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.dea...@arm.com> Signed-off-by: Marc Zyngier <marc.zyng...@arm.com> Signed-off-by: Catalin Marinas <catalin.mari...@arm.com> --- arch/arm64/include/asm/uaccess.h | 377 ++++++++++++++++++++++++++++++++++++ arch/arm64/lib/clear_user.S | 58 ++++++ arch/arm64/lib/copy_from_user.S | 66 +++++++ arch/arm64/lib/copy_in_user.S | 63 ++++++ arch/arm64/lib/copy_to_user.S | 61 ++++++ arch/arm64/lib/getuser.S | 75 +++++++ arch/arm64/lib/putuser.S | 73 +++++++ arch/arm64/lib/strncpy_from_user.S | 50 +++++ arch/arm64/lib/strnlen_user.S | 47 +++++ 9 files changed, 870 insertions(+), 0 deletions(-) create mode 100644 arch/arm64/include/asm/uaccess.h create mode 100644 arch/arm64/lib/clear_user.S create mode 100644 arch/arm64/lib/copy_from_user.S create mode 100644 arch/arm64/lib/copy_in_user.S create mode 100644 arch/arm64/lib/copy_to_user.S create mode 100644 arch/arm64/lib/getuser.S create mode 100644 arch/arm64/lib/putuser.S create mode 100644 arch/arm64/lib/strncpy_from_user.S create mode 100644 arch/arm64/lib/strnlen_user.S diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h new file mode 100644 index 0000000..09d7b53 --- /dev/null +++ b/arch/arm64/include/asm/uaccess.h @@ -0,0 +1,377 @@ +/* + * Based on arch/arm/include/asm/uaccess.h + * + * 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/>. + */ +#ifndef __ASM_UACCESS_H +#define __ASM_UACCESS_H + +/* + * User space memory access functions + */ +#include <linux/string.h> +#include <linux/thread_info.h> + +#include <asm/ptrace.h> +#include <asm/errno.h> +#include <asm/memory.h> +#include <asm/compiler.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, fixup; +}; + +extern int fixup_exception(struct pt_regs *regs); + +/* + * These two are intentionally not defined anywhere - if the kernel + * code generates any references to them, that's a bug. + */ +extern long __get_user_bad(void); +extern long __put_user_bad(void); + +#define KERNEL_DS (-1UL) +#define get_ds() (KERNEL_DS) + +#define USER_DS TASK_SIZE_64 +#define get_fs() (current_thread_info()->addr_limit) + +static inline void set_fs(mm_segment_t fs) +{ + current_thread_info()->addr_limit = fs; +} + +#define segment_eq(a,b) ((a) == (b)) + +/* + * Return 1 if addr < current->addr_limit, 0 otherwise. + */ +#define __addr_ok(addr) \ +({ \ + unsigned long flag; \ + asm("cmp %1, %0; cset %0, lo" \ + : "=&r" (flag) \ + : "r" (addr), "0" (current_thread_info()->addr_limit) \ + : "cc"); \ + flag; \ +}) + +/* + * Test whether a block of memory is a valid user space address. + * Returns 1 if the range is valid, 0 otherwise. + * + * This is equivalent to the following test: + * (u65)addr + (u65)size < (u65)current->addr_limit + * + * This needs 65-bit arithmetic. + */ +#define __range_ok(addr,size) \ +({ \ + unsigned long flag, roksum; \ + __chk_user_ptr(addr); \ + asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, cc" \ + : "=&r" (flag), "=&r" (roksum) \ + : "1" (addr), "Ir" (size), \ + "r" (current_thread_info()->addr_limit) \ + : "cc"); \ + flag; \ +}) + +/* + * Single-value transfer routines. They automatically use the right + * size if we just have the right pointer type. Note that the functions + * which read from user space (*get_*) need to take care not to leak + * kernel data even if the calling code is buggy and fails to check + * the return value. This means zeroing out the destination variable + * or buffer on error. Normally this is done out of line by the + * fixup code, but there are a few places where it intrudes on the + * main code path. When we only write to user space, there is no + * problem. + */ +extern long __get_user_1(void *); +extern long __get_user_2(void *); +extern long __get_user_4(void *); +extern long __get_user_8(void *); + +#define __get_user_x(__r2,__p,__e,__s,__i...) \ + asm volatile( \ + __asmeq("%0", "x0") __asmeq("%1", "x2") \ + "bl __get_user_" #__s \ + : "=&r" (__e), "=r" (__r2) \ + : "0" (__p) \ + : __i, "cc") + +#define get_user(x,p) \ + ({ \ + register const typeof(*(p)) __user *__p asm("x0") = (p);\ + register unsigned long __r2 asm("x2"); \ + register long __e asm("x0"); \ + switch (sizeof(*(__p))) { \ + case 1: \ + __get_user_x(__r2, __p, __e, 1, "x30"); \ + break; \ + case 2: \ + __get_user_x(__r2, __p, __e, 2, "x3", "x30"); \ + break; \ + case 4: \ + __get_user_x(__r2, __p, __e, 4, "x30"); \ + break; \ + case 8: \ + __get_user_x(__r2, __p, __e, 8, "x30"); \ + break; \ + default: __e = __get_user_bad(); break; \ + } \ + x = (typeof(*(p))) __r2; \ + __e; \ + }) + +#define __get_user_unaligned __get_user + +extern long __put_user_1(void *, unsigned long); +extern long __put_user_2(void *, unsigned long); +extern long __put_user_4(void *, unsigned long); +extern long __put_user_8(void *, unsigned long); + +#define __put_user_x(__r2,__p,__e,__s) \ + asm volatile( \ + __asmeq("%0", "x0") __asmeq("%2", "x2") \ + "bl __put_user_" #__s \ + : "=&r" (__e) \ + : "0" (__p), "r" (__r2) \ + : "x8", "x30", "cc") + +#define put_user(x,p) \ + ({ \ + register const typeof(*(p)) __r2 asm("x2") = (x); \ + register const typeof(*(p)) __user *__p asm("x0") = (p);\ + register long __e asm("x0"); \ + switch (sizeof(*(__p))) { \ + case 1: \ + __put_user_x(__r2, __p, __e, 1); \ + break; \ + case 2: \ + __put_user_x(__r2, __p, __e, 2); \ + break; \ + case 4: \ + __put_user_x(__r2, __p, __e, 4); \ + break; \ + case 8: \ + __put_user_x(__r2, __p, __e, 8); \ + break; \ + default: __e = __put_user_bad(); break; \ + } \ + __e; \ + }) + +#define __put_user_unaligned __put_user + +#define access_ok(type,addr,size) __range_ok(addr,size) + +/* + * The "__xxx" versions of the user access functions do not verify the + * address space - it must have been done previously with a separate + * "access_ok()" call. + * + * The "xxx_error" versions set the third argument to EFAULT if an + * error occurs, and leave it unchanged on success. Note that these + * versions are void (ie, don't return a value as such). + */ +#define __get_user(x,ptr) \ +({ \ + long __gu_err = 0; \ + __get_user_err((x),(ptr),__gu_err); \ + __gu_err; \ +}) + +#define __get_user_error(x,ptr,err) \ +({ \ + __get_user_err((x),(ptr),err); \ + (void) 0; \ +}) + +#define __get_user_err(x,ptr,err) \ +do { \ + unsigned long __gu_addr = (unsigned long)(ptr); \ + unsigned long __gu_val; \ + __chk_user_ptr(ptr); \ + switch (sizeof(*(ptr))) { \ + case 1: \ + __get_user_asm("ldrb", "%w", __gu_val, __gu_addr, err); \ + break; \ + case 2: \ + __get_user_asm("ldrh", "%w", __gu_val, __gu_addr, err); \ + break; \ + case 4: \ + __get_user_asm("ldr", "%w", __gu_val, __gu_addr, err); \ + break; \ + case 8: \ + __get_user_asm("ldr", "%", __gu_val, __gu_addr, err); \ + break; \ + default: \ + (__gu_val) = __get_user_bad(); \ + } \ + (x) = (__typeof__(*(ptr)))__gu_val; \ +} while (0) + +#define __get_user_asm(instr, reg, x, addr, err) \ + asm volatile( \ + "1: " instr " " reg "1, [%2]\n" \ + "2:\n" \ + " .section .fixup, \"ax\"\n" \ + " .align 2\n" \ + "3: mov %0, %3\n" \ + " mov %1, #0\n" \ + " b 2b\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .align 3\n" \ + " .quad 1b, 3b\n" \ + " .previous" \ + : "+r" (err), "=&r" (x) \ + : "r" (addr), "i" (-EFAULT) \ + : "cc") + +#define __put_user(x,ptr) \ +({ \ + long __pu_err = 0; \ + __put_user_err((x),(ptr),__pu_err); \ + __pu_err; \ +}) + +#define __put_user_error(x,ptr,err) \ +({ \ + __put_user_err((x),(ptr),err); \ + (void) 0; \ +}) + +#define __put_user_err(x,ptr,err) \ +do { \ + unsigned long __pu_addr = (unsigned long)(ptr); \ + __typeof__(*(ptr)) __pu_val = (x); \ + __chk_user_ptr(ptr); \ + switch (sizeof(*(ptr))) { \ + case 1: \ + __put_user_asm("strb", "%w", __pu_val, __pu_addr, err); \ + break; \ + case 2: \ + __put_user_asm("strh", "%w", __pu_val, __pu_addr, err); \ + break; \ + case 4: \ + __put_user_asm("str", "%w", __pu_val, __pu_addr, err); \ + break; \ + case 8: \ + __put_user_asm("str", "%", __pu_val, __pu_addr, err); \ + break; \ + default: \ + __put_user_bad(); \ + } \ +} while (0) + +#define __put_user_asm(instr, reg, x, __pu_addr, err) \ + asm volatile( \ + "1: " instr " " reg "1, [%2]\n" \ + "2:\n" \ + " .section .fixup,\"ax\"\n" \ + " .align 2\n" \ + "3: mov %0, %3\n" \ + " b 2b\n" \ + " .previous\n" \ + " .section __ex_table,\"a\"\n" \ + " .align 3\n" \ + " .quad 1b, 3b\n" \ + " .previous" \ + : "+r" (err) \ + : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \ + : "cc") + +extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); +extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); +extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n); +extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); + +extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count); +extern unsigned long __must_check __strnlen_user(const char __user *s, long n); + +static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) +{ + if (access_ok(VERIFY_READ, from, n)) + n = __copy_from_user(to, from, n); + else /* security hole - plug it */ + memset(to, 0, n); + return n; +} + +static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) +{ + if (access_ok(VERIFY_WRITE, to, n)) + n = __copy_to_user(to, from, n); + return n; +} + +static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n) +{ + if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n)) + n = __copy_in_user(to, from, n); + return n; +} + +#define __copy_to_user_inatomic __copy_to_user +#define __copy_from_user_inatomic __copy_from_user + +static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) +{ + if (access_ok(VERIFY_WRITE, to, n)) + n = __clear_user(to, n); + return n; +} + +static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count) +{ + long res = -EFAULT; + if (access_ok(VERIFY_READ, src, 1)) + res = __strncpy_from_user(dst, src, count); + return res; +} + +#define strlen_user(s) strnlen_user(s, ~0UL >> 1) + +static inline long __must_check strnlen_user(const char __user *s, long n) +{ + unsigned long res = 0; + + if (__addr_ok(s)) + res = __strnlen_user(s, n); + + return res; +} + +#endif /* __ASM_UACCESS_H */ diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S new file mode 100644 index 0000000..6e0ed93 --- /dev/null +++ b/arch/arm64/lib/clear_user.S @@ -0,0 +1,58 @@ +/* + * Based on arch/arm/lib/clear_user.S + * + * 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> + + .text + +/* Prototype: int __clear_user(void *addr, size_t sz) + * Purpose : clear some user memory + * Params : addr - user memory address to clear + * : sz - number of bytes to clear + * Returns : number of bytes NOT cleared + * + * Alignment fixed up by hardware. + */ +ENTRY(__clear_user) + mov x2, x1 // save the size for fixup return + subs x1, x1, #8 + b.mi 2f +1: +USER(9f, str xzr, [x0], #8 ) + subs x1, x1, #8 + b.pl 1b +2: adds x1, x1, #4 + b.mi 3f +USER(9f, str wzr, [x0], #4 ) + sub x1, x1, #4 +3: adds x1, x1, #2 + b.mi 4f +USER(9f, strh wzr, [x0], #2 ) + sub x1, x1, #2 +4: adds x1, x1, #1 + b.mi 5f + strb wzr, [x0] +5: mov x0, #0 + ret +ENDPROC(__clear_user) + + .section .fixup,"ax" + .align 2 +9: mov x0, x2 // return the original size + ret + .previous diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S new file mode 100644 index 0000000..5e27add --- /dev/null +++ b/arch/arm64/lib/copy_from_user.S @@ -0,0 +1,66 @@ +/* + * 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 from user space to a kernel buffer (alignment handled by the hardware) + * + * Parameters: + * x0 - to + * x1 - from + * x2 - n + * Returns: + * x0 - bytes not copied + */ +ENTRY(__copy_from_user) + add x4, x1, x2 // upper user buffer boundary + subs x2, x2, #8 + b.mi 2f +1: +USER(9f, ldr x3, [x1], #8 ) + subs x2, x2, #8 + 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 + str w3, [x0], #4 +3: adds x2, x2, #2 + b.mi 4f +USER(9f, ldrh w3, [x1], #2 ) + sub x2, x2, #2 + strh w3, [x0], #2 +4: adds x2, x2, #1 + b.mi 5f +USER(9f, ldrb w3, [x1] ) + strb w3, [x0] +5: mov x0, #0 + ret +ENDPROC(__copy_from_user) + + .section .fixup,"ax" + .align 2 +9: sub x2, x4, x1 + mov x3, x2 +10: strb wzr, [x0], #1 // zero remaining buffer space + subs x3, x3, #1 + b.ne 10b + mov x0, x2 // bytes not copied + ret + .previous diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S new file mode 100644 index 0000000..84b6c9b --- /dev/null +++ b/arch/arm64/lib/copy_in_user.S @@ -0,0 +1,63 @@ +/* + * Copy