return *insn == UPROBE_SWBP_INSN;
}
-static void copy_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *opcode)
+/**
+ * is_trap_insn - check if instruction is breakpoint instruction.
+ * @insn: instruction to be checked.
+ * Default implementation of is_trap_insn
+ * Returns true if @insn is a breakpoint instruction.
+ *
+ * This function is needed for the case where an architecture has multiple
+ * trap instructions (like powerpc).
+ */
+bool __weak is_trap_insn(uprobe_opcode_t *insn)
+{
+ return is_swbp_insn(insn);
+}
+
+static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
+{
+ void *kaddr = kmap_atomic(page);
+ memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
+ kunmap_atomic(kaddr);
+}
+
+static void copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len)
{
void *kaddr = kmap_atomic(page);
- memcpy(opcode, kaddr + (vaddr & ~PAGE_MASK), UPROBE_SWBP_INSN_SIZE);
+ memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
kunmap_atomic(kaddr);
}
uprobe_opcode_t old_opcode;
bool is_swbp;
- copy_opcode(page, vaddr, &old_opcode);
+ /*
+ * Note: We only check if the old_opcode is UPROBE_SWBP_INSN here.
+ * We do not check if it is any other 'trap variant' which could
+ * be conditional trap instruction such as the one powerpc supports.
+ *
+ * The logic is that we do not care if the underlying instruction
+ * is a trap variant; uprobes always wins over any other (gdb)
+ * breakpoint.
+ */
+ copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
is_swbp = is_swbp_insn(&old_opcode);
if (is_swbp_insn(new_opcode)) {
* Expect the breakpoint instruction to be the smallest size instruction for
* the architecture. If an arch has variable length instruction and the
* breakpoint instruction is not of the smallest length instruction
- * supported by that architecture then we need to modify is_swbp_at_addr and
+ * supported by that architecture then we need to modify is_trap_at_addr and
* write_opcode accordingly. This would never be a problem for archs that
* have fixed length instructions.
*/
uprobe_opcode_t opcode)
{
struct page *old_page, *new_page;
- void *vaddr_old, *vaddr_new;
struct vm_area_struct *vma;
int ret;
__SetPageUptodate(new_page);
- /* copy the page now that we've got it stable */
- vaddr_old = kmap_atomic(old_page);
- vaddr_new = kmap_atomic(new_page);
-
- memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
- memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE);
-
- kunmap_atomic(vaddr_new);
- kunmap_atomic(vaddr_old);
+ copy_highpage(new_page, old_page);
+ copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
ret = anon_vma_prepare(vma);
if (ret)
unsigned long nbytes, loff_t offset)
{
struct page *page;
- void *vaddr;
- unsigned long off;
- pgoff_t idx;
-
- if (!filp)
- return -EINVAL;
if (!mapping->a_ops->readpage)
return -EIO;
-
- idx = offset >> PAGE_CACHE_SHIFT;
- off = offset & ~PAGE_MASK;
-
/*
* Ensure that the page that has the original instruction is
* populated and in page-cache.
