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    Subject[PATCH v6 06/29] nios2: Memory management
    Date
    This patch contains the initialisation of the memory blocks, MMU
    attributes and the memory map.

    Signed-off-by: Ley Foon Tan <lftan@altera.com>
    ---
    arch/nios2/include/asm/mmu.h | 16 +++
    arch/nios2/include/asm/page.h | 111 +++++++++++++++++++
    arch/nios2/include/asm/uaccess.h | 231 +++++++++++++++++++++++++++++++++++++++
    arch/nios2/mm/init.c | 142 ++++++++++++++++++++++++
    arch/nios2/mm/uaccess.c | 163 +++++++++++++++++++++++++++
    5 files changed, 663 insertions(+)
    create mode 100644 arch/nios2/include/asm/mmu.h
    create mode 100644 arch/nios2/include/asm/page.h
    create mode 100644 arch/nios2/include/asm/uaccess.h
    create mode 100644 arch/nios2/mm/init.c
    create mode 100644 arch/nios2/mm/uaccess.c

    diff --git a/arch/nios2/include/asm/mmu.h b/arch/nios2/include/asm/mmu.h
    new file mode 100644
    index 0000000..d9c0b10
    --- /dev/null
    +++ b/arch/nios2/include/asm/mmu.h
    @@ -0,0 +1,16 @@
    +/*
    + * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
    + * Copyright (C) 2004 Microtronix Datacom Ltd.
    + *
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + */
    +
    +#ifndef _ASM_NIOS2_MMU_H
    +#define _ASM_NIOS2_MMU_H
    +
    +/* Default "unsigned long" context */
    +typedef unsigned long mm_context_t;
    +
    +#endif /* _ASM_NIOS2_MMU_H */
    diff --git a/arch/nios2/include/asm/page.h b/arch/nios2/include/asm/page.h
    new file mode 100644
    index 0000000..7a0d9bd
    --- /dev/null
    +++ b/arch/nios2/include/asm/page.h
    @@ -0,0 +1,111 @@
    +/*
    + * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
    + * Copyright (C) 2004 Microtronix Datacom Ltd.
    + *
    + * MMU support based on asm/page.h from mips which is:
    + *
    + * Copyright (C) 1994 - 1999, 2000, 03 Ralf Baechle
    + * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
    + *
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + */
    +
    +#ifndef _ASM_NIOS2_PAGE_H
    +#define _ASM_NIOS2_PAGE_H
    +
    +#include <linux/pfn.h>
    +#include <linux/const.h>
    +
    +/*
    + * PAGE_SHIFT determines the page size
    + */
    +#define PAGE_SHIFT 12
    +#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
    +#define PAGE_MASK (~(PAGE_SIZE - 1))
    +
    +/*
    + * PAGE_OFFSET -- the first address of the first page of memory.
    + */
    +#define PAGE_OFFSET \
    + (CONFIG_NIOS2_MEM_BASE + CONFIG_NIOS2_KERNEL_REGION_BASE)
    +
    +#ifndef __ASSEMBLY__
    +
    +/*
    + * This gives the physical RAM offset.
    + */
    +#define PHYS_OFFSET CONFIG_NIOS2_MEM_BASE
    +
    +/*
    + * It's normally defined only for FLATMEM config but it's
    + * used in our early mem init code for all memory models.
    + * So always define it.
    + */
    +#define ARCH_PFN_OFFSET PFN_UP(PHYS_OFFSET)
    +
    +#define clear_page(page) memset((page), 0, PAGE_SIZE)
    +#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
    +
    +struct page;
    +
    +extern void clear_user_page(void *addr, unsigned long vaddr, struct page *page);
    +extern void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
    + struct page *to);
    +
    +extern unsigned long shm_align_mask;
    +
    +/*
    + * These are used to make use of C type-checking.
