[PATCH 11/70] x86/boot/compressed/64: Disable red-zone usage
From: Joerg Roedel <joro@8bytes.org>
Date: 2020-03-19 09:19:58
Also in:
kvm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Joerg Roedel <redacted> The x86-64 ABI defines a red-zone on the stack: The 128-byte area beyond the location pointed to by %rsp is considered to be reserved and shall not be modified by signal or interrupt handlers. 10 Therefore, functions may use this area for temporary data that is not needed across function calls. In particular, leaf functions may use this area for their entire stack frame, rather than adjusting the stack pointer in the prologue and epilogue. This area is known as the red zone. This is not compatible with exception handling, so disable it for the pre-decompression boot code. Signed-off-by: Joerg Roedel <redacted> --- arch/x86/boot/Makefile | 2 +- arch/x86/boot/compressed/Makefile | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 012b82fc8617..8f55e4ce1ccc 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile@@ -65,7 +65,7 @@ clean-files += cpustr.h # --------------------------------------------------------------------------- -KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP +KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP -mno-red-zone KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) GCOV_PROFILE := n
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 26050ae0b27e..e186cc0b628d 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile@@ -30,7 +30,7 @@ KBUILD_CFLAGS := -m$(BITS) -O2 KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC) KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING cflags-$(CONFIG_X86_32) := -march=i386 -cflags-$(CONFIG_X86_64) := -mcmodel=small +cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone KBUILD_CFLAGS += $(cflags-y) KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += $(call cc-option,-ffreestanding)
@@ -87,7 +87,7 @@ endif vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o -$(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone +$(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o \ $(objtree)/drivers/firmware/efi/libstub/lib.a
--
2.17.1