unexpected kernel BRK exception at EL1\n"); > return -EFAULT; > } I think we could do the same here with a single call_break_hook() and making sure that the corresponding handlers check the esr for the corresponding BRK encoding.
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index fae2f57a92b7..466d199498b5 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -326,16 +326,20 @@ NOKPROBE_SYMBOL(call_break_hook); static int brk_handler(unsigned long addr, unsigned int esr, struct pt_regs *regs) { - if (user_mode(regs)) { - send_user_sigtrap(TRAP_BRKPT); - } + bool handler_found = false; + #ifdef CONFIG_KPROBES - else if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) { - if (kprobe_breakpoint_handler(regs, esr) != DBG_HOOK_HANDLED) - return -EFAULT; + if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) { + if (kprobe_breakpoint_handler(regs, esr) == DBG_HOOK_HANDLED) + handler_found = true; } #endif - else if (call_break_hook(regs, esr) != DBG_HOOK_HANDLED) { + if (!handler_found && call_break_hook(regs, esr) == DBG_HOOK_HANDLED) + handler_found = true; + + if (!handler_found && user_mode(regs)) { + send_user_sigtrap(TRAP_BRKPT); + } else if (!handler_found) { pr_warn("Unexpected kernel BRK exception at EL1\n"); return -EFAULT; }
uprobe is registered at break_hook with a unique ESR code. So, when a TRAP_BRKPT occurs, call_break_hook checks if it was for uprobe. If not, then send a SIGTRAP to user. Signed-off-by: Pratyush Anand <panand@redhat.com> --- arch/arm64/kernel/debug-monitors.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)