x86, boot: add linked list of struct setup_data

This patch adds a field of 64-bit physical pointer to NULL terminated
single linked list of struct setup_data to real-mode kernel
header. This is used as a more extensible boot parameters passing
mechanism.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 61 insertions, 1 deletions

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 6d2df8d61c54..af86e431acfa 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -120,7 +120,7 @@ _start:
         # Part 2 of the header, from the old setup.S
 
                 .ascii  "HdrS"          # header signature
-                .word   0x0208          # header version number (>= 0x0105)
+                .word   0x0209          # header version number (>= 0x0105)
                                         # or else old loadlin-1.5 will fail)
                 .globl realmode_swtch
 realmode_swtch: .word   0, 0            # default_switch, SETUPSEG
@@ -227,6 +227,10 @@ hardware_subarch_data:	.quad 0
 payload_offset:         .long input_data
 payload_length:         .long input_data_end-input_data
 
+setup_data:             .quad 0                 # 64-bit physical pointer to
+                                                # single linked list of
+                                                # struct setup_data
+
 # End of setup header #####################################################
 
         .section ".inittext", "ax"
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index d31d6b72d60d..e25c57b8aa84 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -11,6 +11,7 @@
 #include <linux/string.h>
 #include <linux/percpu.h>
 #include <linux/start_kernel.h>
+#include <linux/io.h>
 
 #include <asm/processor.h>
 #include <asm/proto.h>
@@ -100,6 +101,24 @@ static void __init reserve_ebda_region(void)
         reserve_early(lowmem, 0x100000, "BIOS reserved");
 }
 
+static void __init reserve_setup_data(void)
+{
+        struct setup_data *data;
+        unsigned long pa_data;
+        char buf[32];
+
+        if (boot_params.hdr.version < 0x0209)
+                return;
+        pa_data = boot_params.hdr.setup_data;
+        while (pa_data) {
+                data = early_ioremap(pa_data, sizeof(*data));
+                sprintf(buf, "setup data %x", data->type);
+                reserve_early(pa_data, pa_data+sizeof(*data)+data->len, buf);
+                pa_data = data->next;
+                early_iounmap(data, sizeof(*data));
+        }
+}
+
 void __init x86_64_start_kernel(char * real_mode_data)
 {
         int i;
@@ -156,6 +175,7 @@ void __init x86_64_start_kernel(char * real_mode_data)
 #endif
 
         reserve_ebda_region();
+        reserve_setup_data();
 
         /*
          * At this point everything still needed from the boot loader
diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 17bdf2343095..e1a21d6b3671 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -264,6 +264,26 @@ void __attribute__((weak)) __init memory_setup(void)
        machine_specific_memory_setup();
 }
 
+static void __init parse_setup_data(void)
+{
+        struct setup_data *data;
+        unsigned long pa_data;
+
+        if (boot_params.hdr.version < 0x0209)
+                return;
+        pa_data = boot_params.hdr.setup_data;
+        while (pa_data) {
+                data = early_ioremap(pa_data, PAGE_SIZE);
+                switch (data->type) {
+                default:
+                        break;
+                }
+                free_early(pa_data, pa_data+sizeof(*data)+data->len);
+                pa_data = data->next;
+                early_iounmap(data, PAGE_SIZE);
+        }
+}
+
 /*
  * setup_arch - architecture-specific boot-time initializations
  *
@@ -316,6 +336,8 @@ void __init setup_arch(char **cmdline_p)
         strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
         *cmdline_p = command_line;
 
+        parse_setup_data();
+
         parse_early_param();
 
 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
diff --git a/include/asm-x86/bootparam.h b/include/asm-x86/bootparam.h
index 51151356840f..e8659909e5f6 100644
--- a/include/asm-x86/bootparam.h
+++ b/include/asm-x86/bootparam.h
@@ -9,6 +9,17 @@
 #include <asm/ist.h>
 #include <video/edid.h>
 
+/* setup data types */
+#define SETUP_NONE                      0
+
+/* extensible setup data list node */
+struct setup_data {
+        u64 next;
+        u32 type;
+        u32 len;
+        u8 data[0];
+};
+
 struct setup_header {
         __u8    setup_sects;
         __u16   root_flags;
@@ -46,6 +57,9 @@ struct setup_header {
         __u32   cmdline_size;
         __u32   hardware_subarch;
         __u64   hardware_subarch_data;
+        __u32   payload_offset;
+        __u32   payload_length;
+        __u64   setup_data;
 } __attribute__((packed));
 
 struct sys_desc_table {