[PATCH 0/3] kexec: pass initrd position in dtb

[PATCH 0/3] kexec: pass initrd position in dtb

[Wang Nan]

The main goal of this patch series is to pass initrd position to
secondary kernel. To makes code clear, patch 2/3 introduce a new
function to handle fdt related operations.

Without these two patches, kexec failed to work on arm.


Change from v1:

 - Remove #include "libfdt_internal.h" since it is for internal use
     for libfdt.

Change from v2:

 - Split into two logically independent patches.
 - Compute memory consumption more accurate.

Change from v3:

 - Introduces helpers in libfdt for memory usage computation.


Wang Nan (3):
  kexec: introduce helpers for computing dtb size
  kexec: introduce setup_dtb_prop to make code clear
  kexec: pass initrd position by dtb

 kexec/arch/arm/kexec-zImage-arm.c | 106 +++++++++++++++++++++++++++++---------
 kexec/libfdt/libfdt.h             |  24 +++++++++
 kexec/libfdt/libfdt_internal.h    |   3 --
 3 files changed, 105 insertions(+), 28 deletions(-)

-- 
1.8.4


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[PATCH 1/3] kexec: introduce helpers for computing dtb size

[Wang Nan]

This patch introduce fdt_node_len and fdt_prop_len to help for computing
memory requirement when operating dtb.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Dave Young <dyoung@redhat.com>
Cc: Geng Hui <hui.geng@huawei.com>
---
 kexec/libfdt/libfdt.h          | 24 ++++++++++++++++++++++++
 kexec/libfdt/libfdt_internal.h |  3 ---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/kexec/libfdt/libfdt.h b/kexec/libfdt/libfdt.h
index ce80e4f..87a24ab 100644
--- a/kexec/libfdt/libfdt.h
+++ b/kexec/libfdt/libfdt.h
@@ -1073,4 +1073,28 @@ int fdt_del_node(void *fdt, int nodeoffset);
 
 const char *fdt_strerror(int errval);
 
+#define FDT_ALIGN(x, a)		(((x) + (a) - 1) & ~((a) - 1))
+#define FDT_TAGALIGN(x)		(FDT_ALIGN((x), FDT_TAGSIZE))
+
+/*
+ * if add a new subnode:
+ * see: fdt_add_subnode -> fdt_add_subnode_namelen
+ */
+static inline int fdt_node_len(const char* node_name)
+{
+	return sizeof(struct fdt_node_header) +
+		FDT_TAGALIGN(strlen(node_name) + 1) + FDT_TAGSIZE;
+}
+
+/*
+ * if add a new prop: (assume prop_name not exist in strtab)
+ * see: fdt_setprop -> _fdt_add_property
+ */
+static inline int fdt_prop_len(const char* prop_name, int len)
+{
+	return (strlen(prop_name) + 1) +
+		sizeof(struct fdt_property) +
+		FDT_TAGALIGN(len);
+}
+
 #endif /* _LIBFDT_H */
diff --git a/kexec/libfdt/libfdt_internal.h b/kexec/libfdt/libfdt_internal.h
index 46eb93e..7e6c4c8 100644
--- a/kexec/libfdt/libfdt_internal.h
+++ b/kexec/libfdt/libfdt_internal.h
@@ -52,9 +52,6 @@
  */
 #include <fdt.h>
 
-#define FDT_ALIGN(x, a)		(((x) + (a) - 1) & ~((a) - 1))
-#define FDT_TAGALIGN(x)		(FDT_ALIGN((x), FDT_TAGSIZE))
-
 #define FDT_CHECK_HEADER(fdt) \
 	{ \
 		int err; \
-- 
1.8.4


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[PATCH 2/3] kexec: introduce setup_dtb_prop to make code clear

[Wang Nan]

This patch introduces setup_dtb_prop(), which is used for dtb operations. The
code is extracted from zImage_arm_load, and this patch makes memory grown
computation more accurate.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Dave Young <dyoung@redhat.com>
Cc: Geng Hui <hui.geng@huawei.com>
---
 kexec/arch/arm/kexec-zImage-arm.c | 93 ++++++++++++++++++++++++++++-----------
 1 file changed, 68 insertions(+), 25 deletions(-)

diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
index 8a35018..aea1278 100644
--- a/kexec/arch/arm/kexec-zImage-arm.c
+++ b/kexec/arch/arm/kexec-zImage-arm.c
@@ -216,6 +216,67 @@ int atag_arm_load(struct kexec_info *info, unsigned long base,
 	return 0;
 }
 
