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authorMike Westerhof <mwester@dls.net>2007-10-10 22:18:14 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2007-10-12 18:43:48 -0400
commit033b8ffe3f1ea8174d51d125838ac6deea60f63f (patch)
treec74af61a3f9c68e15ff858ac0bccc07a2fbbdbd4
parent84aa462e2c2cd1b921f6b8e283f8d41666e02e8e (diff)
[ARM] 4599/1: Preserve ATAG list for use with kexec (2.6.23)
This patch resolves a kexec boot failure that can occur because no ATAGs are passed in to the kexec'd kernel. Currently the newly-kexec'd kernel may fail if it requires specific ATAGs, or it may fail because the fixed memory location at which it expects to find the ATAGs may contain random data instead of ATAGs. The patch ensures that any ATAGs passed to the current kernel at boot time are copied to a static buffer, and are copied back when kexec copies the new kernel into place. Thus the new kernel sees the same ATAGs from kexec and the boot loader. The boot parameters are copied without regard to type, content, or length -- this patch's scope is limited soley to saving and restoring a fixed-size block of memory containing the kernel's boot parameters. Additional functionality to examine, alter, or replace the ATAGs (using kexec, for example) can be implemented by manipulating the static buffer containing the preserved ATAGs. Note: the size of the buffer (1.5KB) is selected to comfortably hold one of each ATAG type, including a maximum-length command line and the maximum number of ATAG_MEM structures currently supported by the kernel. Should an ATAG list exceed that limit, the list will be silently truncated to that limit (to do other- wise at that point in the boot process would make a simple problem exceedingly complicated). [Note: this is the same patch as 4579, modified to accomodate the ATAG changes introduced in 2.6.23] Signed-off-by: Mike Westerhof <mwester at dls.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/kernel/relocate_kernel.S29
-rw-r--r--arch/arm/kernel/setup.c30
-rw-r--r--include/asm-arm/kexec.h2
3 files changed, 60 insertions, 1 deletions
diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
index 7baadae7cb27..062c111c572f 100644
--- a/arch/arm/kernel/relocate_kernel.S
+++ b/arch/arm/kernel/relocate_kernel.S
@@ -7,6 +7,23 @@
7 .globl relocate_new_kernel 7 .globl relocate_new_kernel
8relocate_new_kernel: 8relocate_new_kernel:
9 9
10 /* Move boot params back to where the kernel expects them */
11
12 ldr r0,kexec_boot_params_address
13 teq r0,#0
14 beq 8f
15
16 ldr r1,kexec_boot_params_copy
17 mov r6,#KEXEC_BOOT_PARAMS_SIZE/4
187:
19 ldr r5,[r1],#4
20 str r5,[r0],#4
21 subs r6,r6,#1
22 bne 7b
23
248:
25 /* Boot params moved, now go on with the kernel */
26
10 ldr r0,kexec_indirection_page 27 ldr r0,kexec_indirection_page
11 ldr r1,kexec_start_address 28 ldr r1,kexec_start_address
12 29
@@ -50,7 +67,7 @@ relocate_new_kernel:
50 mov lr,r1 67 mov lr,r1
51 mov r0,#0 68 mov r0,#0
52 ldr r1,kexec_mach_type 69 ldr r1,kexec_mach_type
53 mov r2,#0 70 ldr r2,kexec_boot_params_address
54 mov pc,lr 71 mov pc,lr
55 72
56 .globl kexec_start_address 73 .globl kexec_start_address
@@ -65,6 +82,16 @@ kexec_indirection_page:
65kexec_mach_type: 82kexec_mach_type:
66 .long 0x0 83 .long 0x0
67 84
85 /* phy addr where new kernel will expect to find boot params */
86 .globl kexec_boot_params_address
87kexec_boot_params_address:
88 .long 0x0
89
90 /* phy addr where old kernel put a copy of orig boot params */
91 .globl kexec_boot_params_copy
92kexec_boot_params_copy:
93 .long 0x0
94
68relocate_new_kernel_end: 95relocate_new_kernel_end:
69 96
70 .globl relocate_new_kernel_size 97 .globl relocate_new_kernel_size
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index efac7df72d65..bf56eb337df1 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -24,6 +24,7 @@
24#include <linux/interrupt.h> 24#include <linux/interrupt.h>
25#include <linux/smp.h> 25#include <linux/smp.h>
26#include <linux/fs.h> 26#include <linux/fs.h>
27#include <linux/kexec.h>
27 28
28#include <asm/cpu.h> 29#include <asm/cpu.h>
29#include <asm/elf.h> 30#include <asm/elf.h>
@@ -783,6 +784,23 @@ static int __init customize_machine(void)
783} 784}
784arch_initcall(customize_machine); 785arch_initcall(customize_machine);
785 786
787#ifdef CONFIG_KEXEC
788
789/* Physical addr of where the boot params should be for this machine */
790extern unsigned long kexec_boot_params_address;
791
792/* Physical addr of the buffer into which the boot params are copied */
793extern unsigned long kexec_boot_params_copy;
794
795/* Pointer to the boot params buffer, for manipulation and display */
796unsigned long kexec_boot_params;
797EXPORT_SYMBOL(kexec_boot_params);
798
799/* The buffer itself - make sure it is sized correctly */
800static unsigned long kexec_boot_params_buf[(KEXEC_BOOT_PARAMS_SIZE + 3) / 4];
801
802#endif
803
786void __init setup_arch(char **cmdline_p) 804void __init setup_arch(char **cmdline_p)
787{ 805{
788 struct tag *tags = (struct tag *)&init_tags; 806 struct tag *tags = (struct tag *)&init_tags;
@@ -801,6 +819,18 @@ void __init setup_arch(char **cmdline_p)
801 else if (mdesc->boot_params) 819 else if (mdesc->boot_params)
802 tags = phys_to_virt(mdesc->boot_params); 820 tags = phys_to_virt(mdesc->boot_params);
803 821
822#ifdef CONFIG_KEXEC
823 kexec_boot_params_copy = virt_to_phys(kexec_boot_params_buf);
824 kexec_boot_params = (unsigned long)kexec_boot_params_buf;
825 if (__atags_pointer) {
826 kexec_boot_params_address = __atags_pointer;
827 memcpy((void *)kexec_boot_params, tags, KEXEC_BOOT_PARAMS_SIZE);
828 } else if (mdesc->boot_params) {
829 kexec_boot_params_address = mdesc->boot_params;
830 memcpy((void *)kexec_boot_params, tags, KEXEC_BOOT_PARAMS_SIZE);
831 }
832#endif
833
804 /* 834 /*
805 * If we have the old style parameters, convert them to 835 * If we have the old style parameters, convert them to
806 * a tag list. 836 * a tag list.
diff --git a/include/asm-arm/kexec.h b/include/asm-arm/kexec.h
index b5b030ef633d..46dcc4d0b9bd 100644
--- a/include/asm-arm/kexec.h
+++ b/include/asm-arm/kexec.h
@@ -14,6 +14,8 @@
14 14
15#define KEXEC_ARCH KEXEC_ARCH_ARM 15#define KEXEC_ARCH KEXEC_ARCH_ARM
16 16
17#define KEXEC_BOOT_PARAMS_SIZE 1536
18
17#ifndef __ASSEMBLY__ 19#ifndef __ASSEMBLY__
18 20
19struct kimage; 21struct kimage;