* [PATCH v2 0/2] of: populate of_root_node if not set (alternate)
@ 2023-02-22 22:10 Frank Rowand
2023-02-22 22:10 ` [PATCH v2 1/2] of: create of_root if no dtb provided Frank Rowand
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Frank Rowand @ 2023-02-22 22:10 UTC (permalink / raw)
To: Rob Herring, Clément Léger
Cc: devicetree, linux-kernel, Lizhi Hou, Allan Nielsen,
Horatiu Vultur, Steen Hegelund, Thomas Petazzoni
This series is a different implementation to achieve the goals of
https://lore.kernel.org/r/20220623105044.152832-1-clement.leger@bootlin.com
In order to apply overlays or create new nodes under the root node, the
kernel expects of_root to be set. On some system where a device-tree was
not provided by firmware (x86 for instance) if CONFIG_OF is enabled,
then we will end up with a null of_root. This series adds support to
create this root node using a builtin dtb and removes the manual
creation of the root node done in unittests.c.
Changes since version 1: (patch 1/2)
- refresh for 6.2-rc1
- update Signed-off-by
- fix typo in of_fdt.h: s/of_setup/setup_of
- unflatten_device_tree(): validate size in header field dtb_empty_root
that will be used to copy dtb_empty_root
- add Kconfig option to manually select CONFIG_OF_EARLY_FLATTREE
Changes since version 1: (patch 2/2)
- refresh for 6.2-rc1
- update Signed-off-by
- fix formatting error (leading space) in patch comment
Frank Rowand (2):
of: create of_root if no dtb provided
of: unittest: treat missing of_root as error instead of fixing up
drivers/of/Kconfig | 7 ++++++-
drivers/of/Makefile | 2 +-
drivers/of/empty_root.dts | 6 ++++++
drivers/of/fdt.c | 27 ++++++++++++++++++++++++++-
drivers/of/unittest.c | 16 ++++++----------
include/linux/of_fdt.h | 2 ++
init/main.c | 2 ++
7 files changed, 49 insertions(+), 13 deletions(-)
create mode 100644 drivers/of/empty_root.dts
--
Frank Rowand <frowand.list@gmail.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v2 1/2] of: create of_root if no dtb provided 2023-02-22 22:10 [PATCH v2 0/2] of: populate of_root_node if not set (alternate) Frank Rowand @ 2023-02-22 22:10 ` Frank Rowand 2023-02-23 11:34 ` Clément Léger 2023-02-22 22:10 ` [PATCH v2 2/2] of: unittest: treat missing of_root as error instead of fixing up Frank Rowand 2023-02-23 10:41 ` [PATCH v2 0/2] of: populate of_root_node if not set (alternate) Clément Léger 2 siblings, 1 reply; 6+ messages in thread From: Frank Rowand @ 2023-02-22 22:10 UTC (permalink / raw) To: Rob Herring, Clément Léger Cc: devicetree, linux-kernel, Lizhi Hou, Allan Nielsen, Horatiu Vultur, Steen Hegelund, Thomas Petazzoni When enabling CONFIG_OF on a platform where of_root is not populated by firmware, we end up without a root node. In order to apply overlays and create subnodes of the root node, we need one. Create this root node by unflattening an empty builtin dtb. If firmware provides a flattened device tree (FDT) then the FDT is unflattened via setup_arch(). Otherwise, setup_of() which is called immediately after setup_arch(), and will create the default root node if it does not exist. Signed-off-by: Frank Rowand <frowand.list@gmail.com> --- There are checkpatch warnings. I have reviewed them and feel they can be ignored. Changes since version 1: - refresh for 6.2-rc1 - update Signed-off-by - fix typo in of_fdt.h: s/of_setup/setup_of - unflatten_device_tree(): validate size in header field dtb_empty_root that will be used to copy dtb_empty_root - add Kconfig option to manually select