diff options
| author | Alexandre Ghiti <alexghiti@rivosinc.com> | 2023-03-29 06:53:26 +0200 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2023-04-19 07:46:30 -0700 |
| commit | 39b33072941f8bab82aa2c802044062385a046bf (patch) | |
| tree | 1c7f43e326d8f4b896630d474829bafe7f061d6a /arch/riscv/Makefile | |
| parent | 69a90d2fe107c8bf6a424af0f30d2b223cdeaf7c (diff) | |
riscv: Introduce CONFIG_RELOCATABLE
This config allows to compile 64b kernel as PIE and to relocate it at
any virtual address at runtime: this paves the way to KASLR.
Runtime relocation is possible since relocation metadata are embedded into
the kernel.
Note that relocating at runtime introduces an overhead even if the
kernel is loaded at the same address it was linked at and that the compiler
options are those used in arm64 which uses the same RELA relocation
format.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230329045329.64565-4-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/Makefile')
| -rw-r--r-- | arch/riscv/Makefile | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index 6203c3378922..860b09e409c7 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -7,9 +7,12 @@ # OBJCOPYFLAGS := -O binary -LDFLAGS_vmlinux := +ifeq ($(CONFIG_RELOCATABLE),y) + LDFLAGS_vmlinux += -shared -Bsymbolic -z notext -z norelro + KBUILD_CFLAGS += -fPIE +endif ifeq ($(CONFIG_DYNAMIC_FTRACE),y) - LDFLAGS_vmlinux := --no-relax + LDFLAGS_vmlinux += --no-relax KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY ifeq ($(CONFIG_RISCV_ISA_C),y) CC_FLAGS_FTRACE := -fpatchable-function-entry=4 |