/* GNU/Linux on ARM target support.
- Copyright 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+
+ Copyright 1999, 2000, 2001, 2002, 2003, 2005 Free Software
+ Foundation, Inc.
This file is part of GDB.
#include "frame.h"
#include "regcache.h"
#include "doublest.h"
+#include "solib-svr4.h"
+#include "osabi.h"
#include "arm-tdep.h"
+#include "glibc-tdep.h"
-/* For arm_linux_skip_solib_resolver. */
-#include "symtab.h"
-#include "symfile.h"
-#include "objfiles.h"
-
-/* CALL_DUMMY_WORDS:
- This sequence of words is the instructions
-
- mov lr, pc
- mov pc, r4
- swi bkpt_swi
-
- Note this is 12 bytes. */
-
-LONGEST arm_linux_call_dummy_words[] =
-{
- 0xe1a0e00f, 0xe1a0f004, 0xef9f001
-};
-
-#ifdef GET_LONGJMP_TARGET
+/* Under ARM GNU/Linux the traditional way of performing a breakpoint
+ is to execute a particular software interrupt, rather than use a
+ particular undefined instruction to provoke a trap. Upon exection
+ of the software interrupt the kernel stops the inferior with a
+ SIGTRAP, and wakes the debugger. */
-/* Figure out where the longjmp will land. We expect that we have
- just entered longjmp and haven't yet altered r0, r1, so the
- arguments are still in the registers. (ARM_A1_REGNUM) points at
- the jmp_buf structure from which we extract the pc (JB_PC) that we
- will land at. The pc is copied into ADDR. This routine returns
- true on success. */
+static const char arm_linux_arm_le_breakpoint[] = { 0x01, 0x00, 0x9f, 0xef };
-#define LONGJMP_TARGET_SIZE sizeof(int)
-#define JB_ELEMENT_SIZE sizeof(int)
-#define JB_SL 18
-#define JB_FP 19
-#define JB_SP 20
-#define JB_PC 21
+static const char arm_linux_arm_be_breakpoint[] = { 0xef, 0x9f, 0x00, 0x01 };
-int
-arm_get_longjmp_target (CORE_ADDR * pc)
-{
- CORE_ADDR jb_addr;
- char buf[LONGJMP_TARGET_SIZE];
+static const char arm_linux_thumb_be_breakpoint[] = {0xde, 0x01};
- jb_addr = read_register (ARM_A1_REGNUM);
+static const char arm_linux_thumb_le_breakpoint[] = {0x01, 0xde};
- if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
- LONGJMP_TARGET_SIZE))
- return 0;
-
- *pc = extract_address (buf, LONGJMP_TARGET_SIZE);
- return 1;
-}
-
-#endif /* GET_LONGJMP_TARGET */
+/* Description of the longjmp buffer. */
+#define ARM_LINUX_JB_ELEMENT_SIZE INT_REGISTER_SIZE
+#define ARM_LINUX_JB_PC 21
/* Extract from an array REGBUF containing the (raw) register state
a function return value of type TYPE, and copy that, in virtual format,
into VALBUF. */
-
-void
+/* FIXME rearnsha/2002-02-23: This function shouldn't be necessary.
+ The ARM generic one should be able to handle the model used by
+ linux and the low-level formatting of the registers should be
+ hidden behind the regcache abstraction. */
+static void
arm_linux_extract_return_value (struct type *type,
- char regbuf[REGISTER_BYTES],
+ char regbuf[],
char *valbuf)
{
/* ScottB: This needs to be looked at to handle the different
- floating point emulators on ARM Linux. Right now the code
+ floating point emulators on ARM GNU/Linux. Right now the code
assumes that fetch inferior registers does the right thing for
GDB. I suspect this won't handle NWFPE registers correctly, nor
will the default ARM version (arm_extract_return_value()). */
int regnum = ((TYPE_CODE_FLT == TYPE_CODE (type))
? ARM_F0_REGNUM : ARM_A1_REGNUM);
- memcpy (valbuf, ®buf[REGISTER_BYTE (regnum)], TYPE_LENGTH (type));
+ memcpy (valbuf, ®buf[DEPRECATED_REGISTER_BYTE (regnum)], TYPE_LENGTH (type));
}
-
-/* Note: ScottB
-
- This function does not support passing parameters using the FPA
- variant of the APCS. It passes any floating point arguments in the
- general registers and/or on the stack.
