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authorHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>2009-01-24 02:49:41 +0300
committerH. Peter Anvin <hpa@linux.intel.com>2009-01-24 04:17:36 +0300
commitfe40c0af3cff3ea461cf25bddb979abc7279d4df (patch)
treebe37f58bce212299476186147e44dbd486be34a1 /arch/x86/mm/extable.c
parentcc86c9e0dc1a41451240b948bb39d46bb2536ae8 (diff)
downloadlinux-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/mm/extable.c')
-rw-r--r--arch/x86/mm/extable.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 7e8db53528a7..61b41ca3b5a2 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -23,6 +23,12 @@ int fixup_exception(struct pt_regs *regs)
fixup = search_exception_tables(regs->ip);
if (fixup) {
+ /* If fixup is less than 16, it means uaccess error */
+ if (fixup->fixup < 16) {
+ current_thread_info()->uaccess_err = -EFAULT;
+ regs->ip += fixup->fixup;
+ return 1;
+ }
regs->ip = fixup->fixup;
return 1;
}