From: Kees Cook <keescook@chromium.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Sean Christopherson <seanjc@google.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
kvmarm <kvmarm@lists.cs.columbia.edu>,
kvm@vger.kernel.org, Will McVicker <willmcvicker@google.com>
Subject: Re: [PATCH v4 09/17] perf/core: Use static_call to optimize perf_guest_info_callbacks
Date: Sun, 6 Feb 2022 18:55:56 -0800 [thread overview]
Message-ID: <202202061854.B5B11282@keescook> (raw)
In-Reply-To: <YgAvhG4wvnslbTqP@hirez.programming.kicks-ass.net>
On Sun, Feb 06, 2022 at 09:28:52PM +0100, Peter Zijlstra wrote:
> On Sun, Feb 06, 2022 at 10:45:15AM -0800, Kees Cook wrote:
>
> > I'm digging through the macros to sort this out, but IIUC, an example of
> > the problem is:
> >
>
> > so the caller is expecting "unsigned int (*)(void)" but the prototype
> > of __static_call_return0 is "long (*)(void)":
> >
> > long __static_call_return0(void);
> >
> > Could we simply declare a type-matched ret0 trampoline too?
>
> That'll work for this case, but the next case the function will have
> arguments we'll need even more nonsense...
Shouldn't the typeof() work there too, though? I.e. as long as the
return value can hold a "0", it'd work.
> And as stated in that other email, there's tb_stub_func() having the
> exact same problem as well.
Yeah, I'd need to go look at that again.
> The x86_64 CFI patches had a work-around for this, that could trivially
> be lifted I suppose.
Yeah, I think it'd be similar. I haven't had a chance to go look at that
again...
--
Kees Cook
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next prev parent reply other threads:[~2022-02-07 2:57 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-11 2:07 [PATCH v4 00/17] perf: KVM: Fix, optimize, and clean up callbacks Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 01/17] perf: Protect perf_guest_cbs with RCU Sean Christopherson
2021-11-11 7:26 ` Paolo Bonzini
2021-11-11 10:47 ` Peter Zijlstra
2021-11-12 7:55 ` Paolo Bonzini
2021-11-11 2:07 ` [PATCH v4 02/17] KVM: x86: Register perf callbacks after calling vendor's hardware_setup() Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 03/17] KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 04/17] perf: Stop pretending that perf can handle multiple guest callbacks Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 05/17] perf: Drop dead and useless guest "support" from arm, csky, nds32 and riscv Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 06/17] perf/core: Rework guest callbacks to prepare for static_call support Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 07/17] perf: Add wrappers for invoking guest callbacks Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 08/17] perf: Force architectures to opt-in to " Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 09/17] perf/core: Use static_call to optimize perf_guest_info_callbacks Sean Christopherson
2022-02-02 18:43 ` Sean Christopherson
2022-02-04 17:35 ` Sami Tolvanen
2022-02-06 13:08 ` Peter Zijlstra
2022-02-06 18:45 ` Kees Cook
2022-02-06 20:28 ` Peter Zijlstra
2022-02-07 2:55 ` Kees Cook [this message]
2022-02-18 22:35 ` Will McVicker
2022-08-24 16:45 ` Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 10/17] KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 11/17] KVM: x86: More precisely identify NMI from guest when handling PMI Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 12/17] KVM: Move x86's perf guest info callbacks to generic KVM Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 13/17] KVM: x86: Move Intel Processor Trace interrupt handler to vmx.c Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 14/17] KVM: arm64: Convert to the generic perf callbacks Sean Christopherson
2021-11-11 2:07 ` [PATCH v4 15/17] KVM: arm64: Hide kvm_arm_pmu_available behind CONFIG_HW_PERF_EVENTS=y Sean Christopherson
2021-11-11 21:49 ` Marc Zyngier
2021-11-11 2:07 ` [PATCH v4 16/17] KVM: arm64: Drop perf.c and fold its tiny bits of code into arm.c Sean Christopherson
2021-11-11 21:49 ` Marc Zyngier
2021-11-11 2:07 ` [PATCH v4 17/17] perf: Drop guest callback (un)register stubs Sean Christopherson
2021-11-11 11:19 ` [PATCH v4 00/17] perf: KVM: Fix, optimize, and clean up callbacks Peter Zijlstra
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