From b7ac4b8ee73d4fec0998664c9dd61f089d481044 Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Sat, 22 Jul 2023 14:38:50 +0200 Subject: riscv: libstub: Implement KASLR by using generic functions We can now use arm64 functions to handle the move of the kernel physical mapping: if KASLR is enabled, we will try to get a random seed from the firmware, if not possible, the kernel will be moved to a location that suits its alignment constraints. Signed-off-by: Alexandre Ghiti Tested-by: Conor Dooley Tested-by: Song Shuai Reviewed-by: Sami Tolvanen Tested-by: Sami Tolvanen Link: https://lore.kernel.org/r/20230722123850.634544-6-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/efi.h | 2 ++ arch/riscv/kernel/image-vars.h | 1 + drivers/firmware/efi/libstub/Makefile | 2 +- drivers/firmware/efi/libstub/riscv-stub.c | 33 ++++++++++++++----------------- 4 files changed, 19 insertions(+), 19 deletions(-) diff --git a/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h index 29e9a0d84b16..00b24ba55035 100644 --- a/arch/riscv/include/asm/efi.h +++ b/arch/riscv/include/asm/efi.h @@ -51,4 +51,6 @@ void efi_virtmap_unload(void); unsigned long stext_offset(void); +void efi_icache_sync(unsigned long start, unsigned long end); + #endif /* _ASM_EFI_H */ diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h index 15616155008c..ea1a10355ce9 100644 --- a/arch/riscv/kernel/image-vars.h +++ b/arch/riscv/kernel/image-vars.h @@ -27,6 +27,7 @@ __efistub__start = _start; __efistub__start_kernel = _start_kernel; __efistub__end = _end; __efistub__edata = _edata; +__efistub___init_text_end = __init_text_end; __efistub_screen_info = screen_info; #endif diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 11aba8a041ec..dc90a31b189f 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -88,7 +88,7 @@ lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o string.o intrinsics.o systable.o \ lib-$(CONFIG_ARM) += arm32-stub.o lib-$(CONFIG_ARM64) += kaslr.o arm64.o arm64-stub.o smbios.o lib-$(CONFIG_X86) += x86-stub.o -lib-$(CONFIG_RISCV) += riscv.o riscv-stub.o +lib-$(CONFIG_RISCV) += kaslr.o riscv.o riscv-stub.o lib-$(CONFIG_LOONGARCH) += loongarch.o loongarch-stub.o CFLAGS_arm32-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c index 145c9f0ba217..c96d6dcee86c 100644 --- a/drivers/firmware/efi/libstub/riscv-stub.c +++ b/drivers/firmware/efi/libstub/riscv-stub.c @@ -30,32 +30,29 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, efi_loaded_image_t *image, efi_handle_t image_handle) { - unsigned long kernel_size = 0; - unsigned long preferred_addr; + unsigned long kernel_size, kernel_codesize, kernel_memsize; efi_status_t status; kernel_size = _edata - _start; + kernel_codesize = __init_text_end - _start; + kernel_memsize = kernel_size + (_end - _edata); *image_addr = (unsigned long)_start; - *image_size = kernel_size + (_end - _edata); - - /* - * RISC-V kernel maps PAGE_OFFSET virtual address to the same physical - * address where kernel is booted. That's why kernel should boot from - * as low as possible to avoid wastage of memory. Currently, dram_base - * is occupied by the firmware. So the preferred address for kernel to - * boot is next aligned address. If preferred address is not available, - * relocate_kernel will fall back to efi_low_alloc_above to allocate - * lowest possible memory region as long as the address and size meets - * the alignment constraints. - */ - preferred_addr = EFI_KIMG_PREFERRED_ADDRESS; - status = efi_relocate_kernel(image_addr, kernel_size, *image_size, - preferred_addr, efi_get_kimg_min_align(), - 0x0); + *image_size = kernel_memsize; + *reserve_size = *image_size; + status = efi_kaslr_relocate_kernel(image_addr, + reserve_addr, reserve_size, + kernel_size, kernel_codesize, kernel_memsize, + efi_kaslr_get_phys_seed(image_handle)); if (status != EFI_SUCCESS) { efi_err("Failed to relocate kernel\n"); *image_size = 0; } + return status; } + +void efi_icache_sync(unsigned long start, unsigned long end) +{ + asm volatile ("fence.i" ::: "memory"); +} -- cgit v1.2.3-58-ga151