CONFIG_OF_EARLY_FLATTREE drivers/of/Kconfig | 7 ++++++- drivers/of/Makefile | 2 +- drivers/of/empty_root.dts | 6 ++++++ drivers/of/fdt.c | 27 ++++++++++++++++++++++++++- include/linux/of_fdt.h | 2 ++ init/main.c | 2 ++ 6 files changed, 43 insertions(+), 3 deletions(-) create mode 100644 drivers/of/empty_root.dts diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index 80b5fd44ab1c..591cfe386727 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -42,9 +42,14 @@ config OF_FLATTREE select CRC32 config OF_EARLY_FLATTREE - bool + bool "Functions for accessing Flat Devicetree (FDT) early in boot" select DMA_DECLARE_COHERENT if HAS_DMA select OF_FLATTREE + help + Normally selected by platforms that process an FDT that has been + passed to the kernel by the bootloader. If the bootloader does not + pass an FDT to the kernel and you need an empty devicetree that + contains only a root node to exist, then say Y here. config OF_PROMTREE bool diff --git a/drivers/of/Makefile b/drivers/of/Makefile index e0360a44306e..cbae92c5ed02 100644 --- a/drivers/of/Makefile +++ b/drivers/of/Makefile @@ -2,7 +2,7 @@ obj-y = base.o device.o platform.o property.o obj-$(CONFIG_OF_KOBJ) += kobj.o obj-$(CONFIG_OF_DYNAMIC) += dynamic.o -obj-$(CONFIG_OF_FLATTREE) += fdt.o +obj-$(CONFIG_OF_FLATTREE) += fdt.o empty_root.dtb.o obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o obj-$(CONFIG_OF_PROMTREE) += pdt.o obj-$(CONFIG_OF_ADDRESS) += address.o diff --git a/drivers/of/empty_root.dts b/drivers/of/empty_root.dts new file mode 100644 index 000000000000..cf9e97a60f48 --- /dev/null +++ b/drivers/of/empty_root.dts @@ -0,0 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0-only +/dts-v1/; + +/ { + +}; diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index b2272bccf85c..0d2f6d016b7e 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -33,6 +33,13 @@ #include "of_private.h" +/* + * __dtb_empty_root_begin[] and __dtb_empty_root_end[] magically created by + * cmd_dt_S_dtb in scripts/Makefile.lib + */ +extern void *__dtb_empty_root_begin; +extern void *__dtb_empty_root_end; + /* * of_fdt_limit_memory - limit the number of regions in the /memory node * @limit: maximum entries @@ -1326,8 +1333,19 @@ bool __init early_init_dt_scan(void *params) */ void __init unflatten_device_tree(void) { - __unflatten_device_tree(initial_boot_params, NULL, &of_root, + if (!initial_boot_params) { + initial_boot_params = (void *) __dtb_empty_root_begin; + /* fdt_totalsize() will be used for copy size */ + if (fdt_totalsize(initial_boot_params) > + __dtb_empty_root_end - __dtb_empty_root_begin) { + pr_err("invalid size in dtb_empty_root\n"); + return; + } + unflatten_and_copy_device_tree(); + } else { + __unflatten_device_tree(initial_boot_params, NULL, &of_root, early_init_dt_alloc_memory_arch, false); + } /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */ of_alias_scan(early_init_dt_alloc_memory_arch); @@ -1367,6 +1385,13 @@ void __init unflatten_and_copy_device_tree(void) unflatten_device_tree(); } +void __init setup_of(void) +{ + /* if architecture did not unflatten devicetree, do it now */ + if (!of_root) + unflatten_device_tree(); +} + #ifdef CONFIG_SYSFS static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h index d69ad5bb1eb1..f0dc46d576da 100644 --- a/include/linux/of_fdt.h +++ b/include/linux/of_fdt.h @@ -81,6 +81,7 @@ extern const void *of_flat_dt_match_machine(const void *default_match, /* Other Prototypes */ extern void unflatten_device_tree(void); extern void