/* GNU/Linux on ARM target support.
- Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
- Free Software Foundation, Inc.
+ Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
+ 2009, 2010 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "target.h"
#include "regset.h"
#include "trad-frame.h"
#include "tramp-frame.h"
+#include "breakpoint.h"
#include "arm-tdep.h"
#include "arm-linux-tdep.h"
+#include "linux-tdep.h"
#include "glibc-tdep.h"
+#include "arch-utils.h"
+#include "inferior.h"
+#include "gdbthread.h"
+#include "symfile.h"
#include "gdb_string.h"
static const char arm_linux_thumb_le_breakpoint[] = {0x01, 0xde};
-/* Description of the longjmp buffer. */
+/* Because the 16-bit Thumb breakpoint is affected by Thumb-2 IT blocks,
+ we must use a length-appropriate breakpoint for 32-bit Thumb
+ instructions. See also thumb_get_next_pc. */
+
+static const char arm_linux_thumb2_be_breakpoint[] = { 0xf7, 0xf0, 0xa0, 0x00 };
+
+static const char arm_linux_thumb2_le_breakpoint[] = { 0xf0, 0xf7, 0x00, 0xa0 };
+
+/* Description of the longjmp buffer. The buffer is treated as an array of
+ elements of size ARM_LINUX_JB_ELEMENT_SIZE.
+
+ The location of saved registers in this buffer (in particular the PC
+ to use after longjmp is called) varies depending on the ABI (in
+ particular the FP model) and also (possibly) the C Library.
+
+ For glibc, eglibc, and uclibc the following holds: If the FP model is
+ SoftVFP or VFP (which implies EABI) then the PC is at offset 9 in the
+ buffer. This is also true for the SoftFPA model. However, for the FPA
+ model the PC is at offset 21 in the buffer. */
#define ARM_LINUX_JB_ELEMENT_SIZE INT_REGISTER_SIZE
-#define ARM_LINUX_JB_PC 21
+#define ARM_LINUX_JB_PC_FPA 21
+#define ARM_LINUX_JB_PC_EABI 9
/*
Dynamic Linking on ARM GNU/Linux
#define ARM_SET_R7_RT_SIGRETURN 0xe3a070ad
#define ARM_EABI_SYSCALL 0xef000000
+/* OABI syscall restart trampoline, used for EABI executables too
+ whenever OABI support has been enabled in the kernel. */
+#define ARM_OABI_SYSCALL_RESTART_SYSCALL 0xef900000
+#define ARM_LDR_PC_SP_12 0xe49df00c
+
static void
-arm_linux_sigtramp_cache (struct frame_info *next_frame,
+arm_linux_sigtramp_cache (struct frame_info *this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func, int regs_offset)
{
- CORE_ADDR sp = frame_unwind_register_unsigned (next_frame, ARM_SP_REGNUM);
+ CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
CORE_ADDR base = sp + regs_offset;
int i;
static void
arm_linux_sigreturn_init (const struct tramp_frame *self,
- struct frame_info *next_frame,
+ struct frame_info *this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
- CORE_ADDR sp = frame_unwind_register_unsigned (next_frame, ARM_SP_REGNUM);
- ULONGEST uc_flags = read_memory_unsigned_integer (sp, 4);
+ struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
+ ULONGEST uc_flags = read_memory_unsigned_integer (sp, 4, byte_order);
if (uc_flags == ARM_NEW_SIGFRAME_MAGIC)
- arm_linux_sigtramp_cache (next_frame, this_cache, func,
+ arm_linux_sigtramp_cache (this_frame, this_cache, func,
ARM_UCONTEXT_SIGCONTEXT
+ ARM_SIGCONTEXT_R0);
else
- arm_linux_sigtramp_cache (next_frame, this_cache, func,
+ arm_linux_sigtramp_cache (this_frame, this_cache, func,
