arm64: User access library functions
This patch add support for various user access functions. These functions use the standard LDR/STR instructions and not the LDRT/STRT variants in order to allow kernel addresses (after set_fs(KERNEL_DS)). Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Arnd Bergmann <arnd@arndb.de>hifive-unleashed-5.1
Catalin Marinas
parent
2c020ed8d1
commit
0aea86a217
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@ -0,0 +1,297 @@
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/*
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* Based on arch/arm/include/asm/uaccess.h
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*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_UACCESS_H
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#define __ASM_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/string.h>
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#include <linux/thread_info.h>
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#include <asm/ptrace.h>
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#include <asm/errno.h>
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#include <asm/memory.h>
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#include <asm/compiler.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 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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unsigned long insn, fixup;
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};
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extern int fixup_exception(struct pt_regs *regs);
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#define KERNEL_DS (-1UL)
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#define get_ds() (KERNEL_DS)
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#define USER_DS TASK_SIZE_64
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#define get_fs() (current_thread_info()->addr_limit)
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static inline void set_fs(mm_segment_t fs)
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{
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current_thread_info()->addr_limit = fs;
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}
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#define segment_eq(a,b) ((a) == (b))
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/*
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* Return 1 if addr < current->addr_limit, 0 otherwise.
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*/
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#define __addr_ok(addr) \
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({ \
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unsigned long flag; \
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asm("cmp %1, %0; cset %0, lo" \
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: "=&r" (flag) \
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: "r" (addr), "0" (current_thread_info()->addr_limit) \
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: "cc"); \
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flag; \
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})
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/*
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* Test whether a block of memory is a valid user space address.
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* Returns 1 if the range is valid, 0 otherwise.
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*
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* This is equivalent to the following test:
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* (u65)addr + (u65)size < (u65)current->addr_limit
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*
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* This needs 65-bit arithmetic.
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*/
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#define __range_ok(addr, size) \
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({ \
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unsigned long flag, roksum; \
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__chk_user_ptr(addr); \
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asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, cc" \
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: "=&r" (flag), "=&r" (roksum) \
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: "1" (addr), "Ir" (size), \
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"r" (current_thread_info()->addr_limit) \
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: "cc"); \
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flag; \
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})
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#define access_ok(type, addr, size) __range_ok(addr, size)
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/*
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* The "__xxx" versions of the user access functions do not verify the address
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* space - it must have been done previously with a separate "access_ok()"
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* call.
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*
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* The "__xxx_error" versions set the third argument to -EFAULT if an error
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* occurs, and leave it unchanged on success.
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*/
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#define __get_user_asm(instr, reg, x, addr, err) \
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asm volatile( \
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"1: " instr " " reg "1, [%2]\n" \
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"2:\n" \
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" .section .fixup, \"ax\"\n" \
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" .align 2\n" \
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"3: mov %w0, %3\n" \
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" mov %1, #0\n" \
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" b 2b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .quad 1b, 3b\n" \
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" .previous" \
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: "+r" (err), "=&r" (x) \
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: "r" (addr), "i" (-EFAULT))
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#define __get_user_err(x, ptr, err) \
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do { \
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unsigned long __gu_val; \
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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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__get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \
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break; \
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case 2: \
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__get_user_asm("ldrh", "%w", __gu_val, (ptr), (err)); \
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break; \
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case 4: \
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__get_user_asm("ldr", "%w", __gu_val, (ptr), (err)); \
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break; \
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case 8: \
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__get_user_asm("ldr", "%", __gu_val, (ptr), (err)); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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} while (0)
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#define __get_user(x, ptr) \
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({ \
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int __gu_err = 0; \
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__get_user_err((x), (ptr), __gu_err); \
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__gu_err; \
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})
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#define __get_user_error(x, ptr, err) \
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({ \
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__get_user_err((x), (ptr), (err)); \
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(void)0; \
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})
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#define __get_user_unaligned __get_user
