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linux/arch/s390/include/asm/uaccess.h
Sven Schnelle 56e62a7370 s390: convert to generic entry 
This patch converts s390 to use the generic entry infrastructure from
kernel/entry/*.

There are a few special things on s390:

- PIF_PER_TRAP is moved to TIF_PER_TRAP as the generic code doesn't
  know about our PIF flags in exit_to_user_mode_loop().

- The old code had several ways to restart syscalls:

  a) PIF_SYSCALL_RESTART, which was only set during execve to force a
     restart after upgrading a process (usually qemu-kvm) to pgste page
     table extensions.

  b) PIF_SYSCALL, which is set by do_signal() to indicate that the
     current syscall should be restarted. This is changed so that
     do_signal() now also uses PIF_SYSCALL_RESTART. Continuing to use
     PIF_SYSCALL doesn't work with the generic code, and changing it
     to PIF_SYSCALL_RESTART makes PIF_SYSCALL and PIF_SYSCALL_RESTART
     more unique.

- On s390 calling sys_sigreturn or sys_rt_sigreturn is implemented by
executing a svc instruction on the process stack which causes a fault.
While handling that fault the fault code sets PIF_SYSCALL to hand over
processing to the syscall code on exit to usermode.

The patch introduces PIF_SYSCALL_RET_SET, which is set if ptrace sets
a return value for a syscall. The s390x ptrace ABI uses r2 both for the
syscall number and return value, so ptrace cannot set the syscall number +
return value at the same time. The flag makes handling that a bit easier.
do_syscall() will just skip executing the syscall if PIF_SYSCALL_RET_SET
is set.

CONFIG_DEBUG_ASCE was removd in favour of the generic CONFIG_DEBUG_ENTRY.
CR1/7/13 will be checked both on kernel entry and exit to contain the
correct asces.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-01-19 12:29:26 +01:00

