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2ad5d0845d
X32 has 32-bit long and pointer with 64-bit off_t. Since x32 psABI requires that pointers passed in registers must be zero-extended to 64bit, x32 can share many syscall interfaces with LP64. When a LP64 syscall with long and unsigned long int arguments is used for x32, these arguments must be properly extended to 64-bit. Otherwise if the upper 32 bits of the register have undefined value, such a syscall will be rejected by kernel. For syscalls implemented in assembly codes, 'U' is added to syscall signature key letters for unsigned long, which is zero-extended to 64-bit types. SYSCALL_ULONG_ARG_1 and SYSCALL_ULONG_ARG_2 are passed to syscall-template.S for the first and the second unsigned long int arguments if PSEUDOS_HAVE_ULONG_INDICES is defined. They are used by x32 to zero-extend 32-bit arguments to 64 bits. Tested on i386, x86-64 and x32 as well as with build-many-glibcs.py.
434 lines
14 KiB
C
434 lines
14 KiB
C
/* Copyright (C) 2001-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _LINUX_X86_64_SYSDEP_H
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#define _LINUX_X86_64_SYSDEP_H 1
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/* There is some commonality. */
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#include <sysdeps/unix/sysv/linux/sysdep.h>
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#include <sysdeps/unix/x86_64/sysdep.h>
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#include <tls.h>
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/* Defines RTLD_PRIVATE_ERRNO. */
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#include <dl-sysdep.h>
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/* For Linux we can use the system call table in the header file
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/usr/include/asm/unistd.h
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of the kernel. But these symbols do not follow the SYS_* syntax
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so we have to redefine the `SYS_ify' macro here. */
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#undef SYS_ify
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#define SYS_ify(syscall_name) __NR_##syscall_name
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#ifdef __ASSEMBLER__
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/* Linux uses a negative return value to indicate syscall errors,
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unlike most Unices, which use the condition codes' carry flag.
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Since version 2.1 the return value of a system call might be
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negative even if the call succeeded. E.g., the `lseek' system call
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might return a large offset. Therefore we must not anymore test
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for < 0, but test for a real error by making sure the value in %eax
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is a real error number. Linus said he will make sure the no syscall
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returns a value in -1 .. -4095 as a valid result so we can savely
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test with -4095. */
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/* We don't want the label for the error handle to be global when we define
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it here. */
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# undef SYSCALL_ERROR_LABEL
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# ifdef PIC
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# undef SYSCALL_ERROR_LABEL
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# define SYSCALL_ERROR_LABEL 0f
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# else
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# undef SYSCALL_ERROR_LABEL
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# define SYSCALL_ERROR_LABEL syscall_error
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# endif
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/* PSEUDO and T_PSEUDO macros have 2 extra arguments for unsigned long
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int arguments. */
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# define PSEUDOS_HAVE_ULONG_INDICES 1
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# ifndef SYSCALL_ULONG_ARG_1
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# define SYSCALL_ULONG_ARG_1 0
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# define SYSCALL_ULONG_ARG_2 0
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# endif
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# undef PSEUDO
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# if SYSCALL_ULONG_ARG_1
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# define PSEUDO(name, syscall_name, args, ulong_arg_1, ulong_arg_2) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args, ulong_arg_1, ulong_arg_2); \
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cmpq $-4095, %rax; \
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jae SYSCALL_ERROR_LABEL
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# else
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# define PSEUDO(name, syscall_name, args) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args, 0, 0); \
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cmpq $-4095, %rax; \
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jae SYSCALL_ERROR_LABEL
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# endif
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# undef PSEUDO_END
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# define PSEUDO_END(name) \
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SYSCALL_ERROR_HANDLER \
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END (name)
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# undef PSEUDO_NOERRNO
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# if SYSCALL_ULONG_ARG_1
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# define PSEUDO_NOERRNO(name, syscall_name, args, ulong_arg_1, ulong_arg_2) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args, ulong_arg_1, ulong_arg_2)
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# else
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# define PSEUDO_NOERRNO(name, syscall_name, args) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args, 0, 0)
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# endif
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# undef PSEUDO_END_NOERRNO
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# define PSEUDO_END_NOERRNO(name) \
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END (name)
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# define ret_NOERRNO ret
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# undef PSEUDO_ERRVAL
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# if SYSCALL_ULONG_ARG_1
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# define PSEUDO_ERRVAL(name, syscall_name, args, ulong_arg_1, ulong_arg_2) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args, ulong_arg_1, ulong_arg_2); \
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negq %rax
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# else
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# define PSEUDO_ERRVAL(name, syscall_name, args) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args, 0, 0); \
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negq %rax
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# endif
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# undef PSEUDO_END_ERRVAL
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# define PSEUDO_END_ERRVAL(name) \
