From: Jakub Kicinski <jakub.kicinski@netronome.com>
To: Sandipan Das <sandipan@linux.vnet.ibm.com>
Cc: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au,
naveen.n.rao@linux.vnet.ibm.com
Subject: Re: [PATCH bpf-next v3 06/10] tools: bpftool: resolve calls without using imm field
Date: Tue, 22 May 2018 12:36:43 -0700 [thread overview]
Message-ID: <20180522123643.5ed1e391@cakuba> (raw)
In-Reply-To: <02b16a573269b492d4449c0e587ccc0020973e8c.1527008647.git.sandipan@linux.vnet.ibm.com>
On Tue, 22 May 2018 22:46:09 +0530, Sandipan Das wrote:
> Currently, we resolve the callee's address for a JITed function
> call by using the imm field of the call instruction as an offset
> from __bpf_call_base. If bpf_jit_kallsyms is enabled, we further
> use this address to get the callee's kernel symbol's name.
>
> For some architectures, such as powerpc64, the imm field is not
> large enough to hold this offset. So, instead of assigning this
> offset to the imm field, the verifier now assigns the subprog
> id. Also, a list of kernel symbol addresses for all the JITed
> functions is provided in the program info. We now use the imm
> field as an index for this list to lookup a callee's symbol's
> address and resolve its name.
>
> Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
> Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
next prev parent reply other threads:[~2018-05-22 19:36 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 [this message]
2018-05-22 17:16 ` [PATCH bpf-next v3 07/10] bpf: fix multi-function JITed dump obtained via syscall Sandipan Das
2018-05-22 19:47 ` 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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