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Date: Mon, 28 Nov 2011 20:07:46 +0100
From: Oleg Nesterov <oleg@...hat.com>
To: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@...radead.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Andrew Morton <akpm@...ux-foundation.org>,
LKML <linux-kernel@...r.kernel.org>,
Linux-mm <linux-mm@...ck.org>, Ingo Molnar <mingo@...e.hu>,
Andi Kleen <andi@...stfloor.org>,
Christoph Hellwig <hch@...radead.org>,
Steven Rostedt <rostedt@...dmis.org>,
Roland McGrath <roland@...k.frob.com>,
Thomas Gleixner <tglx@...utronix.de>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Arnaldo Carvalho de Melo <acme@...radead.org>,
Anton Arapov <anton@...hat.com>,
Ananth N Mavinakayanahalli <ananth@...ibm.com>,
Jim Keniston <jkenisto@...ux.vnet.ibm.com>,
Stephen Wilson <wilsons@...rt.ca>
Subject: [PATCH 5/5] uprobes: remove the uprobes_xol_area code
Remove the no longer needed uprobes_xol_area code.
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
include/linux/mm_types.h | 1 -
include/linux/uprobes.h | 24 ------
kernel/fork.c | 2 -
kernel/uprobes.c | 198 ----------------------------------------------
4 files changed, 0 insertions(+), 225 deletions(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 2595c9c..b3f1ece 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -392,7 +392,6 @@ struct mm_struct {
#endif
#ifdef CONFIG_UPROBES
atomic_t mm_uprobes_count;
- struct uprobes_xol_area *uprobes_xol_area;
#endif
};
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index bb59a66..4f92272 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -100,26 +100,6 @@ struct uprobe_task {
struct uprobe *active_uprobe;
};
-/*
- * On a breakpoint hit, thread contests for a slot. It free the
- * slot after singlestep. Only definite number of slots are
- * allocated.
- */
-
-struct uprobes_xol_area {
- wait_queue_head_t wq; /* if all slots are busy */
- atomic_t slot_count; /* currently 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 */
-};
-
#ifdef CONFIG_UPROBES
extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe,
unsigned long vaddr);
@@ -131,7 +111,6 @@ extern int register_uprobe(struct inode *inode, loff_t offset,
extern void unregister_uprobe(struct inode *inode, loff_t offset,
struct uprobe_consumer *consumer);
extern void free_uprobe_utask(struct task_struct *tsk);
-extern void free_uprobes_xol_area(struct mm_struct *mm);
extern int mmap_uprobe(struct vm_area_struct *vma);
extern void munmap_uprobe(struct vm_area_struct *vma);
extern unsigned long __weak get_uprobe_bkpt_addr(struct pt_regs *regs);
@@ -174,8 +153,5 @@ static inline unsigned long get_uprobe_bkpt_addr(struct pt_regs *regs)
static inline void free_uprobe_utask(struct task_struct *tsk)
{
}
-static inline void free_uprobes_xol_area(struct mm_struct *mm)
-{
-}
#endif /* CONFIG_UPROBES */
#endif /* _LINUX_UPROBES_H */
diff --git a/kernel/fork.c b/kernel/fork.c
index 166ee1b..a6b1757 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -553,7 +553,6 @@ void mmput(struct mm_struct *mm)
might_sleep();
if (atomic_dec_and_test(&mm->mm_users)) {
- free_uprobes_xol_area(mm);
exit_aio(mm);
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
@@ -742,7 +741,6 @@ struct mm_struct *dup_mm(struct task_struct *tsk)
#endif
#ifdef CONFIG_UPROBES
atomic_set(&mm->mm_uprobes_count, 0);
- mm->uprobes_xol_area = NULL;
#endif
if (!mm_init(mm, tsk))
diff --git a/kernel/uprobes.c b/kernel/uprobes.c
index c9e2f65..aaab607 100644
--- a/kernel/uprobes.c
+++ b/kernel/uprobes.c
@@ -33,9 +33,6 @@
#include <linux/kdebug.h> /* notifier mechanism */
#include <linux/uprobes.h>
-#define UINSNS_PER_PAGE (PAGE_SIZE/UPROBES_XOL_SLOT_BYTES)
-#define MAX_UPROBES_XOL_SLOTS UINSNS_PER_PAGE
-
static bulkref_t uprobes_srcu;
static struct rb_root uprobes_tree = RB_ROOT;
static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */
@@ -1062,201 +1059,6 @@ void munmap_uprobe(struct vm_area_struct *vma)
return;
}
-/* Slot allocation for XOL */
-static int xol_add_vma(struct uprobes_xol_area *area)
-{
- struct mm_struct *mm;
- int ret;
-
- area->page = alloc_page(GFP_HIGHUSER);
- if (!area->page)
- return -ENOMEM;
-
- mm = current->mm;
- down_write(&mm->mmap_sem);
- ret = -EALREADY;
- if (mm->uprobes_xol_area)
- goto fail;
-
- ret = -ENOMEM;
-
- /* Try to map as high as possible, this is only a hint. */
- area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE,
- PAGE_SIZE, 0, 0);
- if (area->vaddr & ~PAGE_MASK) {
- ret = area->vaddr;
- goto fail;
- }
-
- ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE,
- VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO,
- &area->page);
- if (ret)
- goto fail;
-
- smp_wmb(); /* pairs with get_uprobes_xol_area() */
- mm->uprobes_xol_area = area;
- ret = 0;
-
-fail:
- up_write(&mm->mmap_sem);
- if (ret)
- __free_page(area->page);
-
- return ret;
-}
-
-static struct uprobes_xol_area *get_uprobes_xol_area(struct mm_struct *mm)
-{
- struct uprobes_xol_area *area = mm->uprobes_xol_area;
- smp_read_barrier_depends();/* pairs with wmb in xol_add_vma() */
- return area;
-}
-
-/*
- * xol_alloc_area - Allocate process's uprobes_xol_area.
