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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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f84ed59a61
In __get_user_check, we create an intermediate pointer for the user address we're about to fetch. We currently don't tag this pointer as const. Make it const, as we are simply dereferencing it, and it's scope is limited to the __get_user_check macro. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
428 lines
12 KiB
C
428 lines
12 KiB
C
#ifndef _ARCH_POWERPC_UACCESS_H
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#define _ARCH_POWERPC_UACCESS_H
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#ifdef __KERNEL__
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#ifndef __ASSEMBLY__
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <asm/asm-compat.h>
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#include <asm/ppc_asm.h>
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#include <asm/processor.h>
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#include <asm/page.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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* The fs/ds values are now the highest legal address in the "segment".
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* This simplifies the checking in the routines below.
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*/
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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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#define KERNEL_DS MAKE_MM_SEG(~0UL)
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#ifdef __powerpc64__
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/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
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#define USER_DS MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
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#else
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#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
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#endif
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current->thread.fs)
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#define set_fs(val) (current->thread.fs = (val))
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#define segment_eq(a, b) ((a).seg == (b).seg)
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#define user_addr_max() (get_fs().seg)
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#ifdef __powerpc64__
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/*
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* This check is sufficient because there is a large enough
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* gap between user addresses and the kernel addresses
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*/
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#define __access_ok(addr, size, segment) \
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(((addr) <= (segment).seg) && ((size) <= (segment).seg))
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#else
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#define __access_ok(addr, size, segment) \
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(((addr) <= (segment).seg) && \
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(((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
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#endif
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#define access_ok(type, addr, size) \
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(__chk_user_ptr(addr), \
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__access_ok((__force unsigned long)(addr), (size), get_fs()))
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/*
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* The exception table consists of pairs of relative addresses: the first is
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* the 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 what
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* to do.
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*
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* All the routines below use bits of fixup code that are out of line with the
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* main instruction path. This means when everything is well, we don't even
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* have to jump over them. Further, they do not intrude on our cache or tlb
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* entries.
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*/
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#define ARCH_HAS_RELATIVE_EXTABLE
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struct exception_table_entry {
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int insn;
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int fixup;
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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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/*
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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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* This gets kind of ugly. We want to return _two_ values in "get_user()"
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* and yet we don't want to do any pointers, because that is too much
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* of a performance impact. Thus we have a few rather ugly macros here,
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* and hide all the ugliness from the user.
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*
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* The "__xxx" versions of the user access functions are versions that
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* do not verify the address space, that must have been done previously
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* with a separate "access_ok()" call (this is used when we do multiple
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* accesses to the same area of user memory).
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*
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* As we use the same address space for kernel and user data on the
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* PowerPC, we can just do these as direct assignments. (Of course, the
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* exception handling means that it's no longer "just"...)
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*
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*/
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#define get_user(x, ptr) \
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__get_user_check((x), (ptr), sizeof(*(ptr)))
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#define put_user(x, ptr) \
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__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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#define __get_user(x, ptr) \
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__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
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#define __put_user(x, ptr) \
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__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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#define __get_user_inatomic(x, ptr) \
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__get_user_nosleep((x), (ptr), sizeof(*(ptr)))
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#define __put_user_inatomic(x, ptr) \
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__put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
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#define __get_user_unaligned __get_user
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#define __put_user_unaligned __put_user
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extern long __put_user_bad(void);
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/*
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* We don't tell gcc that we are accessing memory, but this is OK
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* because we do not write to any memory gcc knows about, so there
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* are no aliasing issues.
