From: Sandipan Das <sandipan@linux.vnet.ibm.com>
To: ast@kernel.org, daniel@iogearbox.net
Cc: netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
mpe@ellerman.id.au, naveen.n.rao@linux.vnet.ibm.com,
jakub.kicinski@netronome.com
Subject: [PATCH bpf-next v3 07/10] bpf: fix multi-function JITed dump obtained via syscall
Date: Tue, 22 May 2018 22:46:10 +0530 [thread overview]
Message-ID: <6f245a366d5a2957e2256f4bd89ab56ade6508d5.1527008647.git.sandipan@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1527008646.git.sandipan@linux.vnet.ibm.com>
In-Reply-To: <cover.1527008646.git.sandipan@linux.vnet.ibm.com>
Currently, for multi-function programs, we cannot get the JITed
instructions using the bpf system call's BPF_OBJ_GET_INFO_BY_FD
command. Because of this, userspace tools such as bpftool fail
to identify a multi-function program as being JITed or not.
With the JIT enabled and the test program running, this can be
verified as follows:
# cat /proc/sys/net/core/bpf_jit_enable
1
Before applying this patch:
# bpftool prog list
1: kprobe name foo tag b811aab41a39ad3d gpl
loaded_at 2018-05-16T11:43:38+0530 uid 0
xlated 216B not jited memlock 65536B
...
# bpftool prog dump jited id 1
no instructions returned
After applying this patch:
# bpftool prog list
1: kprobe name foo tag b811aab41a39ad3d gpl
loaded_at 2018-05-16T12:13:01+0530 uid 0
xlated 216B jited 308B memlock 65536B
...
# bpftool prog dump jited id 1
0: nop
4: nop
8: mflr r0
c: std r0,16(r1)
10: stdu r1,-112(r1)
14: std r31,104(r1)
18: addi r31,r1,48
1c: li r3,10
...
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
---
kernel/bpf/syscall.c | 36 +++++++++++++++++++++++++++++++++---
1 file changed, 33 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index f0ad4b5f0224..1c4cba91e523 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1970,13 +1970,43 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
* for offload.
*/
ulen = info.jited_prog_len;
- info.jited_prog_len = prog->jited_len;
+ if (prog->aux->func_cnt) {
+ u32 i;
+
+ info.jited_prog_len = 0;
+ for (i = 0; i < prog->aux->func_cnt; i++)
+ info.jited_prog_len += prog->aux->func[i]->jited_len;
+ } else {
+ info.jited_prog_len = prog->jited_len;
+ }
+
if (info.jited_prog_len && ulen) {
if (bpf_dump_raw_ok()) {
uinsns = u64_to_user_ptr(info.jited_prog_insns);
ulen = min_t(u32, info.jited_prog_len, ulen);
- if (copy_to_user(uinsns, prog->bpf_func, ulen))
- return -EFAULT;
+
+ /* for multi-function programs, copy the JITed
+ * instructions for all the functions
+ */
+ if (prog->aux->func_cnt) {
+ u32 len, free, i;
+ u8 *img;
+
+ free = ulen;
+ for (i = 0; i < prog->aux->func_cnt; i++) {
+ len = prog->aux->func[i]->jited_len;
+ img = (u8 *) prog->aux->func[i]->bpf_func;
+ if (len > free)
+ break;
+ if (copy_to_user(uinsns, img, len))
+ return -EFAULT;
+ uinsns += len;
+ free -= len;
+ }
+ } else {
+ if (copy_to_user(uinsns, prog->bpf_func, ulen))
+ return -EFAULT;
+ }
} else {
info.jited_prog_insns = 0;
}
--
2.14.3
next prev parent reply other threads:[~2018-05-22 17:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-22 17:16 [PATCH bpf-next v3 00/10] bpf: enhancements for multi-function programs Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 01/10] bpf: support 64-bit offsets for bpf function calls Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 02/10] bpf: powerpc64: pad function address loads with NOPs Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 03/10] bpf: powerpc64: add JIT support for multi-function programs Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 04/10] bpf: get kernel symbol addresses via syscall Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 05/10] tools: bpf: sync bpf uapi header Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 06/10] tools: bpftool: resolve calls without using imm field Sandipan Das
2018-05-22 19:36 ` Jakub Kicinski
2018-05-22 17:16 ` Sandipan Das [this message]
2018-05-22 19:47 ` [PATCH bpf-next v3 07/10] bpf: fix multi-function JITed dump obtained via syscall Jakub Kicinski
2018-05-22 17:16 ` [PATCH bpf-next v3 08/10] bpf: get JITed image lengths of functions " Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 09/10] tools: bpf: sync bpf uapi header Sandipan Das
2018-05-22 17:16 ` [PATCH bpf-next v3 10/10] tools: bpftool: add delimiters to multi-function JITed dumps Sandipan Das
2018-05-22 19:55 ` Jakub Kicinski
2018-05-23 9:08 ` Daniel Borkmann
2018-05-23 10:37 ` Sandipan Das
2018-05-23 13:50 ` Daniel Borkmann
2018-05-23 13:59 ` Sandipan Das
2018-05-23 21:32 ` Jakub Kicinski
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