ARM_SIGCONTEXT_R0);
}
static void
arm_linux_rt_sigreturn_init (const struct tramp_frame *self,
- struct frame_info *next_frame,
+ struct frame_info *this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
- CORE_ADDR sp = frame_unwind_register_unsigned (next_frame, ARM_SP_REGNUM);
- ULONGEST pinfo = read_memory_unsigned_integer (sp, 4);
+ struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
+ ULONGEST pinfo = read_memory_unsigned_integer (sp, 4, byte_order);
if (pinfo == sp + ARM_OLD_RT_SIGFRAME_SIGINFO)
- arm_linux_sigtramp_cache (next_frame, this_cache, func,
+ arm_linux_sigtramp_cache (this_frame, this_cache, func,
ARM_OLD_RT_SIGFRAME_UCONTEXT
+ ARM_UCONTEXT_SIGCONTEXT
+ ARM_SIGCONTEXT_R0);
else
- arm_linux_sigtramp_cache (next_frame, this_cache, func,
+ arm_linux_sigtramp_cache (this_frame, this_cache, func,
ARM_NEW_RT_SIGFRAME_UCONTEXT
+ ARM_UCONTEXT_SIGCONTEXT
+ ARM_SIGCONTEXT_R0);
}
+static void
+arm_linux_restart_syscall_init (const struct tramp_frame *self,
+ struct frame_info *this_frame,
+ struct trad_frame_cache *this_cache,
+ CORE_ADDR func)
+{
+ CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
+
+ trad_frame_set_reg_addr (this_cache, ARM_PC_REGNUM, sp);
+ trad_frame_set_reg_value (this_cache, ARM_SP_REGNUM, sp + 12);
+
+ /* Save a frame ID. */
+ trad_frame_set_id (this_cache, frame_id_build (sp, func));
+}
+
static struct tramp_frame arm_linux_sigreturn_tramp_frame = {
SIGTRAMP_FRAME,
4,
arm_linux_rt_sigreturn_init
};
+static struct tramp_frame arm_linux_restart_syscall_tramp_frame = {
+ NORMAL_FRAME,
+ 4,
+ {
+ { ARM_OABI_SYSCALL_RESTART_SYSCALL, -1 },
+ { ARM_LDR_PC_SP_12, -1 },
+ { TRAMP_SENTINEL_INSN }
+ },
+ arm_linux_restart_syscall_init
+};
+
/* Core file and register set support. */
#define ARM_LINUX_SIZEOF_GREGSET (18 * INT_REGISTER_SIZE)
struct regcache *regcache,
int regnum, const void *gregs_buf, size_t len)
{
+ struct gdbarch *gdbarch = get_regcache_arch (regcache);
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
const gdb_byte *gregs = gregs_buf;
int regno;
CORE_ADDR reg_pc;
{
if (arm_apcs_32)
regcache_raw_supply (regcache, ARM_PS_REGNUM,
- gregs + INT_REGISTER_SIZE * ARM_CPSR_REGNUM);
+ gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM);
else
regcache_raw_supply (regcache, ARM_PS_REGNUM,
gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM);
{
reg_pc = extract_unsigned_integer (gregs
+ INT_REGISTER_SIZE * ARM_PC_REGNUM,
- INT_REGISTER_SIZE);
- reg_pc = gdbarch_addr_bits_remove (current_gdbarch, reg_pc);
- store_unsigned_integer (pc_buf, INT_REGISTER_SIZE, reg_pc);
+ INT_REGISTER_SIZE, byte_order);
+ reg_pc = gdbarch_addr_bits_remove (gdbarch, reg_pc);
+ store_unsigned_integer (pc_buf, INT_REGISTER_SIZE, byte_order, reg_pc);
regcache_raw_supply (regcache, ARM_PC_REGNUM, pc_buf);
}
}
{
if (arm_apcs_32)
regcache_raw_collect (regcache, ARM_PS_REGNUM,
- gregs + INT_REGISTER_SIZE * ARM_CPSR_REGNUM);
+ gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM);
else
regcache_raw_collect (regcache, ARM_PS_REGNUM,
gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM);
return NULL;
}
+/* Insert a single step breakpoint at the next executed instruction. */
+
+static int
+arm_linux_software_single_step (struct frame_info *frame)
