diff options
author | Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> | 2009-01-24 02:49:41 +0300 |
---|---|---|
committer | H. Peter Anvin <hpa@linux.intel.com> | 2009-01-24 04:17:36 +0300 |
commit | fe40c0af3cff3ea461cf25bddb979abc7279d4df (patch) | |
tree | be37f58bce212299476186147e44dbd486be34a1 /arch/x86/include | |
parent | cc86c9e0dc1a41451240b948bb39d46bb2536ae8 (diff) | |
download | linux-fe40c0af3cff3ea461cf25bddb979abc7279d4df.tar.xz |
x86: uaccess: introduce try and catch framework
Impact: introduce new uaccess exception handling framework
Introduce {get|put}_user_try and {get|put}_user_catch as new uaccess exception
handling framework.
{get|put}_user_try begins exception block and {get|put}_user_catch(err) ends
the block and gets err if an exception occured in {get|put}_user_ex() in the
block. The exception is stored thread_info->uaccess_err.
The example usage of this framework is below;
int func()
{
int err = 0;
get_user_try {
get_user_ex(...);
get_user_ex(...);
:
} get_user_catch(err);
return err;
}
Note: get_user_ex() is not clear the value when an exception occurs, it's
different from the behavior of __get_user(), but I think it doesn't matter.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include')
-rw-r--r-- | arch/x86/include/asm/thread_info.h | 1 | ||||
-rw-r--r-- | arch/x86/include/asm/uaccess.h | 103 |
2 files changed, 104 insertions, 0 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 98789647baa9..3f90aeb456bc 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -40,6 +40,7 @@ struct thread_info { */ __u8 supervisor_stack[0]; #endif + int uaccess_err; }; #define INIT_THREAD_INFO(tsk) \ diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 69d2757cca9b..0ec6de4bcb0b 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -199,12 +199,22 @@ extern int __get_user_bad(void); : "=r" (err) \ : "A" (x), "r" (addr), "i" (-EFAULT), "0" (err)) +#define __put_user_asm_ex_u64(x, addr) \ + asm volatile("1: movl %%eax,0(%1)\n" \ + "2: movl %%edx,4(%1)\n" \ + "3:\n" \ + _ASM_EXTABLE(1b, 2b - 1b) \ + _ASM_EXTABLE(2b, 3b - 2b) \ + : : "A" (x), "r" (addr)) + #define __put_user_x8(x, ptr, __ret_pu) \ asm volatile("call __put_user_8" : "=a" (__ret_pu) \ : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") #else #define __put_user_asm_u64(x, ptr, retval) \ __put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT) +#define __put_user_asm_ex_u64(x, addr) \ + __put_user_asm_ex(x, addr, "q", "", "Zr") #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) #endif @@ -286,6 +296,27 @@ do { \ } \ } while (0) +#define __put_user_size_ex(x, ptr, size) \ +do { \ + __chk_user_ptr(ptr); \ + switch (size) { \ + case 1: \ + __put_user_asm_ex(x, ptr, "b", "b", "iq"); \ + break; \ + case 2: \ + __put_user_asm_ex(x, ptr, "w", "w", "ir"); \ + break; \ + case 4: \ + __put_user_asm_ex(x, ptr, "l", "k", "ir"); \ + break; \ + case 8: \ + __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \ + break; \ + default: \ + __put_user_bad(); \ + } \ +} while (0) + #else #define __put_user_size(x, ptr, size, retval, errret) \ @@ -311,9 +342,12 @@ do { \ #ifdef CONFIG_X86_32 #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() +#define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() #else #define __get_user_asm_u64(x, ptr, retval, errret) \ __get_user_asm(x, ptr, retval, "q", "", "=r", errret) +#define __get_user_asm_ex_u64(x, ptr) \ + __get_user_asm_ex(x, ptr, "q", "", "=r") #endif #define __get_user_size(x, ptr, size, retval, errret) \ @@ -350,6 +384,33 @@ do { \ : "=r" (err), ltype(x) \ : "m" (__m(addr)), "i" (errret), "0" (err)) +#define __get_user_size_ex(x, ptr, size) \ +do { \ + __chk_user_ptr(ptr); \ + switch (size) { \ + case 1: \ + __get_user_asm_ex(x, ptr, "b", "b", "=q"); \ + break; \ + case 2: \ + __get_user_asm_ex(x, ptr, "w", "w", "=r"); \ + break; \ + case 4: \ + __get_user_asm_ex(x, ptr, "l", "k", "=r"); \ + break; \ + case 8: \ + __get_user_asm_ex_u64(x, ptr); \ + break; \ + default: \ + (x) = __get_user_bad(); \ + } \ +} while (0) + +#define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ + asm volatile("1: mov"itype" %1,%"rtype"0\n" \ + "2:\n" \ + _ASM_EXTABLE(1b, 2b - 1b) \ + : ltype(x) : "m" (__m(addr))) + #define __put_user_nocheck(x, ptr, size) \ ({ \ int __pu_err; \ @@ -385,6 +446,26 @@ struct __large_struct { unsigned long buf[100]; }; _ASM_EXTABLE(1b, 3b) \ : "=r"(err) \ : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) + +#define __put_user_asm_ex(x, addr, itype, rtype, ltype) \ + asm volatile("1: mov"itype" %"rtype"0,%1\n" \ + "2:\n" \ + _ASM_EXTABLE(1b, 2b - 1b) \ + : : ltype(x), "m" (__m(addr))) + +/* + * uaccess_try and catch + */ +#define uaccess_try do { \ + int prev_err = current_thread_info()->uaccess_err; \ + current_thread_info()->uaccess_err = 0; \ + barrier(); + +#define uaccess_catch(err) \ + (err) |= current_thread_info()->uaccess_err; \ + current_thread_info()->uaccess_err = prev_err; \ +} while (0) + /** * __get_user: - Get a simple variable from user space, with less checking. * @x: Variable to store result. @@ -408,6 +489,7 @@ struct __large_struct { unsigned long buf[100]; }; #define __get_user(x, ptr) \ __get_user_nocheck((x), (ptr), sizeof(*(ptr))) + /** * __put_user: - Write a simple value into user space, with less checking. * @x: Value to copy to user space. @@ -435,6 +517,27 @@ struct __large_struct { unsigned long buf[100]; }; #define __put_user_unaligned __put_user /* + * {get|put}_user_try and catch + * + * get_user_try { + * get_user_ex(...); + * } get_user_catch(err) + */ +#define get_user_try uaccess_try +#define get_user_catch(err) uaccess_catch(err) +#define put_user_try uaccess_try +#define put_user_catch(err) uaccess_catch(err) + +#define get_user_ex(x, ptr) do { \ + unsigned long __gue_val; \ + __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \ + (x) = (__force __typeof__(*(ptr)))__gue_val; \ +} while (0) + +#define put_user_ex(x, ptr) \ + __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) + +/* * movsl can be slow when source and dest are not both 8-byte aligned */ #ifdef CONFIG_X86_INTEL_USERCOPY |