arch/arm64/kernel/sys32.c

Source file repositories/reference/linux-study-clean/arch/arm64/kernel/sys32.c

File Facts

System
Linux kernel
Corpus path
arch/arm64/kernel/sys32.c
Extension
.c
Size
3700 bytes
Lines
133
Domain
Architecture Layer
Bucket
arch/arm64
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * arch/arm64/kernel/sys32.c
 *
 * Copyright (C) 2015 ARM Ltd.
 */

#include <linux/compat.h>
#include <linux/compiler.h>
#include <linux/syscalls.h>

#include <asm/syscall.h>
#include <asm/unistd_compat_32.h>

asmlinkage long compat_sys_sigreturn(void);
asmlinkage long compat_sys_rt_sigreturn(void);

COMPAT_SYSCALL_DEFINE3(aarch32_statfs64, const char __user *, pathname,
		       compat_size_t, sz, struct compat_statfs64 __user *, buf)
{
	/*
	 * 32-bit ARM applies an OABI compatibility fixup to statfs64 and
	 * fstatfs64 regardless of whether OABI is in use, and therefore
	 * arbitrary binaries may rely upon it, so we must do the same.
	 * For more details, see commit:
	 *
	 * 713c481519f19df9 ("[ARM] 3108/2: old ABI compat: statfs64 and
	 * fstatfs64")
	 */
	if (sz == 88)
		sz = 84;

	return kcompat_sys_statfs64(pathname, sz, buf);
}

COMPAT_SYSCALL_DEFINE3(aarch32_fstatfs64, unsigned int, fd, compat_size_t, sz,
		       struct compat_statfs64 __user *, buf)
{
	/* see aarch32_statfs64 */
	if (sz == 88)
		sz = 84;

	return kcompat_sys_fstatfs64(fd, sz, buf);
}

/*
 * Note: off_4k is always in units of 4K. If we can't do the
 * requested offset because it is not page-aligned, we return -EINVAL.
 */
COMPAT_SYSCALL_DEFINE6(aarch32_mmap2, unsigned long, addr, unsigned long, len,
		       unsigned long, prot, unsigned long, flags,
		       unsigned long, fd, unsigned long, off_4k)
{
	if (off_4k & (~PAGE_MASK >> 12))
		return -EINVAL;

	off_4k >>= (PAGE_SHIFT - 12);

	return ksys_mmap_pgoff(addr, len, prot, flags, fd, off_4k);
}

#ifdef CONFIG_CPU_BIG_ENDIAN
#define arg_u32p(name)	u32, name##_hi, u32, name##_lo
#else
#define arg_u32p(name)	u32, name##_lo, u32, name##_hi
#endif

#define arg_u64(name)	(((u64)name##_hi << 32) | name##_lo)

COMPAT_SYSCALL_DEFINE6(aarch32_pread64, unsigned int, fd, char __user *, buf,
		       size_t, count, u32, __pad, arg_u32p(pos))
{
	return ksys_pread64(fd, buf, count, arg_u64(pos));
}

COMPAT_SYSCALL_DEFINE6(aarch32_pwrite64, unsigned int, fd,
		       const char __user *, buf, size_t, count, u32, __pad,
		       arg_u32p(pos))
{
	return ksys_pwrite64(fd, buf, count, arg_u64(pos));
}

COMPAT_SYSCALL_DEFINE4(aarch32_truncate64, const char __user *, pathname,
		       u32, __pad, arg_u32p(length))
{
	return ksys_truncate(pathname, arg_u64(length));
}

COMPAT_SYSCALL_DEFINE4(aarch32_ftruncate64, unsigned int, fd, u32, __pad,
		       arg_u32p(length))

Annotation

Implementation Notes