From a55c072dfe520f8fa03cf11b07b9268a8a17820a Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 13 Jun 2014 13:11:51 +0200 Subject: efi/arm64: efistub: remove local copy of linux_banner The shared efistub code for ARM and arm64 contains a local copy of linux_banner, allowing it to be referenced from separate executables such as the ARM decompressor. However, this introduces a dependency on generated header files, causing unnecessary rebuilds of the stub itself and, in case of arm64, vmlinux which contains it. On arm64, the copy is not actually needed since we can reference the original symbol directly, and as it turns out, there may be better ways to deal with this for ARM as well, so let's remove it from the shared code. If it still needs to be reintroduced for ARM later, it should live under arch/arm anyway and not in shared code. Signed-off-by: Ard Biesheuvel Acked-by: Will Deacon Signed-off-by: Matt Fleming --- arch/arm64/kernel/efi-stub.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c index 60e98a639ac5..e786e6cdc400 100644 --- a/arch/arm64/kernel/efi-stub.c +++ b/arch/arm64/kernel/efi-stub.c @@ -12,8 +12,6 @@ #include #include #include -#include -#include /* * AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from -- cgit v1.2.3 From c7fb93ec51d462ec3540a729ba446663c26a0505 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 10 Jul 2014 12:26:20 +0100 Subject: x86/efi: Include a .bss section within the PE/COFF headers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The PE/COFF headers currently describe only the initialised-data portions of the image, and result in no space being allocated for the uninitialised-data portions. Consequently, the EFI boot stub will end up overwriting unexpected areas of memory, with unpredictable results. Fix by including a .bss section in the PE/COFF headers (functionally equivalent to the init_size field in the bzImage header). Signed-off-by: Michael Brown Cc: Thomas Bächler Cc: Josh Boyer Cc: Signed-off-by: Matt Fleming --- arch/x86/boot/header.S | 26 ++++++++++++++++++++++---- arch/x86/boot/tools/build.c | 38 ++++++++++++++++++++++++++++++-------- 2 files changed, 52 insertions(+), 12 deletions(-) (limited to 'arch') diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 84c223479e3c..7a6d43a554d7 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -91,10 +91,9 @@ bs_die: .section ".bsdata", "a" bugger_off_msg: - .ascii "Direct floppy boot is not supported. " - .ascii "Use a boot loader program instead.\r\n" + .ascii "Use a boot loader.\r\n" .ascii "\n" - .ascii "Remove disk and press any key to reboot ...\r\n" + .ascii "Remove disk and press any key to reboot...\r\n" .byte 0 #ifdef CONFIG_EFI_STUB @@ -108,7 +107,7 @@ coff_header: #else .word 0x8664 # x86-64 #endif - .word 3 # nr_sections + .word 4 # nr_sections .long 0 # TimeDateStamp .long 0 # PointerToSymbolTable .long 1 # NumberOfSymbols @@ -250,6 +249,25 @@ section_table: .word 0 # NumberOfLineNumbers .long 0x60500020 # Characteristics (section flags) + # + # The offset & size fields are filled in by build.c. + # + .ascii ".bss" + .byte 0 + .byte 0 + .byte 0 + .byte 0 + .long 0 + .long 0x0 + .long 0 # Size of initialized data + # on disk + .long 0x0 + .long 0 # PointerToRelocations + .long 0 # PointerToLineNumbers + .word 0 # NumberOfRelocations + .word 0 # NumberOfLineNumbers + .long 0xc8000080 # Characteristics (section flags) + #endif /* CONFIG_EFI_STUB */ # Kernel attributes; used by setup. This is part 1 of the diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c index 1a2f2121cada..a7661c430cd9 100644 --- a/arch/x86/boot/tools/build.c +++ b/arch/x86/boot/tools/build.c @@ -143,7 +143,7 @@ static void usage(void) #ifdef CONFIG_EFI_STUB -static void update_pecoff_section_header(char *section_name, u32 offset, u32 size) +static void update_pecoff_section_header_fields(char *section_name, u32 vma, u32 size, u32 datasz, u32 offset) { unsigned int pe_header; unsigned short num_sections; @@ -164,10 +164,10 @@ static void update_pecoff_section_header(char *section_name, u32 offset, u32 siz put_unaligned_le32(size, section + 0x8); /* section header vma field */ - put_unaligned_le32(offset, section + 