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    SubjectRe: [PATCH 12/27] asm-generic: add a NOMMU uaccess.h
    Arnd Bergmann wrote:
    > This uaccess.h can be used by all NOMMU architectures,
    > but it does not provide exception handlers that would
    > be needed for an architecture with an MMU.
    >
    > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    > Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
    > ---
    > arch/parisc/include/asm/uaccess.h | 2 +-
    > arch/sparc/include/asm/uaccess_64.h | 2 +-
    > .../asm-generic/{uaccess.h => uaccess-unaligned.h} | 6 +-
    > include/asm-generic/uaccess.h | 235 +++++++++++++++++---
    > 4 files changed, 214 insertions(+), 31 deletions(-)
    > rename include/asm-generic/{uaccess.h => uaccess-unaligned.h} (82%)
    > rewrite include/asm-generic/uaccess.h (96%)
    >
    > diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
    > index cd4c0b2..7cf799d 100644
    > --- a/arch/parisc/include/asm/uaccess.h
    > +++ b/arch/parisc/include/asm/uaccess.h
    > @@ -7,7 +7,7 @@
    > #include <asm/page.h>
    > #include <asm/system.h>
    > #include <asm/cache.h>
    > -#include <asm-generic/uaccess.h>
    > +#include <asm-generic/uaccess-unaligned.h>
    >
    > #define VERIFY_READ 0
    > #define VERIFY_WRITE 1
    > diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
    > index c64e767..a38c032 100644
    > --- a/arch/sparc/include/asm/uaccess_64.h
    > +++ b/arch/sparc/include/asm/uaccess_64.h
    > @@ -12,7 +12,7 @@
    > #include <asm/asi.h>
    > #include <asm/system.h>
    > #include <asm/spitfire.h>
    > -#include <asm-generic/uaccess.h>
    > +#include <asm-generic/uaccess-unaligned.h>
    > #endif
    >
    > #ifndef __ASSEMBLY__
    > diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess-unaligned.h
    > similarity index 82%
    > rename from include/asm-generic/uaccess.h
    > rename to include/asm-generic/uaccess-unaligned.h
    > index 549cb3a..67deb89 100644
    > --- a/include/asm-generic/uaccess.h
    > +++ b/include/asm-generic/uaccess-unaligned.h
    > @@ -1,5 +1,5 @@
    > -#ifndef _ASM_GENERIC_UACCESS_H_
    > -#define _ASM_GENERIC_UACCESS_H_
    > +#ifndef __ASM_GENERIC_UACCESS_UNALIGNED_H
    > +#define __ASM_GENERIC_UACCESS_UNALIGNED_H
    >
    > /*
    > * This macro should be used instead of __get_user() when accessing
    > @@ -23,4 +23,4 @@
    > __copy_to_user((ptr), &__x, sizeof(*(ptr))) ? -EFAULT : 0; \
    > })
    >
    > -#endif /* _ASM_GENERIC_UACCESS_H */
    > +#endif /* __ASM_GENERIC_UACCESS_UNALIGNED_H */
    > diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
    > dissimilarity index 96%
    > index 549cb3a..ebeacd9 100644
    > --- a/include/asm-generic/uaccess.h
    > +++ b/include/asm-generic/uaccess.h
    > @@ -1,26 +1,209 @@
    > -#ifndef _ASM_GENERIC_UACCESS_H_
    > -#define _ASM_GENERIC_UACCESS_H_
    > -
    > -/*
    > - * This macro should be used instead of __get_user() when accessing
    > - * values at locations that are not known to be aligned.
    > - */
    > -#define __get_user_unaligned(x, ptr) \
    > -({ \
    > - __typeof__ (*(ptr)) __x; \
    > - __copy_from_user(&__x, (ptr), sizeof(*(ptr))) ? -EFAULT : 0; \
    > - (x) = __x; \
    > -})
    > -
    > -
    > -/*
    > - * This macro should be used instead of __put_user() when accessing
    > - * values at locations that are not known to be aligned.
    > - */
    > -#define __put_user_unaligned(x, ptr) \
    > -({ \
    > - __typeof__ (*(ptr)) __x = (x); \
    > - __copy_to_user((ptr), &__x, sizeof(*(ptr))) ? -EFAULT : 0; \
    > -})
    > -
    > -#endif /* _ASM_GENERIC_UACCESS_H */
    > +#ifndef __ASM_GENERIC_UACCESS_H
    > +#define __ASM_GENERIC_UACCESS_H
    > +
    > +/*
    > + * User space memory access functions, these should work
    > + * on a ny machine that has kernel and user data in the same
    > + * address space, e.g. all NOMMU machines.
    > + */
    > +#include <linux/sched.h>
    > +#include <linux/mm.h>
    > +#include <linux/string.h>
    > +
    > +#include <asm/segment.h>
    > +
    > +#ifndef get_fs
    > +#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
    > +#define KERNEL_DS MAKE_MM_SEG(~0UL)
    > +#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
    > +
    > +#define get_ds() (KERNEL_DS)
    > +#define get_fs() (current_thread_info()->addr_limit)
    > +
    > +static inline void set_fs(mm_segment_t fs)
    > +{
    > + current_thread_info()->addr_limit = fs;
    > +}
    > +#endif
    > +
    > +#define segment_eq(a, b) ((a).seg == (b).seg)
    > +
    > +#define VERIFY_READ 0
    > +#define VERIFY_WRITE 1
    > +
    > +#define access_ok(type, addr, size) _access_ok((unsigned long)(addr),(size))
    > +
    > +/*
    > + * The architecture should really override this if possible, at least
    > + * doing a check on the get_fs()
    > + */
    > +#ifndef _access_ok
    > +static inline int _access_ok(unsigned long addr, unsigned long size)
    > +{
    > + return 1;
    > +}
    > +#endif
