8 files changed, 110 insertions, 56 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4b1a8e3d292c..4bd8952eef9a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -894,6 +894,13 @@ config KEXEC
           initially work for you.  It may help to enable device hotplugging
           support.
 
+config ATAGS_PROC
+        bool "Export atags in procfs"
+        default n
+        help
+          Should the atags used to boot the kernel be exported in an "atags"
+          file in procfs. Useful with kexec.
+
 endmenu
 
 if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP || ARCH_IMX || ARCH_PXA)
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index faa761921153..00d44c6fbfe9 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_PCI)		+= bios32.o isa.o
 obj-$(CONFIG_SMP)               += smp.o
 obj-$(CONFIG_KEXEC)             += machine_kexec.o relocate_kernel.o
 obj-$(CONFIG_KPROBES)           += kprobes.o kprobes-decode.o
+obj-$(CONFIG_ATAGS_PROC)        += atags.o
 obj-$(CONFIG_OABI_COMPAT)       += sys_oabi-compat.o
 
 obj-$(CONFIG_CRUNCH)            += crunch.o crunch-bits.o
diff --git a/arch/arm/kernel/atags.c b/arch/arm/kernel/atags.c
new file mode 100644
index 000000000000..e2e934c38080
--- /dev/null
+++ b/arch/arm/kernel/atags.c
@@ -0,0 +1,86 @@
+#include <linux/slab.h>
+#include <linux/kexec.h>
+#include <linux/proc_fs.h>
+#include <asm/setup.h>
+#include <asm/types.h>
+#include <asm/page.h>
+
+struct buffer {
+        size_t size;
+        char *data;
+};
+static struct buffer tags_buffer;
+
+static int
+read_buffer(char* page, char** start, off_t off, int count,
+        int* eof, void* data)
+{
+        struct buffer *buffer = (struct buffer *)data;
+
+        if (off >= buffer->size) {
+                *eof = 1;
+                return 0;
+        }
+
+        count = min((int) (buffer->size - off), count);
+
+        memcpy(page, &buffer->data[off], count);
+
+        return count;
+}
+
+
+static int
+create_proc_entries(void)
+{
+        struct proc_dir_entry* tags_entry;
+
+        tags_entry = create_proc_read_entry("atags", 0400, &proc_root, read_buffer, &tags_buffer);
+        if (!tags_entry)
+                return -ENOMEM;
+
+        return 0;
+}
+
+
+static char __initdata atags_copy_buf[KEXEC_BOOT_PARAMS_SIZE];
+static char __initdata *atags_copy;
+
+void __init save_atags(const struct tag *tags)
+{
+        atags_copy = atags_copy_buf;
+        memcpy(atags_copy, tags, KEXEC_BOOT_PARAMS_SIZE);
+}
+
+
+static int __init init_atags_procfs(void)
+{
+        struct tag *tag;
+        int error;
+
+        if (!atags_copy) {
+                printk(KERN_WARNING "Exporting ATAGs: No saved tags found\n");
+                return -EIO;
+        }
+
+        for (tag = (struct tag *) atags_copy; tag->hdr.size; tag = tag_next(tag))
+                ;
+
+        tags_buffer.size = ((char *) tag - atags_copy) + sizeof(tag->hdr);
+        tags_buffer.data = kmalloc(tags_buffer.size, GFP_KERNEL);
+        if (tags_buffer.data == NULL)
+                return -ENOMEM;
+        memcpy(tags_buffer.data, atags_copy, tags_buffer.size);
+
+        error = create_proc_entries();
+        if (error) {
+                printk(KERN_ERR "Exporting ATAGs: not enough memory\n");
+                kfree(tags_buffer.data);
+                tags_buffer.size = 0;
+                tags_buffer.data = NULL;
+        }
+
+        return error;
+}
+
+arch_initcall(init_atags_procfs);
diff --git a/arch/arm/kernel/atags.h b/arch/arm/kernel/atags.h
new file mode 100644
index 000000000000..e5f028d214a1
--- /dev/null
+++ b/arch/arm/kernel/atags.h
@@ -0,0 +1,5 @@
+#ifdef CONFIG_ATAGS_PROC
+extern void save_atags(struct tag *tags);
+#else
+static inline void save_atags(struct tag *tags) { }
+#endif
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 863c66454f2b..db8f54a3451f 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -21,6 +21,7 @@ extern void setup_mm_for_reboot(char mode);
 extern unsigned long kexec_start_address;
 extern unsigned long kexec_indirection_page;
 extern unsigned long kexec_mach_type;
+extern unsigned long kexec_boot_atags;
 
 /*
  * Provide a dummy crash_notes definition while crash dump arrives to arm.
@@ -62,6 +63,7 @@ void machine_kexec(struct kimage *image)
         kexec_start_address = image->start;
         kexec_indirection_page = page_list;
         kexec_mach_type = machine_arch_type;
+        kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
 
