From 9f9223778ef385e79dc67f5ee48ee4c1fb757f6b Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 17 Feb 2020 12:44:37 +0100 Subject: efi/libstub/arm: Make efi_entry() an ordinary PE/COFF entrypoint Expose efi_entry() as the PE/COFF entrypoint directly, instead of jumping into a wrapper that fiddles with stack buffers and other stuff that the compiler is much better at. The only reason this code exists is to obtain a pointer to the base of the image, but we can get the same value from the loaded_image protocol, which we already need for other reasons anyway. Update the return type as well, to make it consistent with what is required for a PE/COFF executable entrypoint. Signed-off-by: Ard Biesheuvel --- arch/arm/boot/compressed/efi-header.S | 2 +- arch/arm/boot/compressed/head.S | 42 ++++----------- arch/arm64/kernel/efi-entry.S | 86 ++++++------------------------- arch/arm64/kernel/efi-header.S | 2 +- arch/arm64/kernel/image-vars.h | 4 +- drivers/firmware/efi/libstub/arm-stub.c | 46 ++++++++++------- drivers/firmware/efi/libstub/arm32-stub.c | 1 + drivers/firmware/efi/libstub/arm64-stub.c | 3 +- 8 files changed, 59 insertions(+), 127 deletions(-) diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S index a5983588f96b..e38fbda02b93 100644 --- a/arch/arm/boot/compressed/efi-header.S +++ b/arch/arm/boot/compressed/efi-header.S @@ -60,7 +60,7 @@ optional_header: .long __pecoff_code_size @ SizeOfCode .long __pecoff_data_size @ SizeOfInitializedData .long 0 @ SizeOfUninitializedData - .long efi_stub_entry - start @ AddressOfEntryPoint + .long efi_entry - start @ AddressOfEntryPoint .long start_offset @ BaseOfCode .long __pecoff_data_start - start @ BaseOfData diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 8487221bedb0..36ffbeecd30b 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -1437,33 +1437,15 @@ __enter_kernel: reloc_code_end: #ifdef CONFIG_EFI_STUB - .align 2 -_start: .long start - . - -ENTRY(efi_stub_entry) - @ allocate space on stack for passing current zImage address - @ and for the EFI stub to return of new entry point of - @ zImage, as EFI stub may copy the kernel. Pointer address - @ is passed in r2. r0 and r1 are passed through from the - @ EFI firmware to efi_entry - adr ip, _start - ldr r3, [ip] - add r3, r3, ip - stmfd sp!, {r3, lr} - mov r2, sp @ pass zImage address in r2 - bl efi_entry - - @ Check for error return from EFI stub. r0 has FDT address - @ or error code. - cmn r0, #1 - beq efi_load_fail - - @ Preserve return value of efi_entry() in r4 - mov r4, r0 - add r1, r4, #SZ_2M @ DT end +ENTRY(efi_enter_kernel) + mov r7, r0 @ preserve image base + mov r4, r1 @ preserve DT pointer + + mov r0, r4 @ DT start + add r1, r4, r2 @ DT end bl cache_clean_flush - ldr r0, [sp] @ relocated zImage + mov r0, r7 @ relocated zImage ldr r1, =_edata @ size of zImage add r1, r1, r0 @ end of zImage bl cache_clean_flush @@ -1473,9 +1455,8 @@ ENTRY(efi_stub_entry) @ inside the PE/COFF loader allocated region is unsafe. Let's @ assume our own zImage relocation code did a better job, and @ jump into its version of this routine before proceeding. - ldr r0, [sp] @ relocated zImage ldr r1, .Ljmp - sub r1, r0, r1 + sub r1, r7, r1 mov pc, r1 @ no mode switch 0: bl cache_off @@ -1487,12 +1468,7 @@ ENTRY(efi_stub_entry) mov r1, #0xFFFFFFFF mov r2, r4 b __efi_start - -efi_load_fail: - @ Return EFI_LOAD_ERROR to EFI firmware on error. - ldr r0, =0x80000001 - ldmfd sp!, {ip, pc} -ENDPROC(efi_stub_entry) +ENDPROC(efi_enter_kernel) .align 2 .Ljmp: .long start - 0b #endif diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S index 304d5b02ca67..4cfd03c35c49 100644 --- a/arch/arm64/kernel/efi-entry.S +++ b/arch/arm64/kernel/efi-entry.S @@ -10,81 +10,35 @@ #include -#define EFI_LOAD_ERROR 0x8000000000000001 - __INIT - /* - * We arrive here from the EFI boot manager with: - * - * * CPU in little-endian mode - * * MMU on with identity-mapped RAM - * * Icache and Dcache on - * - * We will most likely be running from some place other than where - * we want to be. The kernel image wants to be placed at TEXT_OFFSET - * from start of RAM. - */ -ENTRY(entry) - /* - * Create a stack frame to save FP/LR with extra space - * for image_addr variable passed to efi_entry(). - */ - stp x29, x30, [sp, #-32]! - mov x29, sp - - /* - * Call efi_entry to do the real work. - * x0 and x1 are already set up by firmware. Current runtime - * address of image is calculated and passed via *image_addr. - * - * unsigned long efi_entry(void *handle, - * efi_system_table_t *sys_table, - * unsigned long *image_addr) ; - */ - adr_l x8, _text - add x2, sp, 16 - str x8, [x2] - bl efi_entry - cmn x0, #1 - b.eq efi_load_fail - +ENTRY(efi_enter_kernel) /* * efi_entry() will have copied the kernel image if necessary and we - * return here with device tree address in x0 and the kernel entry - * point stored at *image_addr. Save those values in registers which - * are callee preserved. - */ - mov x20, x0 // DTB address - ldr x0, [sp, #16] // relocated _text address - ldr w21, =stext_offset - add x21, x0, x21 - - /* - * Calculate size of the kernel Image (same for original and copy). + * end up here with device tree address in x1 and the kernel entry + * point stored in x0. Save those values in registers which are + * callee preserved. */ - adr_l x1, _text - adr_l x2, _edata - sub x1, x2, x1 + mov x19, x0 // relocated Image address + mov x20, x1 // DTB address /* * Flush the copied Image to the PoC, and ensure it is not shadowed by * stale icache entries from before relocation. */ + ldr w1, =kernel_size bl __flush_dcache_area ic ialluis + dsb sy /* - * Ensure that the rest of this function (in the original Image) is - * visible when the caches are disabled. The I-cache can't have stale - * entries for the VA range of the current image, so no maintenance is - * necessary. + * Jump across, into the copy of the image that we just cleaned + * to the PoC, so that we can safely disable the MMU and caches. */ - adr x0, entry - adr x1, entry_end - sub x1, x1, x0 - bl __flush_dcache_area - + ldr w0, .Ljmp + sub x0, x19, w0, sxtw + br x0 +0: /* Turn off Dcache and MMU */ mrs x0, CurrentEL cmp x0, #CurrentEL_EL2 @@ -109,12 +63,6 @@ ENTRY(entry) mov x1, xzr mov x2, xzr mov x3, xzr - br x21 - -efi_load_fail: - mov x0, #EFI_LOAD_ERROR - ldp x29, x30, [sp], #32 - ret - -entry_end: -ENDPROC(entry) + b stext +ENDPROC(efi_enter_kernel) +.Ljmp: .long _text - 0b diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S index a7cfacce3e15..40c704c5d3a5 100644 --- a/arch/arm64/kernel/efi-header.S +++ b/arch/arm64/kernel/efi-header.S @@ -27,7 +27,7 @@ optional_header: .long __initdata_begin - efi_header_end // SizeOfCode .long __pecoff_data_size // SizeOfInitializedData .long 0 // SizeOfUninitializedData - .long __efistub_entry - _head // AddressOfEntryPoint + .long __efistub_efi_entry - _head // AddressOfEntryPoint .long efi_header_end - _head // BaseOfCode extra_header_fields: diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 25a2a9b479c2..87cb3d45b4bd 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -12,7 +12,8 @@ #ifdef CONFIG_EFI -__efistub_stext_offset = stext - _text; +__efistub_kernel_size = _edata - _text; + /* * The EFI stub has its own symbol namespace prefixed by __efistub_, to @@ -42,6 +43,7 @@ __efistub___memset = __pi_memset; #endif __efistub__text = _text; +__efistub_stext = stext; __efistub__end = _end; __efistub__edata = _edata; __efistub_screen_info = screen_info; diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 7bbef4a67350..f12736f535b3 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -10,6 +10,7 @@ */ #include +#include #include #include @@ -100,17 +101,22 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *reserve_size, unsigned long dram_base, efi_loaded_image_t *image); + +asmlinkage void __noreturn efi_enter_kernel(unsigned long entrypoint, + unsigned long fdt_addr, + unsigned long fdt_size); + /* * EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint * that is described in the PE/COFF header. Most of the code is the same * for both archictectures, with the arch-specific code provided in the * handle_kernel_image() function. */ -unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, - unsigned long *image_addr) +efi_status_t efi_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg) { efi_loaded_image_t *image; efi_status_t status; + unsigned long image_addr; unsigned long image_size = 0; unsigned long