+{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ struct address_space *aspace = get_frame_address_space (frame);
+ CORE_ADDR next_pc = arm_get_next_pc (frame, get_frame_pc (frame));
+
+ /* 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);
+
+ insert_single_step_breakpoint (gdbarch, aspace, next_pc);
+
+ return 1;
+}
+
+/* Support for displaced stepping of Linux SVC instructions. */
+
+static void
+arm_linux_cleanup_svc (struct gdbarch *gdbarch,
+ struct regcache *regs,
+ struct displaced_step_closure *dsc)
+{
+ CORE_ADDR from = dsc->insn_addr;
+ ULONGEST apparent_pc;
+ int within_scratch;
+
+ regcache_cooked_read_unsigned (regs, ARM_PC_REGNUM, &apparent_pc);
+
+ within_scratch = (apparent_pc >= dsc->scratch_base
+ && apparent_pc < (dsc->scratch_base
+ + DISPLACED_MODIFIED_INSNS * 4 + 4));
+
+ if (debug_displaced)
+ {
+ fprintf_unfiltered (gdb_stdlog, "displaced: PC is apparently %.8lx after "
+ "SVC step ", (unsigned long) apparent_pc);
+ if (within_scratch)
+ fprintf_unfiltered (gdb_stdlog, "(within scratch space)\n");
+ else
+ fprintf_unfiltered (gdb_stdlog, "(outside scratch space)\n");
+ }
+
+ if (within_scratch)
+ displaced_write_reg (regs, dsc, ARM_PC_REGNUM, from + 4, BRANCH_WRITE_PC);
+}
+
+static int
+arm_linux_copy_svc (struct gdbarch *gdbarch, uint32_t insn, CORE_ADDR to,
+ struct regcache *regs, struct displaced_step_closure *dsc)
+{
+ CORE_ADDR from = dsc->insn_addr;
+ struct frame_info *frame;
+ unsigned int svc_number = displaced_read_reg (regs, from, 7);
+
+ if (debug_displaced)
+ fprintf_unfiltered (gdb_stdlog, "displaced: copying Linux svc insn %.8lx\n",
+ (unsigned long) insn);
+
+ frame = get_current_frame ();
+
+ /* Is this a sigreturn or rt_sigreturn syscall? Note: these are only useful
+ for EABI. */
+ if (svc_number == 119 || svc_number == 173)
+ {
+ if (get_frame_type (frame) == SIGTRAMP_FRAME)
+ {
+ CORE_ADDR return_to;
+ struct symtab_and_line sal;
+
+ if (debug_displaced)
+ fprintf_unfiltered (gdb_stdlog, "displaced: found "
+ "sigreturn/rt_sigreturn SVC call. PC in frame = %lx\n",
+ (unsigned long) get_frame_pc (frame));
+
+ return_to = frame_unwind_caller_pc (frame);
+ if (debug_displaced)
+ fprintf_unfiltered (gdb_stdlog, "displaced: unwind pc = %lx. "
+ "Setting momentary breakpoint.\n", (unsigned long) return_to);
+
+ gdb_assert (inferior_thread ()->step_resume_breakpoint == NULL);
+
+ sal = find_pc_line (return_to, 0);
+ sal.pc = return_to;
+ sal.section = find_pc_overlay (return_to);
+ sal.explicit_pc = 1;
+
+ frame = get_prev_frame (frame);
+
+ if (frame)
+ {
+ inferior_thread ()->step_resume_breakpoint
+ = set_momentary_breakpoint (gdbarch, sal, get_frame_id (frame),
+ bp_step_resume);
+
+ /* We need to make sure we actually insert the momentary
+ breakpoint set above. */
+ insert_breakpoints ();
+ }
+ else if (debug_displaced)
+ fprintf_unfiltered (gdb_stderr, "displaced: couldn't find previous "
+ "frame to set momentary breakpoint for "
+ "sigreturn/rt_sigreturn\n");
+ }
+ else if (debug_displaced)
+ fprintf_unfiltered (gdb_stdlog, "displaced: sigreturn/rt_sigreturn "
+ "SVC call not in signal trampoline frame\n");
+ }
+
+ /* Preparation: If we detect sigreturn, set momentary breakpoint at resume
+ location, else nothing.
