From: David Laight <David.Laight@ACULAB.COM>
To: 'Alexei Starovoitov' <alexei.starovoitov@gmail.com>,
Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
Song Liu <songliubraving@fb.com>,
"Kairui Song" <kasong@redhat.com>
Subject: RE: [PATCH 6/9] x86/bpf: Fix JIT frame pointer usage
Date: Fri, 14 Jun 2019 10:50:23 +0000 [thread overview]
Message-ID: <57f6e69da6b3461a9c39d71aa1b58662@AcuMS.aculab.com> (raw)
In-Reply-To: <20190613215807.wjcop6eaadirz5xm@ast-mbp.dhcp.thefacebook.com>
On Thu, Jun 13, 2019 at 08:21:03AM -0500, Josh Poimboeuf wrote:
> The BPF JIT code clobbers RBP. This breaks frame pointer convention and
> thus prevents the FP unwinder from unwinding through JIT generated code.
>
> RBP is currently used as the BPF stack frame pointer register. The
> actual register used is opaque to the user, as long as it's a
> callee-saved register. Change it to use R12 instead.
Could you maintain the system %rbp chain through the BPF stack?
It might even be possible to put something relevant in the %rip
location.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2019-06-14 10:50 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 13:20 [PATCH 0/9] x86/bpf: unwinder fixes Josh Poimboeuf
2019-06-13 13:20 ` [PATCH 1/9] perf/x86: Always store regs->ip in perf_callchain_kernel() Josh Poimboeuf
2019-06-13 13:20 ` [PATCH 2/9] objtool: Fix ORC unwinding in non-JIT BPF generated code Josh Poimboeuf
2019-06-13 20:57 ` Alexei Starovoitov
2019-06-14 1:20 ` Josh Poimboeuf
2019-06-14 1:37 ` Alexei Starovoitov
2019-06-14 1:51 ` Josh Poimboeuf
2019-06-14 7:08 ` Peter Zijlstra
2019-06-14 7:35 ` Alexei Starovoitov
2019-06-14 8:11 ` Peter Zijlstra
2019-06-14 15:13 ` Alexei Starovoitov
2019-06-14 16:11 ` Josh Poimboeuf
2019-06-13 13:21 ` [PATCH 3/9] x86/bpf: Move epilogue generation to a dedicated function Josh Poimboeuf
2019-06-13 18:57 ` Song Liu
2019-06-13 19:12 ` Josh Poimboeuf
2019-06-13 13:21 ` [PATCH 4/9] x86/bpf: Simplify prologue generation Josh Poimboeuf
2019-06-13 13:21 ` [PATCH 5/9] x86/bpf: Support SIB byte generation Josh Poimboeuf
2019-06-13 13:21 ` [PATCH 6/9] x86/bpf: Fix JIT frame pointer usage Josh Poimboeuf
2019-06-13 21:58 ` Alexei Starovoitov
2019-06-14 1:22 ` Josh Poimboeuf
2019-06-14 1:39 ` Alexei Starovoitov
2019-06-14 1:52 ` Josh Poimboeuf
2019-06-14 10:50 ` David Laight [this message]
2019-06-14 13:44 ` Josh Poimboeuf
2019-06-14 13:58 ` David Laight
2019-06-14 17:07 ` Josh Poimboeuf
2019-06-17 15:07 ` David Laight
2019-06-13 13:21 ` [PATCH 7/9] x86/unwind/orc: Fall back to using frame pointers for generated code Josh Poimboeuf
2019-06-13 22:00 ` Alexei Starovoitov
2019-06-14 1:30 ` Josh Poimboeuf
2019-06-14 1:42 ` Alexei Starovoitov
2019-06-14 1:58 ` Josh Poimboeuf
2019-06-14 2:28 ` Josh Poimboeuf
2019-06-14 4:50 ` Josh Poimboeuf
2019-06-14 6:00 ` Alexei Starovoitov
2019-06-14 7:41 ` Peter Zijlstra
2019-06-14 13:31 ` Josh Poimboeuf
2019-06-14 15:29 ` Alexei Starovoitov
2019-06-14 13:34 ` Josh Poimboeuf
2019-06-14 15:31 ` Alexei Starovoitov
2019-06-14 15:56 ` Josh Poimboeuf
2019-06-13 13:21 ` [PATCH 8/9] x86/bpf: Convert asm comments to AT&T syntax Josh Poimboeuf
2019-06-13 18:52 ` Song Liu
2019-06-13 19:11 ` Josh Poimboeuf
2019-06-14 7:42 ` Peter Zijlstra
2019-06-14 15:13 ` Song Liu
2019-06-13 13:21 ` [PATCH 9/9] x86/bpf: Convert MOV function/macro argument ordering " Josh Poimboeuf
2019-06-13 19:00 ` [PATCH 0/9] x86/bpf: unwinder fixes Song Liu
2019-06-13 20:41 ` Peter Zijlstra
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