    > +
    > +/*
    > + * The exception table consists of pairs of addresses: the first is the
    > + * address of an instruction that is allowed to fault, and the second is
    > + * the address at which the program should continue. No registers are
    > + * modified, so it is entirely up to the continuation code to figure out
    > + * what to do.
    > + *
    > + * All the routines below use bits of fixup code that are out of line
    > + * with the main instruction path. This means when everything is well,
    > + * we don't even have to jump over them. Further, they do not intrude
    > + * on our cache or tlb entries.
    > + */
    > +
    > +struct exception_table_entry
    > +{
    > + unsigned long insn, fixup;
    > +};
    > +
    > +/* Returns 0 if exception not found and fixup otherwise. */
    > +extern unsigned long search_exception_table(unsigned long);
    > +
    > +/*
    > + * These are the main single-value transfer routines. They automatically
    > + * use the right size if we just have the right pointer type.
    > + */
    > +#ifndef __put_user
    > +#define __put_user(x, ptr) \
    > +({ \
    > + int __pu_err = 0; \
    > + typeof(*(ptr)) __pu_val = (x); \
    > + switch (sizeof (*(ptr))) { \
    > + case 1: \
    > + case 2: \
    > + case 4: \
    > + *(ptr) = (__pu_val); \
    > + break; \
    > + case 8: \
    > + memcpy(ptr, &__pu_val, sizeof (*(ptr)));\
    > + break; \
    > + default: \
    > + __pu_err = __put_user_bad(); \
    > + break; \
    > + } \
    > + __pu_err; \
    > +})
    > +extern int __put_user_bad(void);
    > +#endif
    > +
    > +#define put_user(x, ptr) ( \
    > + access_ok(VERIFY_WRITE, ptr, sizeof (*ptr)) ? \
    > + __put_user(x, ptr) : \
    > + -EFAULT)
    > +
    > +#ifndef __get_user
    > +#define __get_user(x, ptr) \
    > +({ \
    > + int __gu_err = 0; \
    > + unsigned long __gu_val = (unsigned long)*ptr; \
    > + switch (sizeof(*(ptr))) { \
    > + case 1: \
    > + case 2: \
    > + case 4: \
    > + case 8: \
    > + break; \
    > + default: \
    > + __gu_err = __get_user_bad(); \
    > + __gu_val = 0; \
    > + break; \
    > + } \
    > + (x) = (typeof(*ptr))__gu_val; \
    > + __gu_err; \
    > +})
    > +extern int __get_user_bad(void);
    > +#endif
    > +
    > +#define get_user(x, ptr) ( \
    > + access_ok(VERIFY_READ, ptr, sizeof (*ptr)) ? \
    > + __get_user(x, ptr) : \
    > + -EFAULT)
    > +
    > +#define __copy_from_user(to, from, n) (memcpy(to, from, n), 0)
    > +#define __copy_to_user(to, from, n) (memcpy(to, from, n), 0)
    > +#define __copy_to_user_inatomic __copy_to_user
    > +#define __copy_from_user_inatomic __copy_from_user
    > +
    > +#define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n)) return retval; })
    > +
    > +#define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n)) return retval; })
    > +
    > +static inline long copy_from_user(void *to,
    > + const void __user * from, unsigned long n)
    > +{
    > + if (access_ok(VERIFY_READ, from, n))
    > + __copy_from_user(to, from, n);
    > + else
    > + return n;
    > + return 0;
    > +}
    > +
    > +static inline long copy_to_user(void *to,
    > + const void __user * from, unsigned long n)
    > +{
    > + if (access_ok(VERIFY_WRITE, to, n))
    > + __copy_to_user(to, from, n);
    > + else
    > + return n;
    > + return 0;
    > +}
    > +
    > +/*
    > + * Copy a null terminated string from userspace.
    > + */
    > +
    > +static inline long
    > +__do_strncpy_from_user(char *dst, const char __user *src, long count)
    > +{
    > + char *tmp;
    > + strncpy(dst, src, count);
    > + for (tmp = dst; *tmp && count > 0; tmp++, count--)
    > + ;
    > + return (tmp - dst);
    > +}
    > +
    > +static inline long
    > +strncpy_from_user(char *dst, const char __user *src, long count)
    > +{
    > + if (!access_ok(VERIFY_READ, src, 1))
    > + return -EFAULT;
    > + return __do_strncpy_from_user(dst, src, count);
    > +}
    > +
    > +static inline long
    > +__strncpy_from_user(char *dst, const char __user *src, long count)
    > +{
    > + return __do_strncpy_from_user(dst, src, count);
    > +}
    > +
    > +/*
    > + * Return the size of a string (including the ending 0)
    > + *
    > + * Return 0 on exception, a value greater than N if too long
    > + */
    > +static inline long strnlen_user(const char *src, long n)
    > +{
    > + return strlen(src) + 1;
    > +}

    Here is the cast problem too.

    Michal


    > +
    > +#define strlen_user(str) strnlen_user(str, 32767)
    > +
    > +/*
    > + * Zero Userspace
    > + */
    > +
    > +static inline unsigned long
    > +__clear_user(void *to, unsigned long n)
    > +{
    > + memset(to, 0, n);
    > + return 0;
    > +}
    > +
    > +#define clear_user(to, n) __clear_user(to, n)
    > +
    > +#endif /* __ASM_GENERIC_UACCESS_H */


    --
    Michal Simek, Ing. (M.Eng)
    w: www.monstr.eu p: +42-0-721842854


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