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Commit 5cdb76d6 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates 



Purely cosmetic, no changes in .o,

1. As Jim pointed out arch_uprobe->def looks ambiguous, rename it to
   ->defparam.

2. Add the comment into default_post_xol_op() to explain "regs->sp +=".

3. Remove the stale part of the comment in arch_uprobe_analyze_insn().

Suggested-by: default avatarJim Keniston <jkenisto@us.ibm.com>
Reviewed-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
parent 45e0a79a

arch/x86/include/asm/uprobes.h

+1 −1
Original line number Diff line number Diff line
@@ -52,7 +52,7 @@ struct arch_uprobe { 
		struct {

			u8	fixups;

			u8	ilen;

		} 			def;

		} 			defparam;

	};

};

arch/x86/kernel/uprobes.c

+18 −19
Original line number Diff line number Diff line
@@ -254,7 +254,7 @@ static inline bool is_64bit_mm(struct mm_struct *mm) 
 * If arch_uprobe->insn doesn't use rip-relative addressing, return

 * immediately.  Otherwise, rewrite the instruction so that it accesses

 * its memory operand indirectly through a scratch register.  Set

 * def->fixups accordingly. (The contents of the scratch register

 * defparam->fixups accordingly. (The contents of the scratch register

 * will be saved before we single-step the modified instruction,

 * and restored afterward).

 *
@@ -372,14 +372,14 @@ static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn) 
	 */

	if (reg != 6 && reg2 != 6) {

		reg2 = 6;

		auprobe->def.fixups |= UPROBE_FIX_RIP_SI;

		auprobe->defparam.fixups |= UPROBE_FIX_RIP_SI;

	} else if (reg != 7 && reg2 != 7) {

		reg2 = 7;

		auprobe->def.fixups |= UPROBE_FIX_RIP_DI;

		auprobe->defparam.fixups |= UPROBE_FIX_RIP_DI;

		/* TODO (paranoia): force maskmovq to not use di */

	} else {

		reg2 = 3;

		auprobe->def.fixups |= UPROBE_FIX_RIP_BX;

		auprobe->defparam.fixups |= UPROBE_FIX_RIP_BX;

	}

	/*

	 * Point cursor at the modrm byte.  The next 4 bytes are the
@@ -398,9 +398,9 @@ static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn) 
static inline unsigned long *

scratch_reg(struct arch_uprobe *auprobe, struct pt_regs *regs)

{

	if (auprobe->def.fixups & UPROBE_FIX_RIP_SI)

	if (auprobe->defparam.fixups & UPROBE_FIX_RIP_SI)

		return &regs->si;

	if (auprobe->def.fixups & UPROBE_FIX_RIP_DI)

	if (auprobe->defparam.fixups & UPROBE_FIX_RIP_DI)

		return &regs->di;

	return &regs->bx;

}
@@ -411,18 +411,18 @@ scratch_reg(struct arch_uprobe *auprobe, struct pt_regs *regs) 
 */

static void riprel_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)

{

	if (auprobe->def.fixups & UPROBE_FIX_RIP_MASK) {

	if (auprobe->defparam.fixups & UPROBE_FIX_RIP_MASK) {

		struct uprobe_task *utask = current->utask;

		unsigned long *sr = scratch_reg(auprobe, regs);



		utask->autask.saved_scratch_register = *sr;

		*sr = utask->vaddr + auprobe->def.ilen;

		*sr = utask->vaddr + auprobe->defparam.ilen;

	}

}



static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)

{

	if (auprobe->def.fixups & UPROBE_FIX_RIP_MASK) {

	if (auprobe->defparam.fixups & UPROBE_FIX_RIP_MASK) {

		struct uprobe_task *utask = current->utask;

		unsigned long *sr = scratch_reg(auprobe, regs);
@@ -499,16 +499,16 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs 
	struct uprobe_task *utask = current->utask;



	riprel_post_xol(auprobe, regs);

	if (auprobe->def.fixups & UPROBE_FIX_IP) {

	if (auprobe->defparam.fixups & UPROBE_FIX_IP) {

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

		regs->ip += correction;

	} else if (auprobe->def.fixups & UPROBE_FIX_CALL) {

		regs->sp += sizeof_long();

		if (push_ret_address(regs, utask->vaddr + auprobe->def.ilen))

	} else if (auprobe->defparam.fixups & UPROBE_FIX_CALL) {

		regs->sp += sizeof_long(); /* Pop incorrect return address */

		if (push_ret_address(regs, utask->vaddr + auprobe->defparam.ilen))

			return -ERESTART;

	}

	/* popf; tell the caller to not touch TF */

	if (auprobe->def.fixups & UPROBE_FIX_SETF)

	if (auprobe->defparam.fixups & UPROBE_FIX_SETF)

		utask->autask.saved_tf = true;



	return 0;
@@ -711,12 +711,11 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, 


	/*

	 * Figure out which fixups default_post_xol_op() will need to perform,

	 * and annotate def->fixups accordingly. To start with, ->fixups is

	 * either zero or it reflects rip-related fixups.

	 * and annotate defparam->fixups accordingly.

	 */

	switch (OPCODE1(&insn)) {

	case 0x9d:		/* popf */

		auprobe->def.fixups |= UPROBE_FIX_SETF;

		auprobe->defparam.fixups |= UPROBE_FIX_SETF;

		break;

	case 0xc3:		/* ret or lret -- ip is correct */

	case 0xcb:
@@ -742,8 +741,8 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, 
		riprel_analyze(auprobe, &insn);

	}



	auprobe->def.ilen = insn.length;

	auprobe->def.fixups |= fix_ip_or_call;

	auprobe->defparam.ilen = insn.length;

	auprobe->defparam.fixups |= fix_ip_or_call;



	auprobe->ops = &default_xol_ops;

	return 0;