[PATCH] aarch64 multi-arch part 6: HW breakpoint on unaligned address
Pedro Alves
palves@redhat.com
Tue Oct 13 11:07:00 GMT 2015
On 10/13/2015 11:11 AM, Yao Qi wrote:
> --- a/gdb/gdbserver/linux-aarch64-low.c
> +++ b/gdb/gdbserver/linux-aarch64-low.c
> @@ -315,9 +315,12 @@ aarch64_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
> ret = -1;
> }
> else
> - ret =
> - aarch64_handle_breakpoint (targ_type, addr, len, 1 /* is_insert */,
> - state);
> + {
> + if (len == 3)
> + len = 2;
I think this warrants a comment. E.g., someone reading
arm-linux-low.c:arm_linux_hw_point_initialize quite easily grasps
what 3 means.
> + ret = aarch64_handle_breakpoint (targ_type, addr, len,
> + 1 /* is_insert */, state);
> + }
>
> if (show_debug_regs)
> aarch64_show_debug_reg_state (state, "insert_point", addr, len,
> @@ -353,9 +356,12 @@ aarch64_remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
> aarch64_handle_watchpoint (targ_type, addr, len, 0 /* is_insert */,
> state);
> else
> - ret =
> - aarch64_handle_breakpoint (targ_type, addr, len, 0 /* is_insert */,
> - state);
> + {
> + if (len == 3)
> + len = 2;
> + ret = aarch64_handle_breakpoint (targ_type, addr, len,
> + 0 /* is_insert */, state);
> + }
>
> if (show_debug_regs)
> aarch64_show_debug_reg_state (state, "remove_point", addr, len,
> diff --git a/gdb/nat/aarch64-linux-hw-point.c b/gdb/nat/aarch64-linux-hw-point.c
> index bca6ec1..d15e518 100644
> --- a/gdb/nat/aarch64-linux-hw-point.c
> +++ b/gdb/nat/aarch64-linux-hw-point.c
> @@ -112,8 +112,17 @@ aarch64_point_encode_ctrl_reg (enum target_hw_bp_type type, int len)
> static int
> aarch64_point_is_aligned (int is_watchpoint, CORE_ADDR addr, int len)
> {
> - unsigned int alignment = is_watchpoint ? AARCH64_HWP_ALIGNMENT
> - : AARCH64_HBP_ALIGNMENT;
> + unsigned int alignment = 0;
> +
> + if (is_watchpoint)
> + alignment = AARCH64_HWP_ALIGNMENT;
> + else
> + {
> + /* Set alignment to 2 only if the current process is 32-bit,
> + since thumb instruction can be 2-byte aligned. Otherwise, set
> + alignment to AARCH64_HBP_ALIGNMENT. */
> + alignment = 2;
Is some other code doing what the comment says? I'm not seeing
any obvious 32-bit check.
> + }
>
> if (addr & (alignment - 1))
> return 0;
> @@ -445,7 +454,7 @@ aarch64_handle_breakpoint (enum target_hw_bp_type type, CORE_ADDR addr,
> struct aarch64_debug_reg_state *state)
> {
> /* The hardware breakpoint on AArch64 should always be 4-byte
> - aligned. */
> + aligned, but on AArch32, it can be 2-byte aligned. */
> if (!aarch64_point_is_aligned (0 /* is_watchpoint */ , addr, len))
> return -1;
>
> -- 1.9.1
>
Thanks,
Pedro Alves
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