381 lines
8.8 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
/*
* S390 version
* Copyright IBM Corp. 1999, 2000
* Author(s): Hartmut Penner (hp@de.ibm.com),
* Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* Derived from "include/asm-i386/uaccess.h"
*/
#ifndef __S390_UACCESS_H
#define __S390_UACCESS_H
/*
* User space memory access functions
*/
#include <asm/processor.h>
#include <asm/ctl_reg.h>
#include <asm/extable.h>
#include <asm/facility.h>
void debug_user_asce(int exit);
static inline int __range_ok(unsigned long addr, unsigned long size)
{
return 1;
}
#define __access_ok(addr, size) \
({ \
__chk_user_ptr(addr); \
__range_ok((unsigned long)(addr), (size)); \
})
#define access_ok(addr, size) __access_ok(addr, size)
unsigned long __must_check
raw_copy_from_user(void *to, const void __user *from, unsigned long n);
unsigned long __must_check
raw_copy_to_user(void __user *to, const void *from, unsigned long n);
#ifndef CONFIG_KASAN
#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER
#endif
int __put_user_bad(void) __attribute__((noreturn));
int __get_user_bad(void) __attribute__((noreturn));
#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
#define __put_get_user_asm(to, from, size, spec) \
({ \
register unsigned long __reg0 asm("0") = spec; \
int __rc; \
\
asm volatile( \
"0: mvcos %1,%3,%2\n" \
"1: xr %0,%0\n" \
"2:\n" \
".pushsection .fixup, \"ax\"\n" \
"3: lhi %0,%5\n" \
" jg 2b\n" \
".popsection\n" \
EX_TABLE(0b,3b) EX_TABLE(1b,3b) \
: "=d" (__rc), "+Q" (*(to)) \
: "d" (size), "Q" (*(from)), \
"d" (__reg0), "K" (-EFAULT) \
: "cc"); \
__rc; \
})
static __always_inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
{
unsigned long spec = 0x810000UL;
int rc;
switch (size) {
case 1:
rc = __put_get_user_asm((unsigned char __user *)ptr,
(unsigned char *)x,
size, spec);
break;
case 2:
rc = __put_get_user_asm((unsigned short __user *)ptr,
(unsigned short *)x,
size, spec);
break;
case 4:
rc = __put_get_user_asm((unsigned int __user *)ptr,
(unsigned int *)x,
size, spec);
break;
case 8:
rc = __put_get_user_asm((unsigned long __user *)ptr,
(unsigned long *)x,
size, spec);
break;
default:
__put_user_bad();
break;
}
return rc;
}
static __always_inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
{
unsigned long spec = 0x81UL;
int rc;
switch (size) {
case 1:
rc = __put_get_user_asm((unsigned char *)x,
(unsigned char __user *)ptr,
size, spec);
break;
case 2:
rc = __put_get_user_asm((unsigned short *)x,
(unsigned short __user *)ptr,
size, spec);
break;
case 4:
rc = __put_get_user_asm((unsigned int *)x,
(unsigned int __user *)ptr,
size, spec);
break;
case 8:
rc = __put_get_user_asm((unsigned long *)x,
(unsigned long __user *)ptr,
size, spec);
break;
default:
__get_user_bad();
break;
}
return rc;
}
#else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
{
size = raw_copy_to_user(ptr, x, size);
return size ? -EFAULT : 0;
}
static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
{
size = raw_copy_from_user(x, ptr, size);
return size ? -EFAULT : 0;
}
#endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
*/
#define __put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __x = (x); \
int __pu_err = -EFAULT; \
__chk_user_ptr(ptr); \
switch (sizeof (*(ptr))) { \
case 1: \
case 2: \
case 4: \
case 8: \
__pu_err = __put_user_fn(&__x, ptr, \
sizeof(*(ptr))); \
break; \
default: \
__put_user_bad(); \
break; \
} \
__builtin_expect(__pu_err, 0); \
})
#define put_user(x, ptr) \
({ \
might_fault(); \
__put_user(x, ptr); \
})
#define __get_user(x, ptr) \
({ \
int __gu_err = -EFAULT; \
__chk_user_ptr(ptr); \
switch (sizeof(*(ptr))) { \
case 1: { \
unsigned char __x = 0; \
__gu_err = __get_user_fn(&__x, ptr, \
sizeof(*(ptr))); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 2: { \
unsigned short __x = 0; \
__gu_err = __get_user_fn(&__x, ptr, \
sizeof(*(ptr))); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 4: { \
unsigned int __x = 0; \
__gu_err = __get_user_fn(&__x, ptr, \
sizeof(*(ptr))); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 8: { \
unsigned long long __x = 0; \
__gu_err = __get_user_fn(&__x, ptr, \
sizeof(*(ptr))); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
default: \
__get_user_bad(); \
break; \
} \
__builtin_expect(__gu_err, 0); \
})
#define get_user(x, ptr) \
({ \
might_fault(); \
__get_user(x, ptr); \
})
unsigned long __must_check
raw_copy_in_user(void __user *to, const void __user *from, unsigned long n);
/*
* Copy a null terminated string from userspace.
*/
long __strncpy_from_user(char *dst, const char __user *src, long count);
static inline long __must_check
strncpy_from_user(char *dst, const char __user *src, long count)
{
might_fault();
return __strncpy_from_user(dst, src, count);
}
unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
{
might_fault();
return __strnlen_user(src, n);
}
/*
* Zero Userspace
*/
unsigned long __must_check __clear_user(void __user *to, unsigned long size);
static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
{
might_fault();
return __clear_user(to, n);
}
int copy_to_user_real(void __user *dest, void *src, unsigned long count);
void *s390_kernel_write(void *dst, const void *src, size_t size);
#define HAVE_GET_KERNEL_NOFAULT
int __noreturn __put_kernel_bad(void);
#define __put_kernel_asm(val, to, insn) \
({ \
int __rc; \
\
asm volatile( \
"0: " insn " %2,%1\n" \
"1: xr %0,%0\n" \
"2:\n" \
".pushsection .fixup, \"ax\"\n" \
"3: lhi %0,%3\n" \
" jg 2b\n" \
".popsection\n" \
EX_TABLE(0b,3b) EX_TABLE(1b,3b) \
: "=d" (__rc), "+Q" (*(to)) \
: "d" (val), "K" (-EFAULT) \
: "cc"); \
__rc; \
})
#define __put_kernel_nofault(dst, src, type, err_label) \
do { \
u64 __x = (u64)(*((type *)(src))); \
int __pk_err; \
\
switch (sizeof(type)) { \
case 1: \
__pk_err = __put_kernel_asm(__x, (type *)(dst), "stc"); \
break; \
case 2: \
__pk_err = __put_kernel_asm(__x, (type *)(dst), "sth"); \
break; \
case 4: \
__pk_err = __put_kernel_asm(__x, (type *)(dst), "st"); \
break; \
case 8: \
__pk_err = __put_kernel_asm(__x, (type *)(dst), "stg"); \
break; \
default: \
__pk_err = __put_kernel_bad(); \
break; \
} \
if (unlikely(__pk_err)) \
goto err_label; \
} while (0)
int __noreturn __get_kernel_bad(void);
#define __get_kernel_asm(val, from, insn) \
({ \
int __rc; \
\
asm volatile( \
"0: " insn " %1,%2\n" \
"1: xr %0,%0\n" \
"2:\n" \
".pushsection .fixup, \"ax\"\n" \
"3: lhi %0,%3\n" \
" jg 2b\n" \
".popsection\n" \
EX_TABLE(0b,3b) EX_TABLE(1b,3b) \
: "=d" (__rc), "+d" (val) \
: "Q" (*(from)), "K" (-EFAULT) \
: "cc"); \
__rc; \
})
#define __get_kernel_nofault(dst, src, type, err_label) \
do { \
int __gk_err; \
\
switch (sizeof(type)) { \
case 1: { \
u8 __x = 0; \
\
__gk_err = __get_kernel_asm(__x, (type *)(src), "ic"); \
*((type *)(dst)) = (type)__x; \
break; \
}; \
case 2: { \
u16 __x = 0; \
\
__gk_err = __get_kernel_asm(__x, (type *)(src), "lh"); \
*((type *)(dst)) = (type)__x; \
break; \
}; \
case 4: { \
u32 __x = 0; \
\
__gk_err = __get_kernel_asm(__x, (type *)(src), "l"); \
*((type *)(dst)) = (type)__x; \
break; \
}; \
case 8: { \
u64 __x = 0; \
\
__gk_err = __get_kernel_asm(__x, (type *)(src), "lg"); \
*((type *)(dst)) = (type)__x; \
break; \
}; \
default: \
__gk_err = __get_kernel_bad(); \
break; \
} \
if (unlikely(__gk_err)) \
goto err_label; \
} while (0)
#endif /* __S390_UACCESS_H */
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