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Commit e139e955 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

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



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: default avatarH. 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
parent 49b8c695

arch/x86/include/asm/fpu-internal.h

+17 −0
Original line number Diff line number Diff line
@@ -181,11 +181,28 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx) 
			  "m" (*fx));

}



static inline int fxrstor_user(struct i387_fxsave_struct __user *fx)

{

	if (config_enabled(CONFIG_X86_32))

		return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));

	else if (config_enabled(CONFIG_AS_FXSAVEQ))

		return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));



	/* See comment in fpu_fxsave() below. */

	return user_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx),

			  "m" (*fx));

}



static inline int frstor_checking(struct i387_fsave_struct *fx)

{

	return check_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));

}



static inline int frstor_user(struct i387_fsave_struct __user *fx)

{

	return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));

}



static inline void fpu_fxsave(struct fpu *fpu)

{

	if (config_enabled(CONFIG_X86_32))

arch/x86/kernel/xsave.c

+3 −3
Original line number Diff line number Diff line
@@ -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)