-
- FIXME: This and arm_push_arguments should be merged. However this
- function breaks on a little endian host, big endian target
- using the COFF file format. ELF is ok.
-
- ScottB. */
-
-/* Addresses for calling Thumb functions have the bit 0 set.
- Here are some macros to test, set, or clear bit 0 of addresses. */
-#define IS_THUMB_ADDR(addr) ((addr) & 1)
-#define MAKE_THUMB_ADDR(addr) ((addr) | 1)
-#define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
-CORE_ADDR
-arm_linux_push_arguments (int nargs, struct value **args, CORE_ADDR sp,
- int struct_return, CORE_ADDR struct_addr)
-{
- char *fp;
- int argnum, argreg, nstack_size;
-
- /* Walk through the list of args and determine how large a temporary
- stack is required. Need to take care here as structs may be
- passed on the stack, and we have to to push them. */
- nstack_size = -4 * REGISTER_SIZE; /* Some arguments go into A1-A4. */
-
- if (struct_return) /* The struct address goes in A1. */
- nstack_size += REGISTER_SIZE;
-
- /* Walk through the arguments and add their size to nstack_size. */
- for (argnum = 0; argnum < nargs; argnum++)
- {
- int len;
- struct type *arg_type;
-
- arg_type = check_typedef (VALUE_TYPE (args[argnum]));
- len = TYPE_LENGTH (arg_type);
-
- /* ANSI C code passes float arguments as integers, K&R code
- passes float arguments as doubles. Correct for this here. */
- if (TYPE_CODE_FLT == TYPE_CODE (arg_type) && REGISTER_SIZE == len)
- nstack_size += FP_REGISTER_VIRTUAL_SIZE;
- else
- nstack_size += len;
- }
-
- /* Allocate room on the stack, and initialize our stack frame
- pointer. */
- fp = NULL;
- if (nstack_size > 0)
- {
- sp -= nstack_size;
- fp = (char *) sp;
- }
-
- /* Initialize the integer argument register pointer. */
- argreg = ARM_A1_REGNUM;
-
- /* The struct_return pointer occupies the first parameter passing
- register. */
- if (struct_return)
- write_register (argreg++, struct_addr);
-
- /* Process arguments from left to right. Store as many as allowed
- in the parameter passing registers (A1-A4), and save the rest on
- the temporary stack. */
- for (argnum = 0; argnum < nargs; argnum++)
- {
- int len;
- char *val;
- CORE_ADDR regval;
- enum type_code typecode;
- struct type *arg_type, *target_type;
-
- arg_type = check_typedef (VALUE_TYPE (args[argnum]));
- target_type = TYPE_TARGET_TYPE (arg_type);
- len = TYPE_LENGTH (arg_type);
- typecode = TYPE_CODE (arg_type);
- val = (char *) VALUE_CONTENTS (args[argnum]);
-
- /* ANSI C code passes float arguments as integers, K&R code
- passes float arguments as doubles. The .stabs record for
- for ANSI prototype floating point arguments records the
- type as FP_INTEGER, while a K&R style (no prototype)
- .stabs records the type as FP_FLOAT. In this latter case
- the compiler converts the float arguments to double before
- calling the function. */
- if (TYPE_CODE_FLT == typecode && REGISTER_SIZE == len)
- {
- DOUBLEST dblval;
- dblval = extract_floating (val, len);
- len = TARGET_DOUBLE_BIT / TARGET_CHAR_BIT;
- val = alloca (len);
- store_floating (val, len, dblval);
- }
-
- /* If the argument is a pointer to a function, and it is a Thumb
- function, set the low bit of the pointer. */
- if (TYPE_CODE_PTR == typecode
- && NULL != target_type
- && TYPE_CODE_FUNC == TYPE_CODE (target_type))
- {
- CORE_ADDR regval = extract_address (val, len);
- if (arm_pc_is_thumb (regval))
- store_address (val, len, MAKE_THUMB_ADDR (regval));
- }
-
- /* Copy the argument to general registers or the stack in
- register-sized pieces. Large arguments are split between
- registers and stack. */
- while (len > 0)
- {
