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* [PATCH 0/2] Devicetree support for UML
@ 2021-12-08 15:11 Vincent Whitchurch
  2021-12-08 15:11 ` [PATCH 1/2] um: Extract load file helper from initrd.c Vincent Whitchurch
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: Vincent Whitchurch @ 2021-12-08 15:11 UTC (permalink / raw)
  To: jdike, richard, anton.ivanov
  Cc: kernel, linux-kernel, linux-um, devicetree, Vincent Whitchurch

This series add support for passing a devicetree blob to UML.  It can be used
for testing device drivers.

Vincent Whitchurch (2):
  um: Extract load file helper from initrd.c
  um: Add devicetree support

 arch/um/Kconfig            |  1 +
 arch/um/kernel/Makefile    |  2 ++
 arch/um/kernel/dtb.c       | 41 +++++++++++++++++++++++++
 arch/um/kernel/initrd.c    | 48 ++++--------------------------
 arch/um/kernel/load_file.c | 61 ++++++++++++++++++++++++++++++++++++++
 arch/um/kernel/um_arch.c   |  3 ++
 arch/um/kernel/um_arch.h   | 14 +++++++++
 7 files changed, 127 insertions(+), 43 deletions(-)
 create mode 100644 arch/um/kernel/dtb.c
 create mode 100644 arch/um/kernel/load_file.c
 create mode 100644 arch/um/kernel/um_arch.h

-- 
2.33.1


^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH 1/2] um: Extract load file helper from initrd.c
  2021-12-08 15:11 [PATCH 0/2] Devicetree support for UML Vincent Whitchurch
@ 2021-12-08 15:11 ` Vincent Whitchurch
  2021-12-08 15:11 ` [PATCH 2/2] um: Add devicetree support Vincent Whitchurch
  2021-12-21 20:55 ` [PATCH 0/2] Devicetree support for UML Richard Weinberger
  2 siblings, 0 replies; 10+ messages in thread
From: Vincent Whitchurch @ 2021-12-08 15:11 UTC (permalink / raw)
  To: jdike, richard, anton.ivanov
  Cc: kernel, linux-kernel, linux-um, devicetree, Vincent Whitchurch

The file loading support in initrd.c can be re-used for
loading devicetrees.  Move it out of initrd.c.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
---
 arch/um/kernel/Makefile    |  1 +
 arch/um/kernel/initrd.c    | 48 ++++--------------------------
 arch/um/kernel/load_file.c | 61 ++++++++++++++++++++++++++++++++++++++
 arch/um/kernel/um_arch.h   |  8 +++++
 4 files changed, 75 insertions(+), 43 deletions(-)
 create mode 100644 arch/um/kernel/load_file.c
 create mode 100644 arch/um/kernel/um_arch.h

diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index 1d18e4e46989..92692bfef7ae 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -18,6 +18,7 @@ obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
 	physmem.o process.o ptrace.o reboot.o sigio.o \
 	signal.o syscall.o sysrq.o time.o tlb.o trap.o \
 	um_arch.o umid.o maccess.o kmsg_dump.o capflags.o skas/
+obj-y += load_file.o
 
 obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
 obj-$(CONFIG_GPROF)	+= gprof_syms.o
diff --git a/arch/um/kernel/initrd.c b/arch/um/kernel/initrd.c
index c1981ffb7179..47b8cb1a1156 100644
--- a/arch/um/kernel/initrd.c
+++ b/arch/um/kernel/initrd.c
@@ -10,37 +10,21 @@
 #include <init.h>
 #include <os.h>
 
+#include "um_arch.h"
+
 /* Changed by uml_initrd_setup, which is a setup */
 static char *initrd __initdata = NULL;
-static int load_initrd(char *filename, void *buf, int size);
 
 int __init read_initrd(void)
 {
+	unsigned long long size;
 	void *area;
-	long long size;
-	int err;
-
-	if (initrd == NULL)
-		return 0;
 
-	err = os_file_size(initrd, &size);
-	if (err)
+	if (!initrd)
 		return 0;
 
