1. Extract the ->ia32_compat check from 64bit validate_insn_bits()
   into the new helper, is_64bit_mm(), it will have more users.

   TODO: this checks is actually wrong if mm owner is X32 task,
   we need another fix which changes set_personality_ia32().

   TODO: even worse, the whole 64-or-32-bit logic is very broken
   and the fix is not simple, we need the nontrivial changes in
   the core uprobes code.

2. Kill validate_insn_bits() and change its single caller to use
   uprobe_init_insn(is_64bit_mm(mm).

Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
 arch/x86/kernel/uprobes.c |   20 +++++++++-----------
 1 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 68c63ab..5876ba5 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -231,6 +231,11 @@ 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;
+}
 /*
  * If arch_uprobe->insn doesn't use rip-relative addressing, return
  * immediately.  Otherwise, rewrite the instruction so that it accesses
@@ -355,13 +360,11 @@ handle_riprel_post_xol(struct arch_uprobe *auprobe, 
struct pt_regs *regs, long *
                        *correction += 4;
        }
 }
-
-static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct 
*mm, struct insn *insn)
+#else /* 32-bit: */
+static inline bool is_64bit_mm(struct mm_struct *mm)
 {
-       bool x86_64 = !mm->context.ia32_compat;
-       return uprobe_init_insn(auprobe, insn, x86_64);
+       return false;
 }
-#else /* 32-bit: */
 /*
  * No RIP-relative addressing on 32-bit
  */
@@ -376,11 +379,6 @@ static void handle_riprel_post_xol(struct arch_uprobe 
*auprobe, struct pt_regs *
                                        long *correction)
 {
 }
-
-static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct 
*mm,  struct insn *insn)
-{
-       return uprobe_init_insn(auprobe, insn, false);
-}
 #endif /* CONFIG_X86_64 */
 
 struct uprobe_xol_ops {
@@ -614,7 +612,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, 
struct mm_struct *mm,
        bool fix_ip = true, fix_call = false;
        int ret;
 
-       ret = validate_insn_bits(auprobe, mm, &insn);
+       ret = uprobe_init_insn(auprobe, &insn, is_64bit_mm(mm));
        if (ret)
                return ret;
 
-- 
1.5.5.1

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