x86, boot: Define the 2.12 bzImage boot protocol
Define the 2.12 bzImage boot protocol: add xloadflags and additional
fields to allow the command line, initramfs and struct boot_params to
live above the 4 GiB mark.
The xloadflags now communicates if this is a 64-bit kernel with the
legacy 64-bit entry point and which of the EFI handover entry points
are supported.
Avoid adding new read flags to loadflags because of claimed
bootloaders testing the whole byte for == 1 to determine bzImageness
at least until the issue can be researched further.
This is based on patches by Yinghai Lu and David Woodhouse.
Originally-by: Yinghai Lu <yinghai@kernel.org>
Originally-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1359058816-7615-26-git-send-email-yinghai@kernel.org
Cc: Rob Landley <rob@landley.net>
Cc: Gokul Caushik <caushik1@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joe Millenbach <jmillenbach@gmail.com>
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 8c132a6..944ce59 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -21,6 +21,7 @@
#include <asm/e820.h>
#include <asm/page_types.h>
#include <asm/setup.h>
+#include <asm/bootparam.h>
#include "boot.h"
#include "voffset.h"
#include "zoffset.h"
@@ -255,6 +256,9 @@
# header, from the old boot sector.
.section ".header", "a"
+ .globl sentinel
+sentinel: .byte 0xff, 0xff /* Used to detect broken loaders */
+
.globl hdr
hdr:
setup_sects: .byte 0 /* Filled in by build.c */
@@ -279,7 +283,7 @@
# Part 2 of the header, from the old setup.S
.ascii "HdrS" # header signature
- .word 0x020b # header version number (>= 0x0105)
+ .word 0x020c # header version number (>= 0x0105)
# or else old loadlin-1.5 will fail)
.globl realmode_swtch
realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
@@ -297,13 +301,7 @@
# flags, unused bits must be zero (RFU) bit within loadflags
loadflags:
-LOADED_HIGH = 1 # If set, the kernel is loaded high
-CAN_USE_HEAP = 0x80 # If set, the loader also has set
- # heap_end_ptr to tell how much
- # space behind setup.S can be used for
- # heap purposes.
- # Only the loader knows what is free
- .byte LOADED_HIGH
+ .byte LOADED_HIGH # The kernel is to be loaded high
setup_move_size: .word 0x8000 # size to move, when setup is not
# loaded at 0x90000. We will move setup
@@ -369,7 +367,23 @@
relocatable_kernel: .byte 0
#endif
min_alignment: .byte MIN_KERNEL_ALIGN_LG2 # minimum alignment
-pad3: .word 0
+
+xloadflags:
+#ifdef CONFIG_X86_64
+# define XLF0 XLF_KERNEL_64 /* 64-bit kernel */
+#else
+# define XLF0 0
+#endif
+#ifdef CONFIG_EFI_STUB
+# ifdef CONFIG_X86_64
+# define XLF23 XLF_EFI_HANDOVER_64 /* 64-bit EFI handover ok */
+# else
+# define XLF23 XLF_EFI_HANDOVER_32 /* 32-bit EFI handover ok */
+# endif
+#else
+# define XLF23 0
+#endif
+ .word XLF0 | XLF23
cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
#added with boot protocol
@@ -397,8 +411,13 @@
#define INIT_SIZE VO_INIT_SIZE
#endif
init_size: .long INIT_SIZE # kernel initialization size
-handover_offset: .long 0x30 # offset to the handover
+handover_offset:
+#ifdef CONFIG_EFI_STUB
+ .long 0x30 # offset to the handover
# protocol entry point
+#else
+ .long 0
+#endif
# End of setup header #####################################################
diff --git a/arch/x86/boot/setup.ld b/arch/x86/boot/setup.ld
index 03c0683..96a6c75 100644
--- a/arch/x86/boot/setup.ld
+++ b/arch/x86/boot/setup.ld
@@ -13,7 +13,7 @@
.bstext : { *(.bstext) }