-	/*
-	 * This is necessary because alloc_bootmem craps out if you
-	 * ask for no memory.
-	 */
-	if (size == 0) {
-		printk(KERN_ERR "\"%s\" is a zero-size initrd\n", initrd);
-		return 0;
-	}
-
-	area = memblock_alloc(size, SMP_CACHE_BYTES);
+	area = uml_load_file(initrd, &size);
 	if (!area)
-		panic("%s: Failed to allocate %llu bytes\n", __func__, size);
-
-	if (load_initrd(initrd, area, size) == -1)
 		return 0;
 
 	initrd_start = (unsigned long) area;
@@ -59,25 +43,3 @@ __uml_setup("initrd=", uml_initrd_setup,
 "    This is used to boot UML from an initrd image.  The argument is the\n"
 "    name of the file containing the image.\n\n"
 );
-
-static int load_initrd(char *filename, void *buf, int size)
-{
-	int fd, n;
-
-	fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
-	if (fd < 0) {
-		printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
-		       -fd);
-		return -1;
-	}
-	n = os_read_file(fd, buf, size);
-	if (n != size) {
-		printk(KERN_ERR "Read of %d bytes from '%s' failed, "
-		       "err = %d\n", size,
-		       filename, -n);
-		return -1;
-	}
-
-	os_close_file(fd);
-	return 0;
-}
diff --git a/arch/um/kernel/load_file.c b/arch/um/kernel/load_file.c
new file mode 100644
index 000000000000..5cecd0e291fb
--- /dev/null
+++ b/arch/um/kernel/load_file.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+#include <linux/memblock.h>
+#include <os.h>
+
+#include "um_arch.h"
+
+static int __init __uml_load_file(const char *filename, void *buf, int size)
+{
+	int fd, n;
+
+	fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
+	if (fd < 0) {
+		printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
+		       -fd);
+		return -1;
+	}
+	n = os_read_file(fd, buf, size);
+	if (n != size) {
+		printk(KERN_ERR "Read of %d bytes from '%s' failed, "
+		       "err = %d\n", size,
+		       filename, -n);
+		return -1;
+	}
+
+	os_close_file(fd);
+	return 0;
+}
+
+void *uml_load_file(const char *filename, unsigned long long *size)
+{
+	void *area;
+	int err;
+
+	*size = 0;
+
+	if (!filename)
+		return NULL;
+
+	err = os_file_size(filename, size);
+	if (err)
+		return NULL;
+
+	if (*size == 0) {
+		printk(KERN_ERR "\"%s\" is empty\n", filename);
+		return NULL;
+	}
+
+	area = memblock_alloc(*size, SMP_CACHE_BYTES);
+	if (!area)
+		panic("%s: Failed to allocate %llu bytes\n", __func__, *size);
+
+	if (__uml_load_file(filename, area, *size)) {
+		memblock_free(area, *size);
+		return NULL;
+	}
+
+	return area;
+}
diff --git a/arch/um/kernel/um_arch.h b/arch/um/kernel/um_arch.h
new file mode 100644
index 000000000000..b195df3a09a0
--- /dev/null
+++ b/arch/um/kernel/um_arch.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __UML_ARCH_H__
+#define __UML_ARCH_H__
+
+extern void * __init uml_load_file(const char *filename, unsigned long long *size);
+
+#endif
-- 
2.33.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH 2/2] um: Add devicetree support
  2021-12-08 15:11 [PATCH 0/2] Devicetree support for UML Vincent Whitchurch
  2021-12-08 15:11 ` [PATCH 1/2] um: Extract load file helper from initrd.c Vincent Whitchurch
@ 2021-12-08 15:11 ` Vincent Whitchurch
  2022-01-14 13:49   ` Rob Herring
  2021-12-21 20:55 ` [PATCH 0/2] Devicetree support for UML Richard Weinberger
  2 siblings, 1 reply; 10+ messages in thread
From: Vincent Whitchurch @ 2021-12-08 15:11 UTC (permalink / raw)
  To: jdike, richard, anton.ivanov
  Cc: kernel, linux-kernel, linux-um, devicetree, Vincent Whitchurch

