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Re: [3/3] Userspace probes prototype-take2
This patch handles the executing the registered callback
functions when probes is hit.
Each userspace probe is uniquely identified by the
combination of inode and offset, hence during registeration the inode
and offset combination is added to kprobes hash table. Initially when
breakpoint instruction is hit, the kprobes hash table is looked up
for matching inode and offset. The pre_handlers are called in sequence
if multiple probes are registered. The original instruction is single
stepped out-of-line similar to kernel probes. In kernel space probes,
single stepping out-of-line is achieved by copying the instruction on
to some location within kernel address space and then single step
from that location. But for userspace probes, instruction copied
into kernel address space cannot be single stepped, hence the
instruction should be copied to user address space. The solution is
to find free space in the current process address space and then copy
the original instruction and single step that instruction.
User processes use stack space to store local variables, agruments and
return values. Normally the stack space either below or above the
stack pointer indicates the free stack space. If the stack grows
downwards, the stack space below the stack pointer indicates the
unused stack free space and if the stack grows upwards, the stack
space above the stack pointer indicates the unused stack free space.
The instruction to be single stepped can modify the stack space, hence
before using the unused stack free space, sufficient stack space
should be left. The instruction is copied to the bottom of the page
and check is made such that the copied instruction does not cross the
page boundry. The copied instruction is then single stepped.
Several architectures does not allow the instruction to be executed
from the stack location, since no-exec bit is set for the stack pages.
In those architectures, the page table entry corresponding to the
stack page is identified and the no-exec bit is unset making the
instruction on that stack page to be executed.
There are situations where even the unused free stack space is not
enough for the user instruction to be copied and single stepped. In
such situations, the virtual memory area(vma) can be expanded beyond
the current stack vma. This expaneded stack can be used to copy the
original instruction and single step out-of-line.
Even if the vma cannot be extended then the instruction much be
executed inline, by replacing the breakpoint instruction with original
instruction.
TODO list
--------
1. This patch is not stable yet, should work for most conditions.
2. This patch works only with PREEMPT config option disabled, to work
in PREEMPT enabled condition handlers must be re-written and must
be seperated out from kernel probes allowing preemption.
3. Insert probes on copy-on-write pages. Tracks all COW pages for the
page containing the specified probe point and inserts/removes all the
probe points for that page.
4. Optimize the insertion of probes through readpage hooks. Identify
all the probes to be inserted on the read page and insert them at
once.
5. Resume exectution should handle setting of proper eip and eflags
for special instructions similar to kernel probes.
6. Single stepping out-of-line expands the stack if there is no
enough stack space to copy the original instruction. Expansion of
stack should be shrinked back to the original size after single
stepping or the expanded stack should be reused for single stepping
out-of-line for other probes.
7. A wrapper routines to calculate the offset from the probed file
beginning. In case of dynamic shared library, the offset is
calculated by substracting the address of the probe point from the
beginning of the file mapped address.
8. Handing of page faults while inthe kprobes_handler() and while
single stepping.
9. Accessing user space pages not present in memory, from the
registered callback routines.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
arch/i386/kernel/kprobes.c | 460 +++++++++++++++++++++++++++++++++++++++++++--
include/asm-i386/kprobes.h | 13 +
include/linux/kprobes.h | 7
kernel/kprobes.c | 3
4 files changed, 468 insertions(+), 15 deletions(-)
diff -puN arch/i386/kernel/kprobes.c~kprobes_userspace_probes_ss_out-of-line arch/i386/kernel/kprobes.c