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#define get_user(x, ptr) \
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({ \
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might_sleep(); \
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access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) ? \
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__get_user((x), (ptr)) : \
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((x) = 0, -EFAULT); \
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})
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#define __put_user_asm(instr, reg, x, addr, err) \
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asm volatile( \
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"1: " instr " " reg "1, [%2]\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .align 2\n" \
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"3: mov %w0, %3\n" \
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" b 2b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .quad 1b, 3b\n" \
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" .previous" \
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: "+r" (err) \
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: "r" (x), "r" (addr), "i" (-EFAULT))
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#define __put_user_err(x, ptr, err) \
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do { \
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__typeof__(*(ptr)) __pu_val = (x); \
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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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__put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \
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break; \
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case 2: \
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__put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \
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break; \
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case 4: \
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__put_user_asm("str", "%w", __pu_val, (ptr), (err)); \
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break; \
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case 8: \
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__put_user_asm("str", "%", __pu_val, (ptr), (err)); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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} while (0)
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#define __put_user(x, ptr) \
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({ \
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int __pu_err = 0; \
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__put_user_err((x), (ptr), __pu_err); \
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__pu_err; \
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})
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#define __put_user_error(x, ptr, err) \
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({ \
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__put_user_err((x), (ptr), (err)); \
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(void)0; \
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})
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#define __put_user_unaligned __put_user
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#define put_user(x, ptr) \
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({ \
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might_sleep(); \
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access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \
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__put_user((x), (ptr)) : \
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-EFAULT; \
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})
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extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
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extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
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extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
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extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
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extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
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extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
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static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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if (access_ok(VERIFY_READ, from, n))
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n = __copy_from_user(to, from, n);
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else /* security hole - plug it */
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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 __must_check copy_to_user(void __user *to, 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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n = __copy_to_user(to, from, n);
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return n;
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}
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static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)
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{
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if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
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n = __copy_in_user(to, from, n);
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return n;
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}
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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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static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
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{
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if (access_ok(VERIFY_WRITE, to, n))
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n = __clear_user(to, n);
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return n;
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}
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static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
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{
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long res = -EFAULT;
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if (access_ok(VERIFY_READ, src, 1))
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res = __strncpy_from_user(dst, src, count);
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return res;
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}
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#define strlen_user(s) strnlen_user(s, ~0UL >> 1)
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static inline long __must_check strnlen_user(const char __user *s, long n)
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{
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unsigned long res = 0;
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if (__addr_ok(s))
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res = __strnlen_user(s, n);
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return res;
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}
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#endif /* __ASM_UACCESS_H */
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@ -0,0 +1,58 @@
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/*
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* Based on arch/arm/lib/clear_user.S
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*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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.text
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/* Prototype: int __clear_user(void *addr, size_t sz)
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* Purpose : clear some user memory
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* Params : addr - user memory address to clear
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* : sz - number of bytes to clear
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* Returns : number of bytes NOT cleared
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*
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* Alignment fixed up by hardware.