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*/
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#define __put_user_asm(x, addr, err, op) \
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__asm__ __volatile__( \
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"1: " op " %1,0(%2) # put_user\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: li %0,%3\n" \
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" b 2b\n" \
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".previous\n" \
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EX_TABLE(1b, 3b) \
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: "=r" (err) \
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: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
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#ifdef __powerpc64__
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#define __put_user_asm2(x, ptr, retval) \
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__put_user_asm(x, ptr, retval, "std")
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#else /* __powerpc64__ */
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#define __put_user_asm2(x, addr, err) \
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__asm__ __volatile__( \
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"1: stw %1,0(%2)\n" \
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"2: stw %1+1,4(%2)\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: li %0,%3\n" \
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" b 3b\n" \
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".previous\n" \
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EX_TABLE(1b, 4b) \
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EX_TABLE(2b, 4b) \
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: "=r" (err) \
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: "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
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#endif /* __powerpc64__ */
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#define __put_user_size(x, ptr, size, retval) \
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do { \
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retval = 0; \
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switch (size) { \
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case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
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case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
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case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
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case 8: __put_user_asm2(x, ptr, retval); break; \
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default: __put_user_bad(); \
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} \
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} while (0)
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#define __put_user_nocheck(x, ptr, size) \
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({ \
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long __pu_err; \
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__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
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if (!is_kernel_addr((unsigned long)__pu_addr)) \
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might_fault(); \
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__chk_user_ptr(ptr); \
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__put_user_size((x), __pu_addr, (size), __pu_err); \
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__pu_err; \
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})
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#define __put_user_check(x, ptr, size) \
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({ \
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long __pu_err = -EFAULT; \
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__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
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might_fault(); \
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if (access_ok(VERIFY_WRITE, __pu_addr, size)) \
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__put_user_size((x), __pu_addr, (size), __pu_err); \
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__pu_err; \
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})
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#define __put_user_nosleep(x, ptr, size) \
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({ \
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long __pu_err; \
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__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
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__chk_user_ptr(ptr); \
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__put_user_size((x), __pu_addr, (size), __pu_err); \
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__pu_err; \
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})
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extern long __get_user_bad(void);
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#define __get_user_asm(x, addr, err, op) \
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__asm__ __volatile__( \
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"1: "op" %1,0(%2) # get_user\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: li %0,%3\n" \
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" li %1,0\n" \
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" b 2b\n" \
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".previous\n" \
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EX_TABLE(1b, 3b) \
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: "=r" (err), "=r" (x) \
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: "b" (addr), "i" (-EFAULT), "0" (err))
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#ifdef __powerpc64__
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#define __get_user_asm2(x, addr, err) \
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__get_user_asm(x, addr, err, "ld")
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#else /* __powerpc64__ */
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#define __get_user_asm2(x, addr, err) \
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__asm__ __volatile__( \
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"1: lwz %1,0(%2)\n" \
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"2: lwz %1+1,4(%2)\n" \
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"3:\n" \
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".section .fixup,\"ax\"\n" \
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"4: li %0,%3\n" \
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" li %1,0\n" \
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" li %1+1,0\n" \
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" b 3b\n" \
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".previous\n" \
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EX_TABLE(1b, 4b) \
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EX_TABLE(2b, 4b) \
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: "=r" (err), "=&r" (x) \
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: "b" (addr), "i" (-EFAULT), "0" (err))
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#endif /* __powerpc64__ */
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#define __get_user_size(x, ptr, size, retval) \
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do { \
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retval = 0; \
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__chk_user_ptr(ptr); \
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if (size > sizeof(x)) \
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(x) = __get_user_bad(); \
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switch (size) { \
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case 1: __get_user_asm(x, ptr, retval, "lbz"); break; \
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case 2: __get_user_asm(x, ptr, retval, "lhz"); break; \
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case 4: __get_user_asm(x, ptr, retval, "lwz"); break; \
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case 8: __get_user_asm2(x, ptr, retval); break; \
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default: (x) = __get_user_bad(); \
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} \
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} while (0)
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#define __get_user_nocheck(x, ptr, size) \
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({ \
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long __gu_err; \
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unsigned long __gu_val; \
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__typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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__chk_user_ptr(ptr); \
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if (!is_kernel_addr((unsigned long)__gu_addr)) \
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might_fault(); \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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#define __get_user_check(x, ptr, size) \
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({ \
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long __gu_err = -EFAULT; \
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unsigned long __gu_val = 0; \
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const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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might_fault(); \
