linux-kernel - Re: [RFC PATCH 04/47] mm: asi: ASI support in interrupts/exceptions

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Message-ID: <9f2f1226-f398-f132-06f4-c21a2a2d1033@google.com>
Date:   Mon, 14 Mar 2022 19:01:35 -0700
From:   Junaid Shahid <junaids@...gle.com>
To:     Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org
Cc:     kvm@...r.kernel.org, pbonzini@...hat.com, jmattson@...gle.com,
        pjt@...gle.com, oweisse@...gle.com, alexandre.chartre@...cle.com,
        rppt@...ux.ibm.com, dave.hansen@...ux.intel.com,
        peterz@...radead.org, luto@...nel.org, linux-mm@...ck.org
Subject: Re: [RFC PATCH 04/47] mm: asi: ASI support in interrupts/exceptions

On 3/14/22 08:50, Thomas Gleixner wrote:
> On Tue, Feb 22 2022 at 21:21, Junaid Shahid wrote:
>>   #define DEFINE_IDTENTRY_RAW(func)					\
>> -__visible noinstr void func(struct pt_regs *regs)
>> +static __always_inline void __##func(struct pt_regs *regs);		\
>> +									\
>> +__visible noinstr void func(struct pt_regs *regs)			\
>> +{									\
>> +	asi_intr_enter();						\
> 
> This is wrong. You cannot invoke arbitrary code within a noinstr
> section.
> 
> Please enable CONFIG_VMLINUX_VALIDATION and watch the build result with
> and without your patches.
> 
> Thanks,
> 
>          tglx

Thank you for the pointer. It seems that marking asi_intr_enter/exit and asi_enter/exit, and the few functions that they in turn call, as noinstr would fix this, correct? (Along with removing the VM_BUG_ONs from those functions and using notrace/nodebug variants of a couple of functions).

Thanks,
Junaid