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*/
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ENTRY(__clear_user)
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mov x2, x1 // save the size for fixup return
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subs x1, x1, #8
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b.mi 2f
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1:
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USER(9f, str xzr, [x0], #8 )
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subs x1, x1, #8
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b.pl 1b
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2: adds x1, x1, #4
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b.mi 3f
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USER(9f, str wzr, [x0], #4 )
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sub x1, x1, #4
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3: adds x1, x1, #2
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b.mi 4f
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USER(9f, strh wzr, [x0], #2 )
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sub x1, x1, #2
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4: adds x1, x1, #1
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b.mi 5f
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strb wzr, [x0]
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5: mov x0, #0
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ret
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ENDPROC(__clear_user)
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.section .fixup,"ax"
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.align 2
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9: mov x0, x2 // return the original size
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ret
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.previous
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@ -0,0 +1,66 @@
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/*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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/*
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* Copy from user space to a kernel buffer (alignment handled by the hardware)
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*
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* Parameters:
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* x0 - to
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* x1 - from
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* x2 - n
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* Returns:
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* x0 - bytes not copied
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*/
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ENTRY(__copy_from_user)
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add x4, x1, x2 // upper user buffer boundary
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subs x2, x2, #8
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b.mi 2f
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1:
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USER(9f, ldr x3, [x1], #8 )
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subs x2, x2, #8
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str x3, [x0], #8
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b.pl 1b
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2: adds x2, x2, #4
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b.mi 3f
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USER(9f, ldr w3, [x1], #4 )
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sub x2, x2, #4
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str w3, [x0], #4
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3: adds x2, x2, #2
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b.mi 4f
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USER(9f, ldrh w3, [x1], #2 )
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sub x2, x2, #2
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strh w3, [x0], #2
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4: adds x2, x2, #1
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b.mi 5f
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USER(9f, ldrb w3, [x1] )
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strb w3, [x0]
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5: mov x0, #0
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ret
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ENDPROC(__copy_from_user)
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.section .fixup,"ax"
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.align 2
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9: sub x2, x4, x1
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mov x3, x2
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10: strb wzr, [x0], #1 // zero remaining buffer space
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subs x3, x3, #1
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b.ne 10b
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mov x0, x2 // bytes not copied
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ret
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.previous
