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authorMatt Fleming <matt@console-pimps.org>2014-04-08 13:14:00 +0100
committerMatt Fleming <matt.fleming@intel.com>2014-04-10 21:19:52 +0100
commit7e8213c1f3acc064aef37813a39f13cbfe7c3ce7 (patch)
tree6a24e3cd7ca9994d165bd38e83567ab546d01a92 /arch
parent396f1a08db212138418b38f784e4bbe516d2fdb2 (diff)
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/boot/compressed/eboot.c5
-rw-r--r--arch/x86/boot/compressed/head_32.S8
-rw-r--r--arch/x86/boot/compressed/head_64.S9
3 files changed, 8 insertions, 14 deletions
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 280165524ee4..91d17007323b 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 de9d4200d305..cbed1407a5cd 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 57e58a5fa210..0d558ee899ae 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