- * This area will be used for storing instructions for execution out of
- * line.
- *
- * Returns the allocated area or NULL.
- */
-static struct uprobes_xol_area *xol_alloc_area(void)
-{
- struct uprobes_xol_area *area;
-
- area = kzalloc(sizeof(*area), GFP_KERNEL);
- if (unlikely(!area))
- return NULL;
-
- area->bitmap = kzalloc(BITS_TO_LONGS(UINSNS_PER_PAGE) * sizeof(long),
- GFP_KERNEL);
-
- if (!area->bitmap)
- goto fail;
-
- init_waitqueue_head(&area->wq);
- if (!xol_add_vma(area))
- return area;
-
-fail:
- kfree(area->bitmap);
- kfree(area);
- return get_uprobes_xol_area(current->mm);
-}
-
-/*
- * free_uprobes_xol_area - Free the area allocated for slots.
- */
-void free_uprobes_xol_area(struct mm_struct *mm)
-{
- struct uprobes_xol_area *area = mm->uprobes_xol_area;
-
- if (!area)
- return;
-
- put_page(area->page);
- kfree(area->bitmap);
- kfree(area);
-}
-
-/*
- * - search for a free slot.
- */
-static unsigned long xol_take_insn_slot(struct uprobes_xol_area *area)
-{
- unsigned long slot_addr;
- int slot_nr;
-
- do {
- slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE);
- if (slot_nr < UINSNS_PER_PAGE) {
- if (!test_and_set_bit(slot_nr, area->bitmap))
- break;
-
- slot_nr = UINSNS_PER_PAGE;
- continue;
- }
- wait_event(area->wq,
- (atomic_read(&area->slot_count) < UINSNS_PER_PAGE));
- } while (slot_nr >= UINSNS_PER_PAGE);
-
- slot_addr = area->vaddr + (slot_nr * UPROBES_XOL_SLOT_BYTES);
- atomic_inc(&area->slot_count);
- return slot_addr;
-}
-
-/*
- * xol_get_insn_slot - If was not allocated a slot, then
- * allocate a slot.
- * Returns the allocated slot address or 0.
- */
-static unsigned long xol_get_insn_slot(struct uprobe *uprobe,
- unsigned long slot_addr)
-{
- struct uprobes_xol_area *area;
- unsigned long offset;
- void *vaddr;
-
- area = get_uprobes_xol_area(current->mm);
- if (!area) {
- area = xol_alloc_area();
- if (!area)
- return 0;
- }
- current->utask->xol_vaddr = xol_take_insn_slot(area);
-
- /*
- * Initialize the slot if xol_vaddr points to valid
- * instruction slot.
- */
- if (unlikely(!current->utask->xol_vaddr))
- return 0;
-
- current->utask->vaddr = slot_addr;
- offset = current->utask->xol_vaddr & ~PAGE_MASK;
- vaddr = kmap_atomic(area->page);
- memcpy(vaddr + offset, uprobe->insn, MAX_UINSN_BYTES);
- kunmap_atomic(vaddr);
- return current->utask->xol_vaddr;
-}
-
-/*
- * xol_free_insn_slot - If slot was earlier allocated by
- * @xol_get_insn_slot(), make the slot available for
- * subsequent requests.
- */
-static void xol_free_insn_slot(struct task_struct *tsk)
-{
- struct uprobes_xol_area *area;
- unsigned long vma_end;
- unsigned long slot_addr;
-
- if (!tsk->mm || !tsk->mm->uprobes_xol_area || !tsk->utask)
- return;
-
- slot_addr = tsk->utask->xol_vaddr;
-
- if (unlikely(!slot_addr || IS_ERR_VALUE(slot_addr)))
- return;
-
- area = tsk->mm->uprobes_xol_area;
- vma_end = area->vaddr + PAGE_SIZE;
- if (area->vaddr <= slot_addr && slot_addr < vma_end) {
- int slot_nr;
- unsigned long offset = slot_addr - area->vaddr;
-
- slot_nr = offset / UPROBES_XOL_SLOT_BYTES;
- if (slot_nr >= UINSNS_PER_PAGE)
- return;
-
- clear_bit(slot_nr, area->bitmap);
- atomic_dec(&area->slot_count);
- if (waitqueue_active(&area->wq))
- wake_up(&area->wq);
- tsk->utask->xol_vaddr = 0;
- }
-}
-
/**
* get_uprobe_bkpt_addr - compute address of bkpt given post-bkpt regs
* @regs: Reflects the saved state of the task after it has hit a breakpoint
--
1.5.5.1
--
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