On Tue, Nov 5, 2024 at 5:34 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding len argument to uprobe_write_opcode as preparation
> fo writing longer instructions in following changes.
typo: for
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> 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 28068f9fcdc1..7d23a4fee6f4 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 len);
is len in sizeof(uprobe_opcode_t) units or in bytes? it would be good
to make this clearer
it feels like passing `void *` for insns would be better, tbh...
> 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 e9308649bba3..3e275717789b 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -471,7 +471,7 @@ 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 len)
> {
> struct uprobe *uprobe;
> struct page *old_page, *new_page;
> @@ -480,7 +480,7 @@ 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:
> @@ -491,7 +491,7 @@ 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;
>
> @@ -525,7 +525,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
>
> __SetPageUptodate(new_page);
> copy_highpage(new_page, old_page);
> - copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
> + copy_to_page(new_page, vaddr, insn, len);
>
> if (!is_register) {
> struct page *orig_page;
> @@ -582,7 +582,9 @@ 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);
> }
>
> /**
> @@ -598,7 +600,7 @@ 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
>