--- linux-2.6.16-rc1-mm5/arch/i386/kernel/kprobes.c~kprobes_userspace_probes_ss_out-of-line 2006-02-08 19:26:09.000000000 +0530
+++ linux-2.6.16-rc1-mm5-prasanna/arch/i386/kernel/kprobes.c 2006-02-08 19:26:10.000000000 +0530
@@ -30,6 +30,7 @@
#include <linux/config.h>
#include <linux/kprobes.h>
+#include <linux/hash.h>
#include <linux/ptrace.h>
#include <linux/preempt.h>
#include <asm/cacheflush.h>
@@ -38,8 +39,12 @@
void jprobe_return_end(void);
+static struct uprobe_page *uprobe_page;
+static struct hlist_head uprobe_page_table[KPROBE_TABLE_SIZE];
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+DEFINE_PER_CPU(struct uprobe *, current_uprobe) = NULL;
+DEFINE_PER_CPU(unsigned long, singlestep_addr);
/* insert a jmp code */
static inline void set_jmp_op(void *from, void *to)
@@ -125,6 +130,23 @@ void __kprobes arch_disarm_kprobe(struct
(unsigned long) p->addr + sizeof(kprobe_opcode_t));
}
+void __kprobes arch_disarm_uprobe(struct kprobe *p, kprobe_opcode_t *address)
+{
+ *address = p->opcode;
+}
+
+void __kprobes arch_arm_uprobe(unsigned long *address)
+{
+ *(kprobe_opcode_t *)address = BREAKPOINT_INSTRUCTION;
+}
+
+void __kprobes arch_copy_uprobe(struct kprobe *p, unsigned long *address)
+{
+ memcpy(p->ainsn.insn, (kprobe_opcode_t *)address,
+ MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ p->opcode = *(kprobe_opcode_t *)address;
+}
+
static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
@@ -151,15 +173,326 @@ static inline void set_current_kprobe(st
kcb->kprobe_saved_eflags &= ~IF_MASK;
}
+struct uprobe_page __kprobes *get_upage_current(struct task_struct *tsk)
+{
+ struct hlist_head *head;
+ struct hlist_node *node;
+ struct uprobe_page *upage;
+
+ head = &uprobe_page_table[hash_ptr(current, KPROBE_HASH_BITS)];
+ hlist_for_each_entry(upage, node, head, hlist) {
+ if (upage->tsk == tsk)
+ return upage;
+ }
+ return NULL;
+}
+
+struct uprobe_page __kprobes *get_upage_free(struct task_struct *tsk)
+{
+ int cpu;
+
+ for_each_cpu(cpu) {
+ struct uprobe_page *upage;
+ upage = per_cpu_ptr(uprobe_page, cpu);
+ if (upage->status & UPROBE_PAGE_FREE)
+ return upage;
+ }
+ return NULL;
+}
+
+/**
+ * This routines get the pte of the page containing the specified address.
+ */
+static pte_t __kprobes *get_uprobe_pte(unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte = NULL;
+
+ pgd = pgd_offset(current->mm, address);
+ if (!pgd)
+ goto out;
+
+ pud = pud_offset(pgd, address);
+ if (!pud)
+ goto out;
+
+ pmd = pmd_offset(pud, address);
+ if (!pmd)
+ goto out;
+
+ pte = pte_alloc_map(current->mm, pmd, address);
+
+out:
+ return pte;
+}
+
+/**
+ * This routine check for space in the current process's stack address space.
+ * If enough address space is found, it just maps a new page and copies the
+ * new instruction on that page for single stepping out-of-line.
+ */
+static int __kprobes copy_insn_on_new_page(struct uprobe *uprobe ,
+ struct pt_regs *regs, struct vm_area_struct *vma)
+{
+ unsigned long addr, *vaddr, stack_addr = regs->esp;
+ int size = MAX_INSN_SIZE * sizeof(kprobe_opcode_t);
+ struct uprobe_page *upage;
+ struct page *page;
+ pte_t *pte;
+
+
+ if (vma->vm_flags & VM_GROWSDOWN) {
+ if (((stack_addr - sizeof(long long))) < (vma->vm_start + size))
+ return -ENOMEM;
+
+ addr = vma->vm_start;
+ } else if (vma->vm_flags & VM_GROWSUP) {
+ if ((vma->vm_end - size) < (stack_addr + sizeof(long long)))
+ return -ENOMEM;
+
+ addr = vma->vm_end - size;
+ } else
+ return -EFAULT;
+
+ preempt_enable_no_resched();
+
+ pte = get_uprobe_pte(addr);
+ preempt_disable();
+ if (!pte)
+ return -EFAULT;
+
+ upage = get_upage_free(current);
+ upage->status &= ~UPROBE_PAGE_FREE;
+ upage->tsk = current;
+ INIT_HLIST_NODE(&upage->hlist);
+ hlist_add_head(&upage->hlist,
+ &uprobe_page_table[hash_ptr(current, KPROBE_HASH_BITS)]);
+
+ upage->orig_pte = pte;
+ upage->orig_pte_val = pte_val(*pte);
+ set_pte(pte, (*(upage->alias_pte)));
+
+ page = pte_page(*pte);
+ vaddr = (unsigned long *)kmap_atomic(page, KM_USER1);
+ vaddr = (unsigned long *)((unsigned long)vaddr + (addr & ~PAGE_MASK));
+ memcpy(vaddr, (unsigned long *)uprobe->kp.ainsn.insn, size);
+ kunmap_atomic(vaddr, KM_USER1);
+ regs->eip = addr;
+
+ return 0;
+}
+
+/**
+ * This routine expands the stack beyond the present process address space
+ * and copies the instruction to that location, so that processor can
+ * single step out-of-line.