Add a dtb=<filename> option to boot UML with a devicetree blob.  This
can be used for testing driver code using UML.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
---
 arch/um/Kconfig          |  1 +
 arch/um/kernel/Makefile  |  1 +
 arch/um/kernel/dtb.c     | 41 ++++++++++++++++++++++++++++++++++++++++
 arch/um/kernel/um_arch.c |  3 +++
 arch/um/kernel/um_arch.h |  6 ++++++
 5 files changed, 52 insertions(+)
 create mode 100644 arch/um/kernel/dtb.c

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index c18b45f75d41..1cf7ef3a2b81 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -18,6 +18,7 @@ config UML
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DEBUG_BUGVERBOSE
 	select NO_DMA if !UML_DMA_EMULATION
+	select OF_EARLY_FLATTREE
 	select GENERIC_IRQ_SHOW
 	select GENERIC_CPU_DEVICES
 	select HAVE_GCC_PLUGINS
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index 92692bfef7ae..ebd0cca3ff26 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -22,6 +22,7 @@ obj-y += load_file.o
 
 obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
 obj-$(CONFIG_GPROF)	+= gprof_syms.o
+obj-$(CONFIG_OF) += dtb.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
diff --git a/arch/um/kernel/dtb.c b/arch/um/kernel/dtb.c
new file mode 100644
index 000000000000..ca69d72025f3
--- /dev/null
+++ b/arch/um/kernel/dtb.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/init.h>
+#include <linux/of_fdt.h>
+#include <linux/printk.h>
+#include <linux/memblock.h>
+#include <init.h>
+
+#include "um_arch.h"
+
+static char *dtb __initdata;
+
+void uml_dtb_init(void)
+{
+	long long size;
+	void *area;
+
+	area = uml_load_file(dtb, &size);
+	if (!area)
+		return;
+
+	if (!early_init_dt_scan(area)) {
+		pr_err("invalid DTB %s\n", dtb);
+		memblock_free(area, size);
+		return;
+	}
+
+	unflatten_device_tree();
+	early_init_fdt_scan_reserved_mem();
+}
+
+static int __init uml_dtb_setup(char *line, int *add)
+{
+	dtb = line;
+	return 0;
+}
+
+__uml_setup("dtb=", uml_dtb_setup,
+"dtb=<file>\n"
+"    Boot the kernel with the devicetree blob from the specified file.\n"
+);
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 54447690de11..abceeabe29b9 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -29,6 +29,8 @@
 #include <mem_user.h>
 #include <os.h>
 
+#include "um_arch.h"
+
 #define DEFAULT_COMMAND_LINE_ROOT "root=98:0"
 #define DEFAULT_COMMAND_LINE_CONSOLE "console=tty"
 
@@ -407,6 +409,7 @@ void __init setup_arch(char **cmdline_p)
 	stack_protections((unsigned long) &init_thread_info);
 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 	mem_total_pages(physmem_size, iomem_size, highmem);
+	uml_dtb_init();
 	read_initrd();
 
 	paging_init();
diff --git a/arch/um/kernel/um_arch.h b/arch/um/kernel/um_arch.h
index b195df3a09a0..1e07fb7ee35e 100644
--- a/arch/um/kernel/um_arch.h
+++ b/arch/um/kernel/um_arch.h
@@ -5,4 +5,10 @@
 
 extern void * __init uml_load_file(const char *filename, unsigned long long *size);
 
+#ifdef CONFIG_OF
+extern void __init uml_dtb_init(void);
+#else
+static inline void uml_dtb_init(void) { }
+#endif
+
 #endif
-- 
2.33.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/2] Devicetree support for UML
  2021-12-08 15:11 [PATCH 0/2] Devicetree support for UML Vincent Whitchurch
  2021-12-08 15:11 ` [PATCH 1/2] um: Extract load file helper from initrd.c Vincent Whitchurch
  2021-12-08 15:11 ` [PATCH 2/2] um: Add devicetree support Vincent Whitchurch
@ 2021-12-21 20:55 ` Richard Weinberger
  2021-12-21 20:56   ` Johannes Berg
  2 siblings, 1 reply; 10+ messages in thread
From: Richard Weinberger @ 2021-12-21 20:55 UTC (permalink / raw)
  To: Vincent Whitchurch
  Cc: Jeff Dike, anton ivanov, kernel, linux-kernel, linux-um, devicetree

