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: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas 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: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 883f6b933fa4b6501af7a050fc161eafdb8f8d91..5e8daee7c5c94be6fc48bc7f32e593fb46948557 100644 (file)
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -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)
 {

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 0b81ad67da07fa36e57577de5f7165ab320a55a1..66476244731ef8fba8fafbe1bb6cbd17f1a18b9c 100644 (file)
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -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
  */