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Commit dfa9a942 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/uaccess: Move thread_info::uaccess_err and thread_info::sig_on_uaccess_err to thread_struct 



struct thread_info is a legacy mess.  To prepare for its partial removal,
move the uaccess control fields out -- they're straightforward.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/d0ac4d01c8e4d4d756264604e47445d5acc7900e.1468527351.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2deb4be2

arch/x86/entry/vsyscall/vsyscall_64.c

+3 −3
Original line number Diff line number Diff line
@@ -221,8 +221,8 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) 
	 * With a real vsyscall, page faults cause SIGSEGV.  We want to

	 * preserve that behavior to make writing exploits harder.

	 */

	prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;

	current_thread_info()->sig_on_uaccess_error = 1;

	prev_sig_on_uaccess_error = current->thread.sig_on_uaccess_error;

	current->thread.sig_on_uaccess_error = 1;



	ret = -EFAULT;

	switch (vsyscall_nr) {
@@ -243,7 +243,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) 
		break;

	}



	current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;

	current->thread.sig_on_uaccess_error = prev_sig_on_uaccess_error;



check_fault:

	if (ret == -EFAULT) {

arch/x86/include/asm/processor.h

+3 −0
Original line number Diff line number Diff line
@@ -419,6 +419,9 @@ struct thread_struct { 
	/* Max allowed port in the bitmap, in bytes: */

	unsigned		io_bitmap_max;



	unsigned int		sig_on_uaccess_error:1;

	unsigned int		uaccess_err:1;	/* uaccess failed */



	/* Floating point and extended processor state */

	struct fpu		fpu;

	/*

arch/x86/include/asm/thread_info.h

+0 −2
Original line number Diff line number Diff line
@@ -58,8 +58,6 @@ struct thread_info { 
	__u32			status;		/* thread synchronous flags */

	__u32			cpu;		/* current CPU */

	mm_segment_t		addr_limit;

	unsigned int		sig_on_uaccess_error:1;

	unsigned int		uaccess_err:1;	/* uaccess failed */

};



#define INIT_THREAD_INFO(tsk)			\

arch/x86/include/asm/uaccess.h

+2 −2
Original line number Diff line number Diff line
@@ -487,13 +487,13 @@ struct __large_struct { unsigned long buf[100]; }; 
 * uaccess_try and catch

 */

#define uaccess_try	do {						\

	current_thread_info()->uaccess_err = 0;				\

	current->thread.uaccess_err = 0;				\

	__uaccess_begin();						\

	barrier();



#define uaccess_catch(err)						\

	__uaccess_end();						\

	(err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0);	\

	(err) |= (current->thread.uaccess_err ? -EFAULT : 0);		\

} while (0)



/**

arch/x86/mm/extable.c

+1 −1
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ bool ex_handler_ext(const struct exception_table_entry *fixup, 
		   struct pt_regs *regs, int trapnr)

{

	/* Special hack for uaccess_err */

	current_thread_info()->uaccess_err = 1;

	current->thread.uaccess_err = 1;

	regs->ip = ex_fixup_addr(fixup);

	return true;

}