+ Insn: unmodified svc.
+ Cleanup: if pc lands in scratch space, pc <- insn_addr + 4
+ else leave pc alone. */
+
+ dsc->modinsn[0] = insn;
+
+ dsc->cleanup = &arm_linux_cleanup_svc;
+ /* Pretend we wrote to the PC, so cleanup doesn't set PC to the next
+ instruction. */
+ dsc->wrote_to_pc = 1;
+
+ return 0;
+}
+
+
+/* The following two functions implement single-stepping over calls to Linux
+ kernel helper routines, which perform e.g. atomic operations on architecture
+ variants which don't support them natively.
+
+ When this function is called, the PC will be pointing at the kernel helper
+ (at an address inaccessible to GDB), and r14 will point to the return
+ address. Displaced stepping always executes code in the copy area:
+ so, make the copy-area instruction branch back to the kernel helper (the
+ "from" address), and make r14 point to the breakpoint in the copy area. In
+ that way, we regain control once the kernel helper returns, and can clean
+ up appropriately (as if we had just returned from the kernel helper as it
+ would have been called from the non-displaced location). */
+
+static void
+cleanup_kernel_helper_return (struct gdbarch *gdbarch,
+ struct regcache *regs,
+ struct displaced_step_closure *dsc)
+{
+ displaced_write_reg (regs, dsc, ARM_LR_REGNUM, dsc->tmp[0], CANNOT_WRITE_PC);
+ displaced_write_reg (regs, dsc, ARM_PC_REGNUM, dsc->tmp[0], BRANCH_WRITE_PC);
+}
+
+static void
+arm_catch_kernel_helper_return (struct gdbarch *gdbarch, CORE_ADDR from,
+ CORE_ADDR to, struct regcache *regs,
+ struct displaced_step_closure *dsc)
+{
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+
+ dsc->numinsns = 1;
+ dsc->insn_addr = from;
+ dsc->cleanup = &cleanup_kernel_helper_return;
+ /* Say we wrote to the PC, else cleanup will set PC to the next
+ instruction in the helper, which isn't helpful. */
+ dsc->wrote_to_pc = 1;
+
+ /* Preparation: tmp[0] <- r14
+ r14 <- <scratch space>+4
+ *(<scratch space>+8) <- from
+ Insn: ldr pc, [r14, #4]
+ Cleanup: r14 <- tmp[0], pc <- tmp[0]. */
+
+ dsc->tmp[0] = displaced_read_reg (regs, from, ARM_LR_REGNUM);
+ displaced_write_reg (regs, dsc, ARM_LR_REGNUM, (ULONGEST) to + 4,
+ CANNOT_WRITE_PC);
+ write_memory_unsigned_integer (to + 8, 4, byte_order, from);
+
+ dsc->modinsn[0] = 0xe59ef004; /* ldr pc, [lr, #4]. */
+}
+
+/* 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. */
+
+static struct displaced_step_closure *
+arm_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
+ CORE_ADDR from, CORE_ADDR to,
+ struct regcache *regs)
+{
+ struct displaced_step_closure *dsc
+ = xmalloc (sizeof (struct displaced_step_closure));
+
+ /* Detect when we enter an (inaccessible by GDB) Linux kernel helper, and
+ stop at the return location. */
+ if (from > 0xffff0000)
+ {
+ if (debug_displaced)
+ fprintf_unfiltered (gdb_stdlog, "displaced: detected kernel helper "
+ "at %.8lx\n", (unsigned long) from);
+
+ arm_catch_kernel_helper_return (gdbarch, from, to, regs, dsc);
