From: mka@chromium•org (Matthias Kaehlcke)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/3] efi/libstub: arm64: set -fpie when building the EFI stub
Date: Thu, 8 Jun 2017 12:08:04 -0700 [thread overview]
Message-ID: <20170608190804.GG141096@google.com> (raw)
In-Reply-To: <20170518090953.32628-4-ard.biesheuvel@linaro.org>
El Thu, May 18, 2017 at 10:09:53AM +0100 Ard Biesheuvel ha dit:
> Clang may emit absolute symbol references when building in non-PIC mode,
> even when using the default 'small' code model, which is already mostly
> position independent to begin with, due to its use of adrp/add pairs
> that have a relative range of +/- 4 GB. The remedy is to pass the -fpie
> flag, which can be done safely now that the code has been updated to avoid
> GOT indirections (which may be emitted due to the compiler assuming that
> the PIC/PIE code may end up in a shared library that is subject to ELF
> symbol preemption)
>
> Passing -fpie when building code that needs to execute at an a priori
> unknown offset is arguably an improvement in any case, and given that
> the recent visibility changes allow the PIC build to pass with GCC as
> well, let's add -fpie for all arm64 builds rather than only for Clang.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro•org>
Tested-by: Matthias Kaehlcke <mka@chromium•org>
next prev parent reply other threads:[~2017-06-08 19:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-18 9:09 [PATCH 0/3] efi: arm64: use -fpie for building the stub Ard Biesheuvel
2017-05-18 9:09 ` [PATCH 1/3] efi/libstub: arm64: use hidden attribute for struct screen_info reference Ard Biesheuvel
2017-06-08 19:06 ` Matthias Kaehlcke
2017-05-18 9:09 ` [PATCH 2/3] efi/libstub: arm64: force 'hidden' visibility for section markers Ard Biesheuvel
2017-06-08 19:07 ` Matthias Kaehlcke
2017-05-18 9:09 ` [PATCH 3/3] efi/libstub: arm64: set -fpie when building the EFI stub Ard Biesheuvel
2017-06-08 19:08 ` Matthias Kaehlcke [this message]
2017-06-08 19:18 ` Ard Biesheuvel
2017-06-08 19:44 ` Matthias Kaehlcke
2017-06-09 9:02 ` [PATCH 0/3] efi: arm64: use -fpie for building the stub Ard Biesheuvel
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