123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481 |
- /* Target-dependent code for GNU/Linux m32r.
- Copyright (C) 2004-2022 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 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- 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, see <http://www.gnu.org/licenses/>. */
- #include "defs.h"
- #include "gdbcore.h"
- #include "frame.h"
- #include "value.h"
- #include "regcache.h"
- #include "inferior.h"
- #include "osabi.h"
- #include "reggroups.h"
- #include "regset.h"
- #include "glibc-tdep.h"
- #include "solib-svr4.h"
- #include "symtab.h"
- #include "trad-frame.h"
- #include "frame-unwind.h"
- #include "m32r-tdep.h"
- #include "linux-tdep.h"
- #include "gdbarch.h"
- /* Recognizing signal handler frames. */
- /* GNU/Linux has two flavors of signals. Normal signal handlers, and
- "realtime" (RT) signals. The RT signals can provide additional
- information to the signal handler if the SA_SIGINFO flag is set
- when establishing a signal handler using `sigaction'. It is not
- unlikely that future versions of GNU/Linux will support SA_SIGINFO
- for normal signals too. */
- /* When the m32r Linux kernel calls a signal handler and the
- SA_RESTORER flag isn't set, the return address points to a bit of
- code on the stack. This function returns whether the PC appears to
- be within this bit of code.
- The instruction sequence for normal signals is
- ldi r7, #__NR_sigreturn
- trap #2
- or 0x67 0x77 0x10 0xf2.
- Checking for the code sequence should be somewhat reliable, because
- the effect is to call the system call sigreturn. This is unlikely
- to occur anywhere other than in a signal trampoline.
- It kind of sucks that we have to read memory from the process in
- order to identify a signal trampoline, but there doesn't seem to be
- any other way. Therefore we only do the memory reads if no
- function name could be identified, which should be the case since
- the code is on the stack.
- Detection of signal trampolines for handlers that set the
- SA_RESTORER flag is in general not possible. Unfortunately this is
- what the GNU C Library has been doing for quite some time now.
- However, as of version 2.1.2, the GNU C Library uses signal
- trampolines (named __restore and __restore_rt) that are identical
- to the ones used by the kernel. Therefore, these trampolines are
- supported too. */
- static const gdb_byte linux_sigtramp_code[] = {
- 0x67, 0x77, 0x10, 0xf2,
- };
- /* If PC is in a sigtramp routine, return the address of the start of
- the routine. Otherwise, return 0. */
- static CORE_ADDR
- m32r_linux_sigtramp_start (CORE_ADDR pc, struct frame_info *this_frame)
- {
- gdb_byte buf[4];
- /* We only recognize a signal trampoline if PC is at the start of
- one of the instructions. We optimize for finding the PC at the
- start of the instruction sequence, as will be the case when the
- trampoline is not the first frame on the stack. We assume that
- in the case where the PC is not at the start of the instruction
- sequence, there will be a few trailing readable bytes on the
- stack. */
- if (pc % 2 != 0)
- {
- if (!safe_frame_unwind_memory (this_frame, pc, {buf, 2}))
- return 0;
- if (memcmp (buf, linux_sigtramp_code, 2) == 0)
- pc -= 2;
- else
- return 0;
- }
- if (!safe_frame_unwind_memory (this_frame, pc, {buf, 4}))
- return 0;
- if (memcmp (buf, linux_sigtramp_code, 4) != 0)
- return 0;
- return pc;
- }
- /* This function does the same for RT signals. Here the instruction
- sequence is
- ldi r7, #__NR_rt_sigreturn
- trap #2
- or 0x97 0xf0 0x00 0xad 0x10 0xf2 0xf0 0x00.
