mirror of
https://github.com/bminor/binutils-gdb.git
synced 2025-12-26 09:08:59 +00:00
Support software single step on ARM in GDBServer
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.
(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.
(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.
(arm_is_thumb_mode): Make non-static.
* linux-aarch32-low.h (arm_abi_breakpoint): New macro. Moved
from 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.
(arm_is_thumb_mode): New declaration.
* linux-arm-low.c: Include arch/arm-linux.h
aarch/arm-get-next-pcs.h, sys/syscall.h.
(get_next_pcs_ops): New struct.
(get_next_pcs_addr_bits_remove): New function.
(get_next_pcs_is_thumb): New function.
(get_next_pcs_read_memory_unsigned_integer): Likewise.
(arm_sigreturn_next_pc): Likewise.
(get_next_pcs_syscall_next_pc): Likewise.
(arm_gdbserver_get_next_pcs): Likewise.
(struct linux_target_ops) <arm_gdbserver_get_next_pcs>:
Initialize.
* linux-low.h: Move CORE_ADDR vector definition to gdb_vecs.h.
* server.h: Include gdb_vecs.h.
This commit is contained in:
Antoine Tremblay
@@ -35,6 +35,9 @@
|
||||
#include "auxv.h"
|
||||
#include "xml-syscall.h"
|
||||
|
||||
#include "arch/arm.h"
|
||||
#include "arch/arm-get-next-pcs.h"
|
||||
#include "arch/arm-linux.h"
|
||||
#include "arm-tdep.h"
|
||||
#include "arm-linux-tdep.h"
|
||||
#include "linux-tdep.h"
|
||||
@@ -262,6 +265,14 @@ static const gdb_byte arm_linux_thumb2_le_breakpoint[] = { 0xf0, 0xf7, 0x00, 0xa
|
||||
/* Syscall number for rt_sigreturn. */
|
||||
#define ARM_RT_SIGRETURN 173
|
||||
|
||||
/* Operation function pointers for get_next_pcs. */
|
||||
static struct arm_get_next_pcs_ops arm_linux_get_next_pcs_ops = {
|
||||
arm_get_next_pcs_read_memory_unsigned_integer,
|
||||
arm_get_next_pcs_syscall_next_pc,
|
||||
arm_get_next_pcs_addr_bits_remove,
|
||||
arm_get_next_pcs_is_thumb
|
||||
};
|
||||
|
||||
static void
|
||||
arm_linux_sigtramp_cache (struct frame_info *this_frame,
|
||||
struct trad_frame_cache *this_cache,
|
||||
@@ -283,51 +294,7 @@ arm_linux_sigtramp_cache (struct frame_info *this_frame,
|
||||
trad_frame_set_id (this_cache, frame_id_build (sp, func));
|
||||
}
|
||||
|
||||
/* There are a couple of different possible stack layouts that
|
||||
we need to support.
|
||||
|
||||
Before version 2.6.18, the kernel used completely independent
|
||||
layouts for non-RT and RT signals. For non-RT signals the stack
|
||||
began directly with a struct sigcontext. For RT signals the stack
|
||||
began with two redundant pointers (to the siginfo and ucontext),
|
||||
and then the siginfo and ucontext.
|
||||
|
||||
As of version 2.6.18, the non-RT signal frame layout starts with
|
||||
a ucontext and the RT signal frame starts with a siginfo and then
|
||||
a ucontext. Also, the ucontext now has a designated save area
|
||||
for coprocessor registers.
|
||||
|
||||
For RT signals, it's easy to tell the difference: we look for
|
||||
pinfo, the pointer to the siginfo. If it has the expected
|
||||
value, we have an old layout. If it doesn't, we have the new
|
||||
layout.
|
||||
|
||||
For non-RT signals, it's a bit harder. We need something in one
|
||||
layout or the other with a recognizable offset and value. We can't
|
||||
use the return trampoline, because ARM usually uses SA_RESTORER,
|
||||
in which case the stack return trampoline is not filled in.