         /* copy our kernel relocation code to the control code page */
         memcpy(reboot_code_buffer,
diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
index 062c111c572f..61930eb09029 100644
--- a/arch/arm/kernel/relocate_kernel.S
+++ b/arch/arm/kernel/relocate_kernel.S
@@ -7,23 +7,6 @@
         .globl relocate_new_kernel
 relocate_new_kernel:
 
-        /* Move boot params back to where the kernel expects them */
-
-        ldr     r0,kexec_boot_params_address
-        teq     r0,#0
-        beq     8f
-
-        ldr     r1,kexec_boot_params_copy
-        mov     r6,#KEXEC_BOOT_PARAMS_SIZE/4
-7:
-        ldr     r5,[r1],#4
-        str     r5,[r0],#4
-        subs    r6,r6,#1
-        bne     7b
-
-8:
-        /* Boot params moved, now go on with the kernel */
-
         ldr     r0,kexec_indirection_page
         ldr     r1,kexec_start_address
 
@@ -67,7 +50,7 @@ relocate_new_kernel:
         mov lr,r1
         mov r0,#0
         ldr r1,kexec_mach_type
-        ldr r2,kexec_boot_params_address
+        ldr r2,kexec_boot_atags
         mov pc,lr
 
         .globl kexec_start_address
@@ -82,14 +65,9 @@ kexec_indirection_page:
 kexec_mach_type:
         .long   0x0
 
-        /* phy addr where new kernel will expect to find boot params */
-        .globl kexec_boot_params_address
-kexec_boot_params_address:
-        .long   0x0
-
-        /* phy addr where old kernel put a copy of orig boot params */
-        .globl kexec_boot_params_copy
-kexec_boot_params_copy:
+        /* phy addr of the atags for the new kernel */
+        .globl kexec_boot_atags
+kexec_boot_atags:
         .long   0x0
 
 relocate_new_kernel_end:
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index bf56eb337df1..ae3712d39ab7 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -24,7 +24,6 @@
 #include <linux/interrupt.h>
 #include <linux/smp.h>
 #include <linux/fs.h>
-#include <linux/kexec.h>
 
 #include <asm/cpu.h>
 #include <asm/elf.h>
@@ -39,6 +38,7 @@
 #include <asm/mach/time.h>
 
 #include "compat.h"
+#include "atags.h"
 
 #ifndef MEM_SIZE
 #define MEM_SIZE        (16*1024*1024)
@@ -784,23 +784,6 @@ static int __init customize_machine(void)
 }
 arch_initcall(customize_machine);
 
-#ifdef CONFIG_KEXEC
-
-/* Physical addr of where the boot params should be for this machine */
-extern unsigned long kexec_boot_params_address;
-
-/* Physical addr of the buffer into which the boot params are copied */
-extern unsigned long kexec_boot_params_copy;
-
-/* Pointer to the boot params buffer, for manipulation and display */
-unsigned long kexec_boot_params;
-EXPORT_SYMBOL(kexec_boot_params);
-
-/* The buffer itself - make sure it is sized correctly */
-static unsigned long kexec_boot_params_buf[(KEXEC_BOOT_PARAMS_SIZE + 3) / 4];
-
-#endif
-
 void __init setup_arch(char **cmdline_p)
 {
         struct tag *tags = (struct tag *)&init_tags;
@@ -819,18 +802,6 @@ void __init setup_arch(char **cmdline_p)
         else if (mdesc->boot_params)
                 tags = phys_to_virt(mdesc->boot_params);
 
-#ifdef CONFIG_KEXEC
-        kexec_boot_params_copy = virt_to_phys(kexec_boot_params_buf);
-        kexec_boot_params = (unsigned long)kexec_boot_params_buf;
-        if (__atags_pointer) {
-                kexec_boot_params_address = __atags_pointer;
-                memcpy((void *)kexec_boot_params, tags, KEXEC_BOOT_PARAMS_SIZE);
-        } else if (mdesc->boot_params) {
-                kexec_boot_params_address = mdesc->boot_params;
-                memcpy((void *)kexec_boot_params, tags, KEXEC_BOOT_PARAMS_SIZE);
-        }
-#endif
-
         /*
          * If we have the old style parameters, convert them to
          * a tag list.
@@ -846,6 +817,7 @@ void __init setup_arch(char **cmdline_p)
         if (tags->hdr.tag == ATAG_CORE) {
                 if (meminfo.nr_banks != 0)
                         squash_mem_tags(tags);
+                save_atags(tags);
                 parse_tags(tags);
         }
 
diff --git a/include/asm-arm/kexec.h b/include/asm-arm/kexec.h
index 46dcc4d0b9bd..1ee17b6951d0 100644
--- a/include/asm-arm/kexec.h
+++ b/include/asm-arm/kexec.h
@@ -16,6 +16,9 @@
 
 #define KEXEC_BOOT_PARAMS_SIZE 1536
 
+#define KEXEC_ARM_ATAGS_OFFSET  0x1000
+#define KEXEC_ARM_ZIMAGE_OFFSET 0x8000
+
 #ifndef __ASSEMBLY__
 
 struct kimage;