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END (name)
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# define ret_ERRVAL ret
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# if defined PIC && RTLD_PRIVATE_ERRNO
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# define SYSCALL_SET_ERRNO \
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lea rtld_errno(%rip), %RCX_LP; \
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neg %eax; \
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movl %eax, (%rcx)
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# else
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# if IS_IN (libc)
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# define SYSCALL_ERROR_ERRNO __libc_errno
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# else
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# define SYSCALL_ERROR_ERRNO errno
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# endif
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# define SYSCALL_SET_ERRNO \
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movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\
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neg %eax; \
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movl %eax, %fs:(%rcx);
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# endif
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# ifndef PIC
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# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
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# else
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# define SYSCALL_ERROR_HANDLER \
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0: \
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SYSCALL_SET_ERRNO; \
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or $-1, %RAX_LP; \
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ret;
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# endif /* PIC */
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/* The Linux/x86-64 kernel expects the system call parameters in
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registers according to the following table:
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syscall number rax
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arg 1 rdi
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arg 2 rsi
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arg 3 rdx
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arg 4 r10
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arg 5 r8
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arg 6 r9
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The Linux kernel uses and destroys internally these registers:
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return address from
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syscall rcx
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eflags from syscall r11
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Normal function call, including calls to the system call stub
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functions in the libc, get the first six parameters passed in
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registers and the seventh parameter and later on the stack. The
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register use is as follows:
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system call number in the DO_CALL macro
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arg 1 rdi
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arg 2 rsi
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arg 3 rdx
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arg 4 rcx
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arg 5 r8
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arg 6 r9
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We have to take care that the stack is aligned to 16 bytes. When
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called the stack is not aligned since the return address has just
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been pushed.
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Syscalls of more than 6 arguments are not supported. */
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# undef DO_CALL
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# define DO_CALL(syscall_name, args, ulong_arg_1, ulong_arg_2) \
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DOARGS_##args \
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ZERO_EXTEND_##ulong_arg_1 \
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ZERO_EXTEND_##ulong_arg_2 \
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movl $SYS_ify (syscall_name), %eax; \
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syscall;
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# define DOARGS_0 /* nothing */
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# define DOARGS_1 /* nothing */
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# define DOARGS_2 /* nothing */
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# define DOARGS_3 /* nothing */
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# define DOARGS_4 movq %rcx, %r10;
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# define DOARGS_5 DOARGS_4
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# define DOARGS_6 DOARGS_5
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# define ZERO_EXTEND_0 /* nothing */
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# define ZERO_EXTEND_1 /* nothing */
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# define ZERO_EXTEND_2 /* nothing */
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# define ZERO_EXTEND_3 /* nothing */
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# define ZERO_EXTEND_4 /* nothing */
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# define ZERO_EXTEND_5 /* nothing */
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# define ZERO_EXTEND_6 /* nothing */
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#else /* !__ASSEMBLER__ */
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/* Registers clobbered by syscall. */
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# define REGISTERS_CLOBBERED_BY_SYSCALL "cc", "r11", "cx"
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/* NB: This also works when X is an array. For an array X, type of
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(X) - (X) is ptrdiff_t, which is signed, since size of ptrdiff_t
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== size of pointer, cast is a NOP. */
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#define TYPEFY1(X) __typeof__ ((X) - (X))
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/* Explicit cast the argument. */
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#define ARGIFY(X) ((TYPEFY1 (X)) (X))
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/* Create a variable 'name' based on type of variable 'X' to avoid
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explicit types. */
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#define TYPEFY(X, name) __typeof__ (ARGIFY (X)) name
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#undef INTERNAL_SYSCALL
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#define INTERNAL_SYSCALL(name, nr, args...) \
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internal_syscall##nr (SYS_ify (name), args)
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#undef INTERNAL_SYSCALL_NCS
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#define INTERNAL_SYSCALL_NCS(number, nr, args...) \
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internal_syscall##nr (number, args)
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#undef internal_syscall0
