Removing struct uprobe_trampoline object and it's tracking code, because it's not needed. We can do same thing directly on top of struct vm_area_struct objects.
This makes the code simpler and allows easy propagation of the trampoline vma object into child process in following change. Note the original code called destroy_uprobe_trampoline if the optimiation failed, but it only freed the struct uprobe_trampoline object, not the vma. Signed-off-by: Jiri Olsa <[email protected]> --- arch/x86/kernel/uprobes.c | 102 ++++++++------------------------------ include/linux/uprobes.h | 5 -- kernel/events/uprobes.c | 10 ---- kernel/fork.c | 1 - 4 files changed, 20 insertions(+), 98 deletions(-) diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 2be6707e3320..6824376e253d 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -631,11 +631,6 @@ static struct vm_special_mapping tramp_mapping = { .pages = tramp_mapping_pages, }; -struct uprobe_trampoline { - struct hlist_node node; - unsigned long vaddr; -}; - static bool is_reachable_by_call(unsigned long vtramp, unsigned long vaddr) { long delta = (long)(vaddr + 5 - vtramp); @@ -682,83 +677,32 @@ static unsigned long find_nearest_trampoline(unsigned long vaddr) return high_tramp; } -static struct uprobe_trampoline *create_uprobe_trampoline(unsigned long vaddr) +static struct vm_area_struct *get_uprobe_trampoline(unsigned long vaddr) { struct pt_regs *regs = task_pt_regs(current); - struct mm_struct *mm = current->mm; - struct uprobe_trampoline *tramp; + VMA_ITERATOR(vmi, current->mm, 0); struct vm_area_struct *vma; if (!user_64bit_mode(regs)) - return NULL; - - vaddr = find_nearest_trampoline(vaddr); - if (IS_ERR_VALUE(vaddr)) - return NULL; - - tramp = kzalloc_obj(*tramp); - if (unlikely(!tramp)) - return NULL; - - tramp->vaddr = vaddr; - vma = _install_special_mapping(mm, tramp->vaddr, PAGE_SIZE, - VM_READ|VM_EXEC|VM_MAYEXEC|VM_MAYREAD|VM_DONTCOPY|VM_IO, - &tramp_mapping); - if (IS_ERR(vma)) { - kfree(tramp); - return NULL; - } - return tramp; -} - -static struct uprobe_trampoline *get_uprobe_trampoline(unsigned long vaddr, bool *new) -{ - struct uprobes_state *state = ¤t->mm->uprobes_state; - struct uprobe_trampoline *tramp = NULL; + return ERR_PTR(-EINVAL); if (vaddr > TASK_SIZE || vaddr < PAGE_SIZE) - return NULL; + return ERR_PTR(-EINVAL); - hlist_for_each_entry(tramp, &state->head_tramps, node) { - if (is_reachable_by_call(tramp->vaddr, vaddr)) { - *new = false; - return tramp; - } + for_each_vma(vmi, vma) { + if (!vma_is_special_mapping(vma, &tramp_mapping)) + continue; + if (is_reachable_by_call(vma->vm_start, vaddr)) + return vma; } - tramp = create_uprobe_trampoline(vaddr); - if (!tramp) - return NULL; - - *new = true; - hlist_add_head(&tramp->node, &state->head_tramps); - return tramp; -} - -static void destroy_uprobe_trampoline(struct uprobe_trampoline *tramp) -{ - /* - * We do not unmap and release uprobe trampoline page itself, - * because there's no easy way to make sure none of the threads - * is still inside the trampoline. - */ - hlist_del(&tramp->node); - kfree(tramp); -} - -void arch_uprobe_init_state(struct mm_struct *mm) -{ - INIT_HLIST_HEAD(&mm->uprobes_state.head_tramps); -} - -void arch_uprobe_clear_state(struct mm_struct *mm) -{ - struct uprobes_state *state = &mm->uprobes_state; - struct uprobe_trampoline *tramp; - struct hlist_node *n; + vaddr = find_nearest_trampoline(vaddr); + if (IS_ERR_VALUE(vaddr)) + return ERR_PTR(vaddr); - hlist_for_each_entry_safe(tramp, n, &state->head_tramps, node) - destroy_uprobe_trampoline(tramp); + return _install_special_mapping(current->mm, vaddr, PAGE_SIZE, + VM_READ|VM_EXEC|VM_MAYEXEC|VM_MAYREAD|VM_DONTCOPY|VM_IO, + &tramp_mapping); } static bool __in_uprobe_trampoline(struct mm_struct *mm, unsigned long ip) @@ -1111,21 +1055,15 @@ int set_orig_insn(struct arch_uprobe *auprobe, struct vm_area_struct *vma, static int __arch_uprobe_optimize(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { - struct uprobe_trampoline *tramp; - struct vm_area_struct *vma; - bool new = false; - int err = 0; + struct vm_area_struct *vma, *tramp; vma = find_vma(mm, vaddr); if (!vma) return -EINVAL; - tramp = get_uprobe_trampoline(vaddr, &new); - if (!tramp) - return -EINVAL; - err = swbp_optimize(auprobe, vma, vaddr, tramp->vaddr); - if (WARN_ON_ONCE(err) && new) - destroy_uprobe_trampoline(tramp); - return err; + tramp = get_uprobe_trampoline(vaddr); + if (IS_ERR(tramp)) + return PTR_ERR(tramp); + return WARN_ON_ONCE(swbp_optimize(auprobe, vma, vaddr, tramp->vm_start)); } void arch_uprobe_optimize(struct arch_uprobe *auprobe, unsigned long vaddr) diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index f548fea2adec..18be159bbc34 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -186,9 +186,6 @@ struct xol_area; struct uprobes_state { struct xol_area *xol_area; -#ifdef CONFIG_X86_64 - struct hlist_head head_tramps; -#endif }; typedef int (*uprobe_write_verify_t)(struct page *page, unsigned long vaddr, @@ -238,8 +235,6 @@ extern void uprobe_handle_trampoline(struct pt_regs *regs); extern void *arch_uretprobe_trampoline(unsigned long *psize); extern unsigned long uprobe_get_trampoline_vaddr(void); extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len); -extern void arch_uprobe_clear_state(struct mm_struct *mm); -extern void arch_uprobe_init_state(struct mm_struct *mm); extern void handle_syscall_uprobe(struct pt_regs *regs, unsigned long bp_vaddr); extern void arch_uprobe_optimize(struct arch_uprobe *auprobe, unsigned long vaddr); extern unsigned long arch_uprobe_get_xol_area(void); diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 4084e926e284..b5c516168f84 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1806,14 +1806,6 @@ static struct xol_area *get_xol_area(void) return area; } -void __weak arch_uprobe_clear_state(struct mm_struct *mm) -{ -} - -void __weak arch_uprobe_init_state(struct mm_struct *mm) -{ -} - /* * uprobe_clear_state - Free the area allocated for slots. */ @@ -1825,8 +1817,6 @@ void uprobe_clear_state(struct mm_struct *mm) delayed_uprobe_remove(NULL, mm); mutex_unlock(&delayed_uprobe_lock); - arch_uprobe_clear_state(mm); - if (!area) return; diff --git a/kernel/fork.c b/kernel/fork.c index 5f3fdfdb14c7..9c6baabdc961 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1059,7 +1059,6 @@ static void mm_init_uprobes_state(struct mm_struct *mm) { #ifdef CONFIG_UPROBES mm->uprobes_state.xol_area = NULL; - arch_uprobe_init_state(mm); #endif } -- 2.53.0
