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Merge branch 'uprobes/core' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc into perf/core 

Pull uprobes cleanups from Oleg Nesterov.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2013-11-21 09:59:27 +01:00
parent e98a6e59df ad439356ae
commit 09897d78db
4 changed files with 66 additions and 53 deletions
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5
arch/powerpc/include/asm/uprobes.h
View File

@ -36,9 +36,8 @@ typedef ppc_opcode_t uprobe_opcode_t;
struct arch_uprobe {
union {
u8 insn[MAX_UINSN_BYTES];
u8 ixol[MAX_UINSN_BYTES];
u32 ainsn;
u32 insn;
u32 ixol;
};
};

2
arch/powerpc/kernel/uprobes.c
View File

@ -186,7 +186,7 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
* emulate_step() returns 1 if the insn was successfully emulated.
* For all other cases, we need to single-step in hardware.
*/
ret = emulate_step(regs, auprobe->ainsn);
ret = emulate_step(regs, auprobe->insn);
if (ret > 0)
return true;

52
include/linux/uprobes.h
View File

@ -26,16 +26,13 @@
#include <linux/errno.h>
#include <linux/rbtree.h>
#include <linux/types.h>
struct vm_area_struct;
struct mm_struct;
struct inode;
struct notifier_block;
#ifdef CONFIG_ARCH_SUPPORTS_UPROBES
# include <asm/uprobes.h>
#endif
#define UPROBE_HANDLER_REMOVE 1
#define UPROBE_HANDLER_MASK 1
@ -60,6 +57,8 @@ struct uprobe_consumer {
};
#ifdef CONFIG_UPROBES
#include <asm/uprobes.h>
enum uprobe_task_state {
UTASK_RUNNING,
UTASK_SSTEP,
@ -72,34 +71,27 @@ enum uprobe_task_state {
*/
struct uprobe_task {
enum uprobe_task_state state;
struct arch_uprobe_task autask;
union {
struct {
struct arch_uprobe_task autask;
unsigned long vaddr;
};
struct {
struct callback_head dup_xol_work;
unsigned long dup_xol_addr;
};
};
struct uprobe *active_uprobe;
unsigned long xol_vaddr;
struct return_instance *return_instances;
unsigned int depth;
struct uprobe *active_uprobe;
unsigned long xol_vaddr;
unsigned long vaddr;
};
/*
* On a breakpoint hit, thread contests for a slot. It frees the
* slot after singlestep. Currently a fixed number of slots are
* allocated.
*/
struct xol_area {
wait_queue_head_t wq; /* if all slots are busy */
atomic_t slot_count; /* number of in-use slots */
unsigned long *bitmap; /* 0 = free slot */
struct page *page;
/*
* We keep the vma's vm_start rather than a pointer to the vma
* itself. The probed process or a naughty kernel module could make
* the vma go away, and we must handle that reasonably gracefully.
*/
unsigned long vaddr; /* Page(s) of instruction slots */
};
struct xol_area;
struct uprobes_state {
struct xol_area *xol_area;
@ -109,6 +101,7 @@ extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsign
extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
extern bool __weak is_swbp_insn(uprobe_opcode_t *insn);
extern bool __weak is_trap_insn(uprobe_opcode_t *insn);
extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs);
extern int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool);
@ -120,7 +113,6 @@ extern void uprobe_end_dup_mmap(void);
extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm);
extern void uprobe_free_utask(struct task_struct *t);
extern void uprobe_copy_process(struct task_struct *t, unsigned long flags);
extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs);
extern int uprobe_post_sstep_notifier(struct pt_regs *regs);
extern int uprobe_pre_sstep_notifier(struct pt_regs *regs);
extern void uprobe_notify_resume(struct pt_regs *regs);
@ -176,10 +168,6 @@ static inline bool uprobe_deny_signal(void)
{
return false;
}
static inline unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
{
return 0;
}
static inline void uprobe_free_utask(struct task_struct *t)
{
}