unflatten_and_copy_device_tree(void); +extern void setup_of(void); extern void early_init_devtree(void *); extern void early_get_first_memblock_info(void *, phys_addr_t *); #else /* CONFIG_OF_EARLY_FLATTREE */ @@ -91,6 +92,7 @@ static inline void early_init_fdt_reserve_self(void) {} static inline const char *of_flat_dt_get_machine_name(void) { return NULL; } static inline void unflatten_device_tree(void) {} static inline void unflatten_and_copy_device_tree(void) {} +static inline void setup_of(void) {} #endif /* CONFIG_OF_EARLY_FLATTREE */ #endif /* __ASSEMBLY__ */ diff --git a/init/main.c b/init/main.c index e1c3911d7c70..31e0931b5134 100644 --- a/init/main.c +++ b/init/main.c @@ -101,6 +101,7 @@ #include <linux/init_syscalls.h> #include <linux/stackdepot.h> #include <linux/randomize_kstack.h> +#include <linux/of_fdt.h> #include <net/net_namespace.h> #include <asm/io.h> @@ -961,6 +962,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) pr_notice("%s", linux_banner); early_security_init(); setup_arch(&command_line); + setup_of(); setup_boot_config(); setup_command_line(command_line); setup_nr_cpu_ids(); -- Frank Rowand <frowand.list@gmail.com> ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/2] of: create of_root if no dtb provided 2023-02-22 22:10 ` [PATCH v2 1/2] of: create of_root if no dtb provided Frank Rowand @ 2023-02-23 11:34 ` Clément Léger 2023-02-23 20:59 ` Frank Rowand 0 siblings, 1 reply; 6+ messages in thread From: Clément Léger @ 2023-02-23 11:34 UTC (permalink / raw) To: Frank Rowand Cc: Rob Herring, devicetree, linux-kernel, Lizhi Hou, Allan Nielsen, Horatiu Vultur, Steen Hegelund, Thomas Petazzoni Le Wed, 22 Feb 2023 16:10:50 -0600, Frank Rowand <frowand.list@gmail.com> a écrit : > When enabling CONFIG_OF on a platform where of_root is not populated by > firmware, we end up without a root node. In order to apply overlays and > create subnodes of the root node, we need one. Create this root node > by unflattening an empty builtin dtb. > > If firmware provides a flattened device tree (FDT) then the FDT is > unflattened via setup_arch(). Otherwise, setup_of() which is called > immediately after setup_arch(), and will create the default root node > if it does not exist. > > Signed-off-by: Frank Rowand <frowand.list@gmail.com> > --- > > There are checkpatch warnings. I have reviewed them and feel > they can be ignored. > > Changes since version 1: > - refresh for 6.2-rc1 > - update Signed-off-by > - fix typo in of_fdt.h: s/of_setup/setup_of > - unflatten_device_tree(): validate size in header field dtb_empty_root > that will be used to copy dtb_empty_root > - add Kconfig option to manually select CONFIG_OF_EARLY_FLATTREE > > drivers/of/Kconfig | 7 ++++++- > drivers/of/Makefile | 2 +- > drivers/of/empty_root.dts | 6 ++++++ > drivers/of/fdt.c | 27 ++++++++++++++++++++++++++- > include/linux/of_fdt.h | 2 ++ > init/main.c | 2 ++ > 6 files changed, 43 insertions(+), 3 deletions(-) > create mode 100644 drivers/of/empty_root.dts > > diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig > index 80b5fd44ab1c..591cfe386727 100644 > --- a/drivers/of/Kconfig > +++ b/drivers/of/Kconfig > @@ -42,9 +42,14 @@ config OF_FLATTREE > select CRC32 > > config OF_EARLY_FLATTREE > - bool > + bool "Functions for accessing Flat Devicetree (FDT) early in boot" > select DMA_DECLARE_COHERENT if HAS_DMA > select OF_FLATTREE > + help > + Normally selected by platforms that process an FDT that has been > + passed to the kernel by the