X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Farm-linux-tdep.c;h=aa7d0af2b15176393a56cb060cd51b7d9929f587;hb=790c20f3f358afee041c54335081e4d877924ce3;hp=91fa88fe0add9bf148873d6d72a67d4ef1dbf75b;hpb=6913c89ac7bc62da99c5bb292de820098a2bacd2;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/arm-linux-tdep.c b/gdb/arm-linux-tdep.c index 91fa88fe0a..aa7d0af2b1 100644 --- a/gdb/arm-linux-tdep.c +++ b/gdb/arm-linux-tdep.c @@ -1,11 +1,13 @@ /* GNU/Linux on ARM target support. - Copyright 1999, 2000, 2001, 2002, 2003 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, @@ -14,9 +16,7 @@ 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., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ + along with this program. If not, see . */ #include "defs.h" #include "target.h" @@ -27,205 +27,75 @@ #include "frame.h" #include "regcache.h" #include "doublest.h" +#include "solib-svr4.h" #include "osabi.h" +#include "regset.h" +#include "trad-frame.h" +#include "tramp-frame.h" +#include "breakpoint.h" #include "arm-tdep.h" - -/* For shared library handling. */ -#include "symtab.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 "objfiles.h" + +#include "gdb_string.h" + +extern int arm_apcs_32; /* 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. Since ARM GNU/Linux is little - endian, and doesn't support Thumb at the moment we only override - the ARM little-endian breakpoint. */ - -static const char arm_linux_arm_le_breakpoint[] = {0x01,0x00,0x9f,0xef}; - -/* 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 -}; - -/* Description of the longjmp buffer. */ -#define ARM_LINUX_JB_ELEMENT_SIZE INT_REGISTER_RAW_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. */ -/* 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 *valbuf) -{ - /* ScottB: This needs to be looked at to handle the different - 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)); -} + SIGTRAP, and wakes the debugger. */ -/* 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) - -static 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; +static const char arm_linux_arm_le_breakpoint[] = { 0x01, 0x00, 0x9f, 0xef }; - /* 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. */ +static const char arm_linux_arm_be_breakpoint[] = { 0xef, 0x9f, 0x00, 0x01 }; - if (struct_return) /* The struct address goes in A1. */ - nstack_size += REGISTER_SIZE; +/* However, the EABI syscall interface (new in Nov. 2005) does not look at + the operand of the swi if old-ABI compatibility is disabled. Therefore, + use an undefined instruction instead. This is supported as of kernel + version 2.5.70 (May 2003), so should be a safe assumption for EABI + binaries. */ - /* Walk through the arguments and add their size to nstack_size. */ - for (argnum = 0; argnum < nargs; argnum++) - { - int len; - struct type *arg_type; +static const char eabi_linux_arm_le_breakpoint[] = { 0xf0, 0x01, 0xf0, 0xe7 }; - arg_type = check_typedef (VALUE_TYPE (args[argnum])); - len = TYPE_LENGTH (arg_type); +static const char eabi_linux_arm_be_breakpoint[] = { 0xe7, 0xf0, 0x01, 0xf0 }; - /* 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; - } +/* All the kernels which support Thumb support using a specific undefined + instruction for the Thumb breakpoint. */ - /* Allocate room on the stack, and initialize our stack frame - pointer. */ - fp = NULL; - if (nstack_size > 0) - { - sp -= nstack_size; - fp = (char *) sp; - } +static const char arm_linux_thumb_be_breakpoint[] = {0xde, 0x01}; - /* Initialize the integer argument register pointer. */ - argreg = ARM_A1_REGNUM; +static const char arm_linux_thumb_le_breakpoint[] = {0x01, 0xde}; - /* The struct_return pointer occupies the