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if (access_ok(VERIFY_READ, __gu_addr, (size))) \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__force __typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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#define __get_user_nosleep(x, ptr, size) \
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({ \
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long __gu_err; \
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unsigned long __gu_val; \
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__typeof__(*(ptr)) __user *__gu_addr = (ptr); \
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__chk_user_ptr(ptr); \
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__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
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(x) = (__force __typeof__(*(ptr)))__gu_val; \
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__gu_err; \
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})
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/* more complex routines */
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extern unsigned long __copy_tofrom_user(void __user *to,
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const void __user *from, unsigned long size);
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#ifndef __powerpc64__
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static inline unsigned long copy_from_user(void *to,
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const void __user *from, unsigned long n)
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{
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if (likely(access_ok(VERIFY_READ, from, n))) {
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check_object_size(to, n, false);
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return __copy_tofrom_user((__force void __user *)to, from, n);
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}
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memset(to, 0, n);
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return n;
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}
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static inline unsigned long copy_to_user(void __user *to,
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const void *from, unsigned long n)
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{
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if (access_ok(VERIFY_WRITE, to, n)) {
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check_object_size(from, n, true);
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return __copy_tofrom_user(to, (__force void __user *)from, n);
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}
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return n;
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}
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#else /* __powerpc64__ */
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#define __copy_in_user(to, from, size) \
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__copy_tofrom_user((to), (from), (size))
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extern unsigned long copy_from_user(void *to, const void __user *from,
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unsigned long n);
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extern unsigned long copy_to_user(void __user *to, const void *from,
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unsigned long n);
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extern unsigned long copy_in_user(void __user *to, const void __user *from,
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unsigned long n);
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#endif /* __powerpc64__ */
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static inline unsigned long __copy_from_user_inatomic(void *to,
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const void __user *from, unsigned long n)
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{
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if (__builtin_constant_p(n) && (n <= 8)) {
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unsigned long ret = 1;
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switch (n) {
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case 1:
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__get_user_size(*(u8 *)to, from, 1, ret);
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break;
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case 2:
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__get_user_size(*(u16 *)to, from, 2, ret);
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break;
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case 4:
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__get_user_size(*(u32 *)to, from, 4, ret);
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break;
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case 8:
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__get_user_size(*(u64 *)to, from, 8, ret);
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break;
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}
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if (ret == 0)
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return 0;
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}
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check_object_size(to, n, false);
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return __copy_tofrom_user((__force void __user *)to, from, n);
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}
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static inline unsigned long __copy_to_user_inatomic(void __user *to,
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const void *from, unsigned long n)
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{
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if (__builtin_constant_p(n) && (n <= 8)) {
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unsigned long ret = 1;
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switch (n) {
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case 1:
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__put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
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break;
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case 2:
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__put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
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break;
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case 4:
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__put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
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break;
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case 8:
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__put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
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break;
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}
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if (ret == 0)
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return 0;
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}
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check_object_size(from, n, true);
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return __copy_tofrom_user(to, (__force const void __user *)from, n);
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}
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static inline unsigned long __copy_from_user(void *to,
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const void __user *from, unsigned long size)
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{
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might_fault();
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return __copy_from_user_inatomic(to, from, size);
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}
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static inline unsigned long __copy_to_user(void __user *to,
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const void *from, unsigned long size)
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{
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might_fault();
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return __copy_to_user_inatomic(to, from, size);
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}
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extern unsigned long __clear_user(void __user *addr, unsigned long size);
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static inline unsigned long clear_user(void __user *addr, unsigned long size)
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{
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might_fault();
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if (likely(access_ok(VERIFY_WRITE, addr, size)))
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return __clear_user(addr, size);
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return size;
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}
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extern long strncpy_from_user(char *dst, const char __user *src, long count);
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extern __must_check long strlen_user(const char __user *str);
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extern __must_check long strnlen_user(const char __user *str, long n);
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ARCH_POWERPC_UACCESS_H */
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