bootloader. If the bootloader does not > + pass an FDT to the kernel and you need an empty devicetree that > + contains only a root node to exist, then say Y here. > > config OF_PROMTREE > bool > diff --git a/drivers/of/Makefile b/drivers/of/Makefile > index e0360a44306e..cbae92c5ed02 100644 > --- a/drivers/of/Makefile > +++ b/drivers/of/Makefile > @@ -2,7 +2,7 @@ > obj-y = base.o device.o platform.o property.o > obj-$(CONFIG_OF_KOBJ) += kobj.o > obj-$(CONFIG_OF_DYNAMIC) += dynamic.o > -obj-$(CONFIG_OF_FLATTREE) += fdt.o > +obj-$(CONFIG_OF_FLATTREE) += fdt.o empty_root.dtb.o > obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o > obj-$(CONFIG_OF_PROMTREE) += pdt.o > obj-$(CONFIG_OF_ADDRESS) += address.o > diff --git a/drivers/of/empty_root.dts b/drivers/of/empty_root.dts > new file mode 100644 > index 000000000000..cf9e97a60f48 > --- /dev/null > +++ b/drivers/of/empty_root.dts > @@ -0,0 +1,6 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/dts-v1/; > + > +/ { > + > +}; > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > index b2272bccf85c..0d2f6d016b7e 100644 > --- a/drivers/of/fdt.c > +++ b/drivers/of/fdt.c > @@ -33,6 +33,13 @@ > > #include "of_private.h" > > +/* > + * __dtb_empty_root_begin[] and __dtb_empty_root_end[] magically created by > + * cmd_dt_S_dtb in scripts/Makefile.lib > + */ > +extern void *__dtb_empty_root_begin; > +extern void *__dtb_empty_root_end; > + > /* > * of_fdt_limit_memory - limit the number of regions in the /memory node > * @limit: maximum entries > @@ -1326,8 +1333,19 @@ bool __init early_init_dt_scan(void *params) > */ > void __init unflatten_device_tree(void) > { > - __unflatten_device_tree(initial_boot_params, NULL, &of_root, > + if (!initial_boot_params) { > + initial_boot_params = (void *) __dtb_empty_root_begin; The crash I encountered was actually not due to memblock alloc but to this usage/declaration of the embedded dtb pointers which is wrong. Either declare it as: extern char __dtb_empty_root_begin[]; extern char __dtb_empty_root_end[]; and keep the existing usage in this function or keep the existing declaration but modify this function to use &__dtb_empty_root_begin With this modification, I finally have an empty device-tree present on my system: $ dtc -I fs -O dts /sys/firmware/devicetree/ /dts-v1/; / { }; Thanks, Clément > + /* fdt_totalsize() will be used for copy size */ > + if (fdt_totalsize(initial_boot_params) > > + __dtb_empty_root_end - __dtb_empty_root_begin) { > + pr_err("invalid size in dtb_empty_root\n"); > + return; > + } > + unflatten_and_copy_device_tree(); > + } else { > + __unflatten_device_tree(initial_boot_params, NULL, &of_root, > early_init_dt_alloc_memory_arch, false); > + } > > /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */ > of_alias_scan(early_init_dt_alloc_memory_arch); > @@ -1367,6 +1385,13 @@ void __init unflatten_and_copy_device_tree(void) > unflatten_device_tree(); > } > > +void __init setup_of(void) > +{ > + /* if architecture did not unflatten devicetree, do it now */ > + if (!of_root) > + unflatten_device_tree(); > +} > + > #ifdef CONFIG_SYSFS > static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj, > struct bin_attribute *bin_attr, > diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h > index d69ad5bb1eb1..f0dc46d576da 100644 > --- a/include/linux/of_fdt.h > +++ b/include/linux/of_fdt.h > @@ -81,6 +81,7 @@ extern const void *of_flat_dt_match_machine(const void *default_match, > /* Other Prototypes */ > extern void