/* 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); }