kernel-ark/include/asm-s390/compat.h
Gerald Schaefer c1821c2e97 [S390] noexec protection
This provides a noexec protection on s390 hardware. Our hardware does
not have any bits left in the pte for a hw noexec bit, so this is a
different approach using shadow page tables and a special addressing
mode that allows separate address spaces for code and data.

As a special feature of our "secondary-space" addressing mode, separate
page tables can be specified for the translation of data addresses
(storage operands) and instruction addresses. The shadow page table is
used for the instruction addresses and the standard page table for the
data addresses.
The shadow page table is linked to the standard page table by a pointer
in page->lru.next of the struct page corresponding to the page that
contains the standard page table (since page->private is not really
private with the pte_lock and the page table pages are not in the LRU
list).
Depending on the software bits of a pte, it is either inserted into
both page tables or just into the standard (data) page table. Pages of
a vma that does not have the VM_EXEC bit set get mapped only in the
data address space. Any try to execute code on such a page will cause a
page translation exception. The standard reaction to this is a SIGSEGV
with two exceptions: the two system call opcodes 0x0a77 (sys_sigreturn)
and 0x0aad (sys_rt_sigreturn) are allowed. They are stored by the
kernel to the signal stack frame. Unfortunately, the signal return
mechanism cannot be modified to use an SA_RESTORER because the
exception unwinding code depends on the system call opcode stored
behind the signal stack frame.

This feature requires that user space is executed in secondary-space
mode and the kernel in home-space mode, which means that the addressing
modes need to be switched and that the noexec protection only works
for user space.
After switching the addressing modes, we cannot use the mvcp/mvcs
instructions anymore to copy between kernel and user space. A new
mvcos instruction has been added to the z9 EC/BC hardware which allows
to copy between arbitrary address spaces, but on older hardware the
page tables need to be walked manually.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05 21:18:17 +01:00

