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[92.145.124.62]) by smtp.gmail.com with ESMTPSA id o5-20020a05600c510500b003ef5bb63f13sm915242wms.10.2023.03.28.22.33.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Mar 2023 22:33:35 -0700 (PDT) From: Alexandre Ghiti To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Ard Biesheuvel , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Alexandre Ghiti Subject: [PATCH v2 4/4] riscv: libstub: Implement KASLR by using generic functions Date: Wed, 29 Mar 2023 07:29:26 +0200 Message-Id: <20230329052926.69632-5-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230329052926.69632-1-alexghiti@rivosinc.com> References: <20230329052926.69632-1-alexghiti@rivosinc.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org 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 --- arch/riscv/kernel/image-vars.h | 1 + drivers/firmware/efi/libstub/arm64.c | 5 ++++ .../firmware/efi/libstub/efi-stub-helper.c | 2 +- drivers/firmware/efi/libstub/efistub.h | 2 ++ drivers/firmware/efi/libstub/riscv-stub.c | 28 +++++++------------ drivers/firmware/efi/libstub/riscv.c | 5 ++++ 6 files changed, 24 insertions(+), 19 deletions(-) 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/arm64.c b/drivers/firmware/efi/libstub/arm64.c index 399770266372..48bc7428d6df 100644 --- a/drivers/firmware/efi/libstub/arm64.c +++ b/drivers/firmware/efi/libstub/arm64.c @@ -108,3 +108,8 @@ void __noreturn efi_enter_kernel(unsigned long entrypoint, enter_kernel = (void *)entrypoint + primary_entry_offset(); enter_kernel(fdt_addr, 0, 0, 0); } + +void efi_icache_sync(unsigned long start, unsigned long end) +{ + caches_clean_inval_pou(start, end); +} diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index 40ac2625949c..63c7275d42e7 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -865,7 +865,7 @@ efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size); *image_addr = *reserve_addr; - caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); + efi_icache_sync(*image_addr, *image_addr + kernel_codesize); return status; } diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 64273371ce96..9ce114e04b23 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -1107,4 +1107,6 @@ efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, u32 phys_seed); u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle); +void efi_icache_sync(unsigned long start, unsigned long end); + #endif diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c index 145c9f0ba217..7af07b33a993 100644 --- a/drivers/firmware/efi/libstub/riscv-stub.c +++ b/drivers/firmware/efi/libstub/riscv-stub.c @@ -30,32 +30,24 @@ 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; } diff --git a/drivers/firmware/efi/libstub/riscv.c b/drivers/firmware/efi/libstub/riscv.c index 8022b104c3e6..365f891e598f 100644 --- a/drivers/firmware/efi/libstub/riscv.c +++ b/drivers/firmware/efi/libstub/riscv.c @@ -96,3 +96,8 @@ void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt, csr_write(CSR_SATP, 0); jump_kernel(hartid, fdt); } + +void efi_icache_sync(unsigned long start, unsigned long end) +{ + asm volatile ("fence.i" ::: "memory"); +}