2020-11-11 21:29:44

by Stafford Horne

[permalink] [raw]
Subject: [PATCH] openrisc: fix trap for debugger breakpoint signalling

I have been working on getting native Linux GDB support working for the
OpenRISC port. The trap signal handler here was wrong in a few ways.
During trap handling address (from the EEAR register) is not set by the
CPU, so it is not correct to use here. We want to use trap as a
break-point so use TRAP_BRKPT. Adding 4 to the pc was incorrect and
causing GDB to think the breakpoint was not hit.

Fixing these allows GDB to work now.

Signed-off-by: Stafford Horne <[email protected]>
---
arch/openrisc/kernel/traps.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
index 206e5325e61b..4d61333c2623 100644
--- a/arch/openrisc/kernel/traps.c
+++ b/arch/openrisc/kernel/traps.c
@@ -238,9 +238,7 @@ void __init trap_init(void)

asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
{
- force_sig_fault(SIGTRAP, TRAP_TRACE, (void __user *)address);
-
- regs->pc += 4;
+ force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);
}

asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
--
2.26.2