From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Thomas=20B=C3=A4chler?= , Matt Fleming Subject: [PATCH 3.14 097/158] x86/efi: Correct EFI boot stub use of code32_start Date: Sun, 4 May 2014 11:40:06 -0400 Message-Id: <20140504154043.129294801@linuxfoundation.org> In-Reply-To: <20140504154029.975081050@linuxfoundation.org> References: <20140504154029.975081050@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matt Fleming commit 7e8213c1f3acc064aef37813a39f13cbfe7c3ce7 upstream. code32_start should point at the start of the protected mode code, and *not* at the beginning of the bzImage. This is much easier to do in assembly so document that callers of make_boot_params() need to fill out code32_start. The fallout from this bug is that we would end up relocating the image but copying the image at some offset, resulting in what appeared to be memory corruption. Reported-by: Thomas Bächler Signed-off-by: Matt Fleming Signed-off-by: Greg Kroah-Hartman --- arch/x86/boot/compressed/eboot.c | 5 +++-- arch/x86/boot/compressed/head_32.S | 14 ++++++++------ arch/x86/boot/compressed/head_64.S | 9 +++------ 3 files changed, 14 insertions(+), 14 deletions(-) --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -425,6 +425,9 @@ void setup_graphics(struct boot_params * * Because the x86 boot code expects to be passed a boot_params we * need to create one ourselves (usually the bootloader would create * one for us). + * + * The caller is responsible for filling out ->code32_start in the + * returned boot_params. */ struct boot_params *make_boot_params(void *handle, efi_system_table_t *_table) { @@ -483,8 +486,6 @@ struct boot_params *make_boot_params(voi hdr->vid_mode = 0xffff; hdr->boot_flag = 0xAA55; - hdr->code32_start = (__u64)(unsigned long)image->image_base; - hdr->type_of_loader = 0x21; /* Convert unicode cmdline to ascii */ --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -50,6 +50,13 @@ ENTRY(efi_pe_entry) pushl %eax pushl %esi pushl %ecx + + call reloc +reloc: + popl %ecx + subl reloc, %ecx + movl %ecx, BP_code32_start(%eax) + sub $0x4, %esp ENTRY(efi_stub_entry) @@ -63,12 +70,7 @@ ENTRY(efi_stub_entry) hlt jmp 1b 2: - call 3f -3: - popl %eax - subl $3b, %eax - subl BP_pref_address(%esi), %eax - add BP_code32_start(%esi), %eax + movl BP_code32_start(%esi), %eax leal preferred_addr(%eax), %eax jmp *%eax --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -217,6 +217,8 @@ ENTRY(efi_pe_entry) cmpq $0,%rax je 1f mov %rax, %rdx + leaq startup_32(%rip), %rax + movl %eax, BP_code32_start(%rdx) popq %rsi popq %rdi @@ -230,12 +232,7 @@ ENTRY(efi_stub_entry) hlt jmp 1b 2: - call 3f -3: - popq %rax - subq $3b, %rax - subq BP_pref_address(%rsi), %rax - add BP_code32_start(%esi), %eax + movl BP_code32_start(%esi), %eax leaq preferred_addr(%rax), %rax jmp *%rax