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uprobes/x86: Cleanup the usage of UPROBE_FIX_IP/UPROBE_FIX_CALL

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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>
This commit is contained in:
Oleg Nesterov 2014-04-25 18:53:32 +02:00
parent 1dc76e6eac
commit 83cd591485
1 changed files with 11 additions and 16 deletions
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27
arch/x86/kernel/uprobes.c
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@ -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;