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#define internal_syscall0(number, dummy...) \
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({ \
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unsigned long int resultvar; \
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asm volatile ( \
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"syscall\n\t" \
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: "=a" (resultvar) \
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: "0" (number) \
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: "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
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(long int) resultvar; \
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})
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#undef internal_syscall1
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#define internal_syscall1(number, arg1) \
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({ \
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unsigned long int resultvar; \
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TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
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register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
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asm volatile ( \
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"syscall\n\t" \
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: "=a" (resultvar) \
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: "0" (number), "r" (_a1) \
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: "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
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(long int) resultvar; \
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})
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#undef internal_syscall2
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#define internal_syscall2(number, arg1, arg2) \
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({ \
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unsigned long int resultvar; \
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TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
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TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
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register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
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register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
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asm volatile ( \
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"syscall\n\t" \
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: "=a" (resultvar) \
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: "0" (number), "r" (_a1), "r" (_a2) \
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: "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
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(long int) resultvar; \
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})
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#undef internal_syscall3
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#define internal_syscall3(number, arg1, arg2, arg3) \
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({ \
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unsigned long int resultvar; \
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TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
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TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
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TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
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register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
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register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
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register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
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asm volatile ( \
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"syscall\n\t" \
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: "=a" (resultvar) \
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: "0" (number), "r" (_a1), "r" (_a2), "r" (_a3) \
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: "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
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(long int) resultvar; \
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})
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#undef internal_syscall4
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#define internal_syscall4(number, arg1, arg2, arg3, arg4) \
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({ \
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unsigned long int resultvar; \
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TYPEFY (arg4, __arg4) = ARGIFY (arg4); \
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TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
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TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
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TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
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register TYPEFY (arg4, _a4) asm ("r10") = __arg4; \
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register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
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register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
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register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
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asm volatile ( \
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"syscall\n\t" \
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: "=a" (resultvar) \
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: "0" (number), "r" (_a1), "r" (_a2), "r" (_a3), "r" (_a4) \
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: "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
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(long int) resultvar; \
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})
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#undef internal_syscall5
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#define internal_syscall5(number, arg1, arg2, arg3, arg4, arg5) \
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({ \
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unsigned long int resultvar; \
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TYPEFY (arg5, __arg5) = ARGIFY (arg5); \
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TYPEFY (arg4, __arg4) = ARGIFY (arg4); \
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TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
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TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
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TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
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register TYPEFY (arg5, _a5) asm ("r8") = __arg5; \
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register TYPEFY (arg4, _a4) asm ("r10") = __arg4; \
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register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
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register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
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register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
