Re: [PATCH bpf-next 02/13] uprobes: Make copy_from_page global

Andrii Nakryiko
2024-12-13T00:44:08Z

On Wed, Dec 11, 2024 at 5:34 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Making copy_from_page global and adding uprobe prefix.
> Adding the uprobe prefix to copy_to_page as well for symmetry.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> include/linux/uprobes.h | 1 +
> kernel/events/uprobes.c | 16 ++++++++--------
> 2 files changed, 9 insertions(+), 8 deletions(-)
>

Acked-by: Andrii Nakryiko <andrii@kernel.org>

> diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> index 09a298e416a8..e24fbe496efb 100644
> --- a/include/linux/uprobes.h
> +++ b/include/linux/uprobes.h
> @@ -213,6 +213,7 @@ extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
> 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);
> #else /* !CONFIG_UPROBES */
> struct uprobes_state {
> };
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index e0e3ebb4c0a1..61ec91f635dc 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -249,14 +249,14 @@ bool __weak is_trap_insn(uprobe_opcode_t *insn)
> return is_swbp_insn(insn);
> }
>
> -static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
> +void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
> {
> void *kaddr = kmap_atomic(page);
> memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
> kunmap_atomic(kaddr);
> }
>
> -static void copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len)
> +static void uprobe_copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len)
> {
> void *kaddr = kmap_atomic(page);
> memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
> @@ -277,7 +277,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
> * is a trap variant; uprobes always wins over any other (gdb)
> * breakpoint.
> */
> - copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
> + uprobe_copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
> is_swbp = is_swbp_insn(&old_opcode);
>
> if (is_swbp_insn(new_opcode)) {
> @@ -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);
> - copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
> + uprobe_copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
>
> if (!is_register) {
> struct page *orig_page;
> @@ -1026,7 +1026,7 @@ static int __copy_insn(struct address_space *mapping, struct file *filp,
> if (IS_ERR(page))
> return PTR_ERR(page);
>
> - copy_from_page(page, offset, insn, nbytes);
> + uprobe_copy_from_page(page, offset, insn, nbytes);
> put_page(page);
>
> return 0;
> @@ -1367,7 +1367,7 @@ struct uprobe *uprobe_register(struct inode *inode,
> return ERR_PTR(-EINVAL);
>
> /*
> - * This ensures that copy_from_page(), copy_to_page() and
> + * This ensures that uprobe_copy_from_page(), uprobe_copy_to_page() and
> * __update_ref_ctr() can't cross page boundary.
> */
> if (!IS_ALIGNED(offset, UPROBE_SWBP_INSN_SIZE))
> @@ -1856,7 +1856,7 @@ void __weak arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
> void *src, unsigned long len)
> {
> /* Initialize the slot */
> - copy_to_page(page, vaddr, src, len);
> + uprobe_copy_to_page(page, vaddr, src, len);
>
> /*
> * We probably need flush_icache_user_page() but it needs vma.
> @@ -2287,7 +2287,7 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
> if (result < 0)
> return result;
>
> - copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
> + uprobe_copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
> put_page(page);
> out:
> /* This needs to return true for any variant of the trap insn */
> --
> 2.47.0
>