first parameter passing - register. */ - if (struct_return) - write_register (argreg++, struct_addr); +/* 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. */ - /* 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 = deprecated_extract_floating (val, len); - len = TARGET_DOUBLE_BIT / TARGET_CHAR_BIT; - val = alloca (len); - deprecated_store_floating (val, len, dblval); - } +static const char arm_linux_thumb2_be_breakpoint[] = { 0xf7, 0xf0, 0xa0, 0x00 }; - /* 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)); - } +static const char arm_linux_thumb2_le_breakpoint[] = { 0xf0, 0xf7, 0x00, 0xa0 }; - /* 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; - } +/* Description of the longjmp buffer. The buffer is treated as an array of + elements of size ARM_LINUX_JB_ELEMENT_SIZE. - len -= partial_len; - val += partial_len; - } - } + 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. - /* Return adjusted stack pointer. */ - return sp; -} + 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_FPA 21 +#define ARM_LINUX_JB_PC_EABI 9 /* Dynamic Linking on ARM GNU/Linux @@ -346,173 +216,719 @@ arm_linux_push_arguments (int nargs, struct value **args, CORE_ADDR sp, 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. */ +/* The constants below were determined by examining the following files + in the linux kernel sources: + + arch/arm/kernel/signal.c + - see SWI_SYS_SIGRETURN and SWI_SYS_RT_SIGRETURN + include/asm-arm/unistd.h + - see __NR_sigreturn, __NR_rt_sigreturn, and __NR_SYSCALL_BASE */ + +#define ARM_LINUX_SIGRETURN_INSTR 0xef900077 +#define ARM_LINUX_RT_SIGRETURN_INSTR 0xef9000ad + +/* For ARM EABI, the syscall number is not in the SWI instruction + (instead it is loaded into r7). We recognize the pattern that + glibc uses... alternatively, we could arrange to do this by + function name, but they are not always exported. */ +#define ARM_SET_R7_SIGRETURN 0xe3a07077 +#define ARM_SET_R7_RT_SIGRETURN 0xe3a070ad +#define ARM_EABI_SYSCALL 0xef000000 -static struct minimal_symbol * -find_minsym_and_objfile (char *name, struct objfile **objfile_p) +/* 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 *this_frame, + struct trad_frame_cache *this_cache, + CORE_ADDR func, int regs_offset) { - struct objfile *objfile; + CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); + CORE_ADDR base = sp + regs_offset; + int i; + + for (i = 0; i < 16; i++) + trad_frame_set_reg_addr (this_cache, i, base + i * 4); + + trad_frame_set_reg_addr (this_cache, ARM_PS_REGNUM, base + 16 * 4); + + /* The VFP or iWMMXt registers may be saved on the stack, but there's + no reliable way to restore them (yet). */ + + /* Save a frame ID. */ + 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 - ALL_OBJFILES (objfile) +/* 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 + +static void +arm_linux_sigreturn_init (const struct tramp_frame *self, + struct frame_info *this_frame, + struct trad_frame_cache *this_cache, + CORE_ADDR func) +{ + 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 (this_frame, this_cache, func, + ARM_UCONTEXT_SIGCONTEXT + + ARM_SIGCONTEXT_R0); + else + 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 *this_frame, + struct trad_frame_cache *this_cache, + CORE_ADDR func) +{ + 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 (this_frame, this_cache, func, + ARM_OLD_RT_SIGFRAME_UCONTEXT + + ARM_UCONTEXT_SIGCONTEXT + + ARM_SIGCONTEXT_R0); + else + 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_SIGRETURN_INSTR, -1 }, + { TRAMP_SENTINEL_INSN } + }, + arm_linux_sigreturn_init +}; + +static struct tramp_frame arm_linux_rt_sigreturn_tramp_frame = { + SIGTRAMP_FRAME, + 4, + { + { ARM_LINUX_RT_SIGRETURN_INSTR, -1 }, + { TRAMP_SENTINEL_INSN } + }, + arm_linux_rt_sigreturn_init +}; + +static struct tramp_frame arm_eabi_linux_sigreturn_tramp_frame = { + SIGTRAMP_FRAME, + 4, + { + { ARM_SET_R7_SIGRETURN, -1 }, + { ARM_EABI_SYSCALL, -1 }, + { TRAMP_SENTINEL_INSN } + }, + arm_linux_sigreturn_init +}; + +static struct tramp_frame arm_eabi_linux_rt_sigreturn_tramp_frame = { + SIGTRAMP_FRAME, + 4, + { + { ARM_SET_R7_RT_SIGRETURN, -1 }, + { ARM_EABI_SYSCALL, -1 }, + { TRAMP_SENTINEL_INSN } + }, + 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) + +void +arm_linux_supply_gregset (const struct regset *regset, + 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; + gdb_byte pc_buf[INT_REGISTER_SIZE]; + + for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++) + if (regnum == -1 || regnum == regno) + regcache_raw_supply (regcache, regno, + gregs + INT_REGISTER_SIZE * regno); + + if (regnum == ARM_PS_REGNUM || regnum == -1) { - struct minimal_symbol *msym; + if (arm_apcs_32) + regcache_raw_supply (regcache, ARM_PS_REGNUM, + gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM); + else + regcache_raw_supply (regcache, ARM_PS_REGNUM, + gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); + } - ALL_OBJFILE_MSYMBOLS (objfile, msym) - { - if (DEPRECATED_SYMBOL_NAME (msym) - && strcmp (DEPRECATED_SYMBOL_NAME (msym), name) == 0) - { - *objfile_p = objfile; - return msym; - } - } + if (regnum == ARM_PC_REGNUM || regnum == -1) + { + reg_pc = extract_unsigned_integer (gregs + + INT_REGISTER_SIZE * ARM_PC_REGNUM, + 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); } +} - return 0; +void +arm_linux_collect_gregset (const struct regset *regset, + const struct regcache *regcache, + int regnum, void *gregs_buf, size_t len) +{ + gdb_byte *gregs = gregs_buf; + int regno; + + for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++) + if (regnum == -1 || regnum == regno) + regcache_raw_collect (regcache, regno, + gregs + INT_REGISTER_SIZE * regno); + + if (regnum == ARM_PS_REGNUM || regnum == -1) + { + if (arm_apcs_32) + regcache_raw_collect (regcache, ARM_PS_REGNUM, + gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM); + else + regcache_raw_collect (regcache, ARM_PS_REGNUM, + gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); + } + + if (regnum == ARM_PC_REGNUM || regnum == -1) + regcache_raw_collect (regcache, ARM_PC_REGNUM, + gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); } +/* Support for register format used by the NWFPE FPA emulator. */ -static CORE_ADDR -skip_hurd_resolver (CORE_ADDR pc) +#define typeNone 0x00 +#define typeSingle 0x01 +#define typeDouble 0x02 +#define typeExtended 0x03 + +void +supply_nwfpe_register (struct regcache *regcache, int regno, + const gdb_byte *regs) { - /* 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 GNU/Linux will provide a portable, efficient interface for - debugging programs that use shared libraries. */ + const gdb_byte *reg_data; + gdb_byte reg_tag; + gdb_byte buf[FP_REGISTER_SIZE]; + + reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE; + reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET]; + memset (buf, 0, FP_REGISTER_SIZE); + + switch (reg_tag) + { + case typeSingle: + memcpy (buf, reg_data, 4); + break; + case typeDouble: + memcpy (buf, reg_data + 4, 4); + memcpy (buf + 4, reg_data, 4); + break; + case typeExtended: + /* We want sign and exponent, then least significant bits, + then most significant. NWFPE does sign, most, least. */ + memcpy (buf, reg_data, 4); + memcpy (buf + 4, reg_data + 8, 4); + memcpy (buf + 8, reg_data + 4, 4); + break; + default: + break; + } + + regcache_raw_supply (regcache, regno, buf); +} - struct objfile *objfile; - struct minimal_symbol *resolver - = find_minsym_and_objfile ("_dl_runtime_resolve", &objfile); +void +collect_nwfpe_register (const struct regcache *regcache, int regno, + gdb_byte *regs) +{ + gdb_byte *reg_data; + gdb_byte reg_tag; + gdb_byte buf[FP_REGISTER_SIZE]; + + regcache_raw_collect (regcache, regno, buf); + + /* NOTE drow/2006-06-07: This code uses the tag already in the + register buffer. I've preserved that when moving the code + from the native file to the target file. But this doesn't + always make sense. */ + + reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE; + reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET]; + + switch (reg_tag) + { + case typeSingle: + memcpy (reg_data, buf, 4); + break; + case typeDouble: + memcpy (reg_data, buf + 4, 4); + memcpy (reg_data + 4, buf, 4); + break; + case typeExtended: + memcpy (reg_data, buf, 4); + memcpy (reg_data + 4, buf + 8, 4); + memcpy (reg_data + 8, buf + 4, 4); + break; + default: + break; + } +} + +void +arm_linux_supply_nwfpe (const struct regset *regset, + struct regcache *regcache, + int regnum, const void *regs_buf, size_t len) +{ + const gdb_byte *regs = regs_buf; + int regno; + + if (regnum == ARM_FPS_REGNUM || regnum == -1) + regcache_raw_supply (regcache, ARM_FPS_REGNUM, + regs + NWFPE_FPSR_OFFSET); + + for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++) + if (regnum == -1 || regnum == regno) + supply_nwfpe_register (regcache, regno, regs); +} - if (resolver) +void +arm_linux_collect_nwfpe (const struct regset *regset, + const struct regcache *regcache, + int regnum, void *regs_buf, size_t len) +{ + gdb_byte *regs = regs_buf; + int regno; + + for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++) + if (regnum == -1 || regnum == regno) + collect_nwfpe_register (regcache, regno, regs); + + if (regnum == ARM_FPS_REGNUM || regnum == -1) + regcache_raw_collect (regcache, ARM_FPS_REGNUM, + regs + INT_REGISTER_SIZE * ARM_FPS_REGNUM); +} + +/* Return the appropriate register set for the core section identified + by SECT_NAME and SECT_SIZE. */ + +static const struct regset * +arm_linux_regset_from_core_section (struct gdbarch *gdbarch, + const char *sect_name, size_t sect_size) +{ + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + + if (strcmp (sect_name, ".reg") == 0 + && sect_size == ARM_LINUX_SIZEOF_GREGSET) { - struct minimal_symbol *fixup - = lookup_minimal_symbol ("fixup", NULL, objfile); + if (tdep->gregset == NULL) + tdep->gregset = regset_alloc (gdbarch, arm_linux_supply_gregset, + arm_linux_collect_gregset); + return tdep->gregset; + } - if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc) - return (DEPRECATED_SAVED_PC_AFTER_CALL (get_current_frame ())); + if (strcmp (sect_name, ".reg2") == 0 + && sect_size == ARM_LINUX_SIZEOF_NWFPE) + { + if (tdep->fpregset == NULL) + tdep->fpregset = regset_alloc (gdbarch, arm_linux_supply_nwfpe, + arm_linux_collect_nwfpe); + return tdep->fpregset; } + return NULL; +} + +/* Copy the value of next pc of sigreturn and rt_sigrturn into PC, + and return 1. Return 0 if it is not a rt_sigreturn/sigreturn + syscall. */ +static int +arm_linux_sigreturn_return_addr (struct frame_info *frame, + unsigned long svc_number, + CORE_ADDR *pc) +{ + /* Is this a sigreturn or rt_sigreturn syscall? */ + if (svc_number == 119 || svc_number == 173) + { + if (get_frame_type (frame) == SIGTRAMP_FRAME) + { + *pc = frame_unwind_caller_pc (frame); + return 1; + } + } return 0; -} +} -/* 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. */ +/* When FRAME is at a syscall instruction, return the PC of the next + instruction to be executed. */ -CORE_ADDR -arm_linux_skip_solib_resolver (CORE_ADDR