+ */
+static int __kprobes copy_insn_onexpstack(struct uprobe *uprobe,
+ struct pt_regs *regs, struct vm_area_struct *vma)
+{
+ unsigned long addr, *vaddr, vm_addr;
+ int size = MAX_INSN_SIZE * sizeof(kprobe_opcode_t);
+ struct vm_area_struct *new_vma;
+ struct uprobe_page *upage;
+ struct mm_struct *mm = current->mm;
+ struct page *page;
+ pte_t *pte;
+
+
+ if (vma->vm_flags & VM_GROWSDOWN)
+ vm_addr = vma->vm_start - size;
+ else if (vma->vm_flags & VM_GROWSUP)
+ vm_addr = vma->vm_end + size;
+ else
+ return -EFAULT;
+
+ preempt_enable_no_resched();
+
+ /* TODO: do we need to expand stack if extend_vma fails? */
+ new_vma = find_extend_vma(mm, vm_addr);
+ preempt_disable();
+ if (!new_vma)
+ return -ENOMEM;
+
+ /*
+ * TODO: Expanding stack for every probe is not a good idea, stack must
+ * either be shrunk to its original size after single stepping or the
+ * expanded stack should be kept track of, for the probed application,
+ * so it can be reused to single step out-of-line
+ */
+ if (new_vma->vm_flags & VM_GROWSDOWN)
+ addr = new_vma->vm_start;
+ else
+ addr = new_vma->vm_end - size;
+
+ preempt_enable_no_resched();
+ pte = get_uprobe_pte(addr);
+ preempt_disable();
+ if (!pte)
+ return -EFAULT;
+
+ upage = get_upage_free(current);
+ upage->status &= ~UPROBE_PAGE_FREE;
+ upage->tsk = current;
+ INIT_HLIST_NODE(&upage->hlist);
+ hlist_add_head(&upage->hlist,
+ &uprobe_page_table[hash_ptr(current, KPROBE_HASH_BITS)]);
+ upage->orig_pte = pte;
+ upage->orig_pte_val = pte_val(*pte);
+ set_pte(pte, (*(upage->alias_pte)));
+
+ page = pte_page(*pte);
+ vaddr = (unsigned long *)kmap_atomic(page, KM_USER1);
+ vaddr = (unsigned long *)((unsigned long)vaddr + (addr & ~PAGE_MASK));
+ memcpy(vaddr, (unsigned long *)uprobe->kp.ainsn.insn, size);
+ kunmap_atomic(vaddr, KM_USER1);
+ regs->eip = addr;
+
+ return 0;
+}
+
+/**
+ * This routine checks for stack free space below the stack pointer and
+ * then copies the instructions at that location so that the processor can
+ * single step out-of-line. If there is no enough stack space or if
+ * copy_to_user fails or if the vma is invalid, it returns error.
+ */
+static int __kprobes copy_insn_onstack(struct uprobe *uprobe,
+ struct pt_regs *regs, unsigned long flags)
+{
+ unsigned long page_addr, stack_addr = regs->esp;
+ int size = MAX_INSN_SIZE * sizeof(kprobe_opcode_t);
+ unsigned long *source = (unsigned long *)uprobe->kp.ainsn.insn;
+
+ if (flags & VM_GROWSDOWN) {
+ page_addr = stack_addr & PAGE_MASK;
+
+ if (((stack_addr - sizeof(long long))) < (page_addr + size))
+ return -ENOMEM;
+
+ if (__copy_to_user_inatomic((unsigned long *)page_addr, source,
+ size))
+ return -EFAULT;
+
+ regs->eip = page_addr;
+ } else if (flags & VM_GROWSUP) {
+ page_addr = stack_addr & PAGE_MASK;
+
+ if (page_addr == stack_addr)
+ return -ENOMEM;
+ else
+ page_addr += PAGE_SIZE;
+
+ if ((page_addr - size) < (stack_addr + sizeof(long long)))
+ return -ENOMEM;
+
+ if (__copy_to_user_inatomic((unsigned long *)(page_addr - size),
+ source, size))
+ return -EFAULT;
+
+ regs->eip = page_addr - size;
+ } else
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * This routines get the page containing the probe, maps it and
+ * replaced the instruction at the probed address with specified
+ * opcode.