Vincent,

----- Ursprüngliche Mail -----
> Von: "Vincent Whitchurch" <vincent.whitchurch@axis.com>
> An: "Jeff Dike" <jdike@addtoit.com>, "richard" <richard@nod.at>, "anton ivanov" <anton.ivanov@cambridgegreys.com>
> CC: kernel@axis.com, "linux-kernel" <linux-kernel@vger.kernel.org>, "linux-um" <linux-um@lists.infradead.org>,
> "devicetree" <devicetree@vger.kernel.org>, "Vincent Whitchurch" <vincent.whitchurch@axis.com>
> Gesendet: Mittwoch, 8. Dezember 2021 16:11:21
> Betreff: [PATCH 0/2] Devicetree support for UML

> This series add support for passing a devicetree blob to UML.  It can be used
> for testing device drivers.

Nice feature.
Code looks good so far. But while building I'm facing this warning:

WARNING: unmet direct dependencies detected for OF_EARLY_FLATTREE
  Depends on [n]: OF [=n]
  Selected by [y]:
  - UML [=y]


Please note that my UML config has CONFIG_OF=n.

Thanks,
//richard

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/2] Devicetree support for UML
  2021-12-21 20:55 ` [PATCH 0/2] Devicetree support for UML Richard Weinberger
@ 2021-12-21 20:56   ` Johannes Berg
  2021-12-21 21:13     ` Richard Weinberger
  0 siblings, 1 reply; 10+ messages in thread
From: Johannes Berg @ 2021-12-21 20:56 UTC (permalink / raw)
  To: Richard Weinberger, Vincent Whitchurch
  Cc: Jeff Dike, anton ivanov, kernel, linux-kernel, linux-um, devicetree

On Tue, 2021-12-21 at 21:55 +0100, Richard Weinberger wrote:
> Vincent,
> 
> ----- Ursprüngliche Mail -----
> > Von: "Vincent Whitchurch" <vincent.whitchurch@axis.com>
> > An: "Jeff Dike" <jdike@addtoit.com>, "richard" <richard@nod.at>, "anton ivanov" <anton.ivanov@cambridgegreys.com>
> > CC: kernel@axis.com, "linux-kernel" <linux-kernel@vger.kernel.org>, "linux-um" <linux-um@lists.infradead.org>,
> > "devicetree" <devicetree@vger.kernel.org>, "Vincent Whitchurch" <vincent.whitchurch@axis.com>
> > Gesendet: Mittwoch, 8. Dezember 2021 16:11:21
> > Betreff: [PATCH 0/2] Devicetree support for UML
> 
> > This series add support for passing a devicetree blob to UML.  It can be used
> > for testing device drivers.
> 
> Nice feature.
> Code looks good so far. But while building I'm facing this warning:
> 
> WARNING: unmet direct dependencies detected for OF_EARLY_FLATTREE
>   Depends on [n]: OF [=n]
>   Selected by [y]:
>   - UML [=y]
> 
> 
> Please note that my UML config has CONFIG_OF=n.
> 

Hm. So maybe that needs to be

	select OF_EARLY_FLATTREE if OF

or so?

johannes

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/2] Devicetree support for UML
  2021-12-21 20:56   ` Johannes Berg
@ 2021-12-21 21:13     ` Richard Weinberger
  2021-12-22 10:23       ` Vincent Whitchurch
  0 siblings, 1 reply; 10+ messages in thread
From: Richard Weinberger @ 2021-12-21 21:13 UTC (permalink / raw)
  To: Johannes Berg
  Cc: Vincent Whitchurch, Jeff Dike, anton ivanov, kernel,
	linux-kernel, linux-um, devicetree

----- Ursprüngliche Mail -----
> Von: "Johannes Berg" <johannes@sipsolutions.net>
> An: "richard" <richard@nod.at>, "Vincent Whitchurch" <vincent.whitchurch@axis.com>
> CC: "Jeff Dike" <jdike@addtoit.com>, "anton ivanov" <anton.ivanov@cambridgegreys.com>, "kernel" <kernel@axis.com>,
> "linux-kernel" <linux-kernel@vger.kernel.org>, "linux-um" <linux-um@lists.infradead.org>, "devicetree"
> <devicetree@vger.kernel.org>
> Gesendet: Dienstag, 21. Dezember 2021 21:56:50
> Betreff: Re: [PATCH 0/2] Devicetree support for UML

