diff options
| -rw-r--r-- | arch/x86/boot/compressed/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/vmlinux.lds.S | 1 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/Makefile | 2 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/hidden.h | 6 | ||||
| -rw-r--r-- | include/linux/hidden.h | 19 |
5 files changed, 22 insertions, 7 deletions
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 3962f592633d..7c687a770537 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -43,6 +43,7 @@ KBUILD_CFLAGS += -Wno-pointer-sign KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables KBUILD_CFLAGS += -D__DISABLE_EXPORTS +KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ GCOV_PROFILE := n diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S index b17d218ccdf9..4bcc943842ab 100644 --- a/arch/x86/boot/compressed/vmlinux.lds.S +++ b/arch/x86/boot/compressed/vmlinux.lds.S @@ -81,6 +81,7 @@ SECTIONS DISCARDS } +ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!") #ifdef CONFIG_X86_64 ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0x18, "Unexpected GOT/PLT entries detected!") #else diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 296b18fbd7a2..5eefd60917df 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -26,7 +26,7 @@ cflags-$(CONFIG_ARM) := $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \ cflags-$(CONFIG_EFI_GENERIC_STUB) += -I$(srctree)/scripts/dtc/libfdt KBUILD_CFLAGS := $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \ - -include $(srctree)/drivers/firmware/efi/libstub/hidden.h \ + -include $(srctree)/include/linux/hidden.h \ -D__NO_FORTIFY \ -ffreestanding \ -fno-stack-protector \ diff --git a/drivers/firmware/efi/libstub/hidden.h b/drivers/firmware/efi/libstub/hidden.h deleted file mode 100644 index 3493b041f419..000000000000 --- a/drivers/firmware/efi/libstub/hidden.h +++ /dev/null @@ -1,6 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * To prevent the compiler from emitting GOT-indirected (and thus absolute) - * references to any global symbols, override their visibility as 'hidden' - */ -#pragma GCC visibility push(hidden) diff --git a/include/linux/hidden.h b/include/linux/hidden.h new file mode 100644 index 000000000000..49a17b6b5962 --- /dev/null +++ b/include/linux/hidden.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * When building position independent code with GCC using the -fPIC option, + * (or even the -fPIE one on older versions), it will assume that we are + * building a dynamic object (either a shared library or an executable) that + * may have symbol references that can only be resolved at load time. For a + * variety of reasons (ELF symbol preemption, the CoW footprint of the section + * that is modified by the loader), this results in all references to symbols + * with external linkage to go via entries in the Global Offset Table (GOT), + * which carries absolute addresses which need to be fixed up when the + * executable image is loaded at an offset which is different from its link + * time offset. + * + * Fortunately, there is a way to inform the compiler that such symbol + * references will be satisfied at link time rather than at load time, by + * giving them 'hidden' visibility. + */ + +#pragma GCC visibility push(hidden) |