+static int setup_dtb_prop(char **bufp, off_t *sizep, const char *node_name,
+		const char *prop_name, const void *val, int len)
+{
+	char *dtb_buf;
+	off_t dtb_size;
+	int off;
+	int prop_len = 0;
+	const struct fdt_property *prop;
+
+	if ((bufp == NULL) || (sizep == NULL) || (*bufp == NULL))
+		die("Internal error\n");
+
+	dtb_buf = *bufp;
+	dtb_size = *sizep;
+
+	/* check if the subnode has already exist */
+	off = fdt_path_offset(dtb_buf, node_name);
+	if (off == -FDT_ERR_NOTFOUND) {
+		dtb_size += fdt_node_len(node_name);
+		fdt_set_totalsize(dtb_buf, dtb_size);
+		dtb_buf = xrealloc(dtb_buf, dtb_size);
+		if (dtb_buf == NULL)
+			die("xrealloc failed\n");
+		off = fdt_add_subnode(dtb_buf, off, node_name);
+	}
+
+	if (off < 0) {
+		fprintf(stderr, "FDT: Error adding %s node.\n", node_name);
+		return -1;
+	}
+
+	prop = fdt_get_property(dtb_buf, off, prop_name, &prop_len);
+	if ((prop == NULL) && (prop_len != -FDT_ERR_NOTFOUND)) {
+		die("FDT: fdt_get_property");
+	} else if (prop == NULL) {
+		/* prop_len == -FDT_ERR_NOTFOUND */
+		/* prop doesn't exist */
+		dtb_size += fdt_prop_len(prop_name, len);
+	} else {
+		if (prop_len < len)
+			dtb_size += len - prop_len;
+	}
+
+	if (fdt_totalsize(dtb_buf) < dtb_size) {
+		fdt_set_totalsize(dtb_buf, dtb_size);
+		dtb_buf = xrealloc(dtb_buf, dtb_size);
+		if (dtb_buf == NULL)
+			die("xrealloc failed\n");
+	}
+
+	if (fdt_setprop(dtb_buf, off, prop_name,
+				val, len) != 0) {
+		fprintf(stderr, "FDT: Error setting %s/%s property.\n",
+				node_name, prop_name);
+		return -1;
+	}
+	*bufp = dtb_buf;
+	*sizep = dtb_size;
+	return 0;
+}
+
 int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
 	struct kexec_info *info)
 {
@@ -375,32 +436,14 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
 			}
 
 			if (command_line) {
-				const char *node_name = "/chosen";
-				const char *prop_name = "bootargs";
-				int off;
-
-				dtb_length = fdt_totalsize(dtb_buf) + 1024 +
-					strlen(command_line);
-				dtb_buf = xrealloc(dtb_buf, dtb_length);
-				fdt_set_totalsize(dtb_buf, dtb_length);
-
-				/* check if a /choosen subnode already exists */
-				off = fdt_path_offset(dtb_buf, node_name);
-
-				if (off == -FDT_ERR_NOTFOUND)
-					off = fdt_add_subnode(dtb_buf, off, node_name);
-
-				if (off < 0) {
-					fprintf(stderr, "FDT: Error adding %s node.\n", node_name);
-					return -1;
-				}
-
-				if (fdt_setprop(dtb_buf, off, prop_name,
-						command_line, strlen(command_line) + 1) != 0) {
-					fprintf(stderr, "FDT: Error setting %s/%s property.\n",
-						node_name, prop_name);
+				/*
+				 *  Error should have been reported so
+				 *  directly return -1
+				 */
+				if (setup_dtb_prop(&dtb_buf, &dtb_length, "/chosen",
+						"bootargs", command_line,
+						strlen(command_line) + 1))
 					return -1;
-				}
 			}
 		} else {
 			/*
-- 
1.8.4


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[PATCH 3/3] kexec: pass initrd position by dtb

[Wang Nan]

