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From: Mike Lothian <mike@fireburn.co.uk>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Ard Biesheuvel <ardb@kernel.org>,
	linux-efi <linux-efi@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	X86 ML <x86@kernel.org>
Subject: Re: [PATCH] x86/boot: Mark global variables as static
Date: Tue, 12 May 2020 00:12:26 +0100	[thread overview]
Message-ID: <CAHbf0-HLKiq_+erhHfV9XqMhfchN2975nAsuya4-oXEOUNdhiw@mail.gmail.com> (raw)
In-Reply-To: <20200511225849.1311869-1-nivedita@alum.mit.edu>

Feel free to add my tested by


On Mon, 11 May 2020 at 23:58, Arvind Sankar <nivedita@alum.mit.edu> wrote:
>
> Mike Lothian reports that after commit
>   964124a97b97 ("efi/x86: Remove extra headroom for setup block")
> gcc 10.1.0 fails with
>
>   HOSTCC  arch/x86/boot/tools/build
>   /usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/../../../../x86_64-pc-linux-gnu/bin/ld:
>   error: linker defined: multiple definition of '_end'
>   /usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/../../../../x86_64-pc-linux-gnu/bin/ld:
>   /tmp/ccEkW0jM.o: previous definition here
>   collect2: error: ld returned 1 exit status
>   make[1]: *** [scripts/Makefile.host:103: arch/x86/boot/tools/build] Error 1
>   make: *** [arch/x86/Makefile:303: bzImage] Error 2
>
> The issue is with the _end variable that was added, to hold the end of
> the compressed kernel from zoffsets.h (ZO__end). The name clashes with
> the linker-defined _end symbol that indicates the end of the build
> program itself.
>
> Even when there is no compile-time error, this causes build to use
> memory past the end of its .bss section.
>
> To solve this, mark _end as static, and for symmetry, mark the rest of
> the variables that keep track of symbols from the compressed kernel as
> static as well.
>
> Fixes: 964124a97b97 ("efi/x86: Remove extra headroom for setup block")
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> ---
>  arch/x86/boot/tools/build.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
> index 8f8c8e386cea..c8b8c1a8d1fc 100644
> --- a/arch/x86/boot/tools/build.c
> +++ b/arch/x86/boot/tools/build.c
> @@ -59,14 +59,14 @@ u8 buf[SETUP_SECT_MAX*512];
>  #define PECOFF_COMPAT_RESERVE 0x0
>  #endif
>
> -unsigned long efi32_stub_entry;
> -unsigned long efi64_stub_entry;
> -unsigned long efi_pe_entry;
> -unsigned long efi32_pe_entry;
> -unsigned long kernel_info;
> -unsigned long startup_64;
> -unsigned long _ehead;
> -unsigned long _end;
> +static unsigned long efi32_stub_entry;
> +static unsigned long efi64_stub_entry;
> +static unsigned long efi_pe_entry;
> +static unsigned long efi32_pe_entry;
> +static unsigned long kernel_info;
> +static unsigned long startup_64;
> +static unsigned long _ehead;
> +static unsigned long _end;
>
>  /*----------------------------------------------------------------------*/
>
> --
> 2.26.2
>

  reply	other threads:[~2020-05-11 23:12 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-01 23:05 [PATCH 0/5] Minimize the need to move the kernel in the EFI stub Arvind Sankar
2020-03-01 23:05 ` [PATCH 1/5] x86/boot/compressed/32: Save the output address instead of recalculating it Arvind Sankar
2020-03-03 19:10   ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 2/5] efi/x86: Decompress at start of PE image load address Arvind Sankar
2020-03-03  6:28   ` Mika Penttilä
2020-03-03 13:45     ` Arvind Sankar
2020-03-03 19:08   ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 3/5] efi/x86: Add kernel preferred address to PE header Arvind Sankar
2020-03-03 19:11   ` Ard Biesheuvel
2020-03-01 23:05 ` [PATCH 4/5] efi/x86: Remove extra headroom for setup block Arvind Sankar
2020-03-02  4:21   ` Mika Penttilä
2020-03-03  4:14     ` Arvind Sankar
2020-03-01 23:05 ` [PATCH 5/5] efi/x86: Don't relocate the kernel unless necessary Arvind Sankar
2020-03-03 19:15   ` Ard Biesheuvel
2020-03-03 22:12 ` [PATCH v2 0/5] Minimize the need to move the kernel in the EFI stub Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 1/5] x86/boot/compressed/32: Save the output address instead of recalculating it Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 2/5] efi/x86: Decompress at start of PE image load address Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 3/5] efi/x86: Add kernel preferred address to PE header Arvind Sankar
2020-03-03 22:12   ` [PATCH v2 4/5] efi/x86: Remove extra headroom for setup block Arvind Sankar
2020-05-11 17:01     ` Mike Lothian
2020-05-11 18:36       ` Arvind Sankar
2020-05-11 21:13         ` Ard Biesheuvel
2020-05-11 22:53           ` Arvind Sankar
2020-05-11 22:58             ` [PATCH] x86/boot: Mark global variables as static Arvind Sankar
2020-05-11 23:12               ` Mike Lothian [this message]
2020-05-12 11:05                 ` Ard Biesheuvel
2020-03-03 22:12   ` [PATCH v2 5/5] efi/x86: Don't relocate the kernel unless necessary Arvind Sankar
2020-03-03 23:08     ` Ard Biesheuvel
2020-03-03 23:34       ` Arvind Sankar
2020-03-04  7:30         ` Ard Biesheuvel
2020-03-03 22:26   ` [PATCH v2 0/5] Minimize the need to move the kernel in the EFI stub Ard Biesheuvel

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