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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Linux-mm <linux-mm@kvack.org>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	Christoph Hellwig <hch@infradead.org>,
	Andi Kleen <andi@firstfloor.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Oleg Nesterov <oleg@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Jim Keniston <jkenisto@linux.vnet.ibm.com>,
	Roland McGrath <roland@hack.frob.com>,
	SystemTap <systemtap@sources.redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH v2 2.6.38-rc8-tip 7/20]  7: uprobes: store/restore original instruction.
Date: Mon, 14 Mar 2011 19:05:22 +0530	[thread overview]
Message-ID: <20110314133522.27435.45121.sendpatchset@localhost6.localdomain6> (raw)
In-Reply-To: <20110314133403.27435.7901.sendpatchset@localhost6.localdomain6>


On the first probe insertion, copy the original instruction and opcode.
If multiple vmas map the same text area corresponding to an inode, we
only need to copy the instruction just once.
The copied instruction is further copied to a designated slot on probe
hit.  Its also used at the time of probe removal to restore the original
instruction.
opcode is used to analyze the instruction and determine the fixups.
Determining fixups at probe hit time would result in doing the same
operation on every probe hit. Hence Instruction analysis using the
opcode is done at probe insertion time.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 kernel/uprobes.c |  113 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 105 insertions(+), 8 deletions(-)

diff --git a/kernel/uprobes.c b/kernel/uprobes.c
index 4dbb90f..8730633 100644
--- a/kernel/uprobes.c
+++ b/kernel/uprobes.c
@@ -52,11 +52,12 @@ static int write_opcode(struct task_struct *tsk, struct uprobe * uprobe,
 			unsigned long vaddr, uprobe_opcode_t opcode)
 {
 	struct page *old_page, *new_page;
+	struct address_space *mapping;
 	void *vaddr_old, *vaddr_new;
 	struct vm_area_struct *vma;
 	spinlock_t *ptl;
 	pte_t *orig_pte;
-	unsigned long addr;
+	loff_t addr;
 	int ret = -EINVAL;
 
 	/* Read the page with vaddr into memory */
@@ -73,6 +74,18 @@ static int write_opcode(struct task_struct *tsk, struct uprobe * uprobe,
 	if (!valid_vma(vma))
 		goto put_out;
 
+	mapping = uprobe->inode->i_mapping;
+	if (mapping != vma->vm_file->f_mapping)
+		goto put_out;
+
+	addr = vma->vm_start + uprobe->offset;
+	addr -= vma->vm_pgoff << PAGE_SHIFT;
+	if (addr > ULONG_MAX)
+		goto put_out;
+
+	if (vaddr != (unsigned long) addr)
+		goto put_out;
+
 	/* Allocate a page */
 	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
 	if (!new_page) {
@@ -91,7 +104,6 @@ static int write_opcode(struct task_struct *tsk, struct uprobe * uprobe,
 
 	memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
 	/* poke the new insn in, ASSUMES we don't cross page boundary */
-	addr = vaddr;
 	vaddr &= ~PAGE_MASK;
 	memcpy(vaddr_new + vaddr, &opcode, uprobe_opcode_sz);
 
@@ -435,24 +447,109 @@ static int del_consumer(struct uprobe *uprobe,
 	return ret;
 }
 
+static int __copy_insn(struct address_space *mapping, char *insn,
+			unsigned long nbytes, unsigned long offset)
+{
+	struct page *page;
+	void *vaddr;
+	unsigned long off1;
+	loff_t idx;
+
+	idx = offset >> PAGE_CACHE_SHIFT;
+	off1 = offset &= ~PAGE_MASK;
+	page = grab_cache_page(mapping, (unsigned long)idx);
+	if (!page)
+		return -ENOMEM;
+
+	vaddr = kmap_atomic(page, KM_USER0);
+	memcpy(insn, vaddr + off1, nbytes);
+	kunmap_atomic(vaddr, KM_USER0);
+	unlock_page(page);
+	page_cache_release(page);
+	return 0;
+}
+
+static int copy_insn(struct uprobe *uprobe, unsigned long addr)
+{
+	struct address_space *mapping;
+	int bytes;
+	unsigned long nbytes;
+
+	addr &= ~PAGE_MASK;
+	nbytes = PAGE_SIZE - addr;
+	mapping = uprobe->inode->i_mapping;
+
+	/* Instruction at end of binary; copy only available bytes */
+	if (uprobe->offset + MAX_UINSN_BYTES > uprobe->inode->i_size)
+		bytes = uprobe->inode->i_size - uprobe->offset;
+	else
+		bytes = MAX_UINSN_BYTES;
+
+	/* Instruction at the page-boundary; copy bytes in second page */
+	if (nbytes < bytes) {
+		if (__copy_insn(mapping, uprobe->insn + nbytes,
+				bytes - nbytes, uprobe->offset + nbytes))
+			return -ENOMEM;
+		bytes = nbytes;
+	}
+	return __copy_insn(mapping, uprobe->insn, bytes, uprobe->offset);
+}
+
 static int install_uprobe(struct mm_struct *mm, struct uprobe *uprobe)
 {
-	int ret = 0;
+	struct task_struct *tsk;
+	int ret = -EINVAL;
 
