uprobes/x86: Cleanup the usage of UPROBE_FIX_IP/UPROBE_FIX_CALL

Now that UPROBE_FIX_IP/UPROBE_FIX_CALL are mutually exclusive we can
use a single "fix_ip_or_call" enum instead of 2 fix_* booleans. This
way the logic looks more understandable and clean to me.

While at it, join "case 0xea" with other "ip is correct" ret/lret cases.
Also change default_post_xol_op() to use "else if" for the same reason.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>

1 files changed, 11 insertions, 16 deletions

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 5bcce852628a..d2792e884d54 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -424,10 +424,9 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs
         long correction = (long)(utask->vaddr - utask->xol_vaddr);
 
         handle_riprel_post_xol(auprobe, regs, &correction);
-        if (auprobe->def.fixups & UPROBE_FIX_IP)
+        if (auprobe->def.fixups & UPROBE_FIX_IP) {
                 regs->ip += correction;
-
-        if (auprobe->def.fixups & UPROBE_FIX_CALL) {
+        } else if (auprobe->def.fixups & UPROBE_FIX_CALL) {
                 regs->sp += sizeof_long();
                 if (push_ret_address(regs, utask->vaddr + auprobe->def.ilen))
                         return -ERESTART;
@@ -623,7 +622,7 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr)
 {
         struct insn insn;
-        bool fix_ip = true, fix_call = false;
+        u8 fix_ip_or_call = UPROBE_FIX_IP;
         int ret;
 
         ret = uprobe_init_insn(auprobe, &insn, is_64bit_mm(mm));
@@ -647,21 +646,20 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
         case 0xcb:
         case 0xc2:
         case 0xca:
-                fix_ip = false;
+        case 0xea:              /* jmp absolute -- ip is correct */
+                fix_ip_or_call = 0;
                 break;
         case 0x9a:              /* call absolute - Fix return addr, not ip */
-                fix_call = true;
-                fix_ip = false;
-                break;
-        case 0xea:              /* jmp absolute -- ip is correct */
-                fix_ip = false;
+                fix_ip_or_call = UPROBE_FIX_CALL;
                 break;
         case 0xff:
                 switch (MODRM_REG(&insn)) {
                 case 2: case 3:                 /* call or lcall, indirect */
-                        fix_call = true;
+                        fix_ip_or_call = UPROBE_FIX_CALL;
+                        break;
                 case 4: case 5:                 /* jmp or ljmp, indirect */
-                        fix_ip = false;
+                        fix_ip_or_call = 0;
+                        break;
                 }
                 /* fall through */
         default:
@@ -669,10 +667,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
         }
 
         auprobe->def.ilen = insn.length;
-        if (fix_ip)
-                auprobe->def.fixups |= UPROBE_FIX_IP;
-        if (fix_call)
-                auprobe->def.fixups |= UPROBE_FIX_CALL;
+        auprobe->def.fixups |= fix_ip_or_call;
 
         auprobe->ops = &default_xol_ops;
         return 0;