From 83cd591485e558ab70aed45ce7261ce3f5ee8746 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 25 Apr 2014 18:53:32 +0200 Subject: [PATCH] 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 --- arch/x86/kernel/uprobes.c | 27 +++++++++++---------------- 1 file 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; -- 2.30.2