- int partial_len = len < REGISTER_SIZE ? len : REGISTER_SIZE;
-
- if (argreg <= ARM_LAST_ARG_REGNUM)
- {
- /* It's an argument being passed in a general register. */
- regval = extract_address (val, partial_len);
- write_register (argreg++, regval);
- }
- else
- {
- /* Push the arguments onto the stack. */
- write_memory ((CORE_ADDR) fp, val, REGISTER_SIZE);
- fp += REGISTER_SIZE;
- }
-
- len -= partial_len;
- val += partial_len;
- }
- }
-
- /* Return adjusted stack pointer. */
- return sp;
-}
-
/*
- Dynamic Linking on ARM Linux
- ----------------------------
+ Dynamic Linking on ARM GNU/Linux
+ --------------------------------
Note: PLT = procedure linkage table
GOT = global offset table
When the executable or library is first loaded, each GOT entry is
initialized to point to the code which implements dynamic name
resolution and code finding. This is normally a function in the
- program interpreter (on ARM Linux this is usually ld-linux.so.2,
- but it does not have to be). On the first invocation, the function
- is located and the GOT entry is replaced with the real function
- address. Subsequent calls go through steps 1, 2 and 3 and end up
- calling the real code.
+ program interpreter (on ARM GNU/Linux this is usually
+ ld-linux.so.2, but it does not have to be). On the first
+ invocation, the function is located and the GOT entry is replaced
+ with the real function address. Subsequent calls go through steps
+ 1, 2 and 3 and end up calling the real code.
1) In the code:
with. Before the fixup/resolver code returns, it actually calls
the requested function and repairs &GOT[n+3]. */
-/* Find the minimal symbol named NAME, and return both the minsym
- struct and its objfile. This probably ought to be in minsym.c, but
- everything there is trying to deal with things like C++ and
- SOFUN_ADDRESS_MAYBE_TURQUOISE, ... Since this is so simple, it may
- be considered too special-purpose for general consumption. */
+/* Fetch, and possibly build, an appropriate link_map_offsets structure
+ for ARM linux targets using the struct offsets defined in <link.h>.
+ Note, however, that link.h is not actually referred to in this file.
+ Instead, the relevant structs offsets were obtained from examining
+ link.h. (We can't refer to link.h from this file because the host
+ system won't necessarily have it, or if it does, the structs which
+ it defines will refer to the host system, not the target). */
-static struct minimal_symbol *
-find_minsym_and_objfile (char *name, struct objfile **objfile_p)
+static struct link_map_offsets *
+arm_linux_svr4_fetch_link_map_offsets (void)
{
- struct objfile *objfile;
+ static struct link_map_offsets lmo;
+ static struct link_map_offsets *lmp = 0;
- ALL_OBJFILES (objfile)
+ if (lmp == 0)
{
- struct minimal_symbol *msym;
-
- ALL_OBJFILE_MSYMBOLS (objfile, msym)
- {
- if (SYMBOL_NAME (msym)
- && STREQ (SYMBOL_NAME (msym), name))
- {
- *objfile_p = objfile;
- return msym;
- }
- }
- }
-
- return 0;
-}
+ lmp = &lmo;
+ lmo.r_debug_size = 8; /* Actual size is 20, but this is all we
+ need. */
-static CORE_ADDR
-skip_hurd_resolver (CORE_ADDR pc)
-{
- /* The HURD dynamic linker is part of the GNU C library, so many
- GNU/Linux distributions use it. (All ELF versions, as far as I
- know.) An unresolved PLT entry points to "_dl_runtime_resolve",
- which calls "fixup" to patch the PLT, and then passes control to
- the function.
-
- We look for the symbol `_dl_runtime_resolve', and find `fixup' in
- the same objfile. If we are at the entry point of `fixup', then
- we set a breakpoint at the return address (at the top of the
- stack), and continue.