232 lines
5.1 KiB
C

#ifndef _ASM_S390X_COMPAT_H
#define _ASM_S390X_COMPAT_H
/*
* Architecture specific compatibility types
*/
#include <linux/types.h>
#include <linux/sched.h>
#define PSW32_MASK_PER 0x40000000UL
#define PSW32_MASK_DAT 0x04000000UL
#define PSW32_MASK_IO 0x02000000UL
#define PSW32_MASK_EXT 0x01000000UL
#define PSW32_MASK_KEY 0x00F00000UL
#define PSW32_MASK_MCHECK 0x00040000UL
#define PSW32_MASK_WAIT 0x00020000UL
#define PSW32_MASK_PSTATE 0x00010000UL
#define PSW32_MASK_ASC 0x0000C000UL
#define PSW32_MASK_CC 0x00003000UL
#define PSW32_MASK_PM 0x00000f00UL
#define PSW32_ADDR_AMODE31 0x80000000UL
#define PSW32_ADDR_INSN 0x7FFFFFFFUL
#define PSW32_BASE_BITS 0x00080000UL
#define PSW32_ASC_PRIMARY 0x00000000UL
#define PSW32_ASC_ACCREG 0x00004000UL
#define PSW32_ASC_SECONDARY 0x00008000UL
#define PSW32_ASC_HOME 0x0000C000UL
#define PSW32_MASK_MERGE(CURRENT,NEW) \
(((CURRENT) & ~(PSW32_MASK_CC|PSW32_MASK_PM)) | \
((NEW) & (PSW32_MASK_CC|PSW32_MASK_PM)))
extern long psw32_user_bits;
#define COMPAT_USER_HZ 100
typedef u32 compat_size_t;
typedef s32 compat_ssize_t;
typedef s32 compat_time_t;
typedef s32 compat_clock_t;
typedef s32 compat_pid_t;
typedef u16 __compat_uid_t;
typedef u16 __compat_gid_t;
typedef u32 __compat_uid32_t;
typedef u32 __compat_gid32_t;
typedef u16 compat_mode_t;
typedef u32 compat_ino_t;
typedef u16 compat_dev_t;
typedef s32 compat_off_t;
typedef s64 compat_loff_t;
typedef u16 compat_nlink_t;
typedef u16 compat_ipc_pid_t;
typedef s32 compat_daddr_t;
typedef u32 compat_caddr_t;
typedef __kernel_fsid_t compat_fsid_t;
typedef s32 compat_key_t;
typedef s32 compat_timer_t;
typedef s32 compat_int_t;
typedef s32 compat_long_t;
typedef u32 compat_uint_t;
typedef u32 compat_ulong_t;
struct compat_timespec {
compat_time_t tv_sec;
s32 tv_nsec;
};
struct compat_timeval {
compat_time_t tv_sec;
s32 tv_usec;
};
struct compat_stat {
compat_dev_t st_dev;
u16 __pad1;
compat_ino_t st_ino;
compat_mode_t st_mode;
compat_nlink_t st_nlink;
__compat_uid_t st_uid;
__compat_gid_t st_gid;
compat_dev_t st_rdev;
u16 __pad2;
u32 st_size;
u32 st_blksize;
u32 st_blocks;
u32 st_atime;
u32 st_atime_nsec;
u32 st_mtime;
u32 st_mtime_nsec;
u32 st_ctime;
u32 st_ctime_nsec;
u32 __unused4;
u32 __unused5;
};
struct compat_flock {
short l_type;
short l_whence;
compat_off_t l_start;
compat_off_t l_len;
compat_pid_t l_pid;
};
#define F_GETLK64 12
#define F_SETLK64 13
#define F_SETLKW64 14
struct compat_flock64 {
short l_type;
short l_whence;
compat_loff_t l_start;
compat_loff_t l_len;
compat_pid_t l_pid;
};
struct compat_statfs {
s32 f_type;
s32 f_bsize;
s32 f_blocks;
s32 f_bfree;
s32 f_bavail;
s32 f_files;
s32 f_ffree;
compat_fsid_t f_fsid;
s32 f_namelen;
s32 f_frsize;
s32 f_spare[6];
};
#define COMPAT_RLIM_OLD_INFINITY 0x7fffffff
#define COMPAT_RLIM_INFINITY 0xffffffff
typedef u32 compat_old_sigset_t; /* at least 32 bits */
#define _COMPAT_NSIG 64
#define _COMPAT_NSIG_BPW 32
typedef u32 compat_sigset_word;
#define COMPAT_OFF_T_MAX 0x7fffffff
#define COMPAT_LOFF_T_MAX 0x7fffffffffffffffL
/*
* A pointer passed in from user mode. This should not
* be used for syscall parameters, just declare them
* as pointers because the syscall entry code will have
* appropriately comverted them already.
*/
typedef u32 compat_uptr_t;
static inline void __user *compat_ptr(compat_uptr_t uptr)
{
return (void __user *)(unsigned long)(uptr & 0x7fffffffUL);
}
static inline compat_uptr_t ptr_to_compat(void __user *uptr)
{
return (u32)(unsigned long)uptr;
}
static inline void __user *compat_alloc_user_space(long len)
{
unsigned long stack;
stack = KSTK_ESP(current);
if (test_thread_flag(TIF_31BIT))
stack &= 0x7fffffffUL;
return (void __user *) (stack - len);
}
struct compat_ipc64_perm {
compat_key_t key;
__compat_uid32_t uid;
__compat_gid32_t gid;
__compat_uid32_t cuid;
__compat_gid32_t cgid;
compat_mode_t mode;
unsigned short __pad1;
unsigned short seq;
unsigned short __pad2;
unsigned int __unused1;
unsigned int __unused2;
};
struct compat_semid64_ds {
struct compat_ipc64_perm sem_perm;
compat_time_t sem_otime;
compat_ulong_t __pad1;
compat_time_t sem_ctime;
compat_ulong_t __pad2;
compat_ulong_t sem_nsems;
compat_ulong_t __unused1;
compat_ulong_t __unused2;
};
struct compat_msqid64_ds {
struct compat_ipc64_perm msg_perm;
compat_time_t msg_stime;
compat_ulong_t __pad1;
compat_time_t msg_rtime;
compat_ulong_t __pad2;
compat_time_t msg_ctime;
compat_ulong_t __pad3;
compat_ulong_t msg_cbytes;
compat_ulong_t msg_qnum;
compat_ulong_t msg_qbytes;
compat_pid_t msg_lspid;
compat_pid_t msg_lrpid;
compat_ulong_t __unused1;
compat_ulong_t __unused2;
};
struct compat_shmid64_ds {
struct compat_ipc64_perm shm_perm;
compat_size_t shm_segsz;
compat_time_t shm_atime;
compat_ulong_t __pad1;
compat_time_t shm_dtime;
compat_ulong_t __pad2;
compat_time_t shm_ctime;
compat_ulong_t __pad3;
compat_pid_t shm_cpid;
compat_pid_t shm_lpid;
compat_ulong_t shm_nattch;
compat_ulong_t __unused1;
compat_ulong_t __unused2;
};
#endif /* _ASM_S390X_COMPAT_H */