diff options
Diffstat (limited to 'kernel/arch/x86/boot')
| -rw-r--r-- | kernel/arch/x86/boot/Makefile | 3 | ||||
| -rw-r--r-- | kernel/arch/x86/boot/compressed/Makefile | 14 | ||||
| -rw-r--r-- | kernel/arch/x86/boot/compressed/head_32.S | 28 | ||||
| -rw-r--r-- | kernel/arch/x86/boot/compressed/head_64.S | 8 |
4 files changed, 52 insertions, 1 deletions
diff --git a/kernel/arch/x86/boot/Makefile b/kernel/arch/x86/boot/Makefile index 2ee62dba0..c0cc2a6be 100644 --- a/kernel/arch/x86/boot/Makefile +++ b/kernel/arch/x86/boot/Makefile @@ -162,6 +162,9 @@ isoimage: $(obj)/bzImage for i in lib lib64 share end ; do \ if [ -f /usr/$$i/syslinux/isolinux.bin ] ; then \ cp /usr/$$i/syslinux/isolinux.bin $(obj)/isoimage ; \ + if [ -f /usr/$$i/syslinux/ldlinux.c32 ]; then \ + cp /usr/$$i/syslinux/ldlinux.c32 $(obj)/isoimage ; \ + fi ; \ break ; \ fi ; \ if [ $$i = end ] ; then exit 1 ; fi ; \ diff --git a/kernel/arch/x86/boot/compressed/Makefile b/kernel/arch/x86/boot/compressed/Makefile index 0a291cdfa..efa6073ff 100644 --- a/kernel/arch/x86/boot/compressed/Makefile +++ b/kernel/arch/x86/boot/compressed/Makefile @@ -22,7 +22,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \ vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2 -KBUILD_CFLAGS += -fno-strict-aliasing -fPIC +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 @@ -35,6 +35,18 @@ KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ GCOV_PROFILE := n LDFLAGS := -m elf_$(UTS_MACHINE) +ifeq ($(CONFIG_RELOCATABLE),y) +# If kernel is relocatable, build compressed kernel as PIE. +ifeq ($(CONFIG_X86_32),y) +LDFLAGS += $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker) +else +# To build 64-bit compressed kernel as PIE, we disable relocation +# overflow check to avoid relocation overflow error with a new linker +# command-line option, -z noreloc-overflow. +LDFLAGS += $(shell $(LD) --help 2>&1 | grep -q "\-z noreloc-overflow" \ + && echo "-z noreloc-overflow -pie --no-dynamic-linker") +endif +endif LDFLAGS_vmlinux := -T hostprogs-y := mkpiggy diff --git a/kernel/arch/x86/boot/compressed/head_32.S b/kernel/arch/x86/boot/compressed/head_32.S index 8ef964ddc..0256064da 100644 --- a/kernel/arch/x86/boot/compressed/head_32.S +++ b/kernel/arch/x86/boot/compressed/head_32.S @@ -31,6 +31,34 @@ #include <asm/asm-offsets.h> #include <asm/bootparam.h> +/* + * The 32-bit x86 assembler in binutils 2.26 will generate R_386_GOT32X + * relocation to get the symbol address in PIC. When the compressed x86 + * kernel isn't built as PIC, the linker optimizes R_386_GOT32X + * relocations to their fixed symbol addresses. However, when the + * compressed x86 kernel is loaded at a different address, it leads + * to the following load failure: + * + * Failed to allocate space for phdrs + * + * during the decompression stage. + * + * If the compressed x86 kernel is relocatable at run-time, it should be + * compiled with -fPIE, instead of -fPIC, if possible and should be built as + * Position Independent Executable (PIE) so that linker won't optimize + * R_386_GOT32X relocation to its fixed symbol address. Older + * linkers generate R_386_32 relocations against locally defined symbols, + * _bss, _ebss, _got and _egot, in PIE. It isn't wrong, just less + * optimal than R_386_RELATIVE. But the x86 kernel fails to properly handle + * R_386_32 relocations when relocating the kernel. To generate + * R_386_RELATIVE relocations, we mark _bss, _ebss, _got and _egot as + * hidden: + */ + .hidden _bss + .hidden _ebss + .hidden _got + .hidden _egot + __HEAD ENTRY(startup_32) #ifdef CONFIG_EFI_STUB diff --git a/kernel/arch/x86/boot/compressed/head_64.S b/kernel/arch/x86/boot/compressed/head_64.S index b0c0d16ef..86558a199 100644 --- a/kernel/arch/x86/boot/compressed/head_64.S +++ b/kernel/arch/x86/boot/compressed/head_64.S @@ -33,6 +33,14 @@ #include <asm/asm-offsets.h> #include <asm/bootparam.h> +/* + * Locally defined symbols should be marked hidden: + */ + .hidden _bss + .hidden _ebss + .hidden _got + .hidden _egot + __HEAD .code32 ENTRY(startup_32) |