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Commit b0e9b09b authored by Dave Hansen's avatar Dave Hansen Committed by Ingo Molnar
Browse files

x86: Make is_64bit_mm() widely available 



The uprobes code has a nice helper, is_64bit_mm(), that consults
both the runtime and compile-time flags for 32-bit support.
Instead of reinventing the wheel, pull it in to an x86 header so
we can use it for MPX.

I prefer passing the 'mm' around to test_thread_flag(TIF_IA32)
because it makes it explicit where the context is coming from.

Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150607183704.F0209999@viggo.jf.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent cd4996dc

arch/x86/include/asm/mmu_context.h

+13 −0
Original line number Diff line number Diff line
@@ -142,6 +142,19 @@ static inline void arch_exit_mmap(struct mm_struct *mm) 
	paravirt_arch_exit_mmap(mm);

}



#ifdef CONFIG_X86_64

static inline bool is_64bit_mm(struct mm_struct *mm)

{

	return	!config_enabled(CONFIG_IA32_EMULATION) ||

		!(mm->context.ia32_compat == TIF_IA32);

}

#else

static inline bool is_64bit_mm(struct mm_struct *mm)

{

	return false;

}

#endif



static inline void arch_bprm_mm_init(struct mm_struct *mm,

		struct vm_area_struct *vma)

{

arch/x86/kernel/uprobes.c

+1 −9
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/kdebug.h>

#include <asm/processor.h>

#include <asm/insn.h>

#include <asm/mmu_context.h>



/* Post-execution fixups. */
@@ -312,11 +313,6 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool 
}



#ifdef CONFIG_X86_64

static inline bool is_64bit_mm(struct mm_struct *mm)

{

	return	!config_enabled(CONFIG_IA32_EMULATION) ||

		!(mm->context.ia32_compat == TIF_IA32);

}

/*

 * If arch_uprobe->insn doesn't use rip-relative addressing, return

 * immediately.  Otherwise, rewrite the instruction so that it accesses
@@ -497,10 +493,6 @@ static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 
	}

}

#else /* 32-bit: */

static inline bool is_64bit_mm(struct mm_struct *mm)

{

	return false;

}

/*

 * No RIP-relative addressing on 32-bit

 */