    + */
    +typedef struct page *pgtable_t;
    +typedef struct { unsigned long pte; } pte_t;
    +typedef struct { unsigned long pgd; } pgd_t;
    +typedef struct { unsigned long pgprot; } pgprot_t;
    +
    +#define pte_val(x) ((x).pte)
    +#define pgd_val(x) ((x).pgd)
    +#define pgprot_val(x) ((x).pgprot)
    +
    +#define __pte(x) ((pte_t) { (x) })
    +#define __pgd(x) ((pgd_t) { (x) })
    +#define __pgprot(x) ((pgprot_t) { (x) })
    +
    +extern unsigned long memory_start;
    +extern unsigned long memory_end;
    +extern unsigned long memory_size;
    +
    +extern struct page *mem_map;
    +
    +#endif /* !__ASSEMBLY__ */
    +
    +# define __pa(x) \
    + ((unsigned long)(x) - PAGE_OFFSET + PHYS_OFFSET)
    +# define __va(x) \
    + ((void *)((unsigned long)(x) + PAGE_OFFSET - PHYS_OFFSET))
    +
    +#define page_to_virt(page) \
    + ((((page) - mem_map) << PAGE_SHIFT) + PAGE_OFFSET)
    +
    +# define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
    +# define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && \
    + (pfn) < max_mapnr)
    +
    +# define virt_to_page(vaddr) pfn_to_page(PFN_DOWN(virt_to_phys(vaddr)))
    +# define virt_addr_valid(vaddr) pfn_valid(PFN_DOWN(virt_to_phys(vaddr)))
    +
    +# define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | \
    + VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
    +
    +# define UNCAC_ADDR(addr) \
    + ((void *)((unsigned)(addr) | CONFIG_NIOS2_IO_REGION_BASE))
    +# define CAC_ADDR(addr) \
    + ((void *)(((unsigned)(addr) & ~CONFIG_NIOS2_IO_REGION_BASE) | \
    + CONFIG_NIOS2_KERNEL_REGION_BASE))
    +
    +#include <asm-generic/memory_model.h>
    +
    +#include <asm-generic/getorder.h>
    +
    +#endif /* _ASM_NIOS2_PAGE_H */
    diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h
    new file mode 100644
    index 0000000..acedc0a
    --- /dev/null
    +++ b/arch/nios2/include/asm/uaccess.h
    @@ -0,0 +1,231 @@
    +/*
    + * User space memory access functions for Nios II
    + *
    + * Copyright (C) 2010-2011, Tobias Klauser <tklauser@distanz.ch>
    + * Copyright (C) 2009, Wind River Systems Inc
    + * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
    + *
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + */
    +
    +#ifndef _ASM_NIOS2_UACCESS_H
    +#define _ASM_NIOS2_UACCESS_H
    +
    +#include <linux/errno.h>
    +#include <linux/thread_info.h>
    +#include <linux/string.h>
    +
    +#include <asm/page.h>
    +
    +#define VERIFY_READ 0
    +#define VERIFY_WRITE 1
    +
    +/*
    + * 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;
    + unsigned long fixup;
    +};
    +
    +extern int fixup_exception(struct pt_regs *regs);
    +
    +/*
    + * Segment stuff
    + */
    +#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
    +#define USER_DS MAKE_MM_SEG(0x80000000UL)
    +#define KERNEL_DS MAKE_MM_SEG(0)
    +
    +#define get_ds() (KERNEL_DS)
    +
    +#define get_fs() (current_thread_info()->addr_limit)
    +#define set_fs(seg) (current_thread_info()->addr_limit = (seg))
    +
    +#define segment_eq(a, b) ((a).seg == (b).seg)
    +
    +#define __access_ok(addr, len) \
    + (((signed long)(((long)get_fs().seg) & \
    + ((long)(addr) | (((long)(addr)) + (len)) | (len)))) == 0)
    +
