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Date: Sun, 27 Jan 2013 16:07:14 -0800
From: "tip-bot for H. Peter Anvin" <hpa@...ux.intel.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
yinghai@...nel.org, dwmw2@...radead.org, caushik1@...il.com,
matt.fleming@...el.com, jmillenbach@...il.com,
josh@...htriplett.org, tglx@...utronix.de, hpa@...ux.intel.com,
rob@...dley.net
Subject: [tip:x86/boot] x86, boot: Define the 2.12 bzImage boot protocol
Commit-ID: 09c205afde70c15f20ca76ba0a57409dad175fd0
Gitweb: http://git.kernel.org/tip/09c205afde70c15f20ca76ba0a57409dad175fd0
Author: H. Peter Anvin <hpa@...ux.intel.com>
AuthorDate: Sun, 27 Jan 2013 10:43:28 -0800
Committer: H. Peter Anvin <hpa@...ux.intel.com>
CommitDate: Sun, 27 Jan 2013 15:56:37 -0800
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@...nel.org>
Originally-by: David Woodhouse <dwmw2@...radead.org>
Acked-by: Yinghai Lu <yinghai@...nel.org>
Acked-by: David Woodhouse <dwmw2@...radead.org>
Acked-by: Matt Fleming <matt.fleming@...el.com>
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
Link: http://lkml.kernel.org/r/1359058816-7615-26-git-send-email-yinghai@kernel.org
Cc: Rob Landley <rob@...dley.net>
Cc: Gokul Caushik <caushik1@...il.com>
Cc: Josh Triplett <josh@...htriplett.org>
Cc: Joe Millenbach <jmillenbach@...il.com>
---
Documentation/x86/boot.txt | 27 ++++++++++++++-
Documentation/x86/zero-page.txt | 4 +++
arch/x86/boot/header.S | 39 ++++++++++++++++------
arch/x86/boot/setup.ld | 2 +-
arch/x86/include/uapi/asm/bootparam.h | 63 +++++++++++++++++++++++++----------
5 files changed, 106 insertions(+), 29 deletions(-)
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index 406d82d..3edb4c2 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -57,6 +57,10 @@ Protocol 2.10: (Kernel 2.6.31) Added a protocol for relaxed alignment
Protocol 2.11: (Kernel 3.6) Added a field for offset of EFI handover
protocol entry point.
+Protocol 2.12: (Kernel 3.9) Added the xloadflags field and extension fields
+ to struct boot_params for for loading bzImage and ramdisk
+ above 4G in 64bit.
+
**** MEMORY LAYOUT
The traditional memory map for the kernel loader, used for Image or
@@ -182,7 +186,7 @@ Offset Proto Name Meaning
0230/4 2.05+ kernel_alignment Physical addr alignment required for kernel
0234/1 2.05+ relocatable_kernel Whether kernel is relocatable or not
0235/1 2.10+ min_alignment Minimum alignment, as a power of two
-0236/2 N/A pad3 Unused
+0236/2 2.12+ xloadflags Boot protocol option flags
0238/4 2.06+ cmdline_size Maximum size of the kernel command line
023C/4 2.07+ hardware_subarch Hardware subarchitecture
0240/8 2.07+ hardware_subarch_data Subarchitecture-specific data
@@ -582,6 +586,27 @@ Protocol: 2.10+
misaligned kernel. Therefore, a loader should typically try each
power-of-two alignment from kernel_alignment down to this alignment.
+Field name: xloadflags
+Type: read
+Offset/size: 0x236/2
+Protocol: 2.12+
+
+ This field is a bitmask.
+
+ Bit 0 (read): XLF_KERNEL_64
+ - If 1, this kernel has the legacy 64-bit entry point at 0x200.
+
+ Bit 1 (read): XLF_CAN_BE_LOADED_ABOVE_4G
+ - If 1, kernel/boot_params/cmdline/ramdisk can be above 4G.
+
+ Bit 2 (read): XLF_EFI_HANDOVER_32
+ - If 1, the kernel supports the 32-bit EFI handoff entry point
+ given at handover_offset.
+
+ Bit 3 (read): XLF_EFI_HANDOVER_64
+ - If 1, the kernel supports the 64-bit EFI handoff entry point
+ given at handover_offset + 0x200.
+
Field name: cmdline_size
Type: read
Offset/size: 0x238/4
diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
index cf5437d..199f453 100644
--- a/Documentation/x86/zero-page.txt
+++ b/Documentation/x86/zero-page.txt
@@ -19,6 +19,9 @@ Offset Proto Name Meaning
090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!!
0A0/010 ALL sys_desc_table System description table (struct sys_desc_table)
0B0/010 ALL olpc_ofw_header OLPC's OpenFirmware CIF and friends
+0C0/004 ALL ext_ramdisk_image ramdisk_image high 32bits
+0C4/004 ALL ext_ramdisk_size ramdisk_size high 32bits
+0C8/004 ALL ext_cmd_line_ptr cmd_line_ptr high 32bits
140/080 ALL edid_info Video mode setup (struct edid_info)
1C0/020 ALL efi_info EFI 32 information (struct efi_info)
1E0/004 ALL alk_mem_k Alternative mem check, in KB
@@ -27,6 +30,7 @@ Offset Proto Name Meaning
1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below)
1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer
(below)
+1EF/001 ALL sentinel Used to detect broken bootloaders
290/040 ALL edd_mbr_sig_buffer EDD MBR signatures
2D0/A00 ALL e820_map E820 memory map table
(array of struct e820entry)
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 @@ section_table:
# 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 @@ _start:
# 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 @@ type_of_loader: .byte 0 # 0 means ancient bootloader, newer
# 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 1
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 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr
#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 @@ SECTIONS
.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 @@ struct setup_header {
__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 @@ struct setup_header {
__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 @@ struct setup_header {
__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 @@ struct boot_params {
__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 @@ struct boot_params {
__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 @@ enum {
X86_NR_SUBARCHS,
};
-
+#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_BOOTPARAM_H */
--
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