60
kernel/events/uprobes.c
View File

@ -73,6 +73,17 @@ struct uprobe {
struct inode *inode; /* Also hold a ref to inode */
loff_t offset;
unsigned long flags;
/*
* The generic code assumes that it has two members of unknown type
* owned by the arch-specific code:
*
* insn - copy_insn() saves the original instruction here for
* arch_uprobe_analyze_insn().
*
* ixol - potentially modified instruction to execute out of
* line, copied to xol_area by xol_get_insn_slot().
*/
struct arch_uprobe arch;
};
@ -85,6 +96,29 @@ struct return_instance {
struct return_instance *next; /* keep as stack */
};
/*
* Execute out of line area: anonymous executable mapping installed
* by the probed task to execute the copy of the original instruction
* mangled by set_swbp().
*
* On a breakpoint hit, thread contests for a slot. It frees the
* slot after singlestep. Currently a fixed number of slots are
* allocated.
*/
struct xol_area {
wait_queue_head_t wq; /* if all slots are busy */
atomic_t slot_count; /* number of in-use slots */
unsigned long *bitmap; /* 0 = free slot */
struct page *page;
/*
* We keep the vma's vm_start rather than a pointer to the vma
* itself. The probed process or a naughty kernel module could make
* the vma go away, and we must handle that reasonably gracefully.
*/
unsigned long vaddr; /* Page(s) of instruction slots */
};
/*
* valid_vma: Verify if the specified vma is an executable vma
* Relax restrictions while unregistering: vm_flags might have
@ -330,7 +364,7 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned
int __weak
set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
{
return uprobe_write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn);
return uprobe_write_opcode(mm, vaddr, *(uprobe_opcode_t *)&auprobe->insn);
}
static int match_uprobe(struct uprobe *l, struct uprobe *r)
@ -529,8 +563,8 @@ static int copy_insn(struct uprobe *uprobe, struct file *filp)
{
struct address_space *mapping = uprobe->inode->i_mapping;
loff_t offs = uprobe->offset;
void *insn = uprobe->arch.insn;
int size = MAX_UINSN_BYTES;
void *insn = &uprobe->arch.insn;
int size = sizeof(uprobe->arch.insn);
int len, err = -EIO;
/* Copy only available bytes, -EIO if nothing was read */
@ -569,7 +603,7 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
goto out;
ret = -ENOTSUPP;
if (is_trap_insn((uprobe_opcode_t *)uprobe->arch.insn))
if (is_trap_insn((uprobe_opcode_t *)&uprobe->arch.insn))
goto out;
ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
@ -1264,7 +1298,7 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
/* Initialize the slot */
copy_to_page(area->page, xol_vaddr,
uprobe->arch.ixol, sizeof(uprobe->arch.ixol));
&uprobe->arch.ixol, sizeof(uprobe->arch.ixol));
/*
* We probably need flush_icache_user_range() but it needs vma.
* This should work on supported architectures too.
@ -1403,12 +1437,10 @@ static void uprobe_warn(struct task_struct *t, const char *msg)
static void dup_xol_work(struct callback_head *work)
{
kfree(work);
if (current->flags & PF_EXITING)
return;
if (!__create_xol_area(current->utask->vaddr))
if (!__create_xol_area(current->utask->dup_xol_addr))
uprobe_warn(current, "dup xol area");
}
@ -1419,7 +1451,6 @@ void uprobe_copy_process(struct task_struct *t, unsigned long flags)
{
struct uprobe_task *utask = current->utask;
struct mm_struct *mm = current->mm;
struct callback_head *work;
struct xol_area *area;
t->utask = NULL;
@ -1441,14 +1472,9 @@ void uprobe_copy_process(struct task_struct *t, unsigned long flags)
if (mm == t->mm)
return;
/* TODO: move it into the union in uprobe_task */
work = kmalloc(sizeof(*work), GFP_KERNEL);
if (!work)
return uprobe_warn(t, "dup xol area");
t->utask->vaddr = area->vaddr;
init_task_work(work, dup_xol_work);
task_work_add(t, work, true);
t->utask->dup_xol_addr = area->vaddr;
init_task_work(&t->utask->dup_xol_work, dup_xol_work);
task_work_add(t, &t->utask->dup_xol_work, true);
}
/*