+ */
+void __kprobes replace_original_insn(struct uprobe *uprobe,
+ struct pt_regs *regs, kprobe_opcode_t opcode)
+{
+ kprobe_opcode_t *addr;
+ struct page *page;
+
+ page = find_get_page(uprobe->inode->i_mapping,
+ uprobe->offset >> PAGE_CACHE_SHIFT);
+ lock_page(page);
+
+ addr = (kprobe_opcode_t *)kmap_atomic(page, KM_USER0);
+ addr = (kprobe_opcode_t *)((unsigned long)addr +
+ (unsigned long)(uprobe->offset & ~PAGE_MASK));
+ *addr = opcode;
+ /*TODO: flush vma ? */
+ kunmap_atomic(addr, KM_USER0);
+
+ unlock_page(page);
+
+ page_cache_release(page);
+ regs->eip = (unsigned long)uprobe->kp.addr;
+}
+
+/**
+ * This routine provides the functionality of single stepping out of line.
+ * If single stepping out-of-line cannot be achieved, it replaces with
+ * the original instruction allowing it to single step inline.
+ */
+static inline int uprobe_single_step(struct kprobe *p, struct pt_regs *regs)
+{
+ unsigned long stack_addr = regs->esp, flags;
+ struct vm_area_struct *vma = NULL;
+ struct uprobe *uprobe = __get_cpu_var(current_uprobe);
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ int err = 0;
+
+ down_read(¤t->mm->mmap_sem);
+
+ vma = find_vma(current->mm, (stack_addr & PAGE_MASK));
+ if (!vma) {
+ /* TODO: Need better error reporting? */
+ printk("No vma found\n");
+ up_read(¤t->mm->mmap_sem);
+ return -ENOENT;
+ }
+ flags = vma->vm_flags;
+ up_read(¤t->mm->mmap_sem);
+
+ kcb->kprobe_status |= UPROBE_SS_STACK;
+ err = copy_insn_onstack(uprobe, regs, flags);
+
+ down_write(¤t->mm->mmap_sem);
+
+ if (err) {
+ kcb->kprobe_status |= UPROBE_SS_NEW_STACK;
+ err = copy_insn_on_new_page(uprobe, regs, vma);
+ }
+ if (err) {
+ kcb->kprobe_status |= UPROBE_SS_EXPSTACK;
+ err = copy_insn_onexpstack(uprobe, regs, vma);
+ }
+
+ up_write(¤t->mm->mmap_sem);
+
+ if (err) {
+ kcb->kprobe_status |= UPROBE_SS_INLINE;
+ replace_original_insn(uprobe, regs, uprobe->kp.opcode);
+ }
+
+ __get_cpu_var(singlestep_addr) = regs->eip;
+
+
+ return 0;
+}
+
static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{
regs->eflags |= TF_MASK;
regs->eflags &= ~IF_MASK;
/*single step inline if the instruction is an int3*/
+
if (p->opcode == BREAKPOINT_INSTRUCTION)
regs->eip = (unsigned long)p->addr;
- else
- regs->eip = (unsigned long)&p->ainsn.insn;
+ else {
+ if (!kernel_text_address((unsigned long)p->addr))
+ uprobe_single_step(p, regs);
+ else
+ regs->eip = (unsigned long)&p->ainsn.insn;
+ }
}
/* Called with kretprobe_lock held */
@@ -194,6 +527,7 @@ static int __kprobes kprobe_handler(stru
kprobe_opcode_t *addr = NULL;
unsigned long *lp;
struct kprobe_ctlblk *kcb;
+ unsigned seg = regs->xcs & 0xffff;
#ifdef CONFIG_PREEMPT
unsigned pre_preempt_count = preempt_count();
#endif /* CONFIG_PREEMPT */
@@ -208,14 +542,21 @@ static int __kprobes kprobe_handler(stru
/* Check if the application is using LDT entry for its code segment and
* calculate the address by reading the base address from the LDT entry.
