| Message ID | 20211116054237.100814-3-memxor@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce BPF iterators for io_uring and epoll | expand |
Hi Kumar,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on bpf-next/master]
url: https://github.com/0day-ci/linux/commits/Kumar-Kartikeya-Dwivedi/Introduce-BPF-iterators-for-io_uring-and-epoll/20211116-140234
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: arm-randconfig-r006-20211116 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/567c9b678d5ade1a63c993cfa10394902d4671ca
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Kumar-Kartikeya-Dwivedi/Introduce-BPF-iterators-for-io_uring-and-epoll/20211116-140234
git checkout 567c9b678d5ade1a63c993cfa10394902d4671ca
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
arm-linux-gnueabi-ld: kernel/trace/bpf_trace.o: in function `bpf_tracing_func_proto':
>> bpf_trace.c:(.text+0x1930): undefined reference to `bpf_page_to_pfn_proto'
>> arm-linux-gnueabi-ld: bpf_trace.c:(.text+0x1934): undefined reference to `bpf_page_to_pfn_proto'
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Hi Kumar,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on bpf-next/master]
url: https://github.com/0day-ci/linux/commits/Kumar-Kartikeya-Dwivedi/Introduce-BPF-iterators-for-io_uring-and-epoll/20211116-140234
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: i386-randconfig-a014-20211116 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/567c9b678d5ade1a63c993cfa10394902d4671ca
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Kumar-Kartikeya-Dwivedi/Introduce-BPF-iterators-for-io_uring-and-epoll/20211116-140234
git checkout 567c9b678d5ade1a63c993cfa10394902d4671ca
# save the attached .config to linux build tree
mkdir build_dir
make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
ld: kernel/trace/bpf_trace.o: in function `bpf_tracing_func_proto':
>> kernel/trace/bpf_trace.c:1216: undefined reference to `bpf_page_to_pfn_proto'
vim +1216 kernel/trace/bpf_trace.c
1093
1094 static const struct bpf_func_proto *
1095 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
1096 {
1097 switch (func_id) {
1098 case BPF_FUNC_map_lookup_elem:
1099 return &bpf_map_lookup_elem_proto;
1100 case BPF_FUNC_map_update_elem:
1101 return &bpf_map_update_elem_proto;
1102 case BPF_FUNC_map_delete_elem:
1103 return &bpf_map_delete_elem_proto;
1104 case BPF_FUNC_map_push_elem:
1105 return &bpf_map_push_elem_proto;
1106 case BPF_FUNC_map_pop_elem:
1107 return &bpf_map_pop_elem_proto;
1108 case BPF_FUNC_map_peek_elem:
1109 return &bpf_map_peek_elem_proto;
1110 case BPF_FUNC_ktime_get_ns:
1111 return &bpf_ktime_get_ns_proto;
1112 case BPF_FUNC_ktime_get_boot_ns:
1113 return &bpf_ktime_get_boot_ns_proto;
1114 case BPF_FUNC_ktime_get_coarse_ns:
1115 return &bpf_ktime_get_coarse_ns_proto;
1116 case BPF_FUNC_tail_call:
1117 return &bpf_tail_call_proto;
1118 case BPF_FUNC_get_current_pid_tgid:
1119 return &bpf_get_current_pid_tgid_proto;
1120 case BPF_FUNC_get_current_task:
1121 return &bpf_get_current_task_proto;
1122 case BPF_FUNC_get_current_task_btf:
1123 return &bpf_get_current_task_btf_proto;
1124 case BPF_FUNC_task_pt_regs:
1125 return &bpf_task_pt_regs_proto;
1126 case BPF_FUNC_get_current_uid_gid:
1127 return &bpf_get_current_uid_gid_proto;
1128 case BPF_FUNC_get_current_comm:
1129 return &bpf_get_current_comm_proto;
1130 case BPF_FUNC_trace_printk:
1131 return bpf_get_trace_printk_proto();
1132 case BPF_FUNC_get_smp_processor_id:
1133 return &bpf_get_smp_processor_id_proto;
1134 case BPF_FUNC_get_numa_node_id:
1135 return &bpf_get_numa_node_id_proto;
1136 case BPF_FUNC_perf_event_read:
1137 return &bpf_perf_event_read_proto;
1138 case BPF_FUNC_current_task_under_cgroup:
1139 return &bpf_current_task_under_cgroup_proto;
1140 case BPF_FUNC_get_prandom_u32:
1141 return &bpf_get_prandom_u32_proto;
1142 case BPF_FUNC_probe_write_user:
1143 return security_locked_down(LOCKDOWN_BPF_WRITE_USER) < 0 ?
