Messages in this thread | | | From | Brian Gerst <> | Subject | [PATCH 0/3] x86-64: Stack protector and percpu improvements | Date | Sat, 13 Nov 2021 07:40:32 -0500 |
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Currently, x86-64 uses an unusual per-cpu layout, where the percpu section is linked at absolute address 0. The reason behind this is that older GCC versions placed the stack protector (if enabled) at a fixed offset from the GS segment base. Since the GS segement is also used for percpu variables, this forced the current layout.
GCC since version 8.1 supports a configurable location for the stack protector value, which allows removal of the restriction on where the percpu data is linked. Compatibility with older compilers is maintained until the minimum compiler version is raised.
Brian Gerst (3): x86-64: Use per-cpu stack canary if supported by compiler x86/relocs: Make absolute percpu relocations conditional x86_64: Use relative per-cpu offsets
arch/x86/Kconfig | 9 +++++++++ arch/x86/Makefile | 21 ++++++++++++++------- arch/x86/boot/compressed/Makefile | 3 ++- arch/x86/entry/entry_64.S | 6 +++++- arch/x86/include/asm/percpu.h | 4 ++-- arch/x86/include/asm/processor.h | 14 +++++++++++--- arch/x86/include/asm/stackprotector.h | 17 ++++++----------- arch/x86/kernel/asm-offsets_64.c | 2 +- arch/x86/kernel/cpu/common.c | 14 ++++++++------ arch/x86/kernel/head_64.S | 12 ++++++++---- arch/x86/kernel/setup_percpu.c | 2 +- arch/x86/kernel/vmlinux.lds.S | 16 +++++++--------- arch/x86/tools/relocs.c | 4 ++-- arch/x86/tools/relocs.h | 4 ++-- arch/x86/tools/relocs_common.c | 11 ++++++++--- arch/x86/xen/xen-head.S | 10 ++++------ init/Kconfig | 1 - 17 files changed, 90 insertions(+), 60 deletions(-)
-- 2.31.1
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