    +#define access_ok(type, addr, len) \
    + likely(__access_ok((unsigned long)(addr), (unsigned long)(len)))
    +
    +# define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n"
    +
    +/*
    + * Zero Userspace
    + */
    +
    +static inline unsigned long __must_check __clear_user(void __user *to,
    + unsigned long n)
    +{
    + __asm__ __volatile__ (
    + "1: stb zero, 0(%1)\n"
    + " addi %0, %0, -1\n"
    + " addi %1, %1, 1\n"
    + " bne %0, zero, 1b\n"
    + "2:\n"
    + __EX_TABLE_SECTION
    + ".word 1b, 2b\n"
    + ".previous\n"
    + : "=r" (n), "=r" (to)
    + : "0" (n), "1" (to)
    + );
    +
    + return n;
    +}
    +
    +static inline unsigned long __must_check clear_user(void __user *to,
    + unsigned long n)
    +{
    + if (!access_ok(VERIFY_WRITE, to, n))
    + return n;
    + return __clear_user(to, n);
    +}
    +
    +extern long __copy_from_user(void *to, const void __user *from,
    + unsigned long n);
    +extern long __copy_to_user(void __user *to, const void *from, unsigned long n);
    +
    +static inline long copy_from_user(void *to, const void __user *from,
    + unsigned long n)
    +{
    + if (!access_ok(VERIFY_READ, from, n))
    + return n;
    + return __copy_from_user(to, from, n);
    +}
    +
    +static inline long copy_to_user(void __user *to, const void *from,
    + unsigned long n)
    +{
    + if (!access_ok(VERIFY_WRITE, to, n))
    + return n;
    + return __copy_to_user(to, from, n);
    +}
    +
    +extern long strncpy_from_user(char *__to, const char __user *__from,
    + long __len);
    +extern long strnlen_user(const char __user *s, long n);
    +
    +#define __copy_from_user_inatomic __copy_from_user
    +#define __copy_to_user_inatomic __copy_to_user
    +
    +/* Optimized macros */
    +#define __get_user_asm(val, insn, addr, err) \
    +{ \
    + __asm__ __volatile__( \
    + " movi %0, %3\n" \
    + "1: " insn " %1, 0(%2)\n" \
    + " movi %0, 0\n" \
    + "2:\n" \
    + " .section __ex_table,\"a\"\n" \
    + " .word 1b, 2b\n" \
    + " .previous" \
    + : "=&r" (err), "=r" (val) \
    + : "r" (addr), "i" (-EFAULT)); \
    +}
    +
    +#define __get_user_unknown(val, size, ptr, err) do { \
    + err = 0; \
    + if (copy_from_user(&(val), ptr, size)) { \
    + err = -EFAULT; \
    + } \
    + } while (0)
    +
    +#define __get_user_common(val, size, ptr, err) \
    +do { \
    + switch (size) { \
    + case 1: \
    + __get_user_asm(val, "ldbu", ptr, err); \
    + break; \
    + case 2: \
    + __get_user_asm(val, "ldhu", ptr, err); \
    + break; \
    + case 4: \
    + __get_user_asm(val, "ldw", ptr, err); \
    + break; \
    + default: \
    + __get_user_unknown(val, size, ptr, err); \
    + break; \
    + } \
    +} while (0)
    +
    +#define __get_user(x, ptr) \
    + ({ \
    + long __gu_err = -EFAULT; \
    + const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
    + unsigned long __gu_val; \
    + __get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\
    + (x) = (__typeof__(x))__gu_val; \
    + __gu_err; \
    + })
    +
    +#define get_user(x, ptr) \
    +({ \
    + long __gu_err = -EFAULT; \
    + const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
    + unsigned long __gu_val = 0; \
    + if (access_ok(VERIFY_READ, __gu_ptr, sizeof(*__gu_ptr))) \