1144 NULL : bpf_get_probe_write_proto();
1145 case BPF_FUNC_probe_read_user:
1146 return &bpf_probe_read_user_proto;
1147 case BPF_FUNC_probe_read_kernel:
1148 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1149 NULL : &bpf_probe_read_kernel_proto;
1150 case BPF_FUNC_probe_read_user_str:
1151 return &bpf_probe_read_user_str_proto;
1152 case BPF_FUNC_probe_read_kernel_str:
1153 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1154 NULL : &bpf_probe_read_kernel_str_proto;
1155 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1156 case BPF_FUNC_probe_read:
1157 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1158 NULL : &bpf_probe_read_compat_proto;
1159 case BPF_FUNC_probe_read_str:
1160 return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
1161 NULL : &bpf_probe_read_compat_str_proto;
1162 #endif
1163 #ifdef CONFIG_CGROUPS
1164 case BPF_FUNC_get_current_cgroup_id:
1165 return &bpf_get_current_cgroup_id_proto;
1166 case BPF_FUNC_get_current_ancestor_cgroup_id:
1167 return &bpf_get_current_ancestor_cgroup_id_proto;
1168 #endif
1169 case BPF_FUNC_send_signal:
1170 return &bpf_send_signal_proto;
1171 case BPF_FUNC_send_signal_thread:
1172 return &bpf_send_signal_thread_proto;
1173 case BPF_FUNC_perf_event_read_value:
1174 return &bpf_perf_event_read_value_proto;
1175 case BPF_FUNC_get_ns_current_pid_tgid:
1176 return &bpf_get_ns_current_pid_tgid_proto;
1177 case BPF_FUNC_ringbuf_output:
1178 return &bpf_ringbuf_output_proto;
1179 case BPF_FUNC_ringbuf_reserve:
1180 return &bpf_ringbuf_reserve_proto;
1181 case BPF_FUNC_ringbuf_submit:
1182 return &bpf_ringbuf_submit_proto;
1183 case BPF_FUNC_ringbuf_discard:
1184 return &bpf_ringbuf_discard_proto;
1185 case BPF_FUNC_ringbuf_query:
1186 return &bpf_ringbuf_query_proto;
1187 case BPF_FUNC_jiffies64:
1188 return &bpf_jiffies64_proto;
1189 case BPF_FUNC_get_task_stack:
1190 return &bpf_get_task_stack_proto;
1191 case BPF_FUNC_copy_from_user:
1192 return prog->aux->sleepable ? &bpf_copy_from_user_proto : NULL;
1193 case BPF_FUNC_snprintf_btf:
1194 return &bpf_snprintf_btf_proto;
1195 case BPF_FUNC_per_cpu_ptr:
1196 return &bpf_per_cpu_ptr_proto;
1197 case BPF_FUNC_this_cpu_ptr:
1198 return &bpf_this_cpu_ptr_proto;
1199 case BPF_FUNC_task_storage_get:
1200 return &bpf_task_storage_get_proto;
1201 case BPF_FUNC_task_storage_delete:
1202 return &bpf_task_storage_delete_proto;
1203 case BPF_FUNC_for_each_map_elem:
1204 return &bpf_for_each_map_elem_proto;
1205 case BPF_FUNC_snprintf:
1206 return &bpf_snprintf_proto;
1207 case BPF_FUNC_get_func_ip:
1208 return &bpf_get_func_ip_proto_tracing;
1209 case BPF_FUNC_get_branch_snapshot:
1210 return &bpf_get_branch_snapshot_proto;
1211 case BPF_FUNC_find_vma:
1212 return &bpf_find_vma_proto;
1213 case BPF_FUNC_trace_vprintk:
1214 return bpf_get_trace_vprintk_proto();
1215 case BPF_FUNC_page_to_pfn:
> 1216 return &bpf_page_to_pfn_proto;
1217 default:
1218 return bpf_base_func_proto(func_id);
1219 }
1220 }
1221
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