+ }
+ else
+ {
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ uint32_t insn = read_memory_unsigned_integer (from, 4, byte_order);
+
+ if (debug_displaced)
+ fprintf_unfiltered (gdb_stdlog, "displaced: stepping insn %.8lx "
+ "at %.8lx\n", (unsigned long) insn,
+ (unsigned long) from);
+
+ /* Override the default handling of SVC instructions. */
+ dsc->u.svc.copy_svc_os = arm_linux_copy_svc;
+
+ arm_process_displaced_insn (gdbarch, insn, from, to, regs, dsc);
+ }
+
+ arm_displaced_init_closure (gdbarch, from, to, dsc);
+
+ return dsc;
+}
+
static void
arm_linux_init_abi (struct gdbarch_info info,
struct gdbarch *gdbarch)
else
tdep->arm_breakpoint = arm_linux_arm_be_breakpoint;
tdep->thumb_breakpoint = arm_linux_thumb_be_breakpoint;
+ tdep->thumb2_breakpoint = arm_linux_thumb2_be_breakpoint;
}
else
{
else
tdep->arm_breakpoint = arm_linux_arm_le_breakpoint;
tdep->thumb_breakpoint = arm_linux_thumb_le_breakpoint;
+ tdep->thumb2_breakpoint = arm_linux_thumb2_le_breakpoint;
}
tdep->arm_breakpoint_size = sizeof (arm_linux_arm_le_breakpoint);
tdep->thumb_breakpoint_size = sizeof (arm_linux_thumb_le_breakpoint);
+ tdep->thumb2_breakpoint_size = sizeof (arm_linux_thumb2_le_breakpoint);
if (tdep->fp_model == ARM_FLOAT_AUTO)
tdep->fp_model = ARM_FLOAT_FPA;
- tdep->jb_pc = ARM_LINUX_JB_PC;
+ switch (tdep->fp_model)
+ {
+ case ARM_FLOAT_FPA:
+ tdep->jb_pc = ARM_LINUX_JB_PC_FPA;
+ break;
+ case ARM_FLOAT_SOFT_FPA:
+ case ARM_FLOAT_SOFT_VFP:
+ case ARM_FLOAT_VFP:
+ tdep->jb_pc = ARM_LINUX_JB_PC_EABI;
+ break;
+ default:
+ internal_error
+ (__FILE__, __LINE__,
+ _("arm_linux_init_abi: Floating point model not supported"));
+ break;
+ }
tdep->jb_elt_size = ARM_LINUX_JB_ELEMENT_SIZE;
set_solib_svr4_fetch_link_map_offsets
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
/* Single stepping. */
- set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
+ set_gdbarch_software_single_step (gdbarch, arm_linux_software_single_step);
/* Shared library handling. */
set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
&arm_eabi_linux_sigreturn_tramp_frame);
tramp_frame_prepend_unwinder (gdbarch,
&arm_eabi_linux_rt_sigreturn_tramp_frame);
+ tramp_frame_prepend_unwinder (gdbarch,
+ &arm_linux_restart_syscall_tramp_frame);
/* Core file support. */
set_gdbarch_regset_from_core_section (gdbarch,
arm_linux_regset_from_core_section);
+
+ set_gdbarch_get_siginfo_type (gdbarch, linux_get_siginfo_type);
+
+ /* Displaced stepping. */
+ set_gdbarch_displaced_step_copy_insn (gdbarch,
+ arm_linux_displaced_step_copy_insn);
+ set_gdbarch_displaced_step_fixup (gdbarch, arm_displaced_step_fixup);
+ set_gdbarch_displaced_step_free_closure (gdbarch,
+ simple_displaced_step_free_closure);
+ set_gdbarch_displaced_step_location (gdbarch, displaced_step_at_entry_point);
}
+/* Provide a prototype to silence -Wmissing-prototypes. */
+extern initialize_file_ftype _initialize_arm_linux_tdep;
+
void
_initialize_arm_linux_tdep (void)
{