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

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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: Jim Keniston <jkenisto@us.ibm.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This commit is contained in:
Oleg Nesterov 2014-06-01 21:13:46 +02:00
parent 45e0a79a82
commit 5cdb76d6f0
2 changed files with 19 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/uprobes.h
View File

@ -52,7 +52,7 @@ struct arch_uprobe {
struct {
u8 fixups;
u8 ilen;
} def;
} defparam;
};
};

37
arch/x86/kernel/uprobes.c
View File

@ -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;