This patch append the position of initrd to dtb when loading arm kernel
and initrd without using atag.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Dave Young <dyoung@redhat.com>
Cc: Geng Hui <hui.geng@huawei.com>
---
 kexec/arch/arm/kexec-zImage-arm.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
index aea1278..bfbf290 100644
--- a/kexec/arch/arm/kexec-zImage-arm.c
+++ b/kexec/arch/arm/kexec-zImage-arm.c
@@ -460,6 +460,19 @@ int zImage_arm_load(int argc, char **argv, const char *buf, off_t len,
 		if (ramdisk) {
 			add_segment(info, ramdisk_buf, initrd_size,
 			            initrd_base, initrd_size);
+
+			unsigned long start, end;
+			start = cpu_to_be32((unsigned long)(initrd_base));
+			end = cpu_to_be32((unsigned long)(initrd_base + initrd_size));
+
+			if (setup_dtb_prop(&dtb_buf, &dtb_length, "/chosen",
+					"linux,initrd-start", &start,
+					sizeof(start)))
+				return -1;
+			if (setup_dtb_prop(&dtb_buf, &dtb_length, "/chosen",
+					"linux,initrd-end", &end,
+					sizeof(end)))
+				return -1;
 		}
 
 		/* Stick the dtb at the end of the initrd and page
-- 
1.8.4


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Re: [PATCH 0/3] kexec: pass initrd position in dtb

[Dave Young]

On 03/25/14 at 12:09pm, Wang Nan wrote:
> The main goal of this patch series is to pass initrd position to
> secondary kernel. To makes code clear, patch 2/3 introduce a new
> function to handle fdt related operations.
> 
> Without these two patches, kexec failed to work on arm.
> 
> 
> Change from v1:
> 
>  - Remove #include "libfdt_internal.h" since it is for internal use
>      for libfdt.
> 
> Change from v2:
> 
>  - Split into two logically independent patches.
>  - Compute memory consumption more accurate.
> 
> Change from v3:
> 
>  - Introduces helpers in libfdt for memory usage computation.
> 
> 
> Wang Nan (3):
>   kexec: introduce helpers for computing dtb size
>   kexec: introduce setup_dtb_prop to make code clear
>   kexec: pass initrd position by dtb
> 
>  kexec/arch/arm/kexec-zImage-arm.c | 106 +++++++++++++++++++++++++++++---------
>  kexec/libfdt/libfdt.h             |  24 +++++++++
>  kexec/libfdt/libfdt_internal.h    |   3 --
>  3 files changed, 105 insertions(+), 28 deletions(-)
> 

Thanks for the update.

Acked-by: Dave Young <dyoung@redhat.com>

Thanks
Dave

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Re: [PATCH 0/3] kexec: pass initrd position in dtb

[Simon Horman]

On Thu, Mar 27, 2014 at 09:14:34AM +0800, Dave Young wrote:
> On 03/25/14 at 12:09pm, Wang Nan wrote:
> > The main goal of this patch series is to pass initrd position to
> > secondary kernel. To makes code clear, patch 2/3 introduce a new
> > function to handle fdt related operations.
> > 
> > Without these two patches, kexec failed to work on arm.
> > 
> > 
> > Change from v1:
> > 
> >  - Remove #include "libfdt_internal.h" since it is for internal use
> >      for libfdt.
> > 
> > Change from v2:
> > 
> >  - Split into two logically independent patches.
> >  - Compute memory consumption more accurate.
> > 
> > Change from v3:
> > 
> >  - Introduces helpers in libfdt for memory usage computation.
> > 
> > 
> > Wang Nan (3):
> >   kexec: introduce helpers for computing dtb size
> >   kexec: introduce setup_dtb_prop to make code clear
> >   kexec: pass initrd position by dtb
> > 
> >  kexec/arch/arm/kexec-zImage-arm.c | 106 +++++++++++++++++++++++++++++---------
> >  kexec/libfdt/libfdt.h             |  24 +++++++++
> >  kexec/libfdt/libfdt_internal.h    |   3 --
> >  3 files changed, 105 insertions(+), 28 deletions(-)
> > 
> 
> Thanks for the update.
> 
> Acked-by: Dave Young <dyoung@redhat.com>

Thanks, applied.

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