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>

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 5bcce85..d2792e8 100644 (file)
--- 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;