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- /* GNU/Linux/x86 specific low level interface, for the in-process
- agent library for GDB.
- Copyright (C) 2010-2022 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 "server.h"
- #include <sys/mman.h>
- #include "tracepoint.h"
- #include "linux-x86-tdesc.h"
- #include "gdbsupport/x86-xstate.h"
- /* GDB register numbers. */
- enum i386_gdb_regnum
- {
- I386_EAX_REGNUM, /* %eax */
- I386_ECX_REGNUM, /* %ecx */
- I386_EDX_REGNUM, /* %edx */
- I386_EBX_REGNUM, /* %ebx */
- I386_ESP_REGNUM, /* %esp */
- I386_EBP_REGNUM, /* %ebp */
- I386_ESI_REGNUM, /* %esi */
- I386_EDI_REGNUM, /* %edi */
- I386_EIP_REGNUM, /* %eip */
- I386_EFLAGS_REGNUM, /* %eflags */
- I386_CS_REGNUM, /* %cs */
- I386_SS_REGNUM, /* %ss */
- I386_DS_REGNUM, /* %ds */
- I386_ES_REGNUM, /* %es */
- I386_FS_REGNUM, /* %fs */
- I386_GS_REGNUM, /* %gs */
- I386_ST0_REGNUM /* %st(0) */
- };
- #define i386_num_regs 16
- #define FT_CR_EAX 15
- #define FT_CR_ECX 14
- #define FT_CR_EDX 13
- #define FT_CR_EBX 12
- #define FT_CR_UESP 11
- #define FT_CR_EBP 10
- #define FT_CR_ESI 9
- #define FT_CR_EDI 8
- #define FT_CR_EIP 7
- #define FT_CR_EFL 6
- #define FT_CR_DS 5
- #define FT_CR_ES 4
- #define FT_CR_FS 3
- #define FT_CR_GS 2
- #define FT_CR_SS 1
- #define FT_CR_CS 0
- /* Mapping between the general-purpose registers in jump tracepoint
- format and GDB's register array layout. */
- static const int i386_ft_collect_regmap[] =
- {
- FT_CR_EAX * 4, FT_CR_ECX * 4, FT_CR_EDX * 4, FT_CR_EBX * 4,
- FT_CR_UESP * 4, FT_CR_EBP * 4, FT_CR_ESI * 4, FT_CR_EDI * 4,
- FT_CR_EIP * 4, FT_CR_EFL * 4, FT_CR_CS * 4, FT_CR_SS * 4,
- FT_CR_DS * 4, FT_CR_ES * 4, FT_CR_FS * 4, FT_CR_GS * 4
- };
- void
- supply_fast_tracepoint_registers (struct regcache *regcache,
- const unsigned char *buf)
- {
- int i;
- for (i = 0; i < i386_num_regs; i++)
- {
- int regval;
- if (i >= I386_CS_REGNUM && i <= I386_GS_REGNUM)
- regval = *(short *) (((char *) buf) + i386_ft_collect_regmap[i]);
- else
- regval = *(int *) (((char *) buf) + i386_ft_collect_regmap[i]);
- supply_register (regcache, i, ®val);
- }
- }
- ULONGEST
- get_raw_reg (const unsigned char *raw_regs, int regnum)
- {
- /* This should maybe be allowed to return an error code, or perhaps
- better, have the emit_reg detect this, and emit a constant zero,
- or something. */
- if (regnum > i386_num_regs)
- return 0;
- else if (regnum >= I386_CS_REGNUM && regnum <= I386_GS_REGNUM)
- return *(short *) (raw_regs + i386_ft_collect_regmap[regnum]);
- else
- return *(int *) (raw_regs + i386_ft_collect_regmap[regnum]);
- }
- #ifdef HAVE_UST
- #include <ust/processor.h>
- /* "struct registers" is the UST object type holding the registers at
- the time of the static tracepoint marker call. This doesn't
- contain EIP, but we know what it must have been (the marker
- address). */
- #define ST_REGENTRY(REG) \
- { \
- offsetof (struct registers, REG), \
- sizeof (((struct registers *) NULL)->REG) \
- }
- static struct
- {
- int offset;
- int size;
- } i386_st_collect_regmap[] =
- {
- ST_REGENTRY(eax),
- ST_REGENTRY(ecx),
- ST_REGENTRY(edx),
- ST_REGENTRY(ebx),
- ST_REGENTRY(esp),
- ST_REGENTRY(ebp),
- ST_REGENTRY(esi),
- ST_REGENTRY(edi),
- { -1, 0 }, /* eip */
- ST_REGENTRY(eflags),
- ST_REGENTRY(cs),
- ST_REGENTRY(ss),
- };
- #define i386_NUM_ST_COLLECT_GREGS \
- (sizeof (i386_st_collect_regmap) / sizeof (i386_st_collect_regmap[0]))
- void
- supply_static_tracepoint_registers (struct regcache *regcache,
- const unsigned char *buf,