0xc); + put_unaligned_le32(vma, section + 0xc); /* section header 'size of initialised data' field */ - put_unaligned_le32(size, section + 0x10); + put_unaligned_le32(datasz, section + 0x10); /* section header 'file offset' field */ put_unaligned_le32(offset, section + 0x14); @@ -179,6 +179,11 @@ static void update_pecoff_section_header(char *section_name, u32 offset, u32 siz } } +static void update_pecoff_section_header(char *section_name, u32 offset, u32 size) +{ + update_pecoff_section_header_fields(section_name, offset, size, size, offset); +} + static void update_pecoff_setup_and_reloc(unsigned int size) { u32 setup_offset = 0x200; @@ -203,9 +208,6 @@ static void update_pecoff_text(unsigned int text_start, unsigned int file_sz) pe_header = get_unaligned_le32(&buf[0x3c]); - /* Size of image */ - put_unaligned_le32(file_sz, &buf[pe_header + 0x50]); - /* * Size of code: Subtract the size of the first sector (512 bytes) * which includes the header. @@ -220,6 +222,22 @@ static void update_pecoff_text(unsigned int text_start, unsigned int file_sz) update_pecoff_section_header(".text", text_start, text_sz); } +static void update_pecoff_bss(unsigned int file_sz, unsigned int init_sz) +{ + unsigned int pe_header; + unsigned int bss_sz = init_sz - file_sz; + + pe_header = get_unaligned_le32(&buf[0x3c]); + + /* Size of uninitialized data */ + put_unaligned_le32(bss_sz, &buf[pe_header + 0x24]); + + /* Size of image */ + put_unaligned_le32(init_sz, &buf[pe_header + 0x50]); + + update_pecoff_section_header_fields(".bss", file_sz, bss_sz, 0, 0); +} + static int reserve_pecoff_reloc_section(int c) { /* Reserve 0x20 bytes for .reloc section */ @@ -259,6 +277,8 @@ static void efi_stub_entry_update(void) static inline void update_pecoff_setup_and_reloc(unsigned int size) {} static inline void update_pecoff_text(unsigned int text_start, unsigned int file_sz) {} +static inline void update_pecoff_bss(unsigned int file_sz, + unsigned int init_sz) {} static inline void efi_stub_defaults(void) {} static inline void efi_stub_entry_update(void) {} @@ -310,7 +330,7 @@ static void parse_zoffset(char *fname) int main(int argc, char ** argv) { - unsigned int i, sz, setup_sectors; + unsigned int i, sz, setup_sectors, init_sz; int c; u32 sys_size; struct stat sb; @@ -376,7 +396,9 @@ int main(int argc, char ** argv) buf[0x1f1] = setup_sectors-1; put_unaligned_le32(sys_size, &buf[0x1f4]); - update_pecoff_text(setup_sectors * 512, sz + i + ((sys_size * 16) - sz)); + update_pecoff_text(setup_sectors * 512, i + (sys_size * 16)); + init_sz = get_unaligned_le32(&buf[0x260]); + update_pecoff_bss(i + (sys_size * 16), init_sz); efi_stub_entry_update(); -- cgit v1.2.3 From 7b2a583afb4ab894f78bc0f8bd136e96b6499a7e Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 11 Jul 2014 08:45:25 +0100 Subject: x86/efi: Enforce CONFIG_RELOCATABLE for EFI boot stub MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Without CONFIG_RELOCATABLE the early boot code will decompress the kernel to LOAD_PHYSICAL_ADDR. While this may have been fine in the BIOS days, that isn't going to fly with UEFI since parts of the firmware code/data may be located at LOAD_PHYSICAL_ADDR. Straying outside of the bounds of the regions we've explicitly requested from the firmware will cause all sorts of trouble. Bruno reports that his machine resets while trying to decompress the kernel image. We already go to great pains to ensure the kernel is loaded into a suitably aligned buffer, it's just that the address isn't necessarily LOAD_PHYSICAL_ADDR, because we can't guarantee that address isn't in-use by the firmware. Explicitly enforce CONFIG_RELOCATABLE for the EFI boot stub, so that we can load the kernel at any address with the correct alignment. Reported-by: Bruno Prémont Tested-by: Bruno Prémont Cc: H. Peter Anvin Cc: Signed-off-by: Matt Fleming --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index fcefdda5136d..a24097768463 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1536,6 +1536,7 @@ config EFI config EFI_STUB bool "EFI stub support" depends on EFI + select RELOCATABLE ---help--- This kernel feature allows a bzImage to be loaded directly by EFI firmware without the use of a bootloader. -- cgit v1.2.3