On 11/15/21 9:42 PM, Kumar Kartikeya Dwivedi wrote: > In CRIU, we need to be able to determine whether the page pinned by > io_uring is still present in the same range in the process VMA. > /proc/<pid>/pagemap gives us the PFN, hence using this helper we can > establish this mapping easily from the iterator side. > > It is a simple wrapper over the in-kernel page_to_pfn helper, and > ensures the passed in pointer is a struct page PTR_TO_BTF_ID. This is > obtained from the bvec of io_uring_ubuf for the CRIU usecase. > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > --- > fs/io_uring.c | 17 +++++++++++++++++ > include/linux/bpf.h | 1 + > include/uapi/linux/bpf.h | 9 +++++++++ > kernel/trace/bpf_trace.c | 2 ++ > scripts/bpf_doc.py | 2 ++ > tools/include/uapi/linux/bpf.h | 9 +++++++++ > 6 files changed, 40 insertions(+) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index 46a110989155..9e9df6767e29 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -11295,6 +11295,23 @@ static struct bpf_iter_reg io_uring_buf_reg_info = { > .seq_info = &bpf_io_uring_buf_seq_info, > }; > > +BPF_CALL_1(bpf_page_to_pfn, struct page *, page) > +{ > + /* PTR_TO_BTF_ID can be NULL */ > + if (!page) > + return U64_MAX; > + return page_to_pfn(page); > +} > + > +BTF_ID_LIST_SINGLE(btf_page_to_pfn_ids, struct, page) > + > +const struct bpf_func_proto bpf_page_to_pfn_proto = { > + .func = bpf_page_to_pfn, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_BTF_ID, > + .arg1_btf_id = &btf_page_to_pfn_ids[0], Does this helper need to be gpl_only? > +}; > + > static int __init io_uring_iter_init(void) > { > io_uring_buf_reg_info.ctx_arg_info[0].btf_id = btf_io_uring_ids[0]; [...]
On Thu, Nov 18, 2021 at 10:57:15PM IST, Yonghong Song wrote: > > > On 11/15/21 9:42 PM, Kumar Kartikeya Dwivedi wrote: > > In CRIU, we need to be able to determine whether the page pinned by > > io_uring is still present in the same range in the process VMA. > > /proc/<pid>/pagemap gives us the PFN, hence using this helper we can > > establish this mapping easily from the iterator side. > > > > It is a simple wrapper over the in-kernel page_to_pfn helper, and > > ensures the passed in pointer is a struct page PTR_TO_BTF_ID. This is > > obtained from the bvec of io_uring_ubuf for the CRIU usecase. > > > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > > --- > > fs/io_uring.c | 17 +++++++++++++++++ > > include/linux/bpf.h | 1 + > > include/uapi/linux/bpf.h | 9 +++++++++ > > kernel/trace/bpf_trace.c | 2 ++ > > scripts/bpf_doc.py | 2 ++ > > tools/include/uapi/linux/bpf.h | 9 +++++++++ > > 6 files changed, 40 insertions(+) > > > > diff --git a/fs/io_uring.c b/fs/io_uring.c > > index 46a110989155..9e9df6767e29 100644 > > --- a/fs/io_uring.c > > +++ b/fs/io_uring.c > > @@ -11295,6 +11295,23 @@ static struct bpf_iter_reg io_uring_buf_reg_info = { > > .seq_info = &bpf_io_uring_buf_seq_info, > > }; > > +BPF_CALL_1(bpf_page_to_pfn, struct page *, page) > > +{ > > + /* PTR_TO_BTF_ID can be NULL */ > > + if (!page) > > + return U64_MAX; > > + return page_to_pfn(page); > > +} > > + > > +BTF_ID_LIST_SINGLE(btf_page_to_pfn_ids, struct, page) > > + > > +const struct bpf_func_proto bpf_page_to_pfn_proto = { > > + .func = bpf_page_to_pfn, > > + .ret_type = RET_INTEGER, > > + .arg1_type = ARG_PTR_TO_BTF_ID, > > + .arg1_btf_id = &btf_page_to_pfn_ids[0], > > Does this helper need to be gpl_only? > Not sure about it, it wraps over a macro. > > +}; > > + > > static int __init io_uring_iter_init(void) > > { > > io_uring_buf_reg_info.ctx_arg_info[0].btf_id = btf_io_uring_ids[0]; > [...] -- Kartikeya