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asm volatile ( \
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"syscall\n\t" \
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: "=a" (resultvar) \
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: "0" (number), "r" (_a1), "r" (_a2), "r" (_a3), "r" (_a4), \
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"r" (_a5) \
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: "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
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(long int) resultvar; \
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})
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#undef internal_syscall6
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#define internal_syscall6(number, arg1, arg2, arg3, arg4, arg5, arg6) \
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({ \
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unsigned long int resultvar; \
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TYPEFY (arg6, __arg6) = ARGIFY (arg6); \
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TYPEFY (arg5, __arg5) = ARGIFY (arg5); \
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TYPEFY (arg4, __arg4) = ARGIFY (arg4); \
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TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
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TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
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TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
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register TYPEFY (arg6, _a6) asm ("r9") = __arg6; \
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register TYPEFY (arg5, _a5) asm ("r8") = __arg5; \
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register TYPEFY (arg4, _a4) asm ("r10") = __arg4; \
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register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
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register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
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register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
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asm volatile ( \
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"syscall\n\t" \
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: "=a" (resultvar) \
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: "0" (number), "r" (_a1), "r" (_a2), "r" (_a3), "r" (_a4), \
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"r" (_a5), "r" (_a6) \
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: "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
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(long int) resultvar; \
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})
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# define VDSO_NAME "LINUX_2.6"
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# define VDSO_HASH 61765110
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/* List of system calls which are supported as vsyscalls. */
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# define HAVE_CLOCK_GETTIME64_VSYSCALL "__vdso_clock_gettime"
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# define HAVE_GETTIMEOFDAY_VSYSCALL "__vdso_gettimeofday"
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# define HAVE_TIME_VSYSCALL "__vdso_time"
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# define HAVE_GETCPU_VSYSCALL "__vdso_getcpu"
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# define HAVE_CLOCK_GETRES64_VSYSCALL "__vdso_clock_getres"
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# define SINGLE_THREAD_BY_GLOBAL 1
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#endif /* __ASSEMBLER__ */
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/* Pointer mangling support. */
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#if IS_IN (rtld)
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/* We cannot use the thread descriptor because in ld.so we use setjmp
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earlier than the descriptor is initialized. */
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# ifdef __ASSEMBLER__
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# define PTR_MANGLE(reg) xor __pointer_chk_guard_local(%rip), reg; \
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rol $2*LP_SIZE+1, reg
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# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
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xor __pointer_chk_guard_local(%rip), reg
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# else
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# define PTR_MANGLE(reg) asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \
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"rol $2*" LP_SIZE "+1, %0" \
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: "=r" (reg) : "0" (reg))
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# define PTR_DEMANGLE(reg) asm ("ror $2*" LP_SIZE "+1, %0\n" \
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"xor __pointer_chk_guard_local(%%rip), %0" \
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: "=r" (reg) : "0" (reg))
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# endif
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#else
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# ifdef __ASSEMBLER__
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# define PTR_MANGLE(reg) xor %fs:POINTER_GUARD, reg; \
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rol $2*LP_SIZE+1, reg
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# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
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xor %fs:POINTER_GUARD, reg
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# else
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# define PTR_MANGLE(var) asm ("xor %%fs:%c2, %0\n" \
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"rol $2*" LP_SIZE "+1, %0" \
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: "=r" (var) \
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: "0" (var), \
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"i" (offsetof (tcbhead_t, \
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pointer_guard)))
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# define PTR_DEMANGLE(var) asm ("ror $2*" LP_SIZE "+1, %0\n" \
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"xor %%fs:%c2, %0" \
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: "=r" (var) \
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: "0" (var), \
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"i" (offsetof (tcbhead_t, \
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pointer_guard)))
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# endif
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#endif
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/* How to pass the off{64}_t argument on p{readv,writev}{64}. */
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#undef LO_HI_LONG
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#define LO_HI_LONG(val) (val), 0
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/* Each shadow stack slot takes 8 bytes. Assuming that each stack
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frame takes 256 bytes, this is used to compute shadow stack size
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from stack size. */
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#define STACK_SIZE_TO_SHADOW_STACK_SIZE_SHIFT 5
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#endif /* linux/x86_64/sysdep.h */
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