unflatten_device_tree(void); > extern void unflatten_and_copy_device_tree(void); > +extern void setup_of(void); > extern void early_init_devtree(void *); > extern void early_get_first_memblock_info(void *, phys_addr_t *); > #else /* CONFIG_OF_EARLY_FLATTREE */ > @@ -91,6 +92,7 @@ static inline void early_init_fdt_reserve_self(void) {} > static inline const char *of_flat_dt_get_machine_name(void) { return NULL; } > static inline void unflatten_device_tree(void) {} > static inline void unflatten_and_copy_device_tree(void) {} > +static inline void setup_of(void) {} > #endif /* CONFIG_OF_EARLY_FLATTREE */ > > #endif /* __ASSEMBLY__ */ > diff --git a/init/main.c b/init/main.c > index e1c3911d7c70..31e0931b5134 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -101,6 +101,7 @@ > #include <linux/init_syscalls.h> > #include <linux/stackdepot.h> > #include <linux/randomize_kstack.h> > +#include <linux/of_fdt.h> > #include <net/net_namespace.h> > > #include <asm/io.h> > @@ -961,6 +962,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) > pr_notice("%s", linux_banner); > early_security_init(); > setup_arch(&command_line); > + setup_of(); > setup_boot_config(); > setup_command_line(command_line); > setup_nr_cpu_ids(); -- Clément Léger, Embedded Linux and Kernel engineer at Bootlin https://bootlin.com ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 1/2] of: create of_root if no dtb provided 2023-02-23 11:34 ` Clément Léger @ 2023-02-23 20:59 ` Frank Rowand 0 siblings, 0 replies; 6+ messages in thread From: Frank Rowand @ 2023-02-23 20:59 UTC (permalink / raw) To: Clément Léger Cc: Rob Herring, devicetree, linux-kernel, Lizhi Hou, Allan Nielsen, Horatiu Vultur, Steen Hegelund, Thomas Petazzoni On 2/23/23 05:34, Clément Léger wrote: > Le Wed, 22 Feb 2023 16:10:50 -0600, > Frank Rowand <frowand.list@gmail.com> a écrit : > >> When enabling CONFIG_OF on a platform where of_root is not populated by >> firmware, we end up without a root node. In order to apply overlays and >> create subnodes of the root node, we need one. Create this root node >> by unflattening an empty builtin dtb. >> >> If firmware provides a flattened device tree (FDT) then the FDT is >> unflattened via setup_arch(). Otherwise, setup_of() which is called >> immediately after setup_arch(), and will create the default root node >> if it does not exist. >> >> Signed-off-by: Frank Rowand <frowand.list@gmail.com> >> --- >> >> There are checkpatch warnings. I have reviewed them and feel >> they can be ignored. >> >> Changes since version 1: >> - refresh for 6.2-rc1 >> - update Signed-off-by >> - fix typo in of_fdt.h: s/of_setup/setup_of >> - unflatten_device_tree(): validate size in header field dtb_empty_root >> that will be used to copy dtb_empty_root >> - add Kconfig option to manually select CONFIG_OF_EARLY_FLATTREE >> >> drivers/of/Kconfig | 7 ++++++- >> drivers/of/Makefile | 2 +- >> drivers/of/empty_root.dts | 6 ++++++ >> drivers/of/fdt.c | 27 ++++++++++++++++++++++++++- >> include/linux/of_fdt.h | 2 ++ >> init/main.c | 2 ++ >> 6 files changed, 43 insertions(+), 3 deletions(-) >> create mode 100644 drivers/of/empty_root.dts >> >> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig >> index 80b5fd44ab1c..591cfe386727 100644 >> --- a/drivers/of/Kconfig >> +++ b/drivers/of/Kconfig >> @@ -42,9 +42,14 @@ config OF_FLATTREE >> select CRC32 >> >> config OF_EARLY_FLATTREE >> - bool >> + bool "Functions for accessing Flat Devicetree (FDT) early in boot" >> select DMA_DECLARE_COHERENT if