.bsdata : { *(.bsdata) }
- . = 497;
+ . = 495;
.header : { *(.header) }
.entrytext : { *(.entrytext) }
.inittext : { *(.inittext) }
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 92862cd..c15ddaf 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -1,6 +1,31 @@
#ifndef _ASM_X86_BOOTPARAM_H
#define _ASM_X86_BOOTPARAM_H
+/* setup_data types */
+#define SETUP_NONE 0
+#define SETUP_E820_EXT 1
+#define SETUP_DTB 2
+#define SETUP_PCI 3
+
+/* ram_size flags */
+#define RAMDISK_IMAGE_START_MASK 0x07FF
+#define RAMDISK_PROMPT_FLAG 0x8000
+#define RAMDISK_LOAD_FLAG 0x4000
+
+/* loadflags */
+#define LOADED_HIGH (1<<0)
+#define QUIET_FLAG (1<<5)
+#define KEEP_SEGMENTS (1<<6)
+#define CAN_USE_HEAP (1<<7)
+
+/* xloadflags */
+#define XLF_KERNEL_64 (1<<0)
+#define XLF_CAN_BE_LOADED_ABOVE_4G (1<<1)
+#define XLF_EFI_HANDOVER_32 (1<<2)
+#define XLF_EFI_HANDOVER_64 (1<<3)
+
+#ifndef __ASSEMBLY__
+
#include <linux/types.h>
#include <linux/screen_info.h>
#include <linux/apm_bios.h>
@@ -9,12 +34,6 @@
#include <asm/ist.h>
#include <video/edid.h>
-/* setup data types */
-#define SETUP_NONE 0
-#define SETUP_E820_EXT 1
-#define SETUP_DTB 2
-#define SETUP_PCI 3
-
/* extensible setup data list node */
struct setup_data {
__u64 next;
@@ -28,9 +47,6 @@
__u16 root_flags;
__u32 syssize;
__u16 ram_size;
-#define RAMDISK_IMAGE_START_MASK 0x07FF
-#define RAMDISK_PROMPT_FLAG 0x8000
-#define RAMDISK_LOAD_FLAG 0x4000
__u16 vid_mode;
__u16 root_dev;
__u16 boot_flag;
@@ -42,10 +58,6 @@
__u16 kernel_version;
__u8 type_of_loader;
__u8 loadflags;
-#define LOADED_HIGH (1<<0)
-#define QUIET_FLAG (1<<5)
-#define KEEP_SEGMENTS (1<<6)
-#define CAN_USE_HEAP (1<<7)
__u16 setup_move_size;
__u32 code32_start;
__u32 ramdisk_image;
@@ -58,7 +70,8 @@
__u32 initrd_addr_max;
__u32 kernel_alignment;
__u8 relocatable_kernel;
- __u8 _pad2[3];
+ __u8 min_alignment;
+ __u16 xloadflags;
__u32 cmdline_size;
__u32 hardware_subarch;
__u64 hardware_subarch_data;
@@ -106,7 +119,10 @@
__u8 hd1_info[16]; /* obsolete! */ /* 0x090 */
struct sys_desc_table sys_desc_table; /* 0x0a0 */
struct olpc_ofw_header olpc_ofw_header; /* 0x0b0 */
- __u8 _pad4[128]; /* 0x0c0 */
+ __u32 ext_ramdisk_image; /* 0x0c0 */
+ __u32 ext_ramdisk_size; /* 0x0c4 */
+ __u32 ext_cmd_line_ptr; /* 0x0c8 */
+ __u8 _pad4[116]; /* 0x0cc */
struct edid_info edid_info; /* 0x140 */
struct efi_info efi_info; /* 0x1c0 */
__u32 alt_mem_k; /* 0x1e0 */
@@ -115,7 +131,20 @@
__u8 eddbuf_entries; /* 0x1e9 */
__u8 edd_mbr_sig_buf_entries; /* 0x1ea */
__u8 kbd_status; /* 0x1eb */
- __u8 _pad6[5]; /* 0x1ec */
+ __u8 _pad5[3]; /* 0x1ec */
+ /*
+ * The sentinel is set to a nonzero value (0xff) in header.S.
+ *
+ * A bootloader is supposed to only take setup_header and put
+ * it into a clean boot_params buffer. If it turns out that
+ * it is clumsy or too generous with the buffer, it most
+ * probably will pick up the sentinel variable too. The fact
+ * that this variable then is still 0xff will let kernel
+ * know that some variables in boot_params are invalid and
+ * kernel should zero out certain portions of boot_params.
+ */
+ __u8 sentinel; /* 0x1ef */
+ __u8 _pad6[1]; /* 0x1f0 */
struct setup_header hdr; /* setup header */ /* 0x1f1 */
__u8 _pad7[0x290-0x1f1-sizeof(struct setup_header)];
__u32 edd_mbr_sig_buffer[EDD_MBR_SIG_MAX]; /* 0x290 */
@@ -134,6 +163,6 @@
X86_NR_SUBARCHS,
};
-
+#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_BOOTPARAM_H */