-
- It's kind of gross to do all these checks every time we're
- called, since they don't change once the executable has gotten
- started. But this is only a temporary hack --- upcoming versions
- of Linux will provide a portable, efficient interface for
- debugging programs that use shared libraries. */
-
- struct objfile *objfile;
- struct minimal_symbol *resolver
- = find_minsym_and_objfile ("_dl_runtime_resolve", &objfile);
-
- if (resolver)
- {
- struct minimal_symbol *fixup
- = lookup_minimal_symbol ("fixup", NULL, objfile);
+ lmo.r_map_offset = 4;
+ lmo.r_map_size = 4;
- if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc)
- return (SAVED_PC_AFTER_CALL (get_current_frame ()));
- }
+ lmo.link_map_size = 20; /* Actual size is 552, but this is all we
+ need. */
- return 0;
-}
+ lmo.l_addr_offset = 0;
+ lmo.l_addr_size = 4;
-/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c.
- This function:
- 1) decides whether a PLT has sent us into the linker to resolve
- a function reference, and
- 2) if so, tells us where to set a temporary breakpoint that will
- trigger when the dynamic linker is done. */
+ lmo.l_name_offset = 4;
+ lmo.l_name_size = 4;
-CORE_ADDR
-arm_linux_skip_solib_resolver (CORE_ADDR pc)
-{
- CORE_ADDR result;
+ lmo.l_next_offset = 12;
+ lmo.l_next_size = 4;
- /* Plug in functions for other kinds of resolvers here. */
- result = skip_hurd_resolver (pc);
+ lmo.l_prev_offset = 16;
+ lmo.l_prev_size = 4;
+ }
- if (result)
- return result;
-
- return 0;
+ return lmp;
}
/* The constants below were determined by examining the following files
inst = read_memory_integer (pc, 4);
- if (inst == ARM_LINUX_SIGRETURN_INSTR || inst == ARM_LINUX_RT_SIGRETURN_INSTR)
+ if (inst == ARM_LINUX_SIGRETURN_INSTR
+ || inst == ARM_LINUX_RT_SIGRETURN_INSTR)
{
CORE_ADDR sigcontext_addr;
return reg_addr;
}
+static void
+arm_linux_init_abi (struct gdbarch_info info,
+ struct gdbarch *gdbarch)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ tdep->lowest_pc = 0x8000;
+ if (info.byte_order == BFD_ENDIAN_BIG)
+ {
+ tdep->arm_breakpoint = arm_linux_arm_be_breakpoint;
+ tdep->thumb_breakpoint = arm_linux_thumb_be_breakpoint;
+ }
+ else
+ {
+ tdep->arm_breakpoint = arm_linux_arm_le_breakpoint;
+ tdep->thumb_breakpoint = arm_linux_thumb_le_breakpoint;
+ }
+ tdep->arm_breakpoint_size = sizeof (arm_linux_arm_le_breakpoint);
+ tdep->thumb_breakpoint_size = sizeof (arm_linux_thumb_le_breakpoint);
+
+ if (tdep->fp_model == ARM_FLOAT_AUTO)
+ tdep->fp_model = ARM_FLOAT_FPA;
+
+ tdep->jb_pc = ARM_LINUX_JB_PC;
+ tdep->jb_elt_size = ARM_LINUX_JB_ELEMENT_SIZE;
+
+ set_solib_svr4_fetch_link_map_offsets
+ (gdbarch, arm_linux_svr4_fetch_link_map_offsets);
+
+ /* The following override shouldn't be needed. */
+ set_gdbarch_deprecated_extract_return_value (gdbarch, arm_linux_extract_return_value);
+
+ /* Shared library handling. */
+ set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
+ set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+ /* Enable TLS support. */
+ set_gdbarch_fetch_tls_load_module_address (gdbarch,
+ svr4_fetch_objfile_link_map);
+}
+
void
_initialize_arm_linux_tdep (void)
{
+ gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_LINUX,
+ arm_linux_init_abi);
}
projects / deliverable / binutils-gdb.git / blobdiff