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@ -0,0 +1,63 @@
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/*
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* Copy from user space to user space
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*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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/*
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* Copy from user space to user space (alignment handled by the hardware)
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*
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* Parameters:
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* x0 - to
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* x1 - from
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* x2 - n
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* Returns:
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* x0 - bytes not copied
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*/
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ENTRY(__copy_in_user)
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add x4, x0, x2 // upper user buffer boundary
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subs x2, x2, #8
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b.mi 2f
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1:
|
||||
USER(9f, ldr x3, [x1], #8 )
|
||||
subs x2, x2, #8
|
||||
USER(9f, str x3, [x0], #8 )
|
||||
b.pl 1b
|
||||
2: adds x2, x2, #4
|
||||
b.mi 3f
|
||||
USER(9f, ldr w3, [x1], #4 )
|
||||
sub x2, x2, #4
|
||||
USER(9f, str w3, [x0], #4 )
|
||||
3: adds x2, x2, #2
|
||||
b.mi 4f
|
||||
USER(9f, ldrh w3, [x1], #2 )
|
||||
sub x2, x2, #2
|
||||
USER(9f, strh w3, [x0], #2 )
|
||||
4: adds x2, x2, #1
|
||||
b.mi 5f
|
||||
USER(9f, ldrb w3, [x1] )
|
||||
USER(9f, strb w3, [x0] )
|
||||
5: mov x0, #0
|
||||
ret
|
||||
ENDPROC(__copy_in_user)
|
||||
|
||||
.section .fixup,"ax"
|
||||
.align 2
|
||||
9: sub x0, x4, x0 // bytes not copied
|
||||
ret
|
||||
.previous
|
||||
|
|
@ -0,0 +1,61 @@
|
|||
/*
|
||||
* Copyright (C) 2012 ARM Ltd.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
#include <linux/linkage.h>
|
||||
#include <asm/assembler.h>
|
||||
|
||||
/*
|
||||
* Copy to user space from a kernel buffer (alignment handled by the hardware)
|
||||
*
|
||||
* Parameters:
|
||||
* x0 - to
|
||||
* x1 - from
|
||||
* x2 - n
|
||||
* Returns:
|
||||
* x0 - bytes not copied
|
||||
*/
|
||||
ENTRY(__copy_to_user)
|
||||
add x4, x0, x2 // upper user buffer boundary
|
||||
subs x2, x2, #8
|
||||
b.mi 2f
|
||||
1:
|
||||
ldr x3, [x1], #8
|
||||
subs x2, x2, #8
|
||||
USER(9f, str x3, [x0], #8 )
|
||||
b.pl 1b
|
||||
2: adds x2, x2, #4
|
||||
b.mi 3f
|
||||
ldr w3, [x1], #4
|
||||
sub x2, x2, #4
|
||||
USER(9f, str w3, [x0], #4 )
|
||||
3: adds x2, x2, #2
|
||||
b.mi 4f
|
||||
ldrh w3, [x1], #2
|
||||
sub x2, x2, #2
|
||||
USER(9f, strh w3, [x0], #2 )
|
||||
4: adds x2, x2, #1
|
||||
b.mi 5f
|
||||
ldrb w3, [x1]
|
||||
USER(9f, strb w3, [x0] )
|
||||
5: mov x0, #0
|
||||
ret
|
||||
ENDPROC(__copy_to_user)
|
||||
|
||||
.section .fixup,"ax"
|
||||
.align 2
|
||||
9: sub x0, x4, x0 // bytes not copied
|
||||
ret
|
||||
.previous
|
||||
|
|
@ -0,0 +1,50 @@
|
|||
/*
|
||||
* Based on arch/arm/lib/strncpy_from_user.S
|
||||
*
|
||||
* Copyright (C) 1995-2000 Russell King
|
||||
* Copyright (C) 2012 ARM Ltd.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
#include <linux/linkage.h>
|
||||
#include <asm/assembler.h>
|
||||
#include <asm/errno.h>
|
||||
|
||||
.text
|
||||
.align 5
|
||||
|
||||
/*
|
||||
* Copy a string from user space to kernel space.
|
||||
* x0 = dst, x1 = src, x2 = byte length
|
||||
* returns the number of characters copied (strlen of copied string),
|
||||
* -EFAULT on exception, or "len" if we fill the whole buffer
|
||||
*/
|
||||
ENTRY(__strncpy_from_user)
|
||||
mov x4, x1
|
||||
1: subs x2, x2, #1
|
||||
bmi 2f
|
||||
USER(9f, ldrb w3, [x1], #1 )
|
||||
strb w3, [x0], #1
|
||||
cbnz w3, 1b
|
||||
sub x1, x1, #1 // take NUL character out of count
|
||||
2: sub x0, x1, x4
|
||||
ret
|
||||
ENDPROC(__strncpy_from_user)
|
||||
|
||||
.section .fixup,"ax"
|
||||
.align 0
|
||||
9: strb wzr, [x0] // null terminate
|
||||
mov x0, #-EFAULT
|
||||
ret
|
||||
.previous
|
||||
|
|
@ -0,0 +1,47 @@
|
|||
/*
|
||||
* Based on arch/arm/lib/strnlen_user.S
|
||||
*
|
||||
* Copyright (C) 1995-2000 Russell King
|
||||
* Copyright (C) 2012 ARM Ltd.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
#include <linux/linkage.h>
|
||||
#include <asm/assembler.h>
|
||||
#include <asm/errno.h>
|
||||
|
||||
.text
|
||||
.align 5
|
||||
|
||||
/* Prototype: unsigned long __strnlen_user(const char *str, long n)
|
||||
* Purpose : get length of a string in user memory
|
||||
* Params : str - address of string in user memory
|
||||
* Returns : length of string *including terminator*
|
||||
* or zero on exception, or n if too long
|
||||
*/
|
||||
ENTRY(__strnlen_user)
|
||||
mov x2, x0
|
||||
1: subs x1, x1, #1
|
||||
b.mi 2f
|
||||
USER(9f, ldrb w3, [x0], #1 )
|
||||
cbnz w3, 1b
|
||||
2: sub x0, x0, x2
|
||||
ret
|
||||
ENDPROC(__strnlen_user)
|
||||
|
||||
.section .fixup,"ax"
|
||||
.align 0
|
||||
9: mov x0, #0
|
||||
ret
|
||||
.previous
|
||||
Loading…
Reference in New Issue