Commit 34e7317d authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes/x86: move the UPROBE_FIX_{RIP,IP,CALL} code at the end of pre/post hooks 



No functional changes. Preparation to simplify the review of the next
change. Just reorder the code in arch_uprobe_pre/post_xol() functions
so that UPROBE_FIX_{RIP_*,IP,CALL} logic goes to the end.

Also change arch_uprobe_pre_xol() to use utask instead of autask, to
make the code more symmetrical with arch_uprobe_post_xol().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Reviewed-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: default avatarJim Keniston <jkenisto@us.ibm.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
parent d20737c0

arch/x86/kernel/uprobes.c

+14 −16
Original line number Diff line number Diff line
@@ -474,19 +474,18 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, 
 */

int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)

{

	struct arch_uprobe_task *autask;

	struct uprobe_task *utask = current->utask;



	autask = &current->utask->autask;

	autask->saved_trap_nr = current->thread.trap_nr;

	regs->ip = utask->xol_vaddr;

	utask->autask.saved_trap_nr = current->thread.trap_nr;

	current->thread.trap_nr = UPROBE_TRAP_NR;

	regs->ip = current->utask->xol_vaddr;

	pre_xol_rip_insn(auprobe, regs, autask);



	autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);

	utask->autask.saved_tf = !!(regs->flags & X86_EFLAGS_TF);

	regs->flags |= X86_EFLAGS_TF;

	if (test_tsk_thread_flag(current, TIF_BLOCKSTEP))

		set_task_blockstep(current, false);



	pre_xol_rip_insn(auprobe, regs, &utask->autask);

	return 0;

}
@@ -560,22 +559,13 @@ bool arch_uprobe_xol_was_trapped(struct task_struct *t) 
 */

int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)

{

	struct uprobe_task *utask;

	struct uprobe_task *utask = current->utask;

	long correction;

	int result = 0;



	WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);



	utask = current->utask;

	current->thread.trap_nr = utask->autask.saved_trap_nr;

	correction = (long)(utask->vaddr - utask->xol_vaddr);

	handle_riprel_post_xol(auprobe, regs, &correction);

	if (auprobe->fixups & UPROBE_FIX_IP)

		regs->ip += correction;



	if (auprobe->fixups & UPROBE_FIX_CALL)

		result = adjust_ret_addr(regs->sp, correction);



	/*

	 * arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP

	 * so we can get an extra SIGTRAP if we do not clear TF. We need
@@ -586,6 +576,14 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) 
	else if (!(auprobe->fixups & UPROBE_FIX_SETF))

		regs->flags &= ~X86_EFLAGS_TF;



	correction = (long)(utask->vaddr - utask->xol_vaddr);

	handle_riprel_post_xol(auprobe, regs, &correction);

	if (auprobe->fixups & UPROBE_FIX_IP)

		regs->ip += correction;



	if (auprobe->fixups & UPROBE_FIX_CALL)

		result = adjust_ret_addr(regs->sp, correction);



	return result;

}

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