glibc/sysdeps/mach/x86/thread_state.h
Sergey Bugaev 4a373ea7d6 mach: Define MACHINE_THREAD_STATE_SETUP_CALL
The existing two macros, MACHINE_THREAD_STATE_SET_PC and
MACHINE_THREAD_STATE_SET_SP, can be used to set program counter and the
stack pointer registers in a machine-specific thread state structure.

Useful as it is, this may not be enough to set up the thread to make a
function call, because the machine-specific ABI may impose additional
requirements. In particular, x86_64 ABI requires that upon function
entry, the stack pointer is 8 less than 16-byte aligned (sp & 15 == 8).

To deal with this, introduce a new macro,
MACHINE_THREAD_STATE_SETUP_CALL (), which sets both stack and
instruction pointers, and also applies any machine-specific requirements
to make a valid function call. The default implementation simply
forwards to MACHINE_THREAD_STATE_SET_PC and MACHINE_THREAD_STATE_SET_SP,
but on x86_64 we additionally align the stack pointer.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230517191436.73636-3-bugaevc@gmail.com>
2023-05-17 22:52:39 +02:00

73 lines
2.5 KiB
C

/* Mach thread state definitions for machine-independent code. i386 version.
Copyright (C) 1994-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _MACH_X86_THREAD_STATE_H
#define _MACH_X86_THREAD_STATE_H 1
#include <mach/machine/thread_status.h>
#include <libc-pointer-arith.h>
/* This lets the kernel define segments for a new thread. */
#define MACHINE_NEW_THREAD_STATE_FLAVOR i386_THREAD_STATE
/* This makes the kernel load our segments descriptors. */
#define MACHINE_THREAD_STATE_FLAVOR i386_REGS_SEGS_STATE
#define MACHINE_THREAD_STATE_COUNT i386_THREAD_STATE_COUNT
#define machine_thread_state i386_thread_state
#ifdef __x86_64__
#define PC rip
#define SP ursp
#define SYSRETURN rax
#else
#define PC eip
#define SP uesp
#define SYSRETURN eax
#endif
#define MACHINE_THREAD_STATE_FIX_NEW(ts) do { \
asm ("mov %%cs, %w0" : "=q" ((ts)->cs)); \
asm ("mov %%ds, %w0" : "=q" ((ts)->ds)); \
asm ("mov %%es, %w0" : "=q" ((ts)->es)); \
asm ("mov %%fs, %w0" : "=q" ((ts)->fs)); \
asm ("mov %%gs, %w0" : "=q" ((ts)->gs)); \
} while(0)
struct machine_thread_all_state
{
int set; /* Mask of bits (1 << FLAVOR). */
struct i386_thread_state basic;
struct i386_float_state fpu;
};
#ifdef __x86_64__
/* We're setting up the stack to perform a function call. On function entry,
the stack pointer must be 8 bytes less than 16-aligned. */
#define PTR_ALIGN_DOWN_8_16(ptr) \
({ uintptr_t __ptr = PTR_ALIGN_DOWN (ptr, 8); \
PTR_IS_ALIGNED (__ptr, 16) ? (__ptr - 8) : __ptr; })
#define MACHINE_THREAD_STATE_SETUP_CALL(ts, stack, size, func) \
((ts)->SP = PTR_ALIGN_DOWN_8_16 ((uintptr_t) (stack) + (size)), \
(ts)->PC = (uintptr_t) func)
#endif
#include <sysdeps/mach/thread_state.h>
#endif /* mach/x86/thread_state.h */