*/
- page = read_mapping_page(mapping, idx, filp);
+ page = read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT, filp);
if (IS_ERR(page))
return PTR_ERR(page);
- vaddr = kmap_atomic(page);
- memcpy(insn, vaddr + off, nbytes);
- kunmap_atomic(vaddr);
+ copy_from_page(page, offset, insn, nbytes);
page_cache_release(page);
return 0;
goto out;
ret = -ENOTSUPP;
- if (is_swbp_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);
down_write(&mm->mmap_sem);
vma = find_vma(mm, info->vaddr);
if (!vma || !valid_vma(vma, is_register) ||
- vma->vm_file->f_mapping->host != uprobe->inode)
+ file_inode(vma->vm_file) != uprobe->inode)
goto unlock;
if (vma->vm_start > info->vaddr ||
struct uprobe *uprobe;
int ret;
+ /* Uprobe must have at least one set consumer */
+ if (!uc->handler && !uc->ret_handler)
+ return -EINVAL;
+
+ /* TODO: Implement return probes */
+ if (uc->ret_handler)
+ return -ENOSYS;
+
/* Racy, just to catch the obvious mistakes */
if (offset > i_size_read(inode))
return -EINVAL;
loff_t offset;
if (!valid_vma(vma, false) ||
- vma->vm_file->f_mapping->host != uprobe->inode)
+ file_inode(vma->vm_file) != uprobe->inode)
continue;
offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
if (no_uprobe_events() || !valid_vma(vma, true))
return 0;
- inode = vma->vm_file->f_mapping->host;
+ inode = file_inode(vma->vm_file);
if (!inode)
return 0;
struct inode *inode;
struct rb_node *n;
- inode = vma->vm_file->f_mapping->host;
+ inode = file_inode(vma->vm_file);
min = vaddr_to_offset(vma, start);
max = min + (end - start) - 1;
{
struct mm_struct *mm = current->mm;
struct xol_area *area;
+ uprobe_opcode_t insn = UPROBE_SWBP_INSN;
area = mm->uprobes_state.xol_area;
if (area)
if (!area->page)
goto free_bitmap;
+ /* allocate first slot of task's xol_area for the return probes */
+ set_bit(0, area->bitmap);
+ copy_to_page(area->page, 0, &insn, UPROBE_SWBP_INSN_SIZE);
+ atomic_set(&area->slot_count, 1);
init_waitqueue_head(&area->wq);
+
if (!xol_add_vma(area))
return area;
static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
{
struct xol_area *area;
- unsigned long offset;
unsigned long xol_vaddr;
- void *vaddr;
area = get_xol_area();
if (!area)
return 0;
/* Initialize the slot */
- offset = xol_vaddr & ~PAGE_MASK;
- vaddr = kmap_atomic(area->page);
- memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
- kunmap_atomic(vaddr);
+ copy_to_page(area->page, xol_vaddr, uprobe->arch.insn, MAX_UINSN_BYTES);
/*
* We probably need flush_icache_user_range() but it needs vma.
* This should work on supported architectures too.
return current->utask;
}
+/*
+ * Current area->vaddr notion assume the trampoline address is always
+ * equal area->vaddr.
+ *
+ * Returns -1 in case the xol_area is not allocated.
+ */
+static unsigned long get_trampoline_vaddr(void)
+{
+ struct xol_area *area;
+ unsigned long trampoline_vaddr = -1;
+
+ area = current->mm->uprobes_state.xol_area;
+ smp_read_barrier_depends();
+ if (area)
+ trampoline_vaddr = area->vaddr;
+
+ return trampoline_vaddr;
+}
+
/* Prepare to single-step probed instruction out of line. */
static int
pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
clear_bit(MMF_HAS_UPROBES, &mm->flags);
}
-static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr)
+static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
{
struct page *page;
uprobe_opcode_t opcode;
if (result < 0)
return result;
- copy_opcode(page, vaddr, &opcode);
+ copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
put_page(page);
out:
- return is_swbp_insn(&opcode);
+ /* This needs to return true for any variant of the trap insn */
+ return is_trap_insn(&opcode);
}
static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
vma = find_vma(mm, bp_vaddr);
if (vma && vma->vm_start <= bp_vaddr) {
if (valid_vma(vma, false)) {
- struct inode *inode = vma->vm_file->f_mapping->host;
+ struct inode *inode = file_inode(vma->vm_file);
loff_t offset = vaddr_to_offset(vma, bp_vaddr);
uprobe = find_uprobe(inode, offset);
}
if (!uprobe)
- *is_swbp = is_swbp_at_addr(mm, bp_vaddr);
+ *is_swbp = is_trap_at_addr(mm, bp_vaddr);
} else {
*is_swbp = -EFAULT;
}
down_read(&uprobe->register_rwsem);
for (uc = uprobe->consumers; uc; uc = uc->next) {
- int rc = uc->handler(uc, regs);
+ int rc = 0;
- WARN(rc & ~UPROBE_HANDLER_MASK,
- "bad rc=0x%x from %pf()\n", rc, uc->handler);
+ if (uc->handler) {
+ rc = uc->handler(uc, regs);
+ WARN(rc & ~UPROBE_HANDLER_MASK,
+ "bad rc=0x%x from %pf()\n", rc, uc->handler);
+ }
remove &= rc;
}
projects / mirror_ubuntu-hirsute-kernel.git / blobdiff