On 11/18/21 10:30 AM, Kumar Kartikeya Dwivedi wrote: > On Thu, Nov 18, 2021 at 10:57:15PM IST, Yonghong Song wrote: >> >> >> On 11/15/21 9:42 PM, Kumar Kartikeya Dwivedi wrote: >>> In CRIU, we need to be able to determine whether the page pinned by >>> io_uring is still present in the same range in the process VMA. >>> /proc/<pid>/pagemap gives us the PFN, hence using this helper we can >>> establish this mapping easily from the iterator side. >>> >>> It is a simple wrapper over the in-kernel page_to_pfn helper, and >>> ensures the passed in pointer is a struct page PTR_TO_BTF_ID. This is >>> obtained from the bvec of io_uring_ubuf for the CRIU usecase. >>> >>> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> >>> --- >>> fs/io_uring.c | 17 +++++++++++++++++ >>> include/linux/bpf.h | 1 + >>> include/uapi/linux/bpf.h | 9 +++++++++ >>> kernel/trace/bpf_trace.c | 2 ++ >>> scripts/bpf_doc.py | 2 ++ >>> tools/include/uapi/linux/bpf.h | 9 +++++++++ >>> 6 files changed, 40 insertions(+) >>> >>> diff --git a/fs/io_uring.c b/fs/io_uring.c >>> index 46a110989155..9e9df6767e29 100644 >>> --- a/fs/io_uring.c >>> +++ b/fs/io_uring.c >>> @@ -11295,6 +11295,23 @@ static struct bpf_iter_reg io_uring_buf_reg_info = { >>> .seq_info = &bpf_io_uring_buf_seq_info, >>> }; >>> +BPF_CALL_1(bpf_page_to_pfn, struct page *, page) >>> +{ >>> + /* PTR_TO_BTF_ID can be NULL */ >>> + if (!page) >>> + return U64_MAX; >>> + return page_to_pfn(page); >>> +} >>> + >>> +BTF_ID_LIST_SINGLE(btf_page_to_pfn_ids, struct, page) >>> + >>> +const struct bpf_func_proto bpf_page_to_pfn_proto = { >>> + .func = bpf_page_to_pfn, >>> + .ret_type = RET_INTEGER, >>> + .arg1_type = ARG_PTR_TO_BTF_ID, >>> + .arg1_btf_id = &btf_page_to_pfn_ids[0], >> >> Does this helper need to be gpl_only? The typically guideline whether the same info can be retrieved from userspace. If yes, no gpl is needed. Otherwe, it needs to be gpl. Also, the helper is implemented in io_uring.c and the helper is used by tracing programs. Maybe we can put the helper in bpf_trace.c? The helper itself is not tied to io_uring, right? >> > > Not sure about it, it wraps over a macro. > >>> +}; >>> + >>> static int __init io_uring_iter_init(void) >>> { >>> io_uring_buf_reg_info.ctx_arg_info[0].btf_id = btf_io_uring_ids[0]; >> [...] > > -- > Kartikeya >
On Fri, Nov 19, 2021 at 12:48:39AM IST, Yonghong Song wrote: > > > On 11/18/21 10:30 AM, Kumar Kartikeya Dwivedi wrote: > > On Thu, Nov 18, 2021 at 10:57:15PM IST, Yonghong Song wrote: > > > > > > > > > On 11/15/21 9:42 PM, Kumar Kartikeya Dwivedi wrote: > > > > In CRIU, we need to be able to determine whether the page pinned by > > > > io_uring is still present in the same range in the process VMA. > > > > /proc/<pid>/pagemap gives us the PFN, hence using this helper we can > > > > establish this mapping easily from the iterator side. > > > > > > > > It is a simple wrapper over the in-kernel page_to_pfn helper, and > > > > ensures the passed