HAS_DMA >> select OF_FLATTREE >> + help >> + Normally selected by platforms that process an FDT that has been >> + passed to the kernel by the bootloader. If the bootloader does not >> + pass an FDT to the kernel and you need an empty devicetree that >> + contains only a root node to exist, then say Y here. >> >> config OF_PROMTREE >> bool >> diff --git a/drivers/of/Makefile b/drivers/of/Makefile >> index e0360a44306e..cbae92c5ed02 100644 >> --- a/drivers/of/Makefile >> +++ b/drivers/of/Makefile >> @@ -2,7 +2,7 @@ >> obj-y = base.o device.o platform.o property.o >> obj-$(CONFIG_OF_KOBJ) += kobj.o >> obj-$(CONFIG_OF_DYNAMIC) += dynamic.o >> -obj-$(CONFIG_OF_FLATTREE) += fdt.o >> +obj-$(CONFIG_OF_FLATTREE) += fdt.o empty_root.dtb.o >> obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o >> obj-$(CONFIG_OF_PROMTREE) += pdt.o >> obj-$(CONFIG_OF_ADDRESS) += address.o >> diff --git a/drivers/of/empty_root.dts b/drivers/of/empty_root.dts >> new file mode 100644 >> index 000000000000..cf9e97a60f48 >> --- /dev/null >> +++ b/drivers/of/empty_root.dts >> @@ -0,0 +1,6 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/dts-v1/; >> + >> +/ { >> + >> +}; >> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >> index b2272bccf85c..0d2f6d016b7e 100644 >> --- a/drivers/of/fdt.c >> +++ b/drivers/of/fdt.c >> @@ -33,6 +33,13 @@ >> >> #include "of_private.h" >> >> +/* >> + * __dtb_empty_root_begin[] and __dtb_empty_root_end[] magically created by >> + * cmd_dt_S_dtb in scripts/Makefile.lib >> + */ >> +extern void *__dtb_empty_root_begin; >> +extern void *__dtb_empty_root_end; >> + >> /* >> * of_fdt_limit_memory - limit the number of regions in the /memory node >> * @limit: maximum entries >> @@ -1326,8 +1333,19 @@ bool __init early_init_dt_scan(void *params) >> */ >> void __init unflatten_device_tree(void) >> { >> - __unflatten_device_tree(initial_boot_params, NULL, &of_root, >> + if (!initial_boot_params) { >> + initial_boot_params = (void *) __dtb_empty_root_begin; > > The crash I encountered was actually not due to memblock alloc but to > this usage/declaration of the embedded dtb pointers which is wrong. > > Either declare it as: > > extern char __dtb_empty_root_begin[]; > extern char __dtb_empty_root_end[]; Thanks for catching this, and the fix. I will change to uint8_t instead of char, consistent with the use in drivers/of/unittest.c -Frank > > and keep the existing usage in this function or keep the existing > declaration but modify this function to use &__dtb_empty_root_begin > > With this modification, I finally have an empty device-tree present on > my system: > > $ dtc -I fs -O dts /sys/firmware/devicetree/ > /dts-v1/; > > / { > }; > > Thanks, > > Clément > >> + /* fdt_totalsize() will be used for copy size */ >> + if (fdt_totalsize(initial_boot_params) > >> + __dtb_empty_root_end - __dtb_empty_root_begin) { >> + pr_err("invalid size in dtb_empty_root\n"); >> + return; >> + } >> + unflatten_and_copy_device_tree(); >> + } else { >> + __unflatten_device_tree(initial_boot_params, NULL, &of_root, >> early_init_dt_alloc_memory_arch, false); >> + } >> >> /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */ >> of_alias_scan(early_init_dt_alloc_memory_arch); >> @@ -1367,6 +1385,13 @@ void __init unflatten_and_copy_device_tree(void) >> unflatten_device_tree(); >> } >> >> +void __init setup_of(void) >> +{ >> + /* if architecture did not unflatten devicetree, do it now */ >> + if (!of_root) >> + unflatten_device_tree(); >> +} >> + >> #ifdef