From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>, X86 ML <x86@kernel.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
LKML <linux-kernel@vger.kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Daniel Borkmann <daniel@iogearbox.net>, bpf <bpf@vger.kernel.org>,
Andrii Nakryiko <andrii@kernel.org>
Subject: Re: [PATCH v2 14/14] bpf,x86: Respect X86_FEATURE_RETPOLINE*
Date: Mon, 25 Oct 2021 15:44:24 +0200 [thread overview]
Message-ID: <YXa0uH0fA0P+dM8J@boxer> (raw)
In-Reply-To: <CAADnVQKJojWGaTCpUhkmU+vUxXORPacX_ByjyHWY0V03hGH7KA@mail.gmail.com>
On Fri, Oct 22, 2021 at 08:22:35AM -0700, Alexei Starovoitov wrote:
> On Fri, Oct 22, 2021 at 4:33 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Thu, Oct 21, 2021 at 04:42:12PM -0700, Alexei Starovoitov wrote:
> >
> > > Ahh. Right. It's potentially a different offset for every prog.
> > > Let's put it into struct jit_context then.
> >
> > Something like this...
>
> Yep. Looks nice and clean to me.
>
> > - poke->tailcall_bypass = image + (addr - poke_off - X86_PATCH_SIZE);
> > + poke->tailcall_bypass = ip + (prog - start);
> > poke->adj_off = X86_TAIL_CALL_OFFSET;
> > - poke->tailcall_target = image + (addr - X86_PATCH_SIZE);
> > + poke->tailcall_target = ip + ctx->tail_call_direct_label - X86_PATCH_SIZE;
>
> This part looks correct too, but this is Daniel's magic.
> He'll probably take a look next week when he comes back from PTO.
> I don't recall which test exercises this tailcall poking logic.
> It's only used with dynamic updates to prog_array.
> insmod test_bpf.ko and test_verifier won't go down this path.
Please run ./test_progs -t tailcalls from tools/testing/selftests/bpf and
make sure that all of the tests are passing in there, especially the
tailcall_bpf2bpf* subset.
Thanks!
next prev parent reply other threads:[~2021-10-25 11:44 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 10:44 [PATCH v2 00/14] x86: Rewrite the retpoline rewrite logic Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 01/14] objtool: Tag retpoline thunk symbols Peter Zijlstra
2021-10-20 15:17 ` Josh Poimboeuf
2021-10-26 7:55 ` Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 02/14] objtool: Explicitly avoid self modifying code in .altinstr_replacement Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 03/14] objtool: Shrink struct instruction Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 04/14] objtool,x86: Replace alternatives with .retpoline_sites Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 05/14] x86/retpoline: Remove unused replacement symbols Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 06/14] x86/asm: Fix register order Peter Zijlstra
2021-10-22 19:27 ` David Laight
2021-10-25 14:09 ` Borislav Petkov
2021-10-20 10:44 ` [PATCH v2 07/14] x86/asm: Fixup odd GEN-for-each-reg.h usage Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 08/14] x86/retpoline: Create a retpoline thunk array Peter Zijlstra
2021-10-20 15:57 ` Josh Poimboeuf
2021-10-20 16:46 ` Andrew Cooper
2021-10-20 17:09 ` Josh Poimboeuf
2021-10-20 19:22 ` Peter Zijlstra
2021-10-20 19:43 ` Josh Poimboeuf
2021-10-20 19:34 ` Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 09/14] x86/alternative: Implement .retpoline_sites support Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 10/14] x86/alternative: Handle Jcc __x86_indirect_thunk_\reg Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 11/14] x86/alternative: Try inline spectre_v2=retpoline,amd Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 12/14] x86/alternative: Add debug prints to apply_retpolines() Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 13/14] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Peter Zijlstra
2021-10-20 10:44 ` [PATCH v2 14/14] bpf,x86: Respect X86_FEATURE_RETPOLINE* Peter Zijlstra
2021-10-20 11:09 ` Peter Zijlstra
2021-10-20 16:56 ` Josh Poimboeuf
2021-10-20 19:23 ` Peter Zijlstra
2021-10-21 0:05 ` Alexei Starovoitov
2021-10-21 8:47 ` Peter Zijlstra
2021-10-21 18:03 ` Alexei Starovoitov
2021-10-21 22:37 ` Peter Zijlstra
2021-10-21 23:24 ` Alexei Starovoitov
2021-10-21 23:38 ` Josh Poimboeuf
2021-10-21 23:42 ` Alexei Starovoitov
2021-10-22 11:31 ` Peter Zijlstra
2021-10-22 15:22 ` Alexei Starovoitov
2021-10-25 13:44 ` Maciej Fijalkowski [this message]
2021-10-25 12:42 ` Peter Zijlstra
2021-10-21 23:51 ` Zvi Effron
2021-10-22 8:33 ` Peter Zijlstra
2021-10-22 21:06 ` Zvi Effron
2021-10-21 0:07 ` Alexei Starovoitov
2021-10-21 0:18 ` Josh Poimboeuf
2021-10-21 8:53 ` Peter Zijlstra
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