On Mon, Sep 01, 2025 at 04:30:42PM +0200, Philipp Rudo wrote:
> Hi Pingfan,
>
>
> On Tue, 19 Aug 2025 09:24:22 +0800
> Pingfan Liu <[email protected]> wrote:
>
> > This patch does two things:
> > First, register as a listener on bpf_copy_to_kernel()
> > Second, in order that the hooked bpf-prog can call the sleepable kfuncs,
> > bpf_handle_pefile and bpf_post_handle_pefile are marked as
> > KF_SLEEPABLE.
> >
> > Signed-off-by: Pingfan Liu <[email protected]>
> > Cc: Alexei Starovoitov <[email protected]>
> > Cc: Philipp Rudo <[email protected]>
> > Cc: Baoquan He <[email protected]>
> > Cc: Dave Young <[email protected]>
> > Cc: Andrew Morton <[email protected]>
> > Cc: [email protected]
> > To: [email protected]
> > ---
> > kernel/kexec_pe_image.c | 67 +++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 67 insertions(+)
> >
> > diff --git a/kernel/kexec_pe_image.c b/kernel/kexec_pe_image.c
> > index b0cf9942e68d2..f8debcde6b516 100644
> > --- a/kernel/kexec_pe_image.c
> > +++ b/kernel/kexec_pe_image.c
> > @@ -38,6 +38,51 @@ static struct kexec_res parsed_resource[3] = {
> > { KEXEC_RES_CMDLINE_NAME, },
> > };
> >
> > +/*
> > + * @name should be one of : kernel, initrd, cmdline
> > + */
> > +static int bpf_kexec_carrier(const char *name, struct mem_range_result *r)
> > +{
> > + struct kexec_res *res;
> > + int i;
> > +
> > + if (!r || !name)
> > + return -EINVAL;
> > +
> > + for (i = 0; i < 3; i++) {
> > + if (!strcmp(parsed_resource[i].name, name))
> > + break;
> > + }
> > + if (i >= 3)
> > + return -EINVAL;
>
> Can you please replace the magic '3' by ARRAY_SIZE, just like you did
> below when (un-)registering the listener.
>
Yes, I will introduce a macro KEXEC_RES_ARRAY_SIZE to unify all of them.
Thanks,
Pingfan
> Thanks
> Philipp
>
> > +
> > + res = &parsed_resource[i];
> > + /*
> > + * Replace the intermediate resource generated by the previous step.
> > + */
> > + if (!!res->r)
> > + mem_range_result_put(res->r);
> > + mem_range_result_get(r);
> > + res->r = r;
> > + return 0;
> > +}
> > +
> > +static struct carrier_listener kexec_res_listener[3] = {
> > + { .name = KEXEC_RES_KERNEL_NAME,
> > + .alloc_type = 1,
> > + .handler = bpf_kexec_carrier,
> > + },
> > + { .name = KEXEC_RES_INITRD_NAME,
> > + .alloc_type = 1,
> > + .handler = bpf_kexec_carrier,
> > + },
> > + { .name = KEXEC_RES_CMDLINE_NAME,
> > + /* kmalloc-ed */
> > + .alloc_type = 0,
> > + .handler = bpf_kexec_carrier,
> > + },
> > +};
> > +
> > static bool pe_has_bpf_section(const char *file_buf, unsigned long pe_sz);
> >
> > static bool is_valid_pe(const char *kernel_buf, unsigned long kernel_len)
> > @@ -159,6 +204,22 @@ __attribute__((used, optimize("O0"))) void
> > bpf_post_handle_pefile(struct kexec_c
> > dummy += 2;
> > }
> >
> > +BTF_KFUNCS_START(kexec_modify_return_ids)
> > +BTF_ID_FLAGS(func, bpf_handle_pefile, KF_SLEEPABLE)
> > +BTF_ID_FLAGS(func, bpf_post_handle_pefile, KF_SLEEPABLE)
> > +BTF_KFUNCS_END(kexec_modify_return_ids)
> > +
> > +static const struct btf_kfunc_id_set kexec_modify_return_set = {
> > + .owner = THIS_MODULE,
> > + .set = &kexec_modify_return_ids,
> > +};
> > +
> > +static int __init kexec_bpf_prog_run_init(void)
> > +{
> > + return register_btf_fmodret_id_set(&kexec_modify_return_set);
> > +}
> > +late_initcall(kexec_bpf_prog_run_init);
> > +
> > /*
> > * PE file may be nested and should be unfold one by one.
> > * Query 'kernel', 'initrd', 'cmdline' in cur_phase, as they are inputs
> > for the
> > @@ -213,6 +274,9 @@ static void *pe_image_load(struct kimage *image,
> > cmdline_start = cmdline;
> > cmdline_sz = cmdline_len;
> >
> > + for (int i = 0; i < ARRAY_SIZE(kexec_res_listener); i++)
> > + register_carrier_listener(&kexec_res_listener[i]);
> > +
> > while (is_valid_format(linux_start, linux_sz) &&
> > pe_has_bpf_section(linux_start, linux_sz)) {
> > struct kexec_context context;
> > @@ -250,6 +314,9 @@ static void *pe_image_load(struct kimage *image,
> > disarm_bpf_prog();
> > }
> >
> > + for (int i = 0; i < ARRAY_SIZE(kexec_res_listener); i++)
> > + unregister_carrier_listener(kexec_res_listener[i].name);
> > +
> > /*
> > * image's kernel_buf, initrd_buf, cmdline_buf are set. Now they should
> > * be updated to the new content.
>