- The effect is to call the system call rt_sigreturn. */
- static const gdb_byte linux_rt_sigtramp_code[] = {
- 0x97, 0xf0, 0x00, 0xad, 0x10, 0xf2, 0xf0, 0x00,
- };
- /* If PC is in a RT sigtramp routine, return the address of the start
- of the routine. Otherwise, return 0. */
- static CORE_ADDR
- m32r_linux_rt_sigtramp_start (CORE_ADDR pc, struct frame_info *this_frame)
- {
- gdb_byte buf[4];
- /* We only recognize a signal trampoline if PC is at the start of
- one of the instructions. We optimize for finding the PC at the
- start of the instruction sequence, as will be the case when the
- trampoline is not the first frame on the stack. We assume that
- in the case where the PC is not at the start of the instruction
- sequence, there will be a few trailing readable bytes on the
- stack. */
- if (pc % 2 != 0)
- return 0;
- if (!safe_frame_unwind_memory (this_frame, pc, {buf, 4}))
- return 0;
- if (memcmp (buf, linux_rt_sigtramp_code, 4) == 0)
- {
- if (!safe_frame_unwind_memory (this_frame, pc + 4, {buf, 4}))
- return 0;
- if (memcmp (buf, linux_rt_sigtramp_code + 4, 4) == 0)
- return pc;
- }
- else if (memcmp (buf, linux_rt_sigtramp_code + 4, 4) == 0)
- {
- if (!safe_frame_unwind_memory (this_frame, pc - 4, {buf, 4}))
- return 0;
- if (memcmp (buf, linux_rt_sigtramp_code, 4) == 0)
- return pc - 4;
- }
- return 0;
- }
- static int
- m32r_linux_pc_in_sigtramp (CORE_ADDR pc, const char *name,
- struct frame_info *this_frame)
- {
- /* If we have NAME, we can optimize the search. The trampolines are
- named __restore and __restore_rt. However, they aren't dynamically
- exported from the shared C library, so the trampoline may appear to
- be part of the preceding function. This should always be sigaction,
- __sigaction, or __libc_sigaction (all aliases to the same function). */
- if (name == NULL || strstr (name, "sigaction") != NULL)
- return (m32r_linux_sigtramp_start (pc, this_frame) != 0
- || m32r_linux_rt_sigtramp_start (pc, this_frame) != 0);
- return (strcmp ("__restore", name) == 0
- || strcmp ("__restore_rt", name) == 0);
- }
- /* From <asm/sigcontext.h>. */
- static int m32r_linux_sc_reg_offset[] = {
- 4 * 4, /* r0 */
- 5 * 4, /* r1 */
- 6 * 4, /* r2 */
- 7 * 4, /* r3 */
- 0 * 4, /* r4 */
- 1 * 4, /* r5 */
- 2 * 4, /* r6 */
- 8 * 4, /* r7 */
- 9 * 4, /* r8 */
- 10 * 4, /* r9 */
- 11 * 4, /* r10 */
- 12 * 4, /* r11 */
- 13 * 4, /* r12 */
- 21 * 4, /* fp */
- 22 * 4, /* lr */
- -1 * 4, /* sp */
- 16 * 4, /* psw */
- -1 * 4, /* cbr */
- 23 * 4, /* spi */
- 20 * 4, /* spu */
- 19 * 4, /* bpc */
- 17 * 4, /* pc */
- 15 * 4, /* accl */
- 14 * 4 /* acch */
- };
- struct m32r_frame_cache
- {
- CORE_ADDR base, pc;
- trad_frame_saved_reg *saved_regs;
- };
- static struct m32r_frame_cache *
- m32r_linux_sigtramp_frame_cache (struct frame_info *this_frame,
- void **this_cache)
- {
- struct m32r_frame_cache *cache;
- CORE_ADDR sigcontext_addr, addr;
- int regnum;
- if ((*this_cache) != NULL)
- return (struct m32r_frame_cache *) (*this_cache);
- cache = FRAME_OBSTACK_ZALLOC (struct m32r_frame_cache);
- (*this_cache) = cache;
- cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
- cache->base = get_frame_register_unsigned (this_frame, M32R_SP_REGNUM);
- sigcontext_addr = cache->base + 4;
- cache->pc = get_frame_pc (this_frame);
- addr = m32r_linux_sigtramp_start (cache->pc, this_frame);
- if (addr == 0)
- {
- /* If this is a RT signal trampoline, adjust SIGCONTEXT_ADDR
- accordingly. */
- addr = m32r_linux_rt_sigtramp_start (cache->pc, this_frame);
- if (addr)
- sigcontext_addr += 128;
- else
- addr = get_frame_func (this_frame);
- }
- cache->pc = addr;
- cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
- for (regnum = 0; regnum < sizeof (m32r_linux_sc_reg_offset) / 4; regnum++)
- {
- if (m32r_linux_sc_reg_offset[regnum] >= 0)
- cache->saved_regs[regnum].set_addr (sigcontext_addr
- + m32r_linux_sc_reg_offset[regnum]);
- }
- return cache;
- }
- static void
- m32r_linux_sigtramp_frame_this_id (struct frame_info *this_frame,
- void **this_cache,
- struct frame_id *this_id)
- {
- struct m32r_frame_cache *cache =
- m32r_linux_sigtramp_frame_cache (this_frame, this_cache);
- (*this_id) = frame_id_build (cache->base, cache->pc);
- }
- static struct value *
- m32r_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
- void **this_cache, int regnum)
- {
- struct m32r_frame_cache *cache =
- m32r_linux_sigtramp_frame_cache (this_frame, this_cache);
- return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
- }
- static int
- m32r_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
- struct frame_info *this_frame,
- void **this_cache)
- {
- CORE_ADDR pc = get_frame_pc (this_frame);
- const char *name;
- find_pc_partial_function (pc, &name, NULL, NULL);
- if (m32r_linux_pc_in_sigtramp (pc, name, this_frame))
- return 1;
- return 0;
- }
- static const struct frame_unwind m32r_linux_sigtramp_frame_unwind = {
- "m32r linux sigtramp",
- SIGTRAMP_FRAME,
- default_frame_unwind_stop_reason,
- m32r_linux_sigtramp_frame_this_id,
- m32r_linux_sigtramp_frame_prev_register,
- NULL,
- m32r_linux_sigtramp_frame_sniffer
- };
- /* Mapping between the registers in `struct pt_regs'
- format and GDB's register array layout. */
- static int m32r_pt_regs_offset[] = {
- 4 * 4, /* r0 */
- 4 * 5, /* r1 */
- 4 * 6, /* r2 */
- 4 * 7, /* r3 */
- 4 * 0, /* r4 */
- 4 * 1, /* r5 */
- 4 * 2, /* r6 */
- 4 * 8, /* r7 */
- 4 * 9, /* r8 */
- 4 * 10, /* r9 */
- 4 * 11, /* r10 */
- 4 * 12, /* r11 */
- 4 * 13, /* r12 */
- 4 * 24, /* fp */
- 4 * 25, /* lr */
- 4 * 23, /* sp */
- 4 * 19, /* psw */
- 4 * 19, /* cbr */
- 4 * 26, /* spi */
- 4 * 23, /* spu */
- 4 * 22, /* bpc */
- 4 * 20, /* pc */
- 4 * 16, /* accl */
- 4 * 15 /* acch */
- };
- #define PSW_OFFSET (4 * 19)
- #define BBPSW_OFFSET (4 * 21)
- #define SPU_OFFSET (4 * 23)
- #define SPI_OFFSET (4 * 26)
- #define M32R_LINUX_GREGS_SIZE (4 * 28)
- static void
- m32r_linux_supply_gregset (const struct regset *regset,
- struct regcache *regcache, int regnum,
- const void *gregs, size_t size)
- {
- const gdb_byte *regs = (const gdb_byte *) gregs;
- enum bfd_endian byte_order =
- gdbarch_byte_order (regcache->arch ());
