diff options
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 24 | ||||
| -rw-r--r-- | include/linux/uprobes.h | 1 | ||||
| -rw-r--r-- | kernel/events/uprobes.c | 10 |
3 files changed, 32 insertions, 3 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 7be8e361ca55..619dddf54424 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -1823,3 +1823,27 @@ bool is_uprobe_at_func_entry(struct pt_regs *regs) return false; } + +#ifdef CONFIG_IA32_EMULATION +unsigned long arch_uprobe_get_xol_area(void) +{ + struct thread_info *ti = current_thread_info(); + unsigned long vaddr; + + /* + * HACK: we are not in a syscall, but x86 get_unmapped_area() paths + * ignore TIF_ADDR32 and rely on in_32bit_syscall() to calculate + * vm_unmapped_area_info.high_limit. + * + * The #ifdef above doesn't cover the CONFIG_X86_X32_ABI=y case, + * but in this case in_32bit_syscall() -> in_x32_syscall() always + * (falsely) returns true because ->orig_ax == -1. + */ + if (test_thread_flag(TIF_ADDR32)) + ti->status |= TS_COMPAT; + vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); + ti->status &= ~TS_COMPAT; + + return vaddr; +} +#endif diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index ee3d36eda45d..f548fea2adec 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -242,6 +242,7 @@ 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); #else /* !CONFIG_UPROBES */ struct uprobes_state { }; diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index a7d7d83ca1d7..dfbce021fb02 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1694,6 +1694,12 @@ static const struct vm_special_mapping xol_mapping = { .mremap = xol_mremap, }; +unsigned long __weak arch_uprobe_get_xol_area(void) +{ + /* Try to map as high as possible, this is only a hint. */ + return get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); +} + /* Slot allocation for XOL */ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) { @@ -1709,9 +1715,7 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) } if (!area->vaddr) { - /* 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); + area->vaddr = arch_uprobe_get_xol_area(); if (IS_ERR_VALUE(area->vaddr)) { ret = area->vaddr; goto fail; |