    + __get_user_common(__gu_val, sizeof(*__gu_ptr), \
    + __gu_ptr, __gu_err); \
    + (x) = (__typeof__(x))__gu_val; \
    + __gu_err; \
    +})
    +
    +#define __put_user_asm(val, insn, ptr, err) \
    +{ \
    + __asm__ __volatile__( \
    + " movi %0, %3\n" \
    + "1: " insn " %1, 0(%2)\n" \
    + " movi %0, 0\n" \
    + "2:\n" \
    + " .section __ex_table,\"a\"\n" \
    + " .word 1b, 2b\n" \
    + " .previous\n" \
    + : "=&r" (err) \
    + : "r" (val), "r" (ptr), "i" (-EFAULT)); \
    +}
    +
    +#define put_user(x, ptr) \
    +({ \
    + long __pu_err = -EFAULT; \
    + __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \
    + __typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x); \
    + if (access_ok(VERIFY_WRITE, __pu_ptr, sizeof(*__pu_ptr))) { \
    + switch (sizeof(*__pu_ptr)) { \
    + case 1: \
    + __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \
    + break; \
    + case 2: \
    + __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \
    + break; \
    + case 4: \
    + __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \
    + break; \
    + default: \
    + /* XXX: This looks wrong... */ \
    + __pu_err = 0; \
    + if (copy_to_user(__pu_ptr, &(__pu_val), \
    + sizeof(*__pu_ptr))) \
    + __pu_err = -EFAULT; \
    + break; \
    + } \
    + } \
    + __pu_err; \
    +})
    +
    +#define __put_user(x, ptr) put_user(x, ptr)
    +
    +#endif /* _ASM_NIOS2_UACCESS_H */
    diff --git a/arch/nios2/mm/init.c b/arch/nios2/mm/init.c
    new file mode 100644
    index 0000000..e75c75d
    --- /dev/null
    +++ b/arch/nios2/mm/init.c
    @@ -0,0 +1,142 @@
    +/*
    + * Copyright (C) 2013 Altera Corporation
    + * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
    + * Copyright (C) 2009 Wind River Systems Inc
    + * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
    + * Copyright (C) 2004 Microtronix Datacom Ltd
    + *
    + * based on arch/m68k/mm/init.c
    + *
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + */
    +
    +#include <linux/signal.h>
    +#include <linux/sched.h>
    +#include <linux/kernel.h>
    +#include <linux/errno.h>
    +#include <linux/string.h>
    +#include <linux/types.h>
    +#include <linux/ptrace.h>
    +#include <linux/mman.h>
    +#include <linux/mm.h>
    +#include <linux/init.h>
    +#include <linux/pagemap.h>
    +#include <linux/bootmem.h>
    +#include <linux/slab.h>
    +#include <linux/binfmts.h>
    +
    +#include <asm/setup.h>
    +#include <asm/page.h>
    +#include <asm/pgtable.h>
    +#include <asm/sections.h>
    +#include <asm/tlb.h>
    +#include <asm/mmu_context.h>
    +#include <asm/cpuinfo.h>
    +#include <asm/processor.h>
    +
    +pgd_t *pgd_current;
    +
    +/*
    + * paging_init() continues the virtual memory environment setup which
    + * was begun by the code in arch/head.S.
    + * The parameters are pointers to where to stick the starting and ending
    + * addresses of available kernel virtual memory.
    + */
    +void __init paging_init(void)
    +{
    + unsigned long zones_size[MAX_NR_ZONES];
    +
    + memset(zones_size, 0, sizeof(zones_size));
    +
    + pagetable_init();
    + pgd_current = swapper_pg_dir;
    +
    + zones_size[ZONE_NORMAL] = max_mapnr;
    +
    + /* pass the memory from the bootmem allocator to the main allocator */