pc) +static CORE_ADDR +arm_linux_syscall_next_pc (struct frame_info *frame) { - CORE_ADDR result; + CORE_ADDR pc = get_frame_pc (frame); + CORE_ADDR return_addr = 0; + int is_thumb = arm_frame_is_thumb (frame); + ULONGEST svc_number = 0; + int is_sigreturn = 0; + + if (is_thumb) + { + svc_number = get_frame_register_unsigned (frame, 7); + } + else + { + struct gdbarch *gdbarch = get_frame_arch (frame); + enum bfd_endian byte_order_for_code = + gdbarch_byte_order_for_code (gdbarch); + unsigned long this_instr = + read_memory_unsigned_integer (pc, 4, byte_order_for_code); + + unsigned long svc_operand = (0x00ffffff & this_instr); + if (svc_operand) /* OABI. */ + { + svc_number = svc_operand - 0x900000; + } + else /* EABI. */ + { + svc_number = get_frame_register_unsigned (frame, 7); + } + } - /* Plug in functions for other kinds of resolvers here. */ - result = skip_hurd_resolver (pc); + is_sigreturn = arm_linux_sigreturn_return_addr (frame, svc_number, + &return_addr); - if (result) - return result; + if (is_sigreturn) + return return_addr; - return 0; + if (is_thumb) + { + return_addr = pc + 2; + /* Addresses for calling Thumb functions have the bit 0 set. */ + return_addr |= 1; + } + else + { + return_addr = pc + 4; + } + + return return_addr; } -/* The constants below were determined by examining the following files - in the linux kernel sources: - arch/arm/kernel/signal.c - - see SWI_SYS_SIGRETURN and SWI_SYS_RT_SIGRETURN - include/asm-arm/unistd.h - - see __NR_sigreturn, __NR_rt_sigreturn, and __NR_SYSCALL_BASE */ +/* Insert a single step breakpoint at the next executed instruction. */ -#define ARM_LINUX_SIGRETURN_INSTR 0xef900077 -#define ARM_LINUX_RT_SIGRETURN_INSTR 0xef9000ad +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)); -/* arm_linux_in_sigtramp determines if PC points at one of the - instructions which cause control to return to the Linux kernel upon - return from a signal handler. FUNC_NAME is unused. */ + /* 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); -int -arm_linux_in_sigtramp (CORE_ADDR pc, char *func_name) + 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) { - unsigned long inst; + CORE_ADDR from = dsc->insn_addr; + ULONGEST apparent_pc; + int within_scratch; - inst = read_memory_integer (pc, 4); + regcache_cooked_read_unsigned (regs, ARM_PC_REGNUM, &apparent_pc); - return (inst == ARM_LINUX_SIGRETURN_INSTR - || inst == ARM_LINUX_RT_SIGRETURN_INSTR); + 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); } -/* arm_linux_sigcontext_register_address returns the address in the - sigcontext of register REGNO given a stack pointer value SP and - program counter value PC. The value 0 is returned if PC is not - pointing at one of the signal return instructions or if REGNO is - not saved in the sigcontext struct. */ +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; + CORE_ADDR return_to = 0; + + struct frame_info *frame; + unsigned int svc_number = displaced_read_reg (regs, from, 7); + int is_sigreturn = 0; + + if (debug_displaced) + fprintf_unfiltered (gdb_stdlog, "displaced: copying Linux svc insn %.8lx\n", + (unsigned long) insn); + + frame = get_current_frame (); + + is_sigreturn = arm_linux_sigreturn_return_addr(frame, svc_number, + &return_to); + if (is_sigreturn) + { + 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)); + + 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; -CORE_ADDR -arm_linux_sigcontext_register_address (CORE_ADDR sp, CORE_ADDR pc, int regno) + 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) { - unsigned long inst; - CORE_ADDR reg_addr = 0; + 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); +} - inst = read_memory_integer (pc, 4); +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 <- +4 + *(+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)); - if (inst == ARM_LINUX_SIGRETURN_INSTR - || inst == ARM_LINUX_RT_SIGRETURN_INSTR) + /* Detect when we enter an (inaccessible by GDB) Linux kernel helper, and + stop at the return location. */ + if (from > 0xffff0000) { - CORE_ADDR sigcontext_addr; - - /* The sigcontext structure is at different places for the two - signal return instructions. For ARM_LINUX_SIGRETURN_INSTR, - it starts at the SP value. For ARM_LINUX_RT_SIGRETURN_INSTR, - it is at SP+8. For the latter instruction, it may also be - the case that the address of this structure may be determined - by reading the 4 bytes at SP, but I'm not convinced this is - reliable. - - In any event, these magic constants (0 and 8) may be - determined by examining struct sigframe and struct - rt_sigframe in arch/arm/kernel/signal.c in the Linux kernel - sources. */ - - if (inst == ARM_LINUX_RT_SIGRETURN_INSTR) - sigcontext_addr = sp + 8; - else /* inst == ARM_LINUX_SIGRETURN_INSTR */ - sigcontext_addr = sp + 0; - - /* The layout of the sigcontext structure for ARM GNU/Linux is - in include/asm-arm/sigcontext.h in the Linux kernel sources. - - There are three 4-byte fields which precede the saved r0 - field. (This accounts for the 12 in the code below.) The - sixteen registers (4 bytes per field) follow in order. The - PSR value follows the sixteen registers which accounts for - the constant 19 below. */ - - if (0 <= regno && regno <= ARM_PC_REGNUM) - reg_addr = sigcontext_addr + 12 + (4 * regno); - else if (regno == ARM_PS_REGNUM) - reg_addr = sigcontext_addr + 19 * 4; + 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); - return reg_addr; + /* 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 @@ -521,28 +937,98 @@ arm_linux_init_abi (struct gdbarch_info info, { struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + linux_init_abi (info, gdbarch); + tdep->lowest_pc = 0x8000; - tdep->arm_breakpoint = arm_linux_arm_le_breakpoint; + if (info.byte_order == BFD_ENDIAN_BIG) + { + if (tdep->arm_abi == ARM_ABI_AAPCS) + tdep->arm_breakpoint = eabi_linux_arm_be_breakpoint; + 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 + { + if (tdep->arm_abi == ARM_ABI_AAPCS) + tdep->arm_breakpoint = eabi_linux_arm_le_breakpoint; + 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); - tdep->fp_model = ARM_FLOAT_FPA; + 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_gdbarch_call_dummy_words (gdbarch, arm_linux_call_dummy_words); - set_gdbarch_sizeof_call_dummy_words (gdbarch, - sizeof (arm_linux_call_dummy_words)); + set_solib_svr4_fetch_link_map_offsets + (gdbarch, svr4_ilp32_fetch_link_map_offsets); - /* The following two overrides shouldn't be needed. */ - set_gdbarch_deprecated_extract_return_value (gdbarch, arm_linux_extract_return_value); - set_gdbarch_deprecated_push_arguments (gdbarch, arm_linux_push_arguments); + /* Single stepping. */ + set_gdbarch_software_single_step (gdbarch, arm_linux_software_single_step); /* Shared library handling. */ - set_gdbarch_in_solib_call_trampoline (gdbarch, in_plt_section); 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); + + tramp_frame_prepend_unwinder (gdbarch, + &arm_linux_sigreturn_tramp_frame); + tramp_frame_prepend_unwinder (gdbarch, + &arm_linux_rt_sigreturn_tramp_frame); + tramp_frame_prepend_unwinder (gdbarch, + &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); + + + tdep->syscall_next_pc = arm_linux_syscall_next_pc; } +/* Provide a prototype to silence -Wmissing-prototypes. */ +extern initialize_file_ftype _initialize_arm_linux_tdep; + void _initialize_arm_linux_tdep (void) {