[v6,5/5] riscv: libstub: Implement KASLR by using generic functions
Commit Message
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 <alexghiti@rivosinc.com>
---
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(-)
@@ -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 */
@@ -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
@@ -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)
@@ -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");
+}