-	/*TODO: install breakpoint */
-	if (!ret)
+	get_task_struct(mm->owner);
+	tsk = mm->owner;
+	if (!tsk)
+		return ret;
+
+	if (!uprobe->copy) {
+		ret = copy_insn(uprobe, mm->uprobes_vaddr);
+		if (ret)
+			goto put_return;
+		if (is_bkpt_insn(uprobe->insn)) {
+			print_insert_fail(tsk, mm->uprobes_vaddr,
+				"breakpoint instruction already exists");
+			ret = -EEXIST;
+			goto put_return;
+		}
+		ret = analyze_insn(tsk, uprobe);
+		if (ret) {
+			print_insert_fail(tsk, mm->uprobes_vaddr,
+					"instruction type cannot be probed");
+			goto put_return;
+		}
+		uprobe->copy = 1;
+	}
+
+	ret = set_bkpt(tsk, uprobe, mm->uprobes_vaddr);
+	if (ret < 0)
+		print_insert_fail(tsk, mm->uprobes_vaddr,
+					"failed to insert bkpt instruction");
+	else
 		atomic_inc(&mm->uprobes_count);
+
+put_return:
+	put_task_struct(tsk);
 	return ret;
 }
 
 static int remove_uprobe(struct mm_struct *mm, struct uprobe *uprobe)
 {
-	int ret = 0;
+	struct task_struct *tsk;
+	int ret;
+
+	get_task_struct(mm->owner);
+	tsk = mm->owner;
+	if (!tsk)
+		return -EINVAL;
 
-	/*TODO: remove breakpoint */
+	ret = set_orig_insn(tsk, uprobe, mm->uprobes_vaddr, true);
 	if (!ret)
 		atomic_dec(&mm->uprobes_count);
-
+	put_task_struct(tsk);
 	return ret;
 }
 

