From: Catalin Marinas <catalin.marinas@arm.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Will Deacon <will@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>,
Mark Brown <broonie@kernel.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Kristina Martsenko <kristina.martsenko@arm.com>,
Ionela Voinescu <ionela.voinescu@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Scull <ascull@google.com>,
David Brazdil <dbrazdil@google.com>,
Marc Zyngier <maz@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: Re: [PATCH] [RFC] arm64: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
Date: Wed, 17 Mar 2021 16:18:39 +0000 [thread overview]
Message-ID: <20210317161838.GF12269@arm.com> (raw)
In-Reply-To: <20210317143757.GD12269@arm.com>
On Wed, Mar 17, 2021 at 02:37:57PM +0000, Catalin Marinas wrote:
> On Thu, Feb 25, 2021 at 12:20:56PM +0100, Arnd Bergmann wrote:
> > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
> > index bad2b9eaab22..926cdb597a45 100644
> > --- a/arch/arm64/kernel/vmlinux.lds.S
> > +++ b/arch/arm64/kernel/vmlinux.lds.S
> > @@ -217,7 +217,7 @@ SECTIONS
> > INIT_CALLS
> > CON_INITCALL
> > INIT_RAM_FS
> > - *(.init.altinstructions .init.bss .init.bss.*) /* from the EFI stub */
> > + *(.init.altinstructions .init.data.* .init.bss .init.bss.*) /* from the EFI stub */
>
> INIT_DATA already covers .init.data and .init.data.*, so I don't think
> we need this change.
Ah, INIT_DATA only covers init.data.* (so no dot in front). The above
is needed for the EFI stub.
However, I gave this a quick try and under Qemu with -cpu max and -smp 2
(or more) it fails as below. I haven't debugged but the lr points to
just after the switch_to() call. Maybe some section got discarded and we
patched in the wrong instructions. It is fine with -cpu host or -smp 1.
-------------------8<------------------------
smp: Bringing up secondary CPUs ...
Detected PIPT I-cache on CPU1
CPU1: Booted secondary processor 0x0000000001 [0x000f0510]
Unable to handle kernel paging request at virtual address eb91d81ad2971160
Mem abort info:
ESR = 0x86000004
EC = 0x21: IABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
[eb91d81ad2971160] address between user and kernel address ranges
Internal error: Oops: 86000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 16 Comm: migration/1 Not tainted 5.12.0-rc3-00002-g128e977c1322 #1
Stopper: 0x0 <- 0x0
pstate: 60000085 (nZCv daIf -PAN -UAO -TCO BTYPE=--)
pc : 0xeb91d81ad2971160
lr : __schedule+0x230/0x6b8
sp : ffff80001009bd60
x29: ffff80001009bd60 x28: 0000000000000000
x27: ffff0000000a6760 x26: ffff0000000b7540
x25: 0080000000000000 x24: ffffd81ad3969000
x23: ffff0000000a6200 x22: 6ee0d81ad2971658
x21: ffff0000000a6200 x20: ffff000000080000
x19: ffff00007fbc6bc0 x18: 0000000000000030
x17: 0000000000000000 x16: 0000000000000000
x15: 00008952b30a9a9e x14: 0000000000000366
x13: 0000000000000192 x12: 0000000000000000
x11: 0000000000000003 x10: 00000000000009b0
x9 : ffff80001009bd30 x8 : ffff0000000a6c10
x7 : ffff00007fbc6cc0 x6 : 00000000fffedb30
x5 : 00000000ffffffff x4 : 0000000000000000
x3 : 0000000000000008 x2 : 0000000000000000
x1 : ffff0000000a6200 x0 : ffff0000000a3800
Call trace:
0xeb91d81ad2971160
schedule+0x70/0x108
schedule_preempt_disabled+0x24/0x40
__kthread_parkme+0x68/0xd0
kthread+0x138/0x170
ret_from_fork+0x10/0x30
Code: bad PC value
---[ end trace af3481062ecef3e7 ]---
--
Catalin
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next prev parent reply other threads:[~2021-03-17 16:20 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 11:20 [PATCH] [RFC] arm64: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION Arnd Bergmann
2021-02-25 20:16 ` Kees Cook
2021-02-26 0:36 ` Sedat Dilek
2021-02-26 8:14 ` Arnd Bergmann
2021-02-26 9:05 ` Sedat Dilek
2021-02-26 9:51 ` Arnd Bergmann
2021-02-26 10:02 ` Sedat Dilek
2021-02-26 21:13 ` Fangrui Song
2021-02-27 9:49 ` Arnd Bergmann
2021-03-01 1:11 ` Nicholas Piggin
2021-03-10 20:49 ` Masahiro Yamada
2021-03-10 21:08 ` Arnd Bergmann
2021-03-10 21:24 ` Sedat Dilek
2021-03-10 21:47 ` Nicolas Pitre
2021-03-10 21:57 ` Sedat Dilek
2021-03-10 22:02 ` Nick Desaulniers
2021-03-10 22:08 ` Nicolas Pitre
2021-03-10 22:29 ` Fangrui Song
2021-03-10 21:45 ` Rasmus Villemoes
2021-03-10 21:19 ` Nicolas Pitre
2021-03-10 22:42 ` Fangrui Song
2021-03-17 14:37 ` Catalin Marinas
2021-03-17 16:18 ` Catalin Marinas [this message]
2021-03-18 8:41 ` Arnd Bergmann
2021-03-19 12:25 ` Catalin Marinas
2021-03-19 14:01 ` Arnd Bergmann
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