*/
- if ((regs->xcs & 4) && (current->mm)) {
+
+ if (regs->eflags & VM_MASK)
+ addr = (kprobe_opcode_t *)(((seg << 4) + regs->eip -
+ sizeof(kprobe_opcode_t)) & 0xffff);
+ else if ((regs->xcs & 4) && (current->mm)) {
+ local_irq_enable();
+ down(¤t->mm->context.sem);
lp = (unsigned long *) ((unsigned long)((regs->xcs >> 3) * 8)
+ (char *) current->mm->context.ldt);
addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip -
sizeof(kprobe_opcode_t));
- } else {
+ up(¤t->mm->context.sem);
+ local_irq_disable();
+ } else
addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
- }
/* Check we're not actually recursing */
if (kprobe_running()) {
p = get_kprobe(addr);
@@ -235,7 +576,6 @@ static int __kprobes kprobe_handler(stru
save_previous_kprobe(kcb);
set_current_kprobe(p, regs, kcb);
kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_REENTER;
return 1;
} else {
@@ -307,8 +647,8 @@ static int __kprobes kprobe_handler(stru
}
ss_probe:
- prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
+ prepare_singlestep(p, regs);
return 1;
no_kprobe:
@@ -498,6 +838,33 @@ no_change:
return;
}
+static void __kprobes resume_execution_user(struct uprobe *uprobe,
+ struct pt_regs *regs, struct kprobe_ctlblk *kcb)
+{
+ unsigned long delta;
+ struct uprobe_page *upage;
+
+ /*
+ * TODO :need to fixup special instructions as done with kernel probes.
+ */
+ delta = regs->eip - __get_cpu_var(singlestep_addr);
+ regs->eip = (unsigned long)(uprobe->kp.addr + delta);
+
+ if ((kcb->kprobe_status & UPROBE_SS_EXPSTACK) ||
+ (kcb->kprobe_status & UPROBE_SS_NEW_STACK)) {
+ upage = get_upage_current(current);
+ set_pte(upage->orig_pte, __pte(upage->orig_pte_val));
+ pte_unmap(upage->orig_pte);
+
+ upage->status = UPROBE_PAGE_FREE;
+ hlist_del(&upage->hlist);
+
+ } else if (kcb->kprobe_status & UPROBE_SS_INLINE)
+ replace_original_insn(uprobe, regs,
+ (kprobe_opcode_t)BREAKPOINT_INSTRUCTION);
+ regs->eflags &= ~TF_MASK;
+}
+
/*
* Interrupts are disabled on entry as trap1 is an interrupt gate and they
* remain disabled thoroughout this function.
@@ -510,16 +877,19 @@ static inline int post_kprobe_handler(st
if (!cur)
return 0;
- if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
- kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ if (!(kcb->kprobe_status & KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status |= KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
- resume_execution(cur, regs, kcb);
+ if (!kernel_text_address((unsigned long)cur->addr))
+ resume_execution_user(__get_cpu_var(current_uprobe), regs, kcb);
+ else
+ resume_execution(cur, regs, kcb);
regs->eflags |= kcb->kprobe_saved_eflags;
/*Restore back the original saved kprobes variables and continue. */
- if (kcb->kprobe_status == KPROBE_REENTER) {
+ if (kcb->kprobe_status & KPROBE_REENTER) {
restore_previous_kprobe(kcb);
goto out;
}
@@ -547,7 +917,13 @@ static inline int kprobe_fault_handler(s
return 1;
if (kcb->kprobe_status & KPROBE_HIT_SS) {
- resume_execution(cur, regs, kcb);
+ if (!kernel_text_address((unsigned long)cur->addr)) {
+ struct uprobe *uprobe = __get_cpu_var(current_uprobe);
+ /* TODO: Proper handling of all instruction */
+ replace_original_insn(uprobe, regs, uprobe->kp.opcode);
+ regs->eflags &= ~TF_MASK;
+ } else
+ resume_execution(cur, regs, kcb);
regs->eflags |= kcb->kprobe_old_eflags;
reset_current_kprobe();
@@ -654,7 +1030,67 @@ int __kprobes longjmp_break_handler(stru
return 0;
}
+static void free_alias(void)
+{
+ int cpu;
+
+ for_each_cpu(cpu) {
+ struct uprobe_page *upage;
+ upage = per_cpu_ptr(uprobe_page, cpu);
+
+ if (upage->alias_addr) {
+ set_pte(upage->alias_pte, __pte(upage->alias_pte_val));
+ kfree(upage->alias_addr);
+ }
+ upage->alias_pte = 0;
+ }
+ free_percpu(uprobe_page);
+ return;
+}
+
+static int alloc_alias(void)
+{
+ int cpu;
+
+ uprobe_page = __alloc_percpu(sizeof(struct uprobe_page));
+
+ for_each_cpu(cpu) {
+ struct uprobe_page *upage;
+ upage = per_cpu_ptr(uprobe_page, cpu);
+ upage->alias_addr = kmalloc(PAGE_SIZE, GFP_USER);
+ if (!upage->alias_addr) {
+ free_alias();
+ return -ENOMEM;
+ }
+ upage->alias_pte = lookup_address(
+ (unsigned long)upage->alias_addr);
+ upage->alias_pte_val = pte_val(*upage->alias_pte);
+ if (upage->alias_pte) {
+ upage->status = UPROBE_PAGE_FREE;
+ set_pte(upage->alias_pte,
+ pte_mkdirty(*upage->alias_pte));
+ set_pte(upage->alias_pte,
+ pte_mkexec(*upage->alias_pte));
+ set_pte(upage->alias_pte,
+ pte_mkwrite(*upage->alias_pte));
+ set_pte(upage->alias_pte,
+ pte_mkyoung(*upage->alias_pte));
+ }
+ }
+ return 0;
+}
+
int __init arch_init_kprobes(void)
{
+ int ret = 0;
+ /*
+ * user space probes requires a page to copy the original instruction
+ * so that it can single step if there is no free stack space, allocate
+ * per cpu page.
