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yaml --- r: 100068 b: refs/heads/master c: ca23386 h: refs/heads/master v: v3
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Glauber Costa
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Ingo Molnar
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Jul 9, 2008
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,2 +1,2 @@ | ||
| --- | ||
| refs/heads/master: be9d06bfd48934fbd56ccb7476eabccfa31b4afe | ||
| refs/heads/master: ca23386216b9d4fc3bb211101205077d2b2916ae |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,5 +1,129 @@ | ||
| #ifndef _ASM_UACCES_H_ | ||
| #define _ASM_UACCES_H_ | ||
| /* | ||
| * User space memory access functions | ||
| */ | ||
| #include <linux/errno.h> | ||
| #include <linux/compiler.h> | ||
| #include <linux/thread_info.h> | ||
| #include <linux/prefetch.h> | ||
| #include <linux/string.h> | ||
| #include <asm/asm.h> | ||
| #include <asm/page.h> | ||
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| #define VERIFY_READ 0 | ||
| #define VERIFY_WRITE 1 | ||
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|
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| /* | ||
| * The fs value determines whether argument validity checking should be | ||
| * performed or not. If get_fs() == USER_DS, checking is performed, with | ||
| * get_fs() == KERNEL_DS, checking is bypassed. | ||
| * | ||
| * For historical reasons, these macros are grossly misnamed. | ||
| */ | ||
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| #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) | ||
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| #define KERNEL_DS MAKE_MM_SEG(-1UL) | ||
| #define USER_DS MAKE_MM_SEG(PAGE_OFFSET) | ||
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| #define get_ds() (KERNEL_DS) | ||
| #define get_fs() (current_thread_info()->addr_limit) | ||
| #define set_fs(x) (current_thread_info()->addr_limit = (x)) | ||
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| #define segment_eq(a, b) ((a).seg == (b).seg) | ||
|
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| /* | ||
| * Test whether a block of memory is a valid user space address. | ||
| * Returns 0 if the range is valid, nonzero otherwise. | ||
| * | ||
| * This is equivalent to the following test: | ||
| * (u33)addr + (u33)size >= (u33)current->addr_limit.seg (u65 for x86_64) | ||
| * | ||
| * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... | ||
| */ | ||
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| #define __range_not_ok(addr, size) \ | ||
| ({ \ | ||
| unsigned long flag, roksum; \ | ||
| __chk_user_ptr(addr); \ | ||
| asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ | ||
| : "=&r" (flag), "=r" (roksum) \ | ||
| : "1" (addr), "g" ((long)(size)), \ | ||
| "rm" (current_thread_info()->addr_limit.seg)); \ | ||
| flag; \ | ||
| }) | ||
|
|
||
| /** | ||
| * access_ok: - Checks if a user space pointer is valid | ||
| * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that | ||
| * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe | ||
| * to write to a block, it is always safe to read from it. | ||
| * @addr: User space pointer to start of block to check | ||
| * @size: Size of block to check | ||
| * | ||
| * Context: User context only. This function may sleep. | ||
| * | ||
| * Checks if a pointer to a block of memory in user space is valid. | ||
| * | ||
| * Returns true (nonzero) if the memory block may be valid, false (zero) | ||
| * if it is definitely invalid. | ||
| * | ||
| * Note that, depending on architecture, this function probably just | ||
| * checks that the pointer is in the user space range - after calling | ||
| * this function, memory access functions may still return -EFAULT. | ||
| */ | ||
| #define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0)) | ||
|
|
||
| /* | ||
| * 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. | ||
| */ | ||
|
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| struct exception_table_entry { | ||
| unsigned long insn, fixup; | ||
| }; | ||
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| extern int fixup_exception(struct pt_regs *regs); | ||
|
|
||
| /* | ||
| * These are the main single-value transfer routines. They automatically | ||
| * use the right size if we just have the right pointer type. | ||
| * | ||
| * This gets kind of ugly. We want to return _two_ values in "get_user()" | ||
| * and yet we don't want to do any pointers, because that is too much | ||
| * of a performance impact. Thus we have a few rather ugly macros here, | ||
| * and hide all the ugliness from the user. | ||
| * | ||
| * The "__xxx" versions of the user access functions are versions that | ||
| * do not verify the address space, that must have been done previously | ||
| * with a separate "access_ok()" call (this is used when we do multiple | ||
| * accesses to the same area of user memory). | ||
| */ | ||
|
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| extern int __get_user_1(void); | ||
| extern int __get_user_2(void); | ||
| extern int __get_user_4(void); | ||
| extern int __get_user_8(void); | ||
| extern int __get_user_bad(void); | ||
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| #define __get_user_x(size, ret, x, ptr) \ | ||
| asm volatile("call __get_user_" #size \ | ||
| : "=a" (ret),"=d" (x) \ | ||
| : "0" (ptr)) \ | ||
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| #ifdef CONFIG_X86_32 | ||
| # include "uaccess_32.h" | ||
| #else | ||
| # include "uaccess_64.h" | ||
| #endif | ||
|
|
||
| #endif |
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