diff options
| author | Matt Fleming <matt@console-pimps.org> | 2014-04-08 13:14:00 +0100 |
|---|---|---|
| committer | Matt Fleming <matt.fleming@intel.com> | 2014-04-10 21:19:52 +0100 |
| commit | 7e8213c1f3acc064aef37813a39f13cbfe7c3ce7 (patch) | |
| tree | 6a24e3cd7ca9994d165bd38e83567ab546d01a92 | |
| parent | 396f1a08db212138418b38f784e4bbe516d2fdb2 (diff) | |
| download | rt-linux-7e8213c1f3acc064aef37813a39f13cbfe7c3ce7.tar.gz | |
x86/efi: Correct EFI boot stub use of code32_start
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 <thomas@archlinux.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
| -rw-r--r-- | arch/x86/boot/compressed/eboot.c | 5 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/head_32.S | 8 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 9 |
3 files changed, 8 insertions, 14 deletions
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index 280165524ee442..91d17007323b7c 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -1016,6 +1016,9 @@ void setup_graphics(struct boot_params *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(struct efi_config *c) { @@ -1081,8 +1084,6 @@ struct boot_params *make_boot_params(struct efi_config *c) 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 */ diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index de9d4200d305ba..cbed1407a5cdb7 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -59,6 +59,7 @@ ENTRY(efi_pe_entry) call make_boot_params cmpl $0, %eax je fail + movl %esi, BP_code32_start(%eax) popl %ecx pushl %eax pushl %ecx @@ -90,12 +91,7 @@ fail: hlt jmp fail 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 diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 57e58a5fa21073..0d558ee899aec8 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -261,6 +261,8 @@ ENTRY(efi_pe_entry) cmpq $0,%rax je fail mov %rax, %rsi + leaq startup_32(%rip), %rax + movl %eax, BP_code32_start(%rsi) jmp 2f /* Skip the relocation */ handover_entry: @@ -284,12 +286,7 @@ fail: hlt jmp fail 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 |