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authorMatt Fleming <matt@console-pimps.org>2014-04-08 13:14:00 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-06 07:55:30 -0700
commit35d5134b7d5a55e269c953096224248b9f6f72c2 (patch)
treebf5c5b9e459bb6e71b5d2cc7277469fdd581a1cc
parent9e2dcd00681f852c1cb1864f79e9992ea1b5981f (diff)
x86/efi: Correct EFI boot stub use of code32_start
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 B├Ąchler <thomas@archlinux.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/boot/compressed/eboot.c5
-rw-r--r--arch/x86/boot/compressed/head_32.S14
-rw-r--r--arch/x86/boot/compressed/head_64.S9
3 files changed, 14 insertions, 14 deletions
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index d606463aa6d6..1308beed7abe 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -865,6 +865,9 @@ fail:
* 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)
{
@@ -921,8 +924,6 @@ struct boot_params *make_boot_params(void *handle, efi_system_table_t *_table)
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 1e3184f6072f..abb988a54c69 100644
--- 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
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 16f24e6dad79..92059b8f3f7b 100644
--- 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