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Message-ID: <20140601192520.GA14539@redhat.com>
Date: Sun, 1 Jun 2014 21:25:20 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Ingo Molnar <mingo@...e.hu>
Cc: Denys Vlasenko <dvlasenk@...hat.com>,
Jim Keniston <jkenisto@...ibm.com>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH] uprobes/x86: Rename arch_uprobe->def into ->dflt, minor
comment updates
Purely cosmetic, no changes in .o,
1. As Jim pointed out arch_uprobe->def looks ambiguous, rename it to
->dflt.
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: Jim Keniston <jkenisto@...ibm.com>
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
arch/x86/include/asm/uprobes.h | 2 +-
arch/x86/kernel/uprobes.c | 37 ++++++++++++++++++-------------------
2 files changed, 19 insertions(+), 20 deletions(-)
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 7be3c07..b3d9442 100644
--- a/arch/x86/include/asm/uprobes.h
+++ b/arch/x86/include/asm/uprobes.h
@@ -52,7 +52,7 @@ struct arch_uprobe {
struct {
u8 fixups;
u8 ilen;
- } def;
+ } dflt;
};
};
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index fcf6279..33e239f 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -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
+ * dflt->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->dflt.fixups |= UPROBE_FIX_RIP_SI;
} else if (reg != 7 && reg2 != 7) {
reg2 = 7;
- auprobe->def.fixups |= UPROBE_FIX_RIP_DI;
+ auprobe->dflt.fixups |= UPROBE_FIX_RIP_DI;
/* TODO (paranoia): force maskmovq to not use di */
} else {
reg2 = 3;
- auprobe->def.fixups |= UPROBE_FIX_RIP_BX;
+ auprobe->dflt.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->dflt.fixups & UPROBE_FIX_RIP_SI)
return ®s->si;
- if (auprobe->def.fixups & UPROBE_FIX_RIP_DI)
+ if (auprobe->dflt.fixups & UPROBE_FIX_RIP_DI)
return ®s->di;
return ®s->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->dflt.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->dflt.ilen;
}
}
static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- if (auprobe->def.fixups & UPROBE_FIX_RIP_MASK) {
+ if (auprobe->dflt.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->dflt.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->dflt.fixups & UPROBE_FIX_CALL) {
+ regs->sp += sizeof_long(); /* Pop incorrect return address */
+ if (push_ret_address(regs, utask->vaddr + auprobe->dflt.ilen))
return -ERESTART;
}
/* popf; tell the caller to not touch TF */
- if (auprobe->def.fixups & UPROBE_FIX_SETF)
+ if (auprobe->dflt.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 dflt->fixups accordingly.
*/
switch (OPCODE1(&insn)) {
case 0x9d: /* popf */
- auprobe->def.fixups |= UPROBE_FIX_SETF;
+ auprobe->dflt.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->dflt.ilen = insn.length;
+ auprobe->dflt.fixups |= fix_ip_or_call;
auprobe->ops = &default_xol_ops;
return 0;
--
1.5.5.1
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