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/* GNU/Linux/AArch64 specific low level interface, for the in-process
agent library for GDB.
Copyright (C) 2015-2021 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 "server.h"
#include <sys/mman.h>
#include "tracepoint.h"
#include <elf.h>
#ifdef HAVE_GETAUXVAL
#include <sys/auxv.h>
#endif
#include "linux-aarch64-tdesc.h"
/* Each register saved by the jump pad is in a 16 byte cell. */
#define FT_CR_SIZE 16
#define FT_CR_FPCR 0
#define FT_CR_FPSR 1
#define FT_CR_CPSR 2
#define FT_CR_PC 3
#define FT_CR_SP 4
#define FT_CR_X0 5
#define FT_CR_GPR(n) (FT_CR_X0 + (n))
#define FT_CR_FPR(n) (FT_CR_GPR (31) + (n))
/* Mapping between registers collected by the jump pad and GDB's register
array layout used by regcache.
See linux-aarch64-low.c (aarch64_install_fast_tracepoint_jump_pad) for
more details. */
static const int aarch64_ft_collect_regmap[] = {
FT_CR_GPR (0),
FT_CR_GPR (1),
FT_CR_GPR (2),
FT_CR_GPR (3),
FT_CR_GPR (4),
FT_CR_GPR (5),
FT_CR_GPR (6),
FT_CR_GPR (7),
FT_CR_GPR (8),
FT_CR_GPR (9),
FT_CR_GPR (10),
FT_CR_GPR (11),
FT_CR_GPR (12),
FT_CR_GPR (13),
FT_CR_GPR (14),
FT_CR_GPR (15),
FT_CR_GPR (16),
FT_CR_GPR (17),
FT_CR_GPR (18),
FT_CR_GPR (19),
FT_CR_GPR (20),
FT_CR_GPR (21),
FT_CR_GPR (22),
FT_CR_GPR (23),
FT_CR_GPR (24),
FT_CR_GPR (25),
FT_CR_GPR (26),
FT_CR_GPR (27),
FT_CR_GPR (28),
/* FP */
FT_CR_GPR (29),
/* LR */
FT_CR_GPR (30),
FT_CR_SP,
FT_CR_PC,
FT_CR_CPSR,
FT_CR_FPR (0),
FT_CR_FPR (1),
FT_CR_FPR (2),
FT_CR_FPR (3),
FT_CR_FPR (4),
FT_CR_FPR (5),
FT_CR_FPR (6),
FT_CR_FPR (7),
FT_CR_FPR (8),
FT_CR_FPR (9),
FT_CR_FPR (10),
FT_CR_FPR (11),
FT_CR_FPR (12),
FT_CR_FPR (13),
FT_CR_FPR (14),
FT_CR_FPR (15),
FT_CR_FPR (16),
FT_CR_FPR (17),
FT_CR_FPR (18),
FT_CR_FPR (19),
FT_CR_FPR (20),
FT_CR_FPR (21),
FT_CR_FPR (22),
FT_CR_FPR (23),
FT_CR_FPR (24),
FT_CR_FPR (25),
FT_CR_FPR (26),
FT_CR_FPR (27),
FT_CR_FPR (28),
FT_CR_FPR (29),
FT_CR_FPR (30),
FT_CR_FPR (31),
FT_CR_FPSR,
FT_CR_FPCR
};
#define AARCH64_NUM_FT_COLLECT_GREGS \
(sizeof (aarch64_ft_collect_regmap) / sizeof(aarch64_ft_collect_regmap[0]))
/* Fill in REGCACHE with registers saved by the jump pad in BUF. */
void
supply_fast_tracepoint_registers (struct regcache *regcache,
const unsigned char *buf)
{
int i;
for (i = 0; i < AARCH64_NUM_FT_COLLECT_GREGS; i++)
supply_register (regcache, i,
((char *) buf)
+ (aarch64_ft_collect_regmap[i] * FT_CR_SIZE));
}
ULONGEST
get_raw_reg (const unsigned char *raw_regs, int regnum)
{
if (regnum >= AARCH64_NUM_FT_COLLECT_GREGS)
return 0;
return *(ULONGEST *) (raw_regs
+ aarch64_ft_collect_regmap[regnum] * FT_CR_SIZE);
}
/* Return target_desc to use for IPA, given the tdesc index passed by
gdbserver. Index is ignored, since we have only one tdesc
at the moment. SVE and pauth not yet supported. */
const struct target_desc *
get_ipa_tdesc (int idx)
{
return aarch64_linux_read_description (0, false);
}
/* Allocate buffer for the jump pads. The branch instruction has a reach
of +/- 128MiB, and the executable is loaded at 0x400000 (4MiB).
To maximize the area of executable that can use tracepoints, try
allocating at 0x400000 - size initially, decreasing until we hit
a free area. */
void *
alloc_jump_pad_buffer (size_t size)
{
uintptr_t addr;
uintptr_t exec_base = getauxval (AT_PHDR);
int pagesize;
void *res;
if (exec_base == 0)
exec_base = 0x400000;
pagesize = sysconf (_SC_PAGE_SIZE);
if (pagesize == -1)
perror_with_name ("sysconf");
addr = exec_base - size;
/* size should already be page-aligned, but this can't hurt. */
addr &= ~(pagesize - 1);
/* Search for a free area. If we hit 0, we're out of luck. */
for (; addr; addr -= pagesize)
{
/* No MAP_FIXED - we don't want to zap someone's mapping. */
res = mmap ((void *) addr, size,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
/* If we got what we wanted, return. */
if ((uintptr_t) res == addr)
return res;
/* If we got a mapping, but at a wrong address, undo it. */
if (res != MAP_FAILED)
munmap (res, size);
}
return NULL;
}
void
initialize_low_tracepoint (void)
{
/* SVE and pauth not yet supported. */
aarch64_linux_read_description (0, false);
}
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