[PATCH bpf-next 03/13] uprobes: Add nbytes argument to uprobe_write_opcode

Jiri Olsa
2024-12-11T13:34:42Z

Adding nbytes argument to uprobe_write_opcode as preparation
fo writing longer instructions in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
include/linux/uprobes.h | 3 ++-
kernel/events/uprobes.c | 14 ++++++++------
2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index e24fbe496efb..cc723bc48c1d 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -181,7 +181,8 @@ extern bool is_swbp_insn(uprobe_opcode_t *insn);
extern bool is_trap_insn(uprobe_opcode_t *insn);
extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);
extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
-extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
+extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr,
+ uprobe_opcode_t *insn, int nbytes);
extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool);
extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 61ec91f635dc..7c2ecf11a573 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -470,7 +470,7 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
* Return 0 (success) or a negative errno.
*/
int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
- unsigned long vaddr, uprobe_opcode_t opcode)
+ unsigned long vaddr, uprobe_opcode_t *insn, int nbytes)
{
struct uprobe *uprobe;
struct page *old_page, *new_page;
@@ -479,7 +479,7 @@ 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(&opcode);
+ is_register = is_swbp_insn(insn);
uprobe = container_of(auprobe, struct uprobe, arch);

retry:
@@ -490,7 +490,7 @@ 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, &opcode);
+ ret = verify_opcode(old_page, vaddr, insn);
if (ret <= 0)
goto put_old;

@@ -524,7 +524,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,

__SetPageUptodate(new_page);
copy_highpage(new_page, old_page);
- uprobe_copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+ uprobe_copy_to_page(new_page, vaddr, insn, nbytes);

if (!is_register) {
struct page *orig_page;
@@ -581,7 +581,9 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
*/
int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
{
- return uprobe_write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN);
+ uprobe_opcode_t insn = UPROBE_SWBP_INSN;
+
+ return uprobe_write_opcode(auprobe, mm, vaddr, &insn, UPROBE_SWBP_INSN_SIZE);
}

/**
@@ -597,7 +599,7 @@ int __weak
set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
{
return uprobe_write_opcode(auprobe, mm, vaddr,
- *(uprobe_opcode_t *)&auprobe->insn);
+ (uprobe_opcode_t *)&auprobe->insn, UPROBE_SWBP_INSN_SIZE);
}

/* uprobe should have guaranteed positive refcount */
--
2.47.0