dram_base; /* addr/point and size pairs for memory management*/ @@ -120,7 +126,6 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, unsigned long fdt_size = 0; char *cmdline_ptr = NULL; int cmdline_size = 0; - unsigned long new_fdt_addr; efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID; unsigned long reserve_addr = 0; unsigned long reserve_size = 0; @@ -130,8 +135,10 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, sys_table = sys_table_arg; /* Check if we were booted by the EFI firmware */ - if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) + if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) { + status = EFI_INVALID_PARAMETER; goto fail; + } status = check_platform_features(); if (status != EFI_SUCCESS) @@ -152,6 +159,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, dram_base = get_dram_base(); if (dram_base == EFI_ERROR) { pr_efi_err("Failed to find DRAM base\n"); + status = EFI_LOAD_ERROR; goto fail; } @@ -163,6 +171,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, cmdline_ptr = efi_convert_cmdline(image, &cmdline_size); if (!cmdline_ptr) { pr_efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n"); + status = EFI_OUT_OF_RESOURCES; goto fail; } @@ -178,7 +187,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, si = setup_graphics(); - status = handle_kernel_image(image_addr, &image_size, + status = handle_kernel_image(&image_addr, &image_size, &reserve_addr, &reserve_size, dram_base, image); @@ -227,7 +236,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, status = handle_cmdline_files(image, cmdline_ptr, "initrd=", efi_get_max_initrd_addr(dram_base, - *image_addr), + image_addr), (unsigned long *)&initrd_addr, (unsigned long *)&initrd_size); if (status != EFI_SUCCESS) @@ -257,33 +266,30 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table_arg, install_memreserve_table(); - new_fdt_addr = fdt_addr; - status = allocate_new_fdt_and_exit_boot(handle, - &new_fdt_addr, efi_get_max_fdt_addr(dram_base), - initrd_addr, initrd_size, cmdline_ptr, - fdt_addr, fdt_size); + status = allocate_new_fdt_and_exit_boot(handle, &fdt_addr, + efi_get_max_fdt_addr(dram_base), + initrd_addr, initrd_size, + cmdline_ptr, fdt_addr, fdt_size); + if (status != EFI_SUCCESS) + goto fail_free_initrd; - /* - * If all went well, we need to return the FDT address to the - * calling function so it can be passed to kernel as part of - * the kernel boot protocol. - */ - if (status == EFI_SUCCESS) - return new_fdt_addr; + efi_enter_kernel(image_addr, fdt_addr, fdt_totalsize((void *)fdt_addr)); + /* not reached */ +fail_free_initrd: pr_efi_err("Failed to update FDT and exit boot services\n"); efi_free(initrd_size, initrd_addr); efi_free(fdt_size, fdt_addr); fail_free_image: - efi_free(image_size, *image_addr); + efi_free(image_size, image_addr); efi_free(reserve_size, reserve_addr); fail_free_cmdline: free_screen_info(si); efi_free(cmdline_size, (unsigned long)cmdline_ptr); fail: - return EFI_ERROR; + return status; } static int cmp_mem_desc(const void *l, const void *r) diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c index 7b2a6382b647..7826553af2ba 100644 --- a/drivers/firmware/efi/libstub/arm32-stub.c +++ b/drivers/firmware/efi/libstub/arm32-stub.c @@ -227,6 +227,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, * Relocate the zImage, so that it appears in the lowest 128 MB * memory window. */ + *image_addr = (unsigned long)image->image_base; *image_size = image->image_size; status = efi_relocate_kernel(image_addr, *image_size, *image_size, kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0, 0); diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 2915b44132e6..ad5f24a4489b 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -49,7 +49,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, { efi_status_t status; unsigned long kernel_size, kernel_memsize = 0; - void *old_image_addr = (void *)*image_addr; unsigned long preferred_offset; u64 phys_seed = 0; @@ -147,7 +146,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, } *image_addr = *reserve_addr + TEXT_OFFSET; } - memcpy((void *)*image_addr, old_image_addr, kernel_size); + memcpy((void *)*image_addr, image->image_base, kernel_size); return EFI_SUCCESS; } -- cgit