    + free_area_init(zones_size);
    +
    + flush_dcache_range((unsigned long)empty_zero_page,
    + (unsigned long)empty_zero_page + PAGE_SIZE);
    +}
    +
    +void __init mem_init(void)
    +{
    + unsigned long end_mem = memory_end; /* this must not include
    + kernel stack at top */
    +
    + pr_debug("mem_init: start=%lx, end=%lx\n", memory_start, memory_end);
    +
    + end_mem &= PAGE_MASK;
    + high_memory = __va(end_mem);
    +
    + /* this will put all memory onto the freelists */
    + free_all_bootmem();
    + mem_init_print_info(NULL);
    +}
    +
    +void __init mmu_init(void)
    +{
    + flush_tlb_all();
    +}
    +
    +#ifdef CONFIG_BLK_DEV_INITRD
    +void __init free_initrd_mem(unsigned long start, unsigned long end)
    +{
    + free_reserved_area((void *)start, (void *)end, -1, "initrd");
    +}
    +#endif
    +
    +void __init_refok free_initmem(void)
    +{
    + free_initmem_default(-1);
    +}
    +
    +#define __page_aligned(order) __aligned(PAGE_SIZE << (order))
    +pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned(PGD_ORDER);
    +pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned(PTE_ORDER);
    +static struct page *kuser_page[1];
    +
    +static int alloc_kuser_page(void)
    +{
    + extern char __kuser_helper_start[], __kuser_helper_end[];
    + int kuser_sz = __kuser_helper_end - __kuser_helper_start;
    + unsigned long vpage;
    +
    + vpage = get_zeroed_page(GFP_ATOMIC);
    + if (!vpage)
    + return -ENOMEM;
    +
    + /* Copy kuser helpers */
    + memcpy((void *)vpage, __kuser_helper_start, kuser_sz);
    +
    + flush_icache_range(vpage, vpage + KUSER_SIZE);
    + kuser_page[0] = virt_to_page(vpage);
    +
    + return 0;
    +}
    +arch_initcall(alloc_kuser_page);
    +
    +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
    +{
    + struct mm_struct *mm = current->mm;
    + int ret;
    +
    + down_write(&mm->mmap_sem);
    +
    + /* Map kuser helpers to user space address */
    + ret = install_special_mapping(mm, KUSER_BASE, KUSER_SIZE,
    + VM_READ | VM_EXEC | VM_MAYREAD |
    + VM_MAYEXEC, kuser_page);
    +
    + up_write(&mm->mmap_sem);
    +
    + return ret;
    +}
    +
    +const char *arch_vma_name(struct vm_area_struct *vma)
    +{
    + return (vma->vm_start == KUSER_BASE) ? "[kuser]" : NULL;
    +}
    diff --git a/arch/nios2/mm/uaccess.c b/arch/nios2/mm/uaccess.c
    new file mode 100644
    index 0000000..7663e15
    --- /dev/null
    +++ b/arch/nios2/mm/uaccess.c
    @@ -0,0 +1,163 @@
    +/*
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + *
    + * Copyright (C) 2009, Wind River Systems Inc
    + * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
    + */
    +
    +#include <linux/export.h>
    +#include <linux/uaccess.h>
    +
    +asm(".global __copy_from_user\n"
    + " .type __copy_from_user, @function\n"
    + "__copy_from_user:\n"
    + " movi r2,7\n"
    + " mov r3,r4\n"
    + " bge r2,r6,1f\n"
    + " xor r2,r4,r5\n"
    + " andi r2,r2,3\n"
    + " movi r7,3\n"
    + " beq r2,zero,4f\n"
    + "1: addi r6,r6,-1\n"
    + " movi r2,-1\n"
    + " beq r6,r2,3f\n"
    + " mov r7,r2\n"
    + "2: ldbu r2,0(r5)\n"
    + " addi r6,r6,-1\n"
    + " addi r5,r5,1\n"
    + " stb r2,0(r3)\n"
    + " addi r3,r3,1\n"
