[PATCH 1/2] ARM: kexec: scan for dtb magic in segments
From: Matthew Leach <hidden>
Date: 2012-09-07 08:40:59
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
This patch allows a dtb to be passed to a new kernel using the kexec mechinism. When loading segments from userspace, scan each segment's first four bytes for the dtb magic. If this is found set the kexec_boot_atags parameter to the relocate_kernel code to the phyical address of this segment. Reviewed-by: Simon Horman <horms@verge.net.au> Reviewed-by: Will Deacon <redacted> Signed-off-by: Matthew Leach <redacted> --- arch/arm/kernel/machine_kexec.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index dfcdb9f..a6bbc0f 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c@@ -9,6 +9,7 @@ #include <linux/io.h> #include <linux/irq.h> #include <asm/pgtable.h> +#include <linux/of_fdt.h> #include <asm/pgalloc.h> #include <asm/mmu_context.h> #include <asm/cacheflush.h>
@@ -32,6 +33,22 @@ static atomic_t waiting_for_crash_ipi; int machine_kexec_prepare(struct kimage *image) { + struct kexec_segment *current_segment; + __be32 header; + int i, err; + + /* No segment at default ATAGs address. try to locate + * a dtb using magic */ + for (i = 0; i < image->nr_segments; i++) { + current_segment = &image->segment[i]; + + err = get_user(header, (__be32*)current_segment->buf); + if (err) + return err; + + if (be32_to_cpu(header) == OF_DT_HEADER) + kexec_boot_atags = current_segment->mem; + } return 0; }
@@ -122,7 +139,9 @@ 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; + if (!kexec_boot_atags) + 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,
--
1.7.12