/* GNU/Linux on ARM target support.
- Copyright (C) 1999-2015 Free Software Foundation, Inc.
+ Copyright (C) 1999-2016 Free Software Foundation, Inc.
This file is part of GDB.
#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"
/* Syscall number for rt_sigreturn. */
#define ARM_RT_SIGRETURN 173
+static CORE_ADDR
+ arm_linux_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self,
+ CORE_ADDR pc);
+
+/* 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_linux_get_next_pcs_syscall_next_pc,
+ arm_get_next_pcs_addr_bits_remove,
+ arm_get_next_pcs_is_thumb,
+ arm_linux_get_next_pcs_fixup,
+};
+
static void
arm_linux_sigtramp_cache (struct frame_info *this_frame,
struct trad_frame_cache *this_cache,
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,
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. */
+ based on current processor state. In addition, set IS_THUMB depending
+ on whether we will return to ARM or Thumb code. */
+
static CORE_ADDR
arm_linux_sigreturn_next_pc (struct regcache *regcache,
- unsigned long svc_number)
+ unsigned long svc_number, int *is_thumb)
{
ULONGEST sp;
unsigned long sp_data;
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
int pc_offset = 0;
int is_sigreturn = 0;
+ CORE_ADDR cpsr;
gdb_assert (svc_number == ARM_SIGRETURN
|| svc_number == ARM_RT_SIGRETURN);
next_pc = read_memory_unsigned_integer (sp + pc_offset, 4, byte_order);
+ /* Set IS_THUMB according the CPSR saved on the stack. */
+ cpsr = read_memory_unsigned_integer (sp + pc_offset + 4, 4, byte_order);
+ *is_thumb = ((cpsr & arm_psr_thumb_bit (gdbarch)) != 0);
+
return next_pc;
}
return svc_number;
}
-/* When the processor is at a syscall instruction, return the PC of the
- next instruction to be executed. */
-
static CORE_ADDR
-arm_linux_syscall_next_pc (struct regcache *regcache)
+arm_linux_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self,
+ CORE_ADDR pc)
{
- CORE_ADDR pc = regcache_read_pc (regcache);
CORE_ADDR next_pc = 0;
- int is_thumb = arm_is_thumb (regcache);
+ int is_thumb = arm_is_thumb (self->regcache);
ULONGEST svc_number = 0;
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
+ struct gdbarch *gdbarch = get_regcache_arch (self->regcache);
if (is_thumb)
{
- svc_number = regcache_raw_get_unsigned (regcache, 7);
+ svc_number = regcache_raw_get_unsigned (self->regcache, 7);
next_pc = pc + 2;
}
else
{
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
+ struct gdbarch *gdbarch = get_regcache_arch (self->regcache);
enum bfd_endian byte_order_for_code =
gdbarch_byte_order_for_code (gdbarch);
unsigned long this_instr =
}
else /* EABI. */
{
- svc_number = regcache_raw_get_unsigned (regcache, 7);
+ svc_number = regcache_raw_get_unsigned (self->regcache, 7);
}
next_pc = pc + 4;
}
if (svc_number == ARM_SIGRETURN || svc_number == ARM_RT_SIGRETURN)
- next_pc = arm_linux_sigreturn_next_pc (regcache, svc_number);
+ {
+ /* SIGRETURN or RT_SIGRETURN may affect the arm thumb mode, so
+ update IS_THUMB. */
+ next_pc = arm_linux_sigreturn_next_pc (self->regcache, svc_number,
+ &is_thumb);
+ }
/* Addresses for calling Thumb functions have the bit 0 set. */
if (is_thumb)
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),
+ 1,
+ 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);
- arm_insert_single_step_breakpoint (gdbarch, aspace, next_pc);
+ for (i = 0; VEC_iterate (CORE_ADDR, next_pcs, i, pc); i++)
+ arm_insert_single_step_breakpoint (gdbarch, aspace, pc);
+
+ do_cleanups (old_chain);
return 1;
}
/* Linux-specific displaced step instruction copying function. Detects when
the program has stepped into a Linux kernel helper routine (which must be
- handled as a special case), falling back to arm_displaced_step_copy_insn()
- if it hasn't. */
+ handled as a special case). */
static struct displaced_step_closure *
arm_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
set_gdbarch_stap_parse_special_token (gdbarch,
arm_stap_parse_special_token);
- tdep->syscall_next_pc = arm_linux_syscall_next_pc;
-
/* `catch syscall' */
set_xml_syscall_file_name (gdbarch, "syscalls/arm-linux.xml");
set_gdbarch_get_syscall_number (gdbarch, arm_linux_get_syscall_number);
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