from user space to user space + * + * 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 from user space to user space (alignment handled by the hardware) + * + * Parameters: + * x0 - to + * x1 - from + * x2 - n + * Returns: + * x0 - bytes not copied + */ +ENTRY(__copy_in_user) + add x4, x0, x2 // upper user buffer boundary + subs x2, x2, #8 + b.mi 2f +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 diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S new file mode 100644 index 0000000..a0aeeb9 --- /dev/null +++ b/arch/arm64/lib/copy_to_user.S @@ -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 diff --git a/arch/arm64/lib/getuser.S b/arch/arm64/lib/getuser.S new file mode 100644 index 0000000..1b4da22 --- /dev/null +++ b/arch/arm64/lib/getuser.S @@ -0,0 +1,75 @@ +/* + * Based on arch/arm/lib/getuser.S + * + * Copyright (C) 2012 ARM Ltd. + * Idea from x86 version, (C) Copyright 1998 Linus Torvalds + * + * 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/>. + * + * + * These functions have a non-standard call interface to make them more + * efficient, especially as they return an error value in addition to + * the "real" return value. + * + * __get_user_X + * + * Inputs: x0 contains the address + * Outputs: x0 is the error code + * x2, x3 contains the zero-extended value + * lr corrupted + * + * No other registers must be altered. (see <asm/uaccess.h> + * for specific ASM register usage). + * + * Note also that it is intended that __get_user_bad is not global. + */ + +#include <linux/linkage.h> +#include <asm/errno.h> + +ENTRY(__get_user_1) +1: ldrb w2, [x0] + mov x0, #0 + ret +ENDPROC(__get_user_1) + +ENTRY(__get_user_2) +2: ldrh w2, [x0] + mov x0, #0 + ret +ENDPROC(__get_user_2) + +ENTRY(__get_user_4) +3: ldr w2, [x0] + mov x0, #0 + ret +ENDPROC(__get_user_4) + +ENTRY(__get_user_8) +4: ldr x2, [x0] + mov x0, #0 + ret +ENDPROC(__get_user_4) + +__get_user_bad: + mov x2, #0 + mov x0, #-EFAULT + ret +ENDPROC(__get_user_bad) + +.section __ex_table, "a" + .quad 1b, __get_user_bad + .quad 2b, __get_user_bad + .quad 3b, __get_user_bad + .quad 4b, __get_user_bad +.previous diff --git a/arch/arm64/lib/putuser.S b/arch/arm64/lib/putuser.S new file mode 100644 index 0000000..62d4a42 --- /dev/null +++ b/arch/arm64/lib/putuser.S @@ -0,0 +1,73 @@ +/* + * Based on arch/arm/lib/putuser.S + * + * Copyright (C) 2012 ARM Ltd. + * Idea from x86 version, (C) Copyright 1998 Linus Torvalds + * + * 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/>. + * + * These functions have a non-standard call interface to make + * them more efficient, especially as they return an error + * value in addition to the "real" return value. + * + * __put_user_X + * + * Inputs: x0 contains the address + * x2, x3 contains the value + * Outputs: x0 is the error code + * lr corrupted + * + * No other registers must be altered. (see <asm/uaccess.h> + * for specific ASM register usage). + * + * Note that it is intended that __put_user_bad is not global. + */ + +#include <linux/linkage.h> +#include <asm/errno.h> + +ENTRY(__put_user_1) +1: strb w2, [x0] + mov x0, #0 + ret +ENDPROC(__put_user_1) + +ENTRY(__put_user_2) +2: strh w2, [x0] + mov x0, #0 + ret +ENDPROC(__put_user_2) + +ENTRY(__put_user_4) +3: str w2, [x0] + mov x0, #0 + ret +ENDPROC(__put_user_4) + +ENTRY(__put_user_8) +4: str x2, [x0] + mov x0, #0 + ret +ENDPROC(__put_user_8) + +__put_user_bad: + mov x0, #-EFAULT + ret +ENDPROC(__put_user_bad) + +.section __ex_table, "a" + .quad 1b, __put_user_bad + .quad 2b, __put_user_bad + .quad 3b, __put_user_bad + .quad 4b, __put_user_bad +.previous diff --git a/arch/arm64/lib/strncpy_from_user.S b/arch/arm64/lib/strncpy_from_user.S new file mode 100644 index 0000000..56e448a --- /dev/null +++ b/arch/arm64/lib/strncpy_from_user.S @@ -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 diff --git a/arch/arm64/lib/strnlen_user.S b/arch/arm64/lib/strnlen_user.S new file mode 100644 index 0000000..7f7b176 --- /dev/null +++ b/arch/arm64/lib/strnlen_user.S @@ -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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