in pointer is a struct page PTR_TO_BTF_ID. This is > > > > obtained from the bvec of io_uring_ubuf for the CRIU usecase. > > > > > > > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > > > > --- > > > > fs/io_uring.c | 17 +++++++++++++++++ > > > > include/linux/bpf.h | 1 + > > > > include/uapi/linux/bpf.h | 9 +++++++++ > > > > kernel/trace/bpf_trace.c | 2 ++ > > > > scripts/bpf_doc.py | 2 ++ > > > > tools/include/uapi/linux/bpf.h | 9 +++++++++ > > > > 6 files changed, 40 insertions(+) > > > > > > > > diff --git a/fs/io_uring.c b/fs/io_uring.c > > > > index 46a110989155..9e9df6767e29 100644 > > > > --- a/fs/io_uring.c > > > > +++ b/fs/io_uring.c > > > > @@ -11295,6 +11295,23 @@ static struct bpf_iter_reg io_uring_buf_reg_info = { > > > > .seq_info = &bpf_io_uring_buf_seq_info, > > > > }; > > > > +BPF_CALL_1(bpf_page_to_pfn, struct page *, page) > > > > +{ > > > > + /* PTR_TO_BTF_ID can be NULL */ > > > > + if (!page) > > > > + return U64_MAX; > > > > + return page_to_pfn(page); > > > > +} > > > > + > > > > +BTF_ID_LIST_SINGLE(btf_page_to_pfn_ids, struct, page) > > > > + > > > > +const struct bpf_func_proto bpf_page_to_pfn_proto = { > > > > + .func = bpf_page_to_pfn, > > > > + .ret_type = RET_INTEGER, > > > > + .arg1_type = ARG_PTR_TO_BTF_ID, > > > > + .arg1_btf_id = &btf_page_to_pfn_ids[0], > > > > > > Does this helper need to be gpl_only? > > The typically guideline whether the same info can be retrieved from > userspace. If yes, no gpl is needed. Otherwe, it needs to be gpl. > I think it can already be obtained using /proc/<PID>/pagemap, so not needed. > Also, the helper is implemented in io_uring.c and the helper > is used by tracing programs. Maybe we can put the helper > in bpf_trace.c? The helper itself is not tied to io_uring, right? > Right, I'll move it outside CONFIG_IO_URING in v2. That's also why the build failed on this patch. -- Kartikeya
diff --git a/fs/io_uring.c b/fs/io_uring.c index 46a110989155..9e9df6767e29 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -11295,6 +11295,23 @@ static struct bpf_iter_reg io_uring_buf_reg_info = { .seq_info = &bpf_io_uring_buf_seq_info, }; +BPF_CALL_1(bpf_page_to_pfn, struct page *, page) +{ + /* PTR_TO_BTF_ID can be NULL */ + if (!page) + return U64_MAX; + return page_to_pfn(page); +} + +BTF_ID_LIST_SINGLE(btf_page_to_pfn_ids, struct, page) + +const struct bpf_func_proto bpf_page_to_pfn_proto = { + .func = bpf_page_to_pfn, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &btf_page_to_pfn_ids[0], +}; + static int __init io_uring_iter_init(void) { io_uring_buf_reg_info.ctx_arg_info[0].btf_id = btf_io_uring_ids[0]; diff --git a/include/linux/bpf.h b/include/linux/bpf.h index ddb9d4520a3f..fe7b499da781 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2166,6 +2166,7 @@ extern const struct bpf_func_proto bpf_sk_setsockopt_proto; extern const struct bpf_func_proto bpf_sk_getsockopt_proto; extern const struct bpf_func_proto bpf_kallsyms_lookup_name_proto; extern const struct bpf_func_proto bpf_find_vma_proto; +extern const struct bpf_func_proto bpf_page_to_pfn_proto; const struct bpf_func_proto *tracing_prog_func_proto( enum bpf_func_id func_id, const struct bpf_prog *prog); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3323defa99a1..b70e9da3d722 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4960,6 +4960,14 @@ union bpf_attr { * **-ENOENT** if *task->mm* is NULL, or no vma contains *addr*. * **-EBUSY** if failed to try lock mmap_lock. * **-EINVAL** for invalid **flags**. + * + * long bpf_page_to_pfn(struct page *page) + * Description + * Obtain the page frame number (PFN) for the given *struct page* + * pointer. + * Return + * Page Frame Number corresponding to the page pointed to by the + * *struct page* pointer, or U64_MAX if pointer is NULL. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5143,6 +5151,7 @@ union bpf_attr { FN(skc_to_unix_sock), \ FN(kallsyms_lookup_name), \ FN(find_vma), \ + FN(page_to_pfn), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 25ea521fb8f1..f68a8433be1a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1212,6 +1212,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_find_vma_proto; case BPF_FUNC_trace_vprintk: return bpf_get_trace_vprintk_proto(); + case BPF_FUNC_page_to_pfn: + return &bpf_page_to_pfn_proto; default: return bpf_base_func_proto(func_id); } diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py index a6403ddf5de7..ae68ca794980 100755 --- a/scripts/bpf_doc.py +++ b/scripts/bpf_doc.py @@ -549,6 +549,7 @@ class PrinterHelpers(Printer): 'struct socket', 'struct file', 'struct bpf_timer', + 'struct page', ] known_types = { '...', @@ -598,6 +599,7 @@ class PrinterHelpers(Printer): 'struct socket', 'struct file', 'struct bpf_timer', + 'struct page', } mapped_types = { 'u8': '__u8', diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 3323defa99a1..b70e9da3d722 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4960,6 +4960,14 @@ union bpf_attr { * **-ENOENT** if *task->mm* is NULL, or no vma contains *addr*. * **-EBUSY** if failed to try lock mmap_lock. * **-EINVAL** for invalid **flags**. + * + * long bpf_page_to_pfn(struct page *page) + * Description + * Obtain the page frame number (PFN) for the given *struct page* + * pointer. + * Return + * Page Frame Number corresponding to the page pointed to by the + * *struct page* pointer, or U64_MAX if pointer is NULL. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5143,6 +5151,7 @@ union bpf_attr { FN(skc_to_unix_sock), \ FN(kallsyms_lookup_name), \ FN(find_vma), \ + FN(page_to_pfn), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper
In CRIU, we need to be able to determine whether the page pinned by io_uring is still present in the same range in the process VMA. /proc/<pid>/pagemap gives us the PFN, hence using this helper we can establish this mapping easily from the iterator side. It is a simple wrapper over the in-kernel page_to_pfn helper, and ensures the passed in pointer is a struct page PTR_TO_BTF_ID. This is obtained from the bvec of io_uring_ubuf for the CRIU usecase. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> --- fs/io_uring.c | 17 +++++++++++++++++ include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 9 +++++++++ kernel/trace/bpf_trace.c | 2 ++ scripts/bpf_doc.py | 2 ++ tools/include/uapi/linux/bpf.h | 9 +++++++++ 6 files changed, 40 insertions(+)