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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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8a5d8473dd
Remove the s390 architecture implementation of probe_kernel_write() and instead use a new function s390_kernel_write() to modify kernel text and data everywhere. The s390 implementation of probe_kernel_write() was potentially broken since it modified memory in a read-modify-write fashion, which read four bytes, modified the requested bytes within those four bytes and wrote the result back. If two cpus would modify the same four byte area at different locations within that area, this could lead to corruption. Right now the only places which called probe_kernel_write() did run within stop_machine_run. Therefore the scenario can't happen right now, however that might change at any time. To fix this rename probe_kernel_write() to s390_kernel_write() which can have special semantics, like only call it while running within stop_machine(). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
378 lines
9.9 KiB
C
378 lines
9.9 KiB
C
/*
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* S390 version
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* Copyright IBM Corp. 1999, 2000
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* Author(s): Hartmut Penner (hp@de.ibm.com),
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* Martin Schwidefsky (schwidefsky@de.ibm.com)
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*
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* Derived from "include/asm-i386/uaccess.h"
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*/
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#ifndef __S390_UACCESS_H
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#define __S390_UACCESS_H
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/*
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* User space memory access functions
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*/
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <asm/ctl_reg.h>
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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/*
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* The fs value determines whether argument validity checking should be
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* performed or not. If get_fs() == USER_DS, checking is performed, with
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* get_fs() == KERNEL_DS, checking is bypassed.
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*
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* For historical reasons, these macros are grossly misnamed.
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*/
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#define MAKE_MM_SEG(a) ((mm_segment_t) { (a) })
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#define KERNEL_DS MAKE_MM_SEG(0)
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#define USER_DS MAKE_MM_SEG(1)
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current->thread.mm_segment)
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#define set_fs(x) \
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({ \
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unsigned long __pto; \
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current->thread.mm_segment = (x); \
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__pto = current->thread.mm_segment.ar4 ? \
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S390_lowcore.user_asce : S390_lowcore.kernel_asce; \
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__ctl_load(__pto, 7, 7); \
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})
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#define segment_eq(a,b) ((a).ar4 == (b).ar4)
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static inline int __range_ok(unsigned long addr, unsigned long size)
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{
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return 1;
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}
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#define __access_ok(addr, size) \
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({ \
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__chk_user_ptr(addr); \
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__range_ok((unsigned long)(addr), (size)); \
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})
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#define access_ok(type, addr, size) __access_ok(addr, size)
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/*
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* what to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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struct exception_table_entry
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{
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int insn, fixup;
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};
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static inline unsigned long extable_insn(const struct exception_table_entry *x)
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{
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return (unsigned long)&x->insn + x->insn;
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}
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static inline unsigned long extable_fixup(const struct exception_table_entry *x)
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{
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return (unsigned long)&x->fixup + x->fixup;
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}
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#define ARCH_HAS_SORT_EXTABLE
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#define ARCH_HAS_SEARCH_EXTABLE
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/**
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* __copy_from_user: - Copy a block of data from user space, with less checking.
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* @to: Destination address, in kernel space.
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* @from: Source address, in user space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only. This function may sleep.
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*
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* Copy data from user space to kernel space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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*
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* If some data could not be copied, this function will pad the copied
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* data to the requested size using zero bytes.
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*/
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unsigned long __must_check __copy_from_user(void *to, const void __user *from,
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unsigned long n);
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/**
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* __copy_to_user: - Copy a block of data into user space, with less checking.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only. This function may sleep.
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*
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* Copy data from kernel space to user space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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*/
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unsigned long __must_check __copy_to_user(void __user *to, const void *from,
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unsigned long n);
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#define __copy_to_user_inatomic __copy_to_user
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#define __copy_from_user_inatomic __copy_from_user
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#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
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#define __put_get_user_asm(to, from, size, spec) \
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({ \
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register unsigned long __reg0 asm("0") = spec; \
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int __rc; \
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\
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asm volatile( \
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"0: mvcos %1,%3,%2\n" \
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"1: xr %0,%0\n" \
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"2:\n" \
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".pushsection .fixup, \"ax\"\n" \
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"3: lhi %0,%5\n" \
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" jg 2b\n" \
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".popsection\n" \
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EX_TABLE(0b,3b) EX_TABLE(1b,3b) \
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: "=d" (__rc), "=Q" (*(to)) \
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: "d" (size), "Q" (*(from)), \
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"d" (__reg0), "K" (-EFAULT) \
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: "cc"); \
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__rc; \
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})
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#define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL)
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#define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL)
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#else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
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static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
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{
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size = __copy_to_user(ptr, x, size);
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return size ? -EFAULT : 0;
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}
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static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
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{
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size = __copy_from_user(x, ptr, size);
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return size ? -EFAULT : 0;
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}
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#endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
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/*
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* These are the main single-value transfer routines. They automatically
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* use the right size if we just have the right pointer type.