CONFIG_SYSFS >> static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj, >> struct bin_attribute *bin_attr, >> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h >> index d69ad5bb1eb1..f0dc46d576da 100644 >> --- a/include/linux/of_fdt.h >> +++ b/include/linux/of_fdt.h >> @@ -81,6 +81,7 @@ extern const void *of_flat_dt_match_machine(const void *default_match, >> /* Other Prototypes */ >> extern void unflatten_device_tree(void); >> extern void unflatten_and_copy_device_tree(void); >> +extern void setup_of(void); >> extern void early_init_devtree(void *); >> extern void early_get_first_memblock_info(void *, phys_addr_t *); >> #else /* CONFIG_OF_EARLY_FLATTREE */ >> @@ -91,6 +92,7 @@ static inline void early_init_fdt_reserve_self(void) {} >> static inline const char *of_flat_dt_get_machine_name(void) { return NULL; } >> static inline void unflatten_device_tree(void) {} >> static inline void unflatten_and_copy_device_tree(void) {} >> +static inline void setup_of(void) {} >> #endif /* CONFIG_OF_EARLY_FLATTREE */ >> >> #endif /* __ASSEMBLY__ */ >> diff --git a/init/main.c b/init/main.c >> index e1c3911d7c70..31e0931b5134 100644 >> --- a/init/main.c >> +++ b/init/main.c >> @@ -101,6 +101,7 @@ >> #include <linux/init_syscalls.h> >> #include <linux/stackdepot.h> >> #include <linux/randomize_kstack.h> >> +#include <linux/of_fdt.h> >> #include <net/net_namespace.h> >> >> #include <asm/io.h> >> @@ -961,6 +962,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) >> pr_notice("%s", linux_banner); >> early_security_init(); >> setup_arch(&command_line); >> + setup_of(); >> setup_boot_config(); >> setup_command_line(command_line); >> setup_nr_cpu_ids(); > > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 2/2] of: unittest: treat missing of_root as error instead of fixing up 2023-02-22 22:10 [PATCH v2 0/2] of: populate of_root_node if not set (alternate) Frank Rowand 2023-02-22 22:10 ` [PATCH v2 1/2] of: create of_root if no dtb provided Frank Rowand @ 2023-02-22 22:10 ` Frank Rowand 2023-02-23 10:41 ` [PATCH v2 0/2] of: populate of_root_node if not set (alternate) Clément Léger 2 siblings, 0 replies; 6+ messages in thread From: Frank Rowand @ 2023-02-22 22:10 UTC (permalink / raw) To: Rob Herring, Clément Léger Cc: devicetree, linux-kernel, Lizhi Hou, Allan Nielsen, Horatiu Vultur, Steen Hegelund, Thomas Petazzoni setup_of() now ensures that of_root node is populated with the root of a default devicetree. Remove the unittest code that created of_root if it was missing. Verify that of_root is valid before attempting to attach the testcase-data subtree. Signed-off-by: Frank Rowand <frowand.list@gmail.com> --- Changes since version 1: - refresh for 6.2-rc1 - update Signed-off-by - fix formatting error (leading space) in patch comment drivers/of/unittest.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c index bc0f1e50a4be..006713511c53 100644 --- a/drivers/of/unittest.c +++ b/drivers/of/unittest.c @@ -1469,20 +1469,16 @@ static int __init unittest_data_add(void) return -EINVAL; } - if (!of_root) { - of_root = unittest_data_node; - for_each_of_allnodes(np) - __of_attach_node_sysfs(np); - of_aliases = of_find_node_by_path("/aliases"); - of_chosen = of_find_node_by_path("/chosen"); - of_overlay_mutex_unlock(); - return 0; - } - EXPECT_BEGIN(KERN_INFO, "Duplicate name in testcase-data, renamed to \"duplicate-name#1\""); /* attach the sub-tree to live tree */ + if (!of_root) { + pr_warn("%s: no live tree to attach