[PATCH v6 06/29] nios2: Memory management
From: Ley Foon Tan
Date: Mon Nov 03 2014 - 06:07:48 EST
This patch contains the initialisation of the memory blocks, MMU
attributes and the memory map.
Signed-off-by: Ley Foon Tan <lftan@xxxxxxxxxx>
---
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@xxxxxxxxxx>
+ * 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@xxxxxxxxxx>
+ * 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@xxxxxxxxxx>
+ * Copyright (C) 2009, Wind River Systems Inc
+ * Implemented by fredrik.markstrom@xxxxxxxxx and ivarholmqvist@xxxxxxxxx
+ *
+ * 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@xxxxxxxxxx>
+ * Copyright (C) 2009 Wind River Systems Inc
+ * Implemented by fredrik.markstrom@xxxxxxxxx and ivarholmqvist@xxxxxxxxx
+ * 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@xxxxxxxxx and ivarholmqvist@xxxxxxxxx
+ */
+
+#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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