From: Jiri Olsa <olsajiri@gmail.com>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: "olsajiri@gmail.com" <olsajiri@gmail.com>,
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Subject: Re: [PATCHv5 bpf-next 6/8] x86/shstk: Add return uprobe support
Date: Tue, 21 May 2024 12:11:57 +0200 [thread overview]
Message-ID: <ZkxzbSq3bS2loTJI@krava> (raw)
In-Reply-To: <81afa4ccc661a1598b659958164c7a73cf211d21.camel@intel.com>
On Tue, May 21, 2024 at 01:31:53AM +0000, Edgecombe, Rick P wrote:
> On Mon, 2024-05-20 at 00:18 +0200, Jiri Olsa wrote:
> > anyway I think we can fix that in another way by using the optimized
> > trampoline,
> > but returning to the user space through iret when shadow stack is detected
> > (as I did in the first version, before you adjusted it to the sysret path).
> >
> > we need to update the return address on stack only when returning through the
> > trampoline, but we can jump to original return address directly from syscall
> > through iret.. which is slower, but with shadow stack we don't care
> >
> > basically the only change is adding the shstk_is_enabled check to the
> > following condition in SYSCALL_DEFINE0(uretprobe):
> >
> > if (regs->sp != sp || shstk_is_enabled())
> > return regs->ax;
>
> On the surface it sounds reasonable. Thanks.
>
> And then I guess if tradeoffs are seen differently in the future, and we want to
> enable the fast path for shadow stack we can go with your other solution. So
> this just simply fixes things functionally without much code.
yes, if we want to enable the fast path for shadow stack in future
we'll need to remove that shstk_is_enabled and push extra frame on
shadow stack
jirka
next prev parent reply other threads:[~2024-05-21 10:12 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 10:53 [PATCHv5 bpf-next 0/8] uprobe: uretprobe speed up Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 1/8] uprobe: Wire up uretprobe system call Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 2/8] uprobe: Add uretprobe syscall to speed up return probe Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 3/8] selftests/bpf: Add uretprobe syscall test for regs integrity Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 4/8] selftests/bpf: Add uretprobe syscall test for regs changes Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 bpf-next 5/8] selftests/bpf: Add uretprobe syscall call from user space test Jiri Olsa
2024-05-07 16:57 ` Andrii Nakryiko
2024-05-07 10:53 ` [PATCHv5 bpf-next 6/8] x86/shstk: Add return uprobe support Jiri Olsa
2024-05-07 17:35 ` Edgecombe, Rick P
2024-05-09 8:30 ` Jiri Olsa
2024-05-09 16:24 ` Edgecombe, Rick P
2024-05-11 21:09 ` Jiri Olsa
2024-05-13 9:50 ` Masami Hiramatsu
2024-05-13 17:12 ` Edgecombe, Rick P
2024-05-13 21:23 ` Jiri Olsa
2024-05-15 1:10 ` Edgecombe, Rick P
2024-05-15 1:44 ` Deepak Gupta
2024-05-15 11:19 ` Oleg Nesterov
2024-05-15 14:36 ` Jiri Olsa
2024-05-15 15:18 ` Edgecombe, Rick P
2024-05-15 15:26 ` Oleg Nesterov
2024-05-15 15:31 ` Edgecombe, Rick P
2024-05-15 11:35 ` Oleg Nesterov
2024-05-15 15:13 ` Edgecombe, Rick P
2024-05-15 15:42 ` Oleg Nesterov
2024-05-19 22:18 ` Jiri Olsa
2024-05-21 1:31 ` Edgecombe, Rick P
2024-05-21 10:11 ` Jiri Olsa [this message]
2024-05-07 10:53 ` [PATCHv5 bpf-next 7/8] selftests/x86: Add return uprobe shadow stack test Jiri Olsa
2024-05-13 9:45 ` Masami Hiramatsu
2024-05-13 21:28 ` Jiri Olsa
2024-05-07 10:53 ` [PATCHv5 8/8] man2: Add uretprobe syscall page Jiri Olsa
2024-05-07 11:13 ` Dmitry V. Levin
2024-05-07 11:49 ` Jiri Olsa
2024-05-07 13:44 ` Alejandro Colomar
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