sub-tree\n", __func__); + kfree(unittest_data); + return -ENODEV; + } + np = unittest_data_node->child; while (np) { struct device_node *next = np->sibling; -- Frank Rowand <frowand.list@gmail.com> ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 0/2] of: populate of_root_node if not set (alternate) 2023-02-22 22:10 [PATCH v2 0/2] of: populate of_root_node if not set (alternate) Frank Rowand 2023-02-22 22:10 ` [PATCH v2 1/2] of: create of_root if no dtb provided Frank Rowand 2023-02-22 22:10 ` [PATCH v2 2/2] of: unittest: treat missing of_root as error instead of fixing up Frank Rowand @ 2023-02-23 10:41 ` Clément Léger 2 siblings, 0 replies; 6+ messages in thread From: Clément Léger @ 2023-02-23 10:41 UTC (permalink / raw) To: Frank Rowand Cc: Rob Herring, devicetree, linux-kernel, Lizhi Hou, Allan Nielsen, Horatiu Vultur, Steen Hegelund, Thomas Petazzoni Le Wed, 22 Feb 2023 16:10:49 -0600, Frank Rowand <frowand.list@gmail.com> a écrit : > This series is a different implementation to achieve the goals of > https://lore.kernel.org/r/20220623105044.152832-1-clement.leger@bootlin.com > > In order to apply overlays or create new nodes under the root node, the > kernel expects of_root to be set. On some system where a device-tree was > not provided by firmware (x86 for instance) if CONFIG_OF is enabled, > then we will end up with a null of_root. This series adds support to > create this root node using a builtin dtb and removes the manual > creation of the root node done in unittests.c. Hi Frank, I'm currently testing your series and I encountered some crashes at boot. Looks like it comes from the early_init_dt_alloc_memory_arch() that calls panic. Maybe the memblock allocator is not ready yet. Please note that I'm testing it on a x86 kernel. I'll investigate that. Regarding the series itself it seems ok to me. Thanks, Clément > > Changes since version 1: (patch 1/2) > - refresh for 6.2-rc1 > - update Signed-off-by > - fix typo in of_fdt.h: s/of_setup/setup_of > - unflatten_device_tree(): validate size in header field dtb_empty_root > that will be used to copy dtb_empty_root > - add Kconfig option to manually select CONFIG_OF_EARLY_FLATTREE > > Changes since version 1: (patch 2/2) > - refresh for 6.2-rc1 > - update Signed-off-by > - fix formatting error (leading space) in patch comment > > Frank Rowand (2): > of: create of_root if no dtb provided > of: unittest: treat missing of_root as error instead of fixing up > > drivers/of/Kconfig | 7 ++++++- > drivers/of/Makefile | 2 +- > drivers/of/empty_root.dts | 6 ++++++ > drivers/of/fdt.c | 27 ++++++++++++++++++++++++++- > drivers/of/unittest.c | 16 ++++++---------- > include/linux/of_fdt.h | 2 ++ > init/main.c | 2 ++ > 7 files changed, 49 insertions(+), 13 deletions(-) > create mode 100644 drivers/of/empty_root.dts > -- Clément Léger, Embedded Linux and Kernel engineer at Bootlin https://bootlin.com ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-02-23 20:59 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2023-02-22 22:10 [PATCH v2 0/2] of: populate of_root_node if not set (alternate) Frank Rowand 2023-02-22 22:10 ` [PATCH v2 1/2] of: create of_root if no dtb provided Frank Rowand 2023-02-23 11:34 ` Clément Léger 2023-02-23 20:59 ` Frank Rowand 2023-02-22 22:10 ` [PATCH v2 2/2] of: unittest: treat missing of_root as error instead of fixing up Frank Rowand 2023-02-23 10:41 ` [PATCH v2 0/2] of: populate of_root_node if not set (alternate) Clément Léger
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