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Commit 83cd5914 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

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: default avatarOleg Nesterov <oleg@redhat.com>
parent 1dc76e6e

arch/x86/kernel/uprobes.c

+11 −16
Original line number Diff line number Diff line
@@ -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;