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Message-ID: <cf24db95-9c91-5d30-fe83-3a1e2cbf0cc1@suse.com>
Date: Mon, 19 Jun 2023 09:28:22 +0300
From: Nikolay Borisov <nik.borisov@...e.com>
To: Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org
Cc: linux-kernel@...r.kernel.org, mhocko@...e.com, jslaby@...e.cz
Subject: Re: [PATCH v3 5/5] x86/entry: Make IA32 syscalls' availability depend
on ia32_enabled()
On 19.06.23 г. 0:17 ч., Thomas Gleixner wrote:
> On Fri, Jun 16 2023 at 15:57, Nikolay Borisov wrote:
>> Another major aspect of supporting running of 32bit processes is the
>> ability to access 32bit syscalls. Such syscalls are invoked either by
>> using the legacy int 0x80 call gate interface or via the newer sysenter
>> instruction.
>>
>> Ensure that if ia32 emulation is disabled (either at compile time or
>> runtime) then those 2 syscall mechanisms are also disabled.
>
> AFAICT there are _three_ mechanisms for 32bit syscalls, no?
int 0x80 and sysenter make it 2? Which one is the 3rd one - the "native
64bit syscall" used in for X32 ABI ? This patch specifically deals with
the first 2?
>
>> void __init idt_setup_traps(void)
>> {
>> idt_setup_from_table(idt_table, def_idts, ARRAY_SIZE(def_idts), true);
>> +
>> + if (ia32_enabled()) {
>> + idt_setup_from_table(idt_table, ia32_idt, ARRAY_SIZE(ia32_idt),
>> + true);
>
> Just let it stick out. The 80 character limit is history.
>
> Thanks,
>
> tglx
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