- ULONGEST psw, bbpsw;
- gdb_byte buf[4];
- const gdb_byte *p;
- int i;
- psw = extract_unsigned_integer (regs + PSW_OFFSET, 4, byte_order);
- bbpsw = extract_unsigned_integer (regs + BBPSW_OFFSET, 4, byte_order);
- psw = ((0x00c1 & bbpsw) << 8) | ((0xc100 & psw) >> 8);
- for (i = 0; i < ARRAY_SIZE (m32r_pt_regs_offset); i++)
- {
- if (regnum != -1 && regnum != i)
- continue;
- switch (i)
- {
- case PSW_REGNUM:
- store_unsigned_integer (buf, 4, byte_order, psw);
- p = buf;
- break;
- case CBR_REGNUM:
- store_unsigned_integer (buf, 4, byte_order, psw & 1);
- p = buf;
- break;
- case M32R_SP_REGNUM:
- p = regs + ((psw & 0x80) ? SPU_OFFSET : SPI_OFFSET);
- break;
- default:
- p = regs + m32r_pt_regs_offset[i];
- }
- regcache->raw_supply (i, p);
- }
- }
- static void
- m32r_linux_collect_gregset (const struct regset *regset,
- const struct regcache *regcache,
- int regnum, void *gregs, size_t size)
- {
- gdb_byte *regs = (gdb_byte *) gregs;
- int i;
- enum bfd_endian byte_order =
- gdbarch_byte_order (regcache->arch ());
- ULONGEST psw;
- gdb_byte buf[4];
- regcache->raw_collect (PSW_REGNUM, buf);
- psw = extract_unsigned_integer (buf, 4, byte_order);
- for (i = 0; i < ARRAY_SIZE (m32r_pt_regs_offset); i++)
- {
- if (regnum != -1 && regnum != i)
- continue;
- switch (i)
- {
- case PSW_REGNUM:
- store_unsigned_integer (regs + PSW_OFFSET, 4, byte_order,
- (psw & 0xc1) << 8);
- store_unsigned_integer (regs + BBPSW_OFFSET, 4, byte_order,
- (psw >> 8) & 0xc1);
- break;
- case CBR_REGNUM:
- break;
- case M32R_SP_REGNUM:
- regcache->raw_collect
- (i, regs + ((psw & 0x80) ? SPU_OFFSET : SPI_OFFSET));
- break;
- default:
- regcache->raw_collect (i, regs + m32r_pt_regs_offset[i]);
- }
- }
- }
- static const struct regset m32r_linux_gregset = {
- NULL,
- m32r_linux_supply_gregset, m32r_linux_collect_gregset
- };
- static void
- m32r_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
- iterate_over_regset_sections_cb *cb,
- void *cb_data,
- const struct regcache *regcache)
- {
- cb (".reg", M32R_LINUX_GREGS_SIZE, M32R_LINUX_GREGS_SIZE, &m32r_linux_gregset,
- NULL, cb_data);
- }
- static void
- m32r_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
- {
- linux_init_abi (info, gdbarch, 0);
- /* Since EVB register is not available for native debug, we reduce
- the number of registers. */
- set_gdbarch_num_regs (gdbarch, M32R_NUM_REGS - 1);
- frame_unwind_append_unwinder (gdbarch, &m32r_linux_sigtramp_frame_unwind);
- /* GNU/Linux uses SVR4-style shared libraries. */
- set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
- set_solib_svr4_fetch_link_map_offsets
- (gdbarch, linux_ilp32_fetch_link_map_offsets);
- /* Core file support. */
- set_gdbarch_iterate_over_regset_sections
- (gdbarch, m32r_linux_iterate_over_regset_sections);
- /* Enable TLS support. */
- set_gdbarch_fetch_tls_load_module_address (gdbarch,
- svr4_fetch_objfile_link_map);
- }
- void _initialize_m32r_linux_tdep ();
- void
- _initialize_m32r_linux_tdep ()
- {
- gdbarch_register_osabi (bfd_arch_m32r, 0, GDB_OSABI_LINUX,
- m32r_linux_init_abi);
- }
|