|
||||
We can't use the saved stack pointer, because sigaltstack might
|
||||
be in use. So for now we guess the new layout... */
|
||||
|
||||
/* There are three words (trap_no, error_code, oldmask) in
|
||||
struct sigcontext before r0. */
|
||||
#define ARM_SIGCONTEXT_R0 0xc
|
||||
|
||||
/* There are five words (uc_flags, uc_link, and three for uc_stack)
|
||||
in the ucontext_t before the sigcontext. */
|
||||
#define ARM_UCONTEXT_SIGCONTEXT 0x14
|
||||
|
||||
/* There are three elements in an rt_sigframe before the ucontext:
|
||||
pinfo, puc, and info. The first two are pointers and the third
|
||||
is a struct siginfo, with size 128 bytes. We could follow puc
|
||||
to the ucontext, but it's simpler to skip the whole thing. */
|
||||
#define ARM_OLD_RT_SIGFRAME_SIGINFO 0x8
|
||||
#define ARM_OLD_RT_SIGFRAME_UCONTEXT 0x88
|
||||
|
||||
#define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80
|
||||
|
||||
#define ARM_NEW_SIGFRAME_MAGIC 0x5ac3c35a
|
||||
|
||||
/* See arm-linux.h for stack layout details. */
|
||||
static void
|
||||
arm_linux_sigreturn_init (const struct tramp_frame *self,
|
||||
struct frame_info *this_frame,
|
||||
@@ -810,41 +777,6 @@ arm_linux_sigreturn_return_addr (struct frame_info *frame,
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Calculate the offset from stack pointer of the pc register on the stack
|
||||
in the case of a sigreturn or sigreturn_rt syscall. */
|
||||
static int
|
||||
arm_linux_sigreturn_next_pc_offset (unsigned long sp,
|
||||
unsigned long sp_data,
|
||||
unsigned long svc_number,
|
||||
int is_sigreturn)
|
||||
{
|
||||
/* Offset of R0 register. */
|
||||
int r0_offset = 0;
|
||||
/* Offset of PC register. */
|
||||
int pc_offset = 0;
|
||||
|
||||
if (is_sigreturn)
|
||||
{
|
||||
if (sp_data == ARM_NEW_SIGFRAME_MAGIC)
|
||||
r0_offset = ARM_UCONTEXT_SIGCONTEXT + ARM_SIGCONTEXT_R0;
|
||||
else
|
||||
r0_offset = ARM_SIGCONTEXT_R0;
|
||||
}
|
||||
else
|
||||
{
|
||||
if (sp_data == sp + ARM_OLD_RT_SIGFRAME_SIGINFO)
|
||||
r0_offset = ARM_OLD_RT_SIGFRAME_UCONTEXT;
|
||||
else
|
||||
r0_offset = ARM_NEW_RT_SIGFRAME_UCONTEXT;
|
||||
|
||||
r0_offset += ARM_UCONTEXT_SIGCONTEXT + ARM_SIGCONTEXT_R0;
|
||||
}
|
||||
|
||||
pc_offset = r0_offset + INT_REGISTER_SIZE * ARM_PC_REGNUM;
|
||||
|
||||
return pc_offset;
|
||||
}
|
||||
|
||||
/* Find the value of the next PC after a sigreturn or rt_sigreturn syscall
|
||||
based on current processor state. */
|
||||
static CORE_ADDR
|
||||
@@ -984,28 +916,41 @@ arm_linux_software_single_step (struct frame_info *frame)
|
||||
struct regcache *regcache = get_current_regcache ();
|
||||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||||
struct address_space *aspace = get_regcache_aspace (regcache);
|
||||
|
||||
CORE_ADDR next_pc;
|
||||
|
||||
if (arm_deal_with_atomic_sequence (regcache))
|
||||
return 1;
|
||||
struct arm_get_next_pcs next_pcs_ctx;
|
||||
CORE_ADDR pc;
|
||||
int i;
|
||||
VEC (CORE_ADDR) *next_pcs = NULL;
|
||||
struct cleanup *old_chain = make_cleanup (VEC_cleanup (CORE_ADDR), &next_pcs);
|
||||
|
||||
/* If the target does have hardware single step, GDB doesn't have
|
||||
to bother software single step. */
|
||||
if (target_can_do_single_step () == 1)
|
||||
return 0;
|
||||
|
||||
next_pc = arm_get_next_pc (regcache, regcache_read_pc (regcache));
|
||||
arm_get_next_pcs_ctor (&next_pcs_ctx,
|
||||
&arm_linux_get_next_pcs_ops,
|
||||
gdbarch_byte_order (gdbarch),
|
||||
gdbarch_byte_order_for_code (gdbarch),
|
||||
gdbarch_tdep (gdbarch)->thumb2_breakpoint,
|
||||
regcache);
|
||||
|
||||
/* The Linux kernel offers some user-mode helpers in a high page. We can
|
||||
not read this page (as of 2.6.23), and even if we could then we couldn't
|
||||
set breakpoints in it, and even if we could then the atomic operations
|
||||
would fail when interrupted. They are all called as functions and return
|
||||
to the address in LR, so step to there instead. */
|
||||
if (next_pc > 0xffff0000)
|
||||
next_pc = get_frame_register_unsigned (frame, ARM_LR_REGNUM);
|
||||
next_pcs = arm_get_next_pcs (&next_pcs_ctx, regcache_read_pc (regcache));
|
||||
|
||||
arm_insert_single_step_breakpoint (gdbarch, aspace, next_pc);
|
||||
for (i = 0; VEC_iterate (CORE_ADDR, next_pcs, i, pc); i++)
|
||||
{
|
||||
/* The Linux kernel offers some user-mode helpers in a high page. We can
|
||||
not read this page (as of 2.6.23), and even if we could then we
|
||||
couldn't set breakpoints in it, and even if we could then the atomic
|
||||
operations would fail when interrupted. They are all called as
|
||||
functions and return to the address in LR, so step to there
|
||||
instead. */
|
||||
if (pc > 0xffff0000)
|
||||
pc = get_frame_register_unsigned (frame, ARM_LR_REGNUM);
|
||||
|
||||
arm_insert_single_step_breakpoint (gdbarch, aspace, pc);
|
||||
}
|
||||
|
||||
do_cleanups (old_chain);
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user