> On Tue, 2021-12-21 at 21:55 +0100, Richard Weinberger wrote:
>> Vincent,
>> 
>> ----- Ursprüngliche Mail -----
>> > Von: "Vincent Whitchurch" <vincent.whitchurch@axis.com>
>> > An: "Jeff Dike" <jdike@addtoit.com>, "richard" <richard@nod.at>, "anton ivanov"
>> > <anton.ivanov@cambridgegreys.com>
>> > CC: kernel@axis.com, "linux-kernel" <linux-kernel@vger.kernel.org>, "linux-um"
>> > <linux-um@lists.infradead.org>,
>> > "devicetree" <devicetree@vger.kernel.org>, "Vincent Whitchurch"
>> > <vincent.whitchurch@axis.com>
>> > Gesendet: Mittwoch, 8. Dezember 2021 16:11:21
>> > Betreff: [PATCH 0/2] Devicetree support for UML
>> 
>> > This series add support for passing a devicetree blob to UML.  It can be used
>> > for testing device drivers.
>> 
>> Nice feature.
>> Code looks good so far. But while building I'm facing this warning:
>> 
>> WARNING: unmet direct dependencies detected for OF_EARLY_FLATTREE
>>   Depends on [n]: OF [=n]
>>   Selected by [y]:
>>   - UML [=y]
>> 
>> 
>> Please note that my UML config has CONFIG_OF=n.
>> 
> 
> Hm. So maybe that needs to be
> 
>	select OF_EARLY_FLATTREE if OF

Yeah, IIRC arm and mips use such a pattern too.
Vincent, what do you think?

Thanks,
//richard

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/2] Devicetree support for UML
  2021-12-21 21:13     ` Richard Weinberger
@ 2021-12-22 10:23       ` Vincent Whitchurch
  2021-12-22 19:31         ` Richard Weinberger
  0 siblings, 1 reply; 10+ messages in thread
From: Vincent Whitchurch @ 2021-12-22 10:23 UTC (permalink / raw)
  To: Richard Weinberger
  Cc: Johannes Berg, Jeff Dike, anton ivanov, kernel, linux-kernel,
	linux-um, devicetree

On Tue, Dec 21, 2021 at 10:13:03PM +0100, Richard Weinberger wrote:
> ----- Ursprüngliche Mail -----
> > Von: "Johannes Berg" <johannes@sipsolutions.net>
> > Gesendet: Dienstag, 21. Dezember 2021 21:56:50
> > On Tue, 2021-12-21 at 21:55 +0100, Richard Weinberger wrote:
> >> WARNING: unmet direct dependencies detected for OF_EARLY_FLATTREE
> >>   Depends on [n]: OF [=n]
> >>   Selected by [y]:
> >>   - UML [=y]
> >> 
> >> Please note that my UML config has CONFIG_OF=n.
> >> 
> > Hm. So maybe that needs to be
> > 
> >	select OF_EARLY_FLATTREE if OF
> 
> Yeah, IIRC arm and mips use such a pattern too.  Vincent, what do you
> think?

Yes, that looks like the correct fix.  I've tested it and it works.  Do
you prefer to fix it up locally or should I repost?

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/2] Devicetree support for UML
  2021-12-22 10:23       ` Vincent Whitchurch
@ 2021-12-22 19:31         ` Richard Weinberger
  0 siblings, 0 replies; 10+ messages in thread
From: Richard Weinberger @ 2021-12-22 19:31 UTC (permalink / raw)
  To: Vincent Whitchurch
  Cc: Johannes Berg, Jeff Dike, anton ivanov, kernel, linux-kernel,
	linux-um, devicetree

