kexec: implement ARM crashdump support

Implement support for loading dump capture kernels for ARM architecture. ARM
doesn't need any backup memory regions so only elfcore header is allocated from
the top of the reserved memory region. Only zImages are supported.

The dump capture kernel needs to be loaded to physical address corresponding to
the memory region reserved with 'crashkernel=size@start' kernel command line
parameter.

Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 45 insertions, 2 deletions

diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
index 1a446d9..8e27956 100644
--- a/kexec/arch/arm/kexec-zImage-arm.c
+++ b/kexec/arch/arm/kexec-zImage-arm.c
@@ -12,10 +12,12 @@
 #include <stdint.h>
 #include <unistd.h>
 #include <getopt.h>
+#include <unistd.h>
 #include <arch/options.h>
 #include "../../kexec.h"
+#include "../../kexec-syscall.h"
+#include "crashdump-arm.h"
 
-#define COMMAND_LINE_SIZE 1024
 #define BOOT_PARAMS_SIZE 1536
 
 struct tag_header {
@@ -213,6 +215,7 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
 	unsigned int atag_offset = 0x1000; /* 4k offset from memory start */
 	unsigned int offset = 0x8000;      /* 32k offset from memory start */
 	const char *command_line;
+	char *modified_cmdline = NULL;
 	off_t command_line_len;
 	const char *ramdisk;
 	char *ramdisk_buf;
@@ -266,7 +269,47 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
 		ramdisk_buf = slurp_file(ramdisk, &ramdisk_length);
 	}
 
-	base = locate_hole(info,len+offset,0,0,ULONG_MAX,INT_MAX);
+	/*
+	 * If we are loading a dump capture kernel, we need to update kernel
+	 * command line and also add some additional segments.
+	 */
+	if (info->kexec_flags & KEXEC_ON_CRASH) {
+		uint64_t start, end;
+
+		modified_cmdline = xmalloc(COMMAND_LINE_SIZE);
+		if (!modified_cmdline)
+			return -1;
+
+		if (command_line) {
+			(void) strncpy(modified_cmdline, command_line,
+				       COMMAND_LINE_SIZE);
+			modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
+		}
+
+		if (load_crashdump_segments(info, modified_cmdline) < 0) {
+			free(modified_cmdline);
+			return -1;
+		}
+
+		command_line = modified_cmdline;
+		command_line_len = strlen(command_line) + 1;
+
+		/*
+		 * We put the dump capture kernel at the start of crashkernel
+		 * reserved memory.
+		 */
+		if (parse_iomem_single("Crash kernel\n", &start, &end)) {
+			/*
+			 * No crash kernel memory reserved. We cannot do more
+			 * but just bail out.
+			 */
+			return -1;
+		}
+		base = start;
+	} else {
+		base = locate_hole(info,len+offset,0,0,ULONG_MAX,INT_MAX);
+	}
+
 	if (base == ULONG_MAX)
 		return -1;