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  parent reply	other threads:[~2011-03-14 13:41 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-14 13:34 [PATCH v2 2.6.38-rc8-tip 0/20] 0: Inode based uprobes Srikar Dronamraju
2011-03-14 13:34 ` [PATCH v2 2.6.38-rc8-tip 1/20] 1: mm: Move replace_page() to mm/memory.c Srikar Dronamraju
2011-03-14 14:16   ` Steven Rostedt
2011-03-14 17:02     ` Srikar Dronamraju
2011-03-14 17:13       ` Steven Rostedt
2011-03-14 17:29         ` Srikar Dronamraju
2011-03-14 13:34 ` [PATCH v2 2.6.38-rc8-tip 2/20] 2: X86 specific breakpoint definitions Srikar Dronamraju
2011-03-14 13:34 ` [PATCH v2 2.6.38-rc8-tip 3/20] 3: uprobes: Breakground page replacement Srikar Dronamraju
2011-03-14 15:29   ` Steven Rostedt
2011-03-14 15:38   ` Steven Rostedt
2011-03-14 17:24     ` Srikar Dronamraju
2011-03-14 18:21       ` Steven Rostedt
2011-03-14 18:22       ` Steven Rostedt
2011-03-14 16:58   ` Stephen Wilson
2011-03-14 17:30     ` Srikar Dronamraju
2011-03-15 13:22   ` Thomas Gleixner
2011-03-15 17:51     ` Srikar Dronamraju
2011-03-15 18:03       ` Thomas Gleixner
2011-03-15 18:07         ` Srikar Dronamraju
2011-03-14 13:34 ` [PATCH v2 2.6.38-rc8-tip 4/20] 4: uprobes: Adding and remove a uprobe in a rb tree Srikar Dronamraju
2011-03-15 13:38   ` Thomas Gleixner
2011-03-15 13:43     ` Steven Rostedt
2011-03-15 17:30     ` Srikar Dronamraju
2011-03-15 19:22       ` Thomas Gleixner
2011-03-15 19:48         ` Peter Zijlstra
2011-03-15 22:42           ` Eric Dumazet
2011-03-16  7:54             ` Peter Zijlstra
2011-03-14 13:34 ` [PATCH v2 2.6.38-rc8-tip 5/20] 5: Uprobes: register/unregister probes Srikar Dronamraju
2011-03-14 16:00   ` Steven Rostedt
2011-03-14 17:32     ` Srikar Dronamraju
2011-03-15 14:28   ` Thomas Gleixner
2011-03-15 17:15     ` Srikar Dronamraju
2011-03-15 17:47       ` Steven Rostedt
2011-03-15 17:50         ` Peter Zijlstra
2011-03-15 18:04           ` Srikar Dronamraju
2011-03-15 18:15             ` Peter Zijlstra
2011-03-18 18:53               ` Srikar Dronamraju
2011-03-15 18:15       ` Thomas Gleixner
2011-03-14 13:35 ` [PATCH v2 2.6.38-rc8-tip 6/20] 6: x86: analyze instruction and determine fixups Srikar Dronamraju
2011-03-15 14:36   ` Thomas Gleixner
2011-03-18 18:24     ` Srikar Dronamraju
2011-03-18 18:36       ` Roland McGrath
2011-03-18 18:49         ` Srikar Dronamraju
2011-03-18 19:07           ` Srikar Dronamraju
2011-03-18 19:10           ` Roland McGrath
2011-03-14 13:35 ` Srikar Dronamraju [this message]
2011-03-14 18:09   ` [PATCH v2 2.6.38-rc8-tip 7/20] 7: uprobes: store/restore original instruction Stephen Wilson
2011-03-15  9:22     ` Srikar Dronamraju
2011-03-15 13:47       ` Steven Rostedt
2011-03-15 16:15         ` Stephen Wilson
2011-03-15 16:17           ` Srikar Dronamraju
2011-03-15 16:21           ` Steven Rostedt
2011-03-15 17:57       ` Peter Zijlstra
2011-03-15 18:58         ` Balbir Singh
2011-03-15 19:30           ` Peter Zijlstra
2011-03-15 19:32             ` Steven Rostedt
2011-03-16  5:51               ` Balbir Singh
2011-03-16 17:40                 ` Steven Rostedt
2011-03-15 14:41   ` Thomas Gleixner
2011-03-15 16:25     ` Srikar Dronamraju
2011-03-14 13:35 ` [PATCH v2 2.6.38-rc8-tip 8/20] 8: uprobes: mmap and fork hooks Srikar Dronamraju
2011-03-14 13:35 ` [PATCH v2 2.6.38-rc8-tip 9/20] 9: x86: architecture specific task information Srikar Dronamraju
2011-03-14 13:36 ` [PATCH v2 2.6.38-rc8-tip 10/20] 10: uprobes: task specific information Srikar Dronamraju
2011-03-14 13:36 ` [PATCH v2 2.6.38-rc8-tip 11/20] 11: uprobes: slot allocation for uprobes Srikar Dronamraju
2011-03-15 19:10   ` Jonathan Corbet
2011-03-16  4:58     ` Srikar Dronamraju
2011-03-15 20:31   ` Stephen Wilson
2011-03-16  4:50     ` Srikar Dronamraju
2011-03-14 13:36 ` [PATCH v2 2.6.38-rc8-tip 12/20] 12: uprobes: get the breakpoint address Srikar Dronamraju
2011-03-14 13:36 ` [PATCH v2 2.6.38-rc8-tip 13/20] 13: x86: x86 specific probe handling Srikar Dronamraju
2011-03-14 13:36 ` [PATCH v2 2.6.38-rc8-tip 14/20] 14: uprobes: Handing int3 and singlestep exception Srikar Dronamraju
2011-03-14 13:36 ` [PATCH v2 2.6.38-rc8-tip 15/20] 15: x86: uprobes exception notifier for x86 Srikar Dronamraju
2011-03-14 13:37 ` [PATCH v2 2.6.38-rc8-tip 16/20] 16: uprobes: register a notifier for uprobes Srikar Dronamraju
2011-03-15 19:56   ` Stephen Wilson
2011-03-18 19:28     ` Srikar Dronamraju
2011-03-14 13:37 ` [PATCH v2 2.6.38-rc8-tip 17/20] 17: uprobes: filter chain Srikar Dronamraju
2011-03-15 19:49   ` Stephen Wilson
2011-03-18 19:16     ` Srikar Dronamraju
2011-03-18 22:10       ` Stephen Wilson
2011-03-14 13:37 ` [PATCH v2 2.6.38-rc8-tip 18/20] 18: uprobes: commonly used filters Srikar Dronamraju
2011-03-14 13:37 ` [PATCH v2 2.6.38-rc8-tip 19/20] 19: tracing: Extract out common code for kprobes/uprobes traceevents Srikar Dronamraju
2011-03-14 13:37 ` [PATCH v2 2.6.38-rc8-tip 20/20] 20: tracing: uprobes trace_event interface Srikar Dronamraju
2011-03-14 23:30 ` [PATCH v2 2.6.38-rc8-tip 0/20] 0: Inode based uprobes Andrew Morton
2011-03-14 23:47   ` Andi Kleen
2011-03-15  0:22     ` Thomas Gleixner
2011-03-15 18:06       ` Andi Kleen
2011-03-15 19:43         ` Thomas Gleixner
2011-03-15 20:01           ` Steven Rostedt
2011-03-15 20:09             ` Thomas Gleixner
2011-03-15 20:44               ` Steven Rostedt
2011-03-16 17:32                 ` Tom Tromey
2011-03-16 17:44                   ` Steven Rostedt
2011-03-16 17:27               ` Tom Tromey
2011-03-15  1:13   ` Frank Ch. Eigler
2011-03-15  1:35     ` Thomas Gleixner
2011-03-15  5:21       ` Srikar Dronamraju
2011-03-15 11:02         ` Thomas Gleixner
2011-03-15 11:37           ` Srikar Dronamraju
2011-03-15  1:57   ` Srikar Dronamraju
2011-03-15  2:52   ` Steven Rostedt

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