Thank you Ard. Good catch on jump-table stuff. Acked-by: Jiewen Yao <[email protected]>
> -----Original Message----- > From: Ard Biesheuvel <[email protected]> > Sent: Tuesday, June 9, 2020 1:34 AM > To: [email protected] > Cc: Ard Biesheuvel <[email protected]>; Feng, Bob C > <[email protected]>; Gao, Liming <[email protected]>; Laszlo Ersek > <[email protected]>; Leif Lindholm <[email protected]>; Ilias Apalodimas > <[email protected]>; Julien Grall <[email protected]>; Yao, Jiewen > <[email protected]> > Subject: [PATCH 0/4] ArmVirtPkg: use PE/COFF metadata for self relocation > > As suggested by Jiewen in response to Ilias RFC [0], it is better to use > the PE/COFF metadata for self-relocating executables than to rely on ELF > metadata, given how the latter is only available when using ELF based > toolchains. Also, we have had some maintenance issues with this code in > the past, as PIE linking of non-position independent objects is not a well > tested code path in toolchains in general. > > So implement this for the self-relocating PrePi in ArmVirtPkg first. > > First, we need to ensure that the module in question is emitted with its > PE/COFF relocation metadata preserved, by creating a special FDF rule. > > We also need to provide a way for the code to refer to the start of the > image directly, by adding it to the linker script. > > Then, it is simply a matter of swapping out the two assembly routines, > and adding the C code that serves the same purpose but based on PE/COFF > base relocations. > > Note that PE/COFF relocations are considerably more compact than ELF RELA > relocations, so this does not impact the memory footprint of the resulting > image adversely. > > [0] https://edk2.groups.io/g/devel/message/60835 > > Cc: Bob Feng <[email protected]> > Cc: Liming Gao <[email protected]> > Cc: Laszlo Ersek <[email protected]> > Cc: Leif Lindholm <[email protected]> > Cc: Ilias Apalodimas <[email protected]> > Cc: Julien Grall <[email protected]> > Cc: Jiewen Yao <[email protected]> > > Ard Biesheuvel (4): > ArmVirtPkg: add FDF rule for self-relocating PrePi > BaseTools/Scripts/GccBase.lds: export image base symbol > ArmVirtPkg/PrePi: use standard PeCoff routines for self-relocation > ArmVirtPkg: remove unused files > > ArmVirtPkg/ArmVirtQemuKernel.dsc | 10 ++-- > ArmVirtPkg/ArmVirtXen.dsc | 10 ++-- > ArmVirtPkg/ArmVirtQemuKernel.fdf | 2 +- > ArmVirtPkg/ArmVirtXen.fdf | 2 +- > ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf | 4 +- > ArmVirtPkg/Include/Platform/Hidden.h | 22 --------- > ArmVirtPkg/PrePi/PrePi.c | 21 +++++++++ > ArmVirtPkg/ArmVirtRules.fdf.inc | 5 ++ > ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S | 49 +++++--------------- > ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S | 47 +++++-------------- > ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds | 41 ---------------- > BaseTools/Scripts/GccBase.lds | 2 + > 12 files changed, 63 insertions(+), 152 deletions(-) > delete mode 100644 ArmVirtPkg/Include/Platform/Hidden.h > delete mode 100644 ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds > > -- > 2.26.2 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#60918): https://edk2.groups.io/g/devel/message/60918 Mute This Topic: https://groups.io/mt/74757206/21656 Group Owner: [email protected] Unsubscribe: https://edk2.groups.io/g/devel/unsub [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
