lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Wed, 8 May 2024 12:43:28 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Andy Chiu <andy.chiu@...ive.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>,
 Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
 Conor Dooley <conor.dooley@...rochip.com>, Heiko Stuebner <heiko@...ech.de>,
 Guo Ren <guoren@...nel.org>, Conor Dooley <conor@...nel.org>,
 Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 Jonathan Corbet <corbet@....net>, Evan Green <evan@...osinc.com>,
 Clément Léger <cleger@...osinc.com>,
 Shuah Khan <shuah@...nel.org>, linux-riscv@...ts.infradead.org,
 linux-kernel@...r.kernel.org, Palmer Dabbelt <palmer@...osinc.com>,
 Vincent Chen <vincent.chen@...ive.com>,
 Greentime Hu <greentime.hu@...ive.com>, devicetree@...r.kernel.org,
 linux-doc@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v4 2/9] riscv: smp: fail booting up smp if inconsistent
 vlen is detected

Hi Andy,

On 08/05/2024 10:21, Andy Chiu wrote:
> On Thu, Apr 25, 2024 at 4:01 AM Alexandre Ghiti <alex@...ti.fr> wrote:
>> Hi Andy,
>>
>> On 12/04/2024 08:48, Andy Chiu wrote:
>>> Currently we only support Vector for SMP platforms, that is, all SMP
>>> cores have the same vlenb. If we happen to detect a mismatching vlen, it
>>> is better to just fail bootting it up to prevent further race/scheduling
>>> issues.
>>>
>>> Also, move .Lsecondary_park forward and chage `tail smp_callin` into a
>>> regular call in the early assembly. So a core would be parked right
>>> after a return from smp_callin. Note that a successful smp_callin
>>> does not return.
>>>
>>> Fixes: 7017858eb2d7 ("riscv: Introduce riscv_v_vsize to record size of Vector context")
>>> Reported-by: Conor Dooley <conor.dooley@...rochip.com>
>>> Closes: https://lore.kernel.org/linux-riscv/20240228-vicinity-cornstalk-4b8eb5fe5730@spud/
>>> Signed-off-by: Andy Chiu <andy.chiu@...ive.com>
>>> ---
>>> Changelog v4:
>>>    - update comment also in the assembly code (Yunhui)
>>> Changelog v2:
>>>    - update commit message to explain asm code change (Conor)
>>> ---
>>>    arch/riscv/kernel/head.S    | 19 ++++++++++++-------
>>>    arch/riscv/kernel/smpboot.c | 14 +++++++++-----
>>>    2 files changed, 21 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
>>> index 4236a69c35cb..a00f7523cb91 100644
>>> --- a/arch/riscv/kernel/head.S
>>> +++ b/arch/riscv/kernel/head.S
>>> @@ -165,9 +165,20 @@ secondary_start_sbi:
>>>    #endif
>>>        call .Lsetup_trap_vector
>>>        scs_load_current
>>> -     tail smp_callin
>>> +     call smp_callin
>>>    #endif /* CONFIG_SMP */
>>>
>>> +.align 2
>>> +.Lsecondary_park:
>>> +     /*
>>> +      * Park this hart if we:
>>> +      *  - have too many harts on CONFIG_RISCV_BOOT_SPINWAIT
>>> +      *  - receive an early trap, before setup_trap_vector finished
>>> +      *  - fail in smp_callin(), as a successful one wouldn't return
>>> +      */
>>> +     wfi
>>> +     j .Lsecondary_park
>>> +
>>>    .align 2
>>>    .Lsetup_trap_vector:
>>>        /* Set trap vector to exception handler */
>>> @@ -181,12 +192,6 @@ secondary_start_sbi:
>>>        csrw CSR_SCRATCH, zero
>>>        ret
>>>
>>> -.align 2
>>> -.Lsecondary_park:
>>> -     /* We lack SMP support or have too many harts, so park this hart */
>>> -     wfi
>>> -     j .Lsecondary_park
>>> -
>>>    SYM_CODE_END(_start)
>>>
>>>    SYM_CODE_START(_start_kernel)
>>> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
>>> index d41090fc3203..673437ccc13d 100644
>>> --- a/arch/riscv/kernel/smpboot.c
>>> +++ b/arch/riscv/kernel/smpboot.c
>>> @@ -214,6 +214,15 @@ asmlinkage __visible void smp_callin(void)
>>>        struct mm_struct *mm = &init_mm;
>>>        unsigned int curr_cpuid = smp_processor_id();
>>>
>>> +     if (has_vector()) {
>>> +             /*
>>> +              * Return as early as possible so the hart with a mismatching
>>> +              * vlen won't boot.
>>> +              */
>>> +             if (riscv_v_setup_vsize())
>>> +                     return;
>>> +     }
>>> +
>>>        /* All kernel threads share the same mm context.  */
>>>        mmgrab(mm);
>>>        current->active_mm = mm;
>>> @@ -226,11 +235,6 @@ asmlinkage __visible void smp_callin(void)
>>>        numa_add_cpu(curr_cpuid);
>>>        set_cpu_online(curr_cpuid, 1);
>>>
>>> -     if (has_vector()) {
>>> -             if (riscv_v_setup_vsize())
>>> -                     elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
>>> -     }
>>> -
>>>        riscv_user_isa_enable();
>>>
>>>        /*
>>>
>> So this should go into -fixes, would you mind sending a single patch for
>> this fix?
> I thought it would be magically picked up by a bot as long as we have
> a fix tag. Am I assuming something wrong?


It gets backported to stable when it is merged, but then it is missing 
from the first stable releases (as long as it is not merged).

But anyway, 6.9 fixes are all out, so let's hope this series makes it to 
6.10.

Thanks,

Alex


>
>> Your patch 8 is actually already fixed by Clement's patch
>> https://lore.kernel.org/linux-riscv/20240409143839.558784-1-cleger@rivosinc.com/
> Okay, I will drop it at the next revision.
>
>> and I already mentioned this one to Palmer.
>>
>> Thanks,
>>
>> Alex
>>
> Thanks,
> Andy
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