[PATCH v7.2] Support software single step on ARM in GDBServer

[Yao Qi]

Antoine Tremblay <antoine.tremblay@ericsson.com> writes:

>   Change the name of the ops read_memory_unsigned_integer to read_mem_uint
>
> OK like that ?

Yes.

>
> ---
> This patch teaches GDBServer how to software single step on ARM
> linux by sharing code with GDB.
>
> The arm_get_next_pcs function in GDB is now shared with GDBServer.  So that
> GDBServer can use the function to return the possible addresses of the next PC.
>
> A proper shared context was also needed so that we could share the code, this
> context is described in the arm_get_next_pcs structure.
>
> Testing :
>
> No regressions, tested on ubuntu 14.04 ARMv7 and x86.
> With gdbserver-{native,extended} / { -marm -mthumb }
>
> gdb/ChangeLog:
>
> 	* Makefile.in (ALL_TARGET_OBS): Append arm-get-next-pcs.o, arm-linux.o.
> 	(ALLDEPFILES): Append arm-get-next-pcs.c, arm-linux.c
> 	(arm-linux.o): New rule.
> 	(arm-get-next-pcs.o): New rule.
> 	* arch/arm-get-next-pcs.c: New file.
> 	* arch/arm-get-next-pcs.h: New file.
> 	* arch/arm-linux.h: New file.
> 	* arch/arm-linux.c: New file.
> 	* arm.c: Include common-regcache.c.
> 	(thumb_advance_itstate): Moved from arm-tdep.c.
> 	(arm_instruction_changes_pc): Likewise.
> 	(thumb_instruction_changes_pc): Likewise.
> 	(thumb2_instruction_changes_pc): Likewise.
> 	(shifted_reg_val): Likewise.
> 	* arm.h (submask): Move macro from arm-tdep.h
> 	(bit): Likewise.
> 	(bits): Likewise.
> 	(sbits): Likewise.
> 	(BranchDest): Likewise.
> 	(thumb_advance_itstate): Moved declaration from arm-tdep.h
> 	(arm_instruction_changes_pc): Likewise.
> 	(thumb_instruction_changes_pc): Likewise.
> 	(thumb2_instruction_changes_pc): Likewise.
> 	(shifted_reg_val): Likewise.
> 	* arm-linux-tdep.c: Include arch/arm.h, arch/arm-get-next-pcs.h
> 	arch/arm-linux.h.
> 	(arm_linux_get_next_pcs_ops): New struct.
> 	(ARM_SIGCONTEXT_R0, ARM_UCONTEXT_SIGCONTEXT,
> 	ARM_OLD_RT_SIGFRAME_SIGINFO, ARM_OLD_RT_SIGFRAME_UCONTEXT,
> 	ARM_NEW_RT_SIGFRAME_UCONTEXT, ARM_NEW_SIGFRAME_MAGIC): Move stack
> 	layout defines to arch/arm-linux.h.
> 	(arm_linux_sigreturn_next_pc_offset): Move to arch/arm-linux.c.
> 	(arm_linux_software_single_step): Adjust for arm_get_next_pcs
> 	implementation.
> 	* arm-tdep.c: Include arch/arm-get-next-pcs.h.
> 	(arm_get_next_pcs_ops): New struct.
> 	(submask): Move macro to arm.h.
> 	(bit): Likewise.
> 	(bits): Likewise.
> 	(sbits): Likewise.
> 	(BranchDest): Likewise.
> 	(thumb_instruction_changes_pc): Move to arm.c
> 	(thumb2_instruction_changes_pc): Likewise.
> 	(arm_instruction_changes_pc): Likewise.
> 	(shifted_reg_val): Likewise.
> 	(thumb_advance_itstate): Likewise.
> 	(thumb_get_next_pc_raw): Move to arm-get-next-pcs.c.
> 	(arm_get_next_pc_raw): Likewise.
> 	(arm_get_next_pc): Likewise.
> 	(thumb_deal_with_atomic_sequence_raw): Likewise.
> 	(arm_deal_with_atomic_sequence_raw): Likewise.
> 	(arm_deal_with_atomic_sequence): Likewise.
> 	(arm_get_next_pcs_read_memory_unsigned_integer): New function.
> 	(arm_get_next_pcs_addr_bits_remove): Likewise.
> 	(arm_get_next_pcs_syscall_next_pc): Likewise.
> 	(arm_get_next_pcs_is_thumb): Likewise.
> 	(arm_software_single_step): Adjust for arm_get_next_pcs
> 	implementation.
> 	* arm-tdep.h: (arm_get_next_pc): Remove declaration.
> 	(arm_get_next_pcs_read_memory_unsigned_integer):
> 	New declaration.
> 	(arm_get_next_pcs_addr_bits_remove): Likewise.
> 	(arm_get_next_pcs_syscall_next_pc): Likewise.
> 	(arm_get_next_pcs_is_thumb): Likewise.
> 	(arm_deal_with_atomic_sequence: Remove declaration.
> 	* common/gdb_vecs.h: Add CORE_ADDR vector definition.
> 	* configure.tgt (aarch64*-*-linux): Add arm-get-next-pcs.o, arm-linux.o.

ChangeLog line max length is 74.
https://sourceware.org/gdb/wiki/ContributionChecklist

> 	(arm*-wince-pe): Add arm-get-next-pcs.o.
> 	(arm*-*-linux*): Add arm-get-next-pcs.o, arm-linux.o, arm-get-next-pcs.o
> 	(arm*-*-netbsd* | arm*-*-knetbsd*-gnu): Add arm-get-next-pcs.o.

Replace "|" with ",".

> 	(arm*-*-openbsd*): Likewise.
> 	(arm*-*-symbianelf*): Likewise.
> 	(arm*-*-*): Likewise.
> 	* symtab.h: Move CORE_ADDR vector definition to gdb_vecs.h.
>
> gdb/gdbserver/ChangeLog:
>
> 	* Makefile.in (SFILES): Append arch/arm-linux.c,
> 	arch/arm-get-next-pcs.c.
> 	(arm-linux.o): New rule.
> 	(arm-get-next-pcs.o): New rule.
> 	* configure.srv (arm*-*-linux*): Add arm-get-next-pcs.o,
> 	arm-linux.o.
> 	* linux-aarch32-low.c (arm_abi_breakpoint): Remove macro.  Moved
>         to linux-aarch32-low.c.
>         (arm_eabi_breakpoint, arm_breakpoint): Likewise.
>         (arm_breakpoint_len, thumb_breakpoint): Likewise.
>         (thumb_breakpoint_len, thumb2_breakpoint): Likewise.
>         (thumb2_breakpoint_len): Likewise.

These are not started with TAB.

> +
> +  if ((inst1 & 0xff00) == 0xbd00)	/* pop {rlist, pc} */
> +    {
> +      CORE_ADDR sp;
> +
> +      /* Fetch the saved PC from the stack.  It's stored above
> +         all of the other registers.  */
> +      offset = bitcount (bits (inst1, 0, 7)) * INT_REGISTER_SIZE;
> +      sp = regcache_raw_get_unsigned (regcache, ARM_SP_REGNUM);
> +      nextpc = self->ops->read_mem_uint	(sp + offset, 4, byte_order);

Redundant spaces.

-- 
Yao (齐尧)