[bpf-next,04/13] uprobes: Add arch_uprobe_verify_opcode function

Commit Message

Jiri Olsa Dec. 11, 2024, 1:33 p.m. UTC

Adding arch_uprobe_verify_opcode function, so we can overload
verification for each architecture in following changes.

Signed-off-by: Jiri Olsa <[e-mail]>
---
 include/linux/uprobes.h |  5 +++++
 kernel/events/uprobes.c | 19 ++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

Patch

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index cc723bc48c1d..8843b7f99ed0 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -215,6 +215,11 @@  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 int uprobe_verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode);
+extern int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
+				     unsigned long vaddr, uprobe_opcode_t *new_opcode,
+				     int nbytes);
+extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes);
 #else /* !CONFIG_UPROBES */
 struct uprobes_state {
 };
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 7c2ecf11a573..8068f91de9e3 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -263,7 +263,13 @@  static void uprobe_copy_to_page(struct page *page, unsigned long vaddr, const vo
 	kunmap_atomic(kaddr);
 }
 
-static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
+__weak bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes)
+{
+	return is_swbp_insn(insn);
+}
+
+int uprobe_verify_opcode(struct page *page, unsigned long vaddr,
+			 uprobe_opcode_t *new_opcode)
 {
 	uprobe_opcode_t old_opcode;
 	bool is_swbp;
@@ -291,6 +297,13 @@  static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
 	return 1;
 }
 
+__weak int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
+				     unsigned long vaddr, uprobe_opcode_t *new_opcode,
+				     int nbytes)
+{
+	return uprobe_verify_opcode(page, vaddr, new_opcode);
+}
+
 static struct delayed_uprobe *
 delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
 {
@@ -479,7 +492,7 @@  int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	bool orig_page_huge = false;
 	unsigned int gup_flags = FOLL_FORCE;
 
-	is_register = is_swbp_insn(insn);
+	is_register = arch_uprobe_is_register(insn, nbytes);
 	uprobe = container_of(auprobe, struct uprobe, arch);
 
 retry:
@@ -490,7 +503,7 @@  int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	if (IS_ERR(old_page))
 		return PTR_ERR(old_page);
 
-	ret = verify_opcode(old_page, vaddr, insn);
+	ret = arch_uprobe_verify_opcode(auprobe, old_page, vaddr, insn, nbytes);
 	if (ret <= 0)
 		goto put_old;