From: Joerg Roedel <jroedel@suse.de>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: x86@kernel.org, Borislav Petkov <bp@alien8.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 5/5] x86/head/64: Disable stack protection for head$(BITS).o
Date: Fri, 9 Oct 2020 16:49:36 +0200 [thread overview]
Message-ID: <20201009144936.GC3302@suse.de> (raw)
In-Reply-To: <20201008191623.2881677-6-nivedita@alum.mit.edu>
On Thu, Oct 08, 2020 at 03:16:23PM -0400, Arvind Sankar wrote:
> On 64-bit, the startup_64_setup_env() function added in
> 866b556efa12 ("x86/head/64: Install startup GDT")
> has stack protection enabled because of set_bringup_idt_handler().
>
> At this point, %gs is not yet initialized, and this doesn't cause a
> crash only because the #PF handler from the decompressor stub is still
> installed and handles the page fault.
>
> Disable stack protection for the whole file, and do it on 32-bit as
> well to avoid surprises.
>
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> ---
> arch/x86/kernel/Makefile | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 04ceea8f4a89..68608bd892c0 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -47,6 +47,8 @@ endif
> # non-deterministic coverage.
> KCOV_INSTRUMENT := n
>
> +CFLAGS_head$(BITS).o += -fno-stack-protector
> +
> CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
>
> obj-y := process_$(BITS).o signal.o
> --
> 2.26.2
Reviewed-by: Joerg Roedel <jroedel@suse.de>
next prev parent reply other threads:[~2020-10-09 14:49 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 19:16 [PATCH v2 0/5] Couple of bugfixes to sev-es series Arvind Sankar
2020-10-08 19:16 ` [PATCH v2 1/5] x86/boot: Initialize boot_params in startup code Arvind Sankar
2020-10-08 19:16 ` [PATCH v2 2/5] x86/boot: Split out command-line related declarations Arvind Sankar
2020-10-08 19:16 ` [PATCH v2 3/5] x86/boot/64: Show original faulting address in case of error Arvind Sankar
2020-10-09 14:42 ` Joerg Roedel
2020-10-08 19:16 ` [PATCH v2 4/5] x86/boot/64: Explicitly map boot_params and command line Arvind Sankar
2020-10-09 14:49 ` Joerg Roedel
2020-10-16 16:27 ` Borislav Petkov
2020-10-16 16:47 ` Arvind Sankar
2020-10-16 17:07 ` Borislav Petkov
2020-10-16 17:20 ` Arvind Sankar
2020-10-16 17:32 ` Borislav Petkov
2020-10-16 20:04 ` [PATCH v3 1/4] " Arvind Sankar
2020-10-16 20:04 ` [PATCH v3 2/4] x86/boot: Initialize boot_params in startup code Arvind Sankar
2020-10-16 20:04 ` [PATCH v3 3/4] x86/boot: Split out command-line related declarations Arvind Sankar
2020-10-16 20:04 ` [PATCH v3 4/4] x86/boot/64: Show original faulting address in case of error Arvind Sankar
2020-10-19 14:51 ` [PATCH v3 1/4] x86/boot/64: Explicitly map boot_params and command line Borislav Petkov
2020-10-19 17:12 ` Arvind Sankar
2020-10-19 17:31 ` Borislav Petkov
2020-10-19 19:44 ` [tip: x86/seves] " tip-bot2 for Arvind Sankar
2020-10-16 21:18 ` [PATCH v2 4/5] " Arvind Sankar
2020-10-16 21:23 ` Borislav Petkov
2020-10-08 19:16 ` [PATCH v2 5/5] x86/head/64: Disable stack protection for head$(BITS).o Arvind Sankar
2020-10-09 14:49 ` Joerg Roedel [this message]
2020-10-16 11:17 ` Borislav Petkov
2020-10-16 12:43 ` Arvind Sankar
2020-10-16 13:15 ` Borislav Petkov
2020-10-16 14:16 ` Arvind Sankar
2020-10-19 19:44 ` [tip: x86/seves] " tip-bot2 for Arvind Sankar
2020-10-10 19:11 ` [PATCH] x86/boot/64: Initialize 5-level paging variables earlier Arvind Sankar
2020-10-10 19:26 ` Arvind Sankar
2020-10-12 14:08 ` Kirill A. Shutemov
2020-10-12 15:35 ` Arvind Sankar
2020-10-13 8:11 ` Borislav Petkov
2020-10-13 8:20 ` Kirill A. Shutemov
2020-10-13 8:33 ` Borislav Petkov
2020-10-13 9:12 ` Kirill A. Shutemov
2020-10-13 9:46 ` Borislav Petkov
2020-10-15 13:52 ` Kirill A. Shutemov
2020-10-16 10:21 ` Borislav Petkov
2020-10-13 8:59 ` Joerg Roedel
2020-10-19 19:44 ` [tip: x86/seves] " tip-bot2 for Arvind Sankar
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