x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments

For the 32-bit syscall interface, 64-bit arguments (loff_t) are passed via
a pair of 32-bit registers.  These register pairs end up in consecutive stack
slots, which matches the C ABI for 64-bit arguments.  But when accessing the
registers directly from pt_regs, the wrapper needs to manually reassemble the
64-bit value.  These wrappers already exist for 32-bit compat, so make them
available to 32-bit native in preparation for enabling pt_regs-based syscalls.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://lkml.kernel.org/r/20200313195144.164260-16-brgerst@gmail.com

1 files changed, 255 insertions, 0 deletions

diff --git a/arch/x86/kernel/sys_ia32.c b/arch/x86/kernel/sys_ia32.c
new file mode 100644
index 000000000000..ab03fede1422
--- /dev/null
+++ b/arch/x86/kernel/sys_ia32.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * sys_ia32.c: Conversion between 32bit and 64bit native syscalls. Based on
+ *             sys_sparc32
+ *
+ * Copyright (C) 2000		VA Linux Co
+ * Copyright (C) 2000		Don Dugger <n0ano@valinux.com>
+ * Copyright (C) 1999		Arun Sharma <arun.sharma@intel.com>
+ * Copyright (C) 1997,1998	Jakub Jelinek (jj@sunsite.mff.cuni.cz)
+ * Copyright (C) 1997		David S. Miller (davem@caip.rutgers.edu)
+ * Copyright (C) 2000		Hewlett-Packard Co.
+ * Copyright (C) 2000		David Mosberger-Tang <davidm@hpl.hp.com>
+ * Copyright (C) 2000,2001,2002	Andi Kleen, SuSE Labs (x86-64 port)
+ *
+ * These routines maintain argument size conversion between 32bit and 64bit
+ * environment. In 2.5 most of this should be moved to a generic directory.
+ *
+ * This file assumes that there is a hole at the end of user address space.
+ *
+ * Some of the functions are LE specific currently. These are
+ * hopefully all marked.  This should be fixed.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/signal.h>
+#include <linux/syscalls.h>
+#include <linux/times.h>
+#include <linux/utsname.h>
+#include <linux/mm.h>
+#include <linux/uio.h>
+#include <linux/poll.h>
+#include <linux/personality.h>
+#include <linux/stat.h>
+#include <linux/rwsem.h>
+#include <linux/compat.h>
+#include <linux/vfs.h>
+#include <linux/ptrace.h>
+#include <linux/highuid.h>
+#include <linux/sysctl.h>
+#include <linux/slab.h>
+#include <linux/sched/task.h>
+#include <asm/mman.h>
+#include <asm/types.h>
+#include <linux/uaccess.h>
+#include <linux/atomic.h>
+#include <asm/vgtod.h>
+#include <asm/ia32.h>
+
+#define AA(__x)		((unsigned long)(__x))
+
+SYSCALL_DEFINE3(ia32_truncate64, const char __user *, filename,
+		unsigned long, offset_low, unsigned long, offset_high)
+{
+	return ksys_truncate(filename,
+			    ((loff_t) offset_high << 32) | offset_low);
+}
+
+SYSCALL_DEFINE3(ia32_ftruncate64, unsigned int, fd,
+		unsigned long, offset_low, unsigned long, offset_high)
+{
+	return ksys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low);
+}
+
+/* warning: next two assume little endian */
+SYSCALL_DEFINE5(ia32_pread64, unsigned int, fd, char __user *, ubuf,
+		u32, count, u32, poslo, u32, poshi)
+{
+	return ksys_pread64(fd, ubuf, count,
+			    ((loff_t)AA(poshi) << 32) | AA(poslo));
+}
+
+SYSCALL_DEFINE5(ia32_pwrite64, unsigned int, fd, const char __user *, ubuf,
+		u32, count, u32, poslo, u32, poshi)
+{
+	return ksys_pwrite64(fd, ubuf, count,
+			     ((loff_t)AA(poshi) << 32) | AA(poslo));
+}
+
+
+/*
+ * Some system calls that need sign extended arguments. This could be
+ * done by a generic wrapper.
+ */
+SYSCALL_DEFINE6(ia32_fadvise64_64, int, fd, __u32, offset_low,
+		__u32, offset_high, __u32, len_low, __u32, len_high,
+		int, advice)
+{
+	return ksys_fadvise64_64(fd,
+				 (((u64)offset_high)<<32) | offset_low,
+				 (((u64)len_high)<<32) | len_low,
+				 advice);
+}
+
+SYSCALL_DEFINE4(ia32_readahead, int, fd, unsigned int, off_lo,
+		unsigned int, off_hi, size_t, count)
+{
+	return ksys_readahead(fd, ((u64)off_hi << 32) | off_lo, count);
+}
+
+SYSCALL_DEFINE6(ia32_sync_file_range, int, fd, unsigned int, off_low,
+		unsigned int, off_hi, unsigned int, n_low,
+		unsigned int, n_hi, int, flags)
+{
+	return ksys_sync_file_range(fd,
+				    ((u64)off_hi << 32) | off_low,
+				    ((u64)n_hi << 32) | n_low, flags);
