diff options
Diffstat (limited to 'arch/arc/kernel/entry.S')
| -rw-r--r-- | arch/arc/kernel/entry.S | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index ed08ac14fbc..d625b77c14b 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -470,7 +470,11 @@ resume_user_mode_begin: bbit0 r9, TIF_SIGPENDING, .Lchk_notify_resume - ; save CALLEE Regs. + ; Normal Trap/IRQ entry only saves Scratch (caller-saved) regs + ; in pt_reg since the "C" ABI (kernel code) will automatically + ; save/restore callee-saved regs. + ; + ; However, here we need to explicitly save callee regs because ; (i) If this signal causes coredump - full regfile needed ; (ii) If signal is SIGTRAP/SIGSTOP, task is being traced thus ; tracer might call PEEKUSR(CALLEE reg) @@ -484,8 +488,9 @@ resume_user_mode_begin: bl @do_signal - ; unwind SP for cheap discard of Callee saved Regs - DISCARD_CALLEE_SAVED_USER + ; Ideally we want to discard the Callee reg above, however if this was + ; a tracing signal, tracer could have done a POKEUSR(CALLEE reg) + RESTORE_CALLEE_SAVED_USER b resume_user_mode_begin ; loop back to start of U mode ret |