Allow arches to customize how the instruction is filled into the xol
slot. ARM will use this to insert an undefined instruction after the
real instruction in order to simulate a single step of the instruction
without hardware support.
Signed-off-by: Rabin Vincent <ra...@rab.in>
Signed-off-by: David A. Long <dave.l...@linaro.org>
---
include/linux/uprobes.h | 1 +
kernel/events/uprobes.c | 10 +++++++++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index eca5bd5..2a0aa10 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -134,6 +134,7 @@ extern bool arch_uprobe_xol_was_trapped(struct
task_struct *tsk);
extern int arch_uprobe_exception_notify(struct notifier_block *self,
unsigned long val, void *data);
extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct
pt_regs *regs);
extern bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct
pt_regs *regs);
+extern void __weak arch_uprobe_xol_copy(struct arch_uprobe *auprobe,
void *vaddr);
#else /* !CONFIG_UPROBES */
struct uprobes_state {
};
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 2f3a4cb..64471bd 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1238,6 +1238,11 @@ static unsigned long xol_take_insn_slot(struct
xol_area *area)
return slot_addr;
}
+void __weak arch_uprobe_xol_copy(struct arch_uprobe *auprobe, void *vaddr)
+{
+ memcpy(vaddr, auprobe->insn, MAX_UINSN_BYTES);
+}
+
/*
* xol_get_insn_slot - allocate a slot for xol.
* Returns the allocated slot address or 0.
@@ -1246,6 +1251,7 @@ static unsigned long xol_get_insn_slot(struct
uprobe *uprobe)
{
struct xol_area *area;
unsigned long xol_vaddr;
+ void *kaddr;
area = get_xol_area();
if (!area)
@@ -1256,7 +1262,9 @@ static unsigned long xol_get_insn_slot(struct
uprobe *uprobe)
return 0;
/* Initialize the slot */
- copy_to_page(area->page, xol_vaddr, uprobe->arch.insn, MAX_UINSN_BYTES);
+ kaddr = kmap_atomic(area->page);
+ arch_uprobe_xol_copy(&uprobe->arch, kaddr + (xol_vaddr & ~PAGE_MASK));
+ kunmap_atomic(kaddr);
/*
* We probably need flush_icache_user_range() but it needs vma.
* This should work on supported architectures too.
--
1.8.1.2
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