+}
+
+SYSCALL_DEFINE5(ia32_fadvise64, int, fd, unsigned int, offset_lo,
+		unsigned int, offset_hi, size_t, len, int, advice)
+{
+	return ksys_fadvise64_64(fd, ((u64)offset_hi << 32) | offset_lo,
+				 len, advice);
+}
+
+SYSCALL_DEFINE6(ia32_fallocate, int, fd, int, mode,
+		unsigned int, offset_lo, unsigned int, offset_hi,
+		unsigned int, len_lo, unsigned int, len_hi)
+{
+	return ksys_fallocate(fd, mode, ((u64)offset_hi << 32) | offset_lo,
+			      ((u64)len_hi << 32) | len_lo);
+}
+
+#ifdef CONFIG_IA32_EMULATION
+/*
+ * Another set for IA32/LFS -- x86_64 struct stat is different due to
+ * support for 64bit inode numbers.
+ */
+static int cp_stat64(struct stat64 __user *ubuf, struct kstat *stat)
+{
+	typeof(ubuf->st_uid) uid = 0;
+	typeof(ubuf->st_gid) gid = 0;
+	SET_UID(uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(gid, from_kgid_munged(current_user_ns(), stat->gid));
+	if (!access_ok(ubuf, sizeof(struct stat64)) ||
+	    __put_user(huge_encode_dev(stat->dev), &ubuf->st_dev) ||
+	    __put_user(stat->ino, &ubuf->__st_ino) ||
+	    __put_user(stat->ino, &ubuf->st_ino) ||
+	    __put_user(stat->mode, &ubuf->st_mode) ||
+	    __put_user(stat->nlink, &ubuf->st_nlink) ||
+	    __put_user(uid, &ubuf->st_uid) ||
+	    __put_user(gid, &ubuf->st_gid) ||
+	    __put_user(huge_encode_dev(stat->rdev), &ubuf->st_rdev) ||
+	    __put_user(stat->size, &ubuf->st_size) ||
+	    __put_user(stat->atime.tv_sec, &ubuf->st_atime) ||
+	    __put_user(stat->atime.tv_nsec, &ubuf->st_atime_nsec) ||
+	    __put_user(stat->mtime.tv_sec, &ubuf->st_mtime) ||
+	    __put_user(stat->mtime.tv_nsec, &ubuf->st_mtime_nsec) ||
+	    __put_user(stat->ctime.tv_sec, &ubuf->st_ctime) ||
+	    __put_user(stat->ctime.tv_nsec, &ubuf->st_ctime_nsec) ||
+	    __put_user(stat->blksize, &ubuf->st_blksize) ||
+	    __put_user(stat->blocks, &ubuf->st_blocks))
+		return -EFAULT;
+	return 0;
+}
+
+COMPAT_SYSCALL_DEFINE2(ia32_stat64, const char __user *, filename,
+		       struct stat64 __user *, statbuf)
+{
+	struct kstat stat;
+	int ret = vfs_stat(filename, &stat);
+
+	if (!ret)
+		ret = cp_stat64(statbuf, &stat);
+	return ret;
+}
+
+COMPAT_SYSCALL_DEFINE2(ia32_lstat64, const char __user *, filename,
+		       struct stat64 __user *, statbuf)
+{
+	struct kstat stat;
+	int ret = vfs_lstat(filename, &stat);
+	if (!ret)
+		ret = cp_stat64(statbuf, &stat);
+	return ret;
+}
+
+COMPAT_SYSCALL_DEFINE2(ia32_fstat64, unsigned int, fd,
+		       struct stat64 __user *, statbuf)
+{
+	struct kstat stat;
+	int ret = vfs_fstat(fd, &stat);
+	if (!ret)
+		ret = cp_stat64(statbuf, &stat);
+	return ret;
+}
+
+COMPAT_SYSCALL_DEFINE4(ia32_fstatat64, unsigned int, dfd,
+		       const char __user *, filename,
+		       struct stat64 __user *, statbuf, int, flag)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_fstatat(dfd, filename, &stat, flag);
+	if (error)
+		return error;
+	return cp_stat64(statbuf, &stat);
+}
+
+/*
+ * Linux/i386 didn't use to be able to handle more than
+ * 4 system call parameters, so these system calls used a memory
+ * block for parameter passing..
+ */
+
+struct mmap_arg_struct32 {
+	unsigned int addr;
+	unsigned int len;
+	unsigned int prot;
+	unsigned int flags;
+	unsigned int fd;
+	unsigned int offset;
+};
+
+COMPAT_SYSCALL_DEFINE1(ia32_mmap, struct mmap_arg_struct32 __user *, arg)
+{
+	struct mmap_arg_struct32 a;
+
+	if (copy_from_user(&a, arg, sizeof(a)))
+		return -EFAULT;
+
+	if (a.offset & ~PAGE_MASK)
+		return -EINVAL;
+
+	return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
+			       a.offset>>PAGE_SHIFT);
+}
+
+/*
+ * The 32-bit clone ABI is CONFIG_CLONE_BACKWARDS
+ */
+COMPAT_SYSCALL_DEFINE5(ia32_clone, unsigned long, clone_flags,
+		       unsigned long, newsp, int __user *, parent_tidptr,
+		       unsigned long, tls_val, int __user *, child_tidptr)
+{
+	struct kernel_clone_args args = {
+		.flags		= (clone_flags & ~CSIGNAL),
+		.pidfd		= parent_tidptr,
+		.child_tid	= child_tidptr,
+		.parent_tid	= parent_tidptr,
+		.exit_signal	= (clone_flags & CSIGNAL),
+		.stack		= newsp,
+		.tls		= tls_val,
+	};
+
+	if (!legacy_clone_args_valid(&args))
+		return -EINVAL;
+
+	return _do_fork(&args);
+}
+#endif /* CONFIG_IA32_EMULATION */