- CORE_ADDR pc)
- {
- int i;
- unsigned int newpc = pc;
- supply_register (regcache, I386_EIP_REGNUM, &newpc);
- for (i = 0; i < i386_NUM_ST_COLLECT_GREGS; i++)
- if (i386_st_collect_regmap[i].offset != -1)
- {
- switch (i386_st_collect_regmap[i].size)
- {
- case 4:
- supply_register (regcache, i,
- ((char *) buf)
- + i386_st_collect_regmap[i].offset);
- break;
- case 2:
- {
- unsigned long reg
- = * (short *) (((char *) buf)
- + i386_st_collect_regmap[i].offset);
- reg &= 0xffff;
- supply_register (regcache, i, ®);
- }
- break;
- default:
- internal_error (__FILE__, __LINE__, "unhandled register size: %d",
- i386_st_collect_regmap[i].size);
- }
- }
- }
- #endif /* HAVE_UST */
- /* This is only needed because reg-i386-linux-lib.o references it. We
- may use it proper at some point. */
- const char *gdbserver_xmltarget;
- /* Attempt to allocate memory for trampolines in the first 64 KiB of
- memory to enable smaller jump patches. */
- static void
- initialize_fast_tracepoint_trampoline_buffer (void)
- {
- const CORE_ADDR buffer_end = 64 * 1024;
- /* Ensure that the buffer will be at least 1 KiB in size, which is
- enough space for over 200 fast tracepoints. */
- const int min_buffer_size = 1024;
- char buf[IPA_BUFSIZ];
- CORE_ADDR mmap_min_addr = buffer_end + 1;
- ULONGEST buffer_size;
- FILE *f = fopen ("/proc/sys/vm/mmap_min_addr", "r");
- if (!f)
- {
- snprintf (buf, sizeof (buf), "mmap_min_addr open failed: %s",
- safe_strerror (errno));
- set_trampoline_buffer_space (0, 0, buf);
- return;
- }
- if (fgets (buf, IPA_BUFSIZ, f))
- sscanf (buf, "%llu", &mmap_min_addr);
-
- fclose (f);
-
- buffer_size = buffer_end - mmap_min_addr;
- if (buffer_size >= min_buffer_size)
- {
- if (mmap ((void *) (uintptr_t) mmap_min_addr, buffer_size,
- PROT_READ | PROT_EXEC | PROT_WRITE,
- MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
- -1, 0)
- != MAP_FAILED)
- set_trampoline_buffer_space (mmap_min_addr, buffer_end, NULL);
- else
- {
- snprintf (buf, IPA_BUFSIZ, "low-64K-buffer mmap() failed: %s",
- safe_strerror (errno));
- set_trampoline_buffer_space (0, 0, buf);
- }
- }
- else
- {
- snprintf (buf, IPA_BUFSIZ, "mmap_min_addr is %d, must be %d or less",
- (int) mmap_min_addr, (int) buffer_end - min_buffer_size);
- set_trampoline_buffer_space (0, 0, buf);
- }
- }
- /* Map the tdesc index to xcr0 mask. */
- static uint64_t idx2mask[X86_TDESC_LAST] = {
- X86_XSTATE_X87_MASK,
- X86_XSTATE_SSE_MASK,
- X86_XSTATE_AVX_MASK,
- X86_XSTATE_MPX_MASK,
- X86_XSTATE_AVX_MPX_MASK,
- X86_XSTATE_AVX_AVX512_MASK,
- X86_XSTATE_AVX_MPX_AVX512_PKU_MASK,
- };
- /* Return target_desc to use for IPA, given the tdesc index passed by
- gdbserver. */
- const struct target_desc *
- get_ipa_tdesc (int idx)
- {
- if (idx >= X86_TDESC_LAST)
- {
- internal_error (__FILE__, __LINE__,
- "unknown ipa tdesc index: %d", idx);
- }
- return i386_linux_read_description (idx2mask[idx]);
- }
- /* Allocate buffer for the jump pads. On i386, we can reach an arbitrary
- address with a jump instruction, so just allocate normally. */
- void *
- alloc_jump_pad_buffer (size_t size)
- {
- void *res = mmap (NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,
- MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
- if (res == MAP_FAILED)
- return NULL;
- return res;
- }
- void
- initialize_low_tracepoint (void)
- {
- initialize_fast_tracepoint_trampoline_buffer ();
- for (auto i = 0; i < X86_TDESC_LAST; i++)
- i386_linux_read_description (idx2mask[i]);
- }
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