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*/
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#define __put_user(x, ptr) \
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({ \
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__typeof__(*(ptr)) __x = (x); \
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int __pu_err = -EFAULT; \
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__chk_user_ptr(ptr); \
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switch (sizeof (*(ptr))) { \
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case 1: \
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case 2: \
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case 4: \
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case 8: \
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__pu_err = __put_user_fn(&__x, ptr, \
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sizeof(*(ptr))); \
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break; \
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default: \
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__put_user_bad(); \
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break; \
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} \
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__pu_err; \
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})
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#define put_user(x, ptr) \
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({ \
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might_fault(); \
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__put_user(x, ptr); \
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})
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int __put_user_bad(void) __attribute__((noreturn));
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#define __get_user(x, ptr) \
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({ \
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int __gu_err = -EFAULT; \
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__chk_user_ptr(ptr); \
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switch (sizeof(*(ptr))) { \
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case 1: { \
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unsigned char __x; \
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__gu_err = __get_user_fn(&__x, ptr, \
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sizeof(*(ptr))); \
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(x) = *(__force __typeof__(*(ptr)) *) &__x; \
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break; \
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}; \
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case 2: { \
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unsigned short __x; \
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__gu_err = __get_user_fn(&__x, ptr, \
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sizeof(*(ptr))); \
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(x) = *(__force __typeof__(*(ptr)) *) &__x; \
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break; \
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}; \
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case 4: { \
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unsigned int __x; \
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__gu_err = __get_user_fn(&__x, ptr, \
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sizeof(*(ptr))); \
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(x) = *(__force __typeof__(*(ptr)) *) &__x; \
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break; \
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}; \
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case 8: { \
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unsigned long long __x; \
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__gu_err = __get_user_fn(&__x, ptr, \
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sizeof(*(ptr))); \
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(x) = *(__force __typeof__(*(ptr)) *) &__x; \
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break; \
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}; \
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default: \
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__get_user_bad(); \
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break; \
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} \
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__gu_err; \
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})
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#define get_user(x, ptr) \
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({ \
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might_fault(); \
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__get_user(x, ptr); \
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})
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int __get_user_bad(void) __attribute__((noreturn));
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#define __put_user_unaligned __put_user
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#define __get_user_unaligned __get_user
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/**
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* copy_to_user: - Copy a block of data into user space.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only. This function may sleep.
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*
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* Copy data from kernel space to user space.
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*
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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*/
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static inline unsigned long __must_check
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copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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might_fault();
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return __copy_to_user(to, from, n);
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}
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void copy_from_user_overflow(void)
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#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
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__compiletime_warning("copy_from_user() buffer size is not provably correct")
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#endif
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;
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/**
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* copy_from_user: - Copy a block of data from user space.
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* @to: Destination address, in kernel space.
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* @from: Source address, in user space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only. This function may sleep.
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*
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* Copy data from user space to kernel space.
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*
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* Returns number of bytes that could not be copied.
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* On success, this will be zero.
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*
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* If some data could not be copied, this function will pad the copied
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* data to the requested size using zero bytes.
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*/
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static inline unsigned long __must_check
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copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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unsigned int sz = __compiletime_object_size(to);
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might_fault();
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if (unlikely(sz != -1 && sz < n)) {
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copy_from_user_overflow();
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return n;
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}
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return __copy_from_user(to, from, n);
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}
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unsigned long __must_check
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__copy_in_user(void __user *to, const void __user *from, unsigned long n);
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static inline unsigned long __must_check
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copy_in_user(void __user *to, const void __user *from, unsigned long n)
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{
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might_fault();
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return __copy_in_user(to, from, n);
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}
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/*
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* Copy a null terminated string from userspace.
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*/
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long __strncpy_from_user(char *dst, const char __user *src, long count);
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static inline long __must_check
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strncpy_from_user(char *dst, const char __user *src, long count)
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{
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might_fault();
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return __strncpy_from_user(dst, src, count);
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}
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unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
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static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
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{
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might_fault();
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return __strnlen_user(src, n);
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}
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/**
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* strlen_user: - Get the size of a string in user space.
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* @str: The string to measure.
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*
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* Context: User context only. This function may sleep.
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*
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* Get the size of a NUL-terminated string in user space.
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*
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* Returns the size of the string INCLUDING the terminating NUL.
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* On exception, returns 0.
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*
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* If there is a limit on the length of a valid string, you may wish to
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* consider using strnlen_user() instead.
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*/
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#define strlen_user(str) strnlen_user(str, ~0UL)
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/*
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* Zero Userspace
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*/
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unsigned long __must_check __clear_user(void __user *to, unsigned long size);
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static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
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{
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might_fault();
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return __clear_user(to, n);
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}
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int copy_to_user_real(void __user *dest, void *src, unsigned long count);
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void s390_kernel_write(void *dst, const void *src, size_t size);
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#endif /* __S390_UACCESS_H */
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