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x86, smap: Do not abuse the [f][x]rstor_checking() functions for user space

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With SMAP, the [f][x]rstor_checking() functions are no longer usable
for user-space pointers by applying a simple __force cast.  Instead,
create new [f][x]rstor_user() functions which do the proper SMAP
magic.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1343171129-2747-3-git-send-email-suresh.b.siddha@intel.com
This commit is contained in:
H. Peter Anvin
2012-09-25 15:42:18 -07:00
parent 49b8c695e3
commit e139e95590
2 changed files with 20 additions and 3 deletions
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6
arch/x86/kernel/xsave.c
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@@ -315,7 +315,7 @@ static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
if ((unsigned long)buf % 64 || fx_only) {
u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE;
xrstor_state(init_xstate_buf, init_bv);
return fxrstor_checking((__force void *) buf);
return fxrstor_user(buf);
} else {
u64 init_bv = pcntxt_mask & ~xbv;
if (unlikely(init_bv))
@@ -323,9 +323,9 @@ static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
return xrestore_user(buf, xbv);
}
} else if (use_fxsr()) {
return fxrstor_checking((__force void *) buf);
return fxrstor_user(buf);
} else
return frstor_checking((__force void *) buf);
return frstor_user(buf);
}
int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)