Vincent,

----- Ursprüngliche Mail -----
> Von: "Vincent Whitchurch" <vincent.whitchurch@axis.com>
> An: "richard" <richard@nod.at>
> CC: "Johannes Berg" <johannes@sipsolutions.net>, "Jeff Dike" <jdike@addtoit.com>, "anton ivanov"
> <anton.ivanov@cambridgegreys.com>, "kernel" <kernel@axis.com>, "linux-kernel" <linux-kernel@vger.kernel.org>,
> "linux-um" <linux-um@lists.infradead.org>, "devicetree" <devicetree@vger.kernel.org>
> Gesendet: Mittwoch, 22. Dezember 2021 11:23:57
> Betreff: Re: [PATCH 0/2] Devicetree support for UML

> On Tue, Dec 21, 2021 at 10:13:03PM +0100, Richard Weinberger wrote:
>> ----- Ursprüngliche Mail -----
>> > Von: "Johannes Berg" <johannes@sipsolutions.net>
>> > Gesendet: Dienstag, 21. Dezember 2021 21:56:50
>> > On Tue, 2021-12-21 at 21:55 +0100, Richard Weinberger wrote:
>> >> WARNING: unmet direct dependencies detected for OF_EARLY_FLATTREE
>> >>   Depends on [n]: OF [=n]
>> >>   Selected by [y]:
>> >>   - UML [=y]
>> >> 
>> >> Please note that my UML config has CONFIG_OF=n.
>> >> 
>> > Hm. So maybe that needs to be
>> > 
>> >	select OF_EARLY_FLATTREE if OF
>> 
>> Yeah, IIRC arm and mips use such a pattern too.  Vincent, what do you
>> think?
> 
> Yes, that looks like the correct fix.  I've tested it and it works.  Do
> you prefer to fix it up locally or should I repost?

I'll fix it myself. :-)

Thanks,
//richard

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 2/2] um: Add devicetree support
  2021-12-08 15:11 ` [PATCH 2/2] um: Add devicetree support Vincent Whitchurch
@ 2022-01-14 13:49   ` Rob Herring
  2022-01-18 14:20     ` Vincent Whitchurch
  0 siblings, 1 reply; 10+ messages in thread
From: Rob Herring @ 2022-01-14 13:49 UTC (permalink / raw)
  To: Vincent Whitchurch
  Cc: jdike, richard, anton.ivanov, kernel, linux-kernel, linux-um, devicetree

On Wed, Dec 08, 2021 at 04:11:23PM +0100, Vincent Whitchurch wrote:
> Add a dtb=<filename> option to boot UML with a devicetree blob.  This
> can be used for testing driver code using UML.

Neat!

> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
> ---
>  arch/um/Kconfig          |  1 +
>  arch/um/kernel/Makefile  |  1 +
>  arch/um/kernel/dtb.c     | 41 ++++++++++++++++++++++++++++++++++++++++
>  arch/um/kernel/um_arch.c |  3 +++
>  arch/um/kernel/um_arch.h |  6 ++++++
>  5 files changed, 52 insertions(+)
>  create mode 100644 arch/um/kernel/dtb.c
> 
> diff --git a/arch/um/Kconfig b/arch/um/Kconfig
> index c18b45f75d41..1cf7ef3a2b81 100644
> --- a/arch/um/Kconfig
> +++ b/arch/um/Kconfig
> @@ -18,6 +18,7 @@ config UML
>  	select HAVE_DEBUG_KMEMLEAK
>  	select HAVE_DEBUG_BUGVERBOSE
>  	select NO_DMA if !UML_DMA_EMULATION
> +	select OF_EARLY_FLATTREE
>  	select GENERIC_IRQ_SHOW
>  	select GENERIC_CPU_DEVICES
>  	select HAVE_GCC_PLUGINS
> diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
> index 92692bfef7ae..ebd0cca3ff26 100644
> --- a/arch/um/kernel/Makefile
> +++ b/arch/um/kernel/Makefile
> @@ -22,6 +22,7 @@ obj-y += load_file.o
>  
>  obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
>  obj-$(CONFIG_GPROF)	+= gprof_syms.o
> +obj-$(CONFIG_OF) += dtb.o
>  obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
>  obj-$(CONFIG_STACKTRACE) += stacktrace.o
>  obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
> diff --git a/arch/um/kernel/dtb.c b/arch/um/kernel/dtb.c
> new file mode 100644
> index 000000000000..ca69d72025f3
> --- /dev/null
> +++ b/arch/um/kernel/dtb.c
> @@ -0,0 +1,41 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <linux/init.h>
> +#include <linux/of_fdt.h>
> +#include <linux/printk.h>
> +#include <linux/memblock.h>
> +#include <init.h>
> +
> +#include "um_arch.h"
> +
> +static char *dtb __initdata;
> +
> +void uml_dtb_init(void)
> +{
> +	long long size;
> +	void *area;
> +
> +	area = uml_load_file(dtb, &size);
> +	if (!area)
> +		return;
> +
> +	if (!early_init_dt_scan(area)) {
> +		pr_err("invalid DTB %s\n", dtb);
> +		memblock_free(area, size);
> +		return;
> +	}
> +
> +	unflatten_device_tree();
> +	early_init_fdt_scan_reserved_mem();

