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uprobes/x86: Gather "riprel" functions together 

Cosmetic. Move pre_xol_rip_insn() and handle_riprel_post_xol() up to
the closely related handle_riprel_insn(). This way it is simpler to
read and understand this code, and this lessens the number of ifdef's.

While at it, update the comment in handle_riprel_post_xol() as Jim
suggested.

TODO: rename them somehow to make the naming consistent.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
This commit is contained in:
Oleg Nesterov 2014-03-31 18:35:09 +02:00
Родитель 59078d4b96
Коммит d20737c07a
1 изменённых файлов: 53 добавлений и 65 удалений
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118
arch/x86/kernel/uprobes.c
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@ -313,6 +313,48 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
}
}
/*
* If we're emulating a rip-relative instruction, save the contents
* of the scratch register and store the target address in that register.
*/
static void
pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
struct arch_uprobe_task *autask)
{
if (auprobe->fixups & UPROBE_FIX_RIP_AX) {
autask->saved_scratch_register = regs->ax;
regs->ax = current->utask->vaddr;
regs->ax += auprobe->rip_rela_target_address;
} else if (auprobe->fixups & UPROBE_FIX_RIP_CX) {
autask->saved_scratch_register = regs->cx;
regs->cx = current->utask->vaddr;
regs->cx += auprobe->rip_rela_target_address;
}
}
static void
handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
{
if (auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) {
struct arch_uprobe_task *autask;
autask = &current->utask->autask;
if (auprobe->fixups & UPROBE_FIX_RIP_AX)
regs->ax = autask->saved_scratch_register;
else
regs->cx = autask->saved_scratch_register;
/*
* The original instruction includes a displacement, and so
* is 4 bytes longer than what we've just single-stepped.
* Caller may need to apply other fixups to handle stuff
* like "jmpq *...(%rip)" and "callq *...(%rip)".
*/
if (correction)
*correction += 4;
}
}
static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn)
{
insn_init(insn, auprobe->insn, true);
@ -339,9 +381,19 @@ static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm,
return validate_insn_64bits(auprobe, insn);
}
#else /* 32-bit: */
/*
* No RIP-relative addressing on 32-bit
*/
static void handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
{
/* No RIP-relative addressing on 32-bit */
}
static void pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
struct arch_uprobe_task *autask)
{
}
static void handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs,
long *correction)
{
}
static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn)
@ -415,34 +467,6 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
return 0;
}
#ifdef CONFIG_X86_64
/*
* If we're emulating a rip-relative instruction, save the contents
* of the scratch register and store the target address in that register.
*/
static void
pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
struct arch_uprobe_task *autask)
{
if (auprobe->fixups & UPROBE_FIX_RIP_AX) {
autask->saved_scratch_register = regs->ax;
regs->ax = current->utask->vaddr;
regs->ax += auprobe->rip_rela_target_address;
} else if (auprobe->fixups & UPROBE_FIX_RIP_CX) {
autask->saved_scratch_register = regs->cx;
regs->cx = current->utask->vaddr;
regs->cx += auprobe->rip_rela_target_address;
}
}
#else
static void
pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
struct arch_uprobe_task *autask)
{
/* No RIP-relative addressing on 32-bit */
}
#endif
/*
* arch_uprobe_pre_xol - prepare to execute out of line.
* @auprobe: the probepoint information.
@ -492,42 +516,6 @@ static int adjust_ret_addr(unsigned long sp, long correction)
return 0;
}
#ifdef CONFIG_X86_64
static bool is_riprel_insn(struct arch_uprobe *auprobe)
{
return ((auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) != 0);
}
static void
handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
{
if (is_riprel_insn(auprobe)) {
struct arch_uprobe_task *autask;
autask = &current->utask->autask;
if (auprobe->fixups & UPROBE_FIX_RIP_AX)
regs->ax = autask->saved_scratch_register;
else
regs->cx = autask->saved_scratch_register;
/*
* The original instruction includes a displacement, and so
* is 4 bytes longer than what we've just single-stepped.
* Fall through to handle stuff like "jmpq *...(%rip)" and
* "callq *...(%rip)".
*/
if (correction)
*correction += 4;
}
}
#else
static void
handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
{
/* No RIP-relative addressing on 32-bit */
}
#endif
/*
* If xol insn itself traps and generates a signal(Say,
* SIGILL/SIGSEGV/etc), then detect the case where a singlestepped