    + " bne r6,r7,2b\n"
    + "3:\n"
    + " addi r2,r6,1\n"
    + " ret\n"
    + "13:mov r2,r6\n"
    + " ret\n"
    + "4: andi r2,r4,1\n"
    + " cmpeq r2,r2,zero\n"
    + " beq r2,zero,7f\n"
    + "5: andi r2,r3,2\n"
    + " beq r2,zero,6f\n"
    + "9: ldhu r2,0(r5)\n"
    + " addi r6,r6,-2\n"
    + " addi r5,r5,2\n"
    + " sth r2,0(r3)\n"
    + " addi r3,r3,2\n"
    + "6: bge r7,r6,1b\n"
    + "10:ldw r2,0(r5)\n"
    + " addi r6,r6,-4\n"
    + " addi r5,r5,4\n"
    + " stw r2,0(r3)\n"
    + " addi r3,r3,4\n"
    + " br 6b\n"
    + "7: ldbu r2,0(r5)\n"
    + " addi r6,r6,-1\n"
    + " addi r5,r5,1\n"
    + " addi r3,r4,1\n"
    + " stb r2,0(r4)\n"
    + " br 5b\n"
    + ".section __ex_table,\"a\"\n"
    + ".word 2b,3b\n"
    + ".word 9b,13b\n"
    + ".word 10b,13b\n"
    + ".word 7b,13b\n"
    + ".previous\n"
    + );
    +EXPORT_SYMBOL(__copy_from_user);
    +
    +asm(
    + " .global __copy_to_user\n"
    + " .type __copy_to_user, @function\n"
    + "__copy_to_user:\n"
    + " movi r2,7\n"
    + " mov r3,r4\n"
    + " bge r2,r6,1f\n"
    + " xor r2,r4,r5\n"
    + " andi r2,r2,3\n"
    + " movi r7,3\n"
    + " beq r2,zero,4f\n"
    + /* Bail if we try to copy zero bytes */
    + "1: addi r6,r6,-1\n"
    + " movi r2,-1\n"
    + " beq r6,r2,3f\n"
    + /* Copy byte by byte for small copies and if src^dst != 0 */
    + " mov r7,r2\n"
    + "2: ldbu r2,0(r5)\n"
    + " addi r5,r5,1\n"
    + "9: stb r2,0(r3)\n"
    + " addi r6,r6,-1\n"
    + " addi r3,r3,1\n"
    + " bne r6,r7,2b\n"
    + "3: addi r2,r6,1\n"
    + " ret\n"
    + "13:mov r2,r6\n"
    + " ret\n"
    + /* If 'to' is an odd address byte copy */
    + "4: andi r2,r4,1\n"
    + " cmpeq r2,r2,zero\n"
    + " beq r2,zero,7f\n"
    + /* If 'to' is not divideable by four copy halfwords */
    + "5: andi r2,r3,2\n"
    + " beq r2,zero,6f\n"
    + " ldhu r2,0(r5)\n"
    + " addi r5,r5,2\n"
    + "10:sth r2,0(r3)\n"
    + " addi r6,r6,-2\n"
    + " addi r3,r3,2\n"
    + /* Copy words */
    + "6: bge r7,r6,1b\n"
    + " ldw r2,0(r5)\n"
    + " addi r5,r5,4\n"
    + "11:stw r2,0(r3)\n"
    + " addi r6,r6,-4\n"
    + " addi r3,r3,4\n"
    + " br 6b\n"
    + /* Copy remaining bytes */
    + "7: ldbu r2,0(r5)\n"
    + " addi r5,r5,1\n"
    + " addi r3,r4,1\n"
    + "12: stb r2,0(r4)\n"
    + " addi r6,r6,-1\n"
    + " br 5b\n"
    + ".section __ex_table,\"a\"\n"
    + ".word 9b,3b\n"
    + ".word 10b,13b\n"
    + ".word 11b,13b\n"
    + ".word 12b,13b\n"
    + ".previous\n");
    +EXPORT_SYMBOL(__copy_to_user);
    +
    +long strncpy_from_user(char *__to, const char __user *__from, long __len)
    +{
    + int l = strnlen_user(__from, __len);
    + int is_zt = 1;
    +
    + if (l > __len) {
    + is_zt = 0;
    + l = __len;
    + }
    +
    + if (l == 0 || copy_from_user(__to, __from, l))
    + return -EFAULT;
    +
    + if (is_zt)
    + l--;
    + return l;
    +}
    +
    +long strnlen_user(const char __user *s, long n)
    +{
    + long i;
    +
    + for (i = 0; i < n; i++) {
    + char c;
    +
    + if (get_user(c, s + i) == -EFAULT)
    + return 0;
    + if (c == 0)
    + return i + 1;
    + }
    + return n + 1;
    +}
    --
    1.8.2.1


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      Last update: 2014-11-03 12:41    [W:3.265 / U:0.460 seconds]
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