+ */
+
+ if ((ret = alloc_alias()))
+ return ret;
+
return 0;
}
diff -puN include/asm-i386/kprobes.h~kprobes_userspace_probes_ss_out-of-line include/asm-i386/kprobes.h
--- linux-2.6.16-rc1-mm5/include/asm-i386/kprobes.h~kprobes_userspace_probes_ss_out-of-line 2006-02-08 19:26:09.000000000 +0530
+++ linux-2.6.16-rc1-mm5-prasanna/include/asm-i386/kprobes.h 2006-02-08 19:26:10.000000000 +0530
@@ -42,6 +42,7 @@ typedef u8 kprobe_opcode_t;
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
#define ARCH_SUPPORTS_KRETPROBES
#define arch_remove_kprobe(p) do {} while (0)
+#define UPROBE_PAGE_FREE 0x00000001
void kretprobe_trampoline(void);
@@ -74,6 +75,18 @@ struct kprobe_ctlblk {
struct prev_kprobe prev_kprobe;
};
+/* per cpu uprobe page structure */
+struct uprobe_page {
+ struct hlist_node hlist;
+ pte_t *alias_pte;
+ pte_t *orig_pte;
+ unsigned long orig_pte_val;
+ unsigned long alias_pte_val;
+ void *alias_addr;
+ struct task_struct *tsk;
+ unsigned long status;
+};
+
/* trap3/1 are intr gates for kprobes. So, restore the status of IF,
* if necessary, before executing the original int3/1 (trap) handler.
*/
diff -puN include/linux/kprobes.h~kprobes_userspace_probes_ss_out-of-line include/linux/kprobes.h
--- linux-2.6.16-rc1-mm5/include/linux/kprobes.h~kprobes_userspace_probes_ss_out-of-line 2006-02-08 19:26:09.000000000 +0530
+++ linux-2.6.16-rc1-mm5-prasanna/include/linux/kprobes.h 2006-02-08 19:26:10.000000000 +0530
@@ -45,11 +45,18 @@
#ifdef CONFIG_KPROBES
#include <asm/kprobes.h>
+#define KPROBE_HASH_BITS 6
+#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
+
/* kprobe_status settings */
#define KPROBE_HIT_ACTIVE 0x00000001
#define KPROBE_HIT_SS 0x00000002
#define KPROBE_REENTER 0x00000004
#define KPROBE_HIT_SSDONE 0x00000008
+#define UPROBE_SS_STACK 0x00000010
+#define UPROBE_SS_EXPSTACK 0x00000020
+#define UPROBE_SS_INLINE 0x00000040
+#define UPROBE_SS_NEW_STACK 0x00000080
/* Attach to insert probes on any functions which should be ignored*/
#define __kprobes __attribute__((__section__(".kprobes.text")))
diff -puN kernel/kprobes.c~kprobes_userspace_probes_ss_out-of-line kernel/kprobes.c
--- linux-2.6.16-rc1-mm5/kernel/kprobes.c~kprobes_userspace_probes_ss_out-of-line 2006-02-08 19:26:10.000000000 +0530
+++ linux-2.6.16-rc1-mm5-prasanna/kernel/kprobes.c 2006-02-08 19:26:10.000000000 +0530
@@ -42,9 +42,6 @@
#include <asm/errno.h>
#include <asm/kdebug.h>
-#define KPROBE_HASH_BITS 6
-#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
-
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
static struct list_head uprobe_module_list;
_
--
Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Email: prasanna@in.ibm.com
Ph: 91-80-51776329