These should be reversed. early_init_fdt_scan_reserved_mem() works on 
the flat tree. Reserved memory needs to be reserved before 
unflatten_device_tree() starts allocating memory. Though I imagine that 
doesn't really matter for UML.

Also, does the dtb end up in permanently allocated memory (i.e. not 
init)? It needs to be if not.

Rob

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 2/2] um: Add devicetree support
  2022-01-14 13:49   ` Rob Herring
@ 2022-01-18 14:20     ` Vincent Whitchurch
  0 siblings, 0 replies; 10+ messages in thread
From: Vincent Whitchurch @ 2022-01-18 14:20 UTC (permalink / raw)
  To: Rob Herring
  Cc: jdike, richard, anton.ivanov, kernel, linux-kernel, linux-um, devicetree

On Fri, Jan 14, 2022 at 02:49:09PM +0100, Rob Herring wrote:
> On Wed, Dec 08, 2021 at 04:11:23PM +0100, Vincent Whitchurch wrote:
> > --- /dev/null
> > +++ b/arch/um/kernel/dtb.c
> > @@ -0,0 +1,41 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include <linux/init.h>
> > +#include <linux/of_fdt.h>
> > +#include <linux/printk.h>
> > +#include <linux/memblock.h>
> > +#include <init.h>
> > +
> > +#include "um_arch.h"
> > +
> > +static char *dtb __initdata;
> > +
> > +void uml_dtb_init(void)
> > +{
> > +	long long size;
> > +	void *area;
> > +
> > +	area = uml_load_file(dtb, &size);
> > +	if (!area)
> > +		return;
> > +
> > +	if (!early_init_dt_scan(area)) {
> > +		pr_err("invalid DTB %s\n", dtb);
> > +		memblock_free(area, size);
> > +		return;
> > +	}
> > +
> > +	unflatten_device_tree();
> > +	early_init_fdt_scan_reserved_mem();
> 
> These should be reversed. early_init_fdt_scan_reserved_mem() works on 
> the flat tree. Reserved memory needs to be reserved before 
> unflatten_device_tree() starts allocating memory. Though I imagine that 
> doesn't really matter for UML.

I only tested dynamic allocation of reserved memory, and that,
unsuprisingly, works regardless of the order.  But I'll send a patch to
change it.

> Also, does the dtb end up in permanently allocated memory (i.e. not 
> init)? It needs to be if not.

The dtb is allocated with memblock_alloc() in arch/um/kernel/load_file.c
and is never freed (except on an error from early_init_dt_scan() as in
the above hunk), so I think this is already taken care of.

^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2022-01-18 14:20 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-12-08 15:11 [PATCH 0/2] Devicetree support for UML Vincent Whitchurch
2021-12-08 15:11 ` [PATCH 1/2] um: Extract load file helper from initrd.c Vincent Whitchurch
2021-12-08 15:11 ` [PATCH 2/2] um: Add devicetree support Vincent Whitchurch
2022-01-14 13:49   ` Rob Herring
2022-01-18 14:20     ` Vincent Whitchurch
2021-12-21 20:55 ` [PATCH 0/2] Devicetree support for UML Richard Weinberger
2021-12-21 20:56   ` Johannes Berg
2021-12-21 21:13     ` Richard Weinberger
2021-12-22 10:23       ` Vincent Whitchurch
2021-12-22 19:31         ` Richard Weinberger

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