3.10-stable review patch. If anyone has any objections, please let me know.
------------------ From: Vineet Gupta <[email protected]> [Based on mainline commit 502a0c775c7f0a: "ARC: pt_regs update #5"] gdbserver needs @stop_pc, served by ptrace, but fetched from pt_regs differently, based on in_brkpt_traps(), which in turn relies on additional machine state in pt_regs->event bitfield. unsigned long orig_r8:16, event:16; For big endian config, this macro was returning false, despite being in breakpoint Trap exception, causing wrong @stop_pc to be returned to gdb. Issue #1: In BE, @event above is at offset 2 in word, while a STW insn at offset 0 was used to update it. Resort to using ST insn which updates the half-word at right location. Issue #2: The union involving bitfields causes all the members to be laid out at offset 0. So with fix #1 above, ASM was now updating at offset 2, "C" code was still referencing at offset 0. Fixed by wrapping bitfield in a struct. Reported-by: Noam Camus <[email protected]> Tested-by: Anton Kolesov <[email protected]> Signed-off-by: Vineet Gupta <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arc/include/asm/ptrace.h | 2 ++ arch/arc/kernel/entry.S | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) --- a/arch/arc/include/asm/ptrace.h +++ b/arch/arc/include/asm/ptrace.h @@ -52,12 +52,14 @@ struct pt_regs { /*to distinguish bet excp, syscall, irq */ union { + struct { #ifdef CONFIG_CPU_BIG_ENDIAN /* so that assembly code is same for LE/BE */ unsigned long orig_r8:16, event:16; #else unsigned long event:16, orig_r8:16; #endif + }; long orig_r8_word; }; }; --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -498,7 +498,7 @@ tracesys_exit: trap_with_param: ; stop_pc info by gdb needs this info - stw orig_r8_IS_BRKPT, [sp, PT_orig_r8] + st orig_r8_IS_BRKPT, [sp, PT_orig_r8] mov r0, r12 lr r1, [efa] @@ -723,7 +723,7 @@ not_exception: ; things to what they were, before returning from L2 context ;---------------------------------------------------------------- - ldw r9, [sp, PT_orig_r8] ; get orig_r8 to make sure it is + ld r9, [sp, PT_orig_r8] ; get orig_r8 to make sure it is brne r9, orig_r8_IS_IRQ2, 149f ; infact a L2 ISR ret path ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
