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* [PATCH v3] kheaders: Move from proc to sysfs
@ 2019-05-06  1:34 Joel Fernandes (Google)
  2019-05-08  3:43 ` Masahiro Yamada
  0 siblings, 1 reply; 3+ messages in thread
From: Joel Fernandes (Google) @ 2019-05-06  1:34 UTC (permalink / raw)
  To: linux-kernel
  Cc: Joel Fernandes (Google),
	Steven Rostedt, Adrian Ratiu, Alexei Starovoitov, Andrew Morton,
	atishp04, bpf, Brendan Gregg, Brendan Gregg, dancol,
	Daniel Borkmann, Dan Williams, dietmar.eggemann, duyuchao,
	gregkh, Guenter Roeck, Jonathan Corbet, Karim Yaghmour,
	Kees Cook, kernel-team, linux-doc, linux-kselftest,
	linux-trace-devel, Manjo Raja Rao, Masahiro Yamada,
	Masami Hiramatsu, Michał Gregorczyk, Michal Gregorczyk,
	Mohammad Husain, Olof Johansson, qais.yousef, rdunlap,
	Shuah Khan, Srinivas Ramana, Tamir Carmeli, yhs

The kheaders archive consisting of the kernel headers used for compiling
bpf programs is in /proc. However there is concern that moving it here
will make it permanent. Let us move it to /sys/kernel as discussed [1].

[1] https://lore.kernel.org/patchwork/patch/1067310/#1265969

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
This patch applies on top of the previous patch that was applied to the
driver tree:
https://lore.kernel.org/patchwork/patch/1067310/

v2->v3: Fixed sysfs file mode nit (Greg).
v1->v2: Fixed some kconfig nits.

 init/Kconfig                                | 16 ++++-----
 kernel/Makefile                             |  4 +--
 kernel/{gen_ikh_data.sh => gen_kheaders.sh} |  2 +-
 kernel/kheaders.c                           | 40 +++++++++------------
 4 files changed, 26 insertions(+), 36 deletions(-)
 rename kernel/{gen_ikh_data.sh => gen_kheaders.sh} (98%)

diff --git a/init/Kconfig b/init/Kconfig
index 26a364a95b57..c3661991b089 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -579,15 +579,13 @@ config IKCONFIG_PROC
 	  This option enables access to the kernel configuration file
 	  through /proc/config.gz.
 
-config IKHEADERS_PROC
-	tristate "Enable kernel header artifacts through /proc/kheaders.tar.xz"
-	depends on PROC_FS
-	help
-	  This option enables access to the kernel header and other artifacts that
-	  are generated during the build process. These can be used to build eBPF
-	  tracing programs, or similar programs.  If you build the headers as a
-	  module, a module called kheaders.ko is built which can be loaded on-demand
-	  to get access to the headers.
+config IKHEADERS
+	tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
+	help
+	  This option enables access to the in-kernel headers that are generated during
+	  the build process. These can be used to build eBPF tracing programs,
+	  or similar programs.  If you build the headers as a module, a module called
+	  kheaders.ko is built which can be loaded on-demand to get access to headers.
 
 config LOG_BUF_SHIFT
 	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
diff --git a/kernel/Makefile b/kernel/Makefile
index 12399614c350..b32a558fae2f 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -70,7 +70,7 @@ obj-$(CONFIG_UTS_NS) += utsname.o
 obj-$(CONFIG_USER_NS) += user_namespace.o
 obj-$(CONFIG_PID_NS) += pid_namespace.o
 obj-$(CONFIG_IKCONFIG) += configs.o
-obj-$(CONFIG_IKHEADERS_PROC) += kheaders.o
+obj-$(CONFIG_IKHEADERS) += kheaders.o
 obj-$(CONFIG_SMP) += stop_machine.o
 obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
 obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
@@ -126,7 +126,7 @@ $(obj)/config_data.gz: $(KCONFIG_CONFIG) FORCE
 $(obj)/kheaders.o: $(obj)/kheaders_data.tar.xz
 
 quiet_cmd_genikh = CHK     $(obj)/kheaders_data.tar.xz
-cmd_genikh = $(srctree)/kernel/gen_ikh_data.sh $@
+cmd_genikh = $(srctree)/kernel/gen_kheaders.sh $@
 $(obj)/kheaders_data.tar.xz: FORCE
 	$(call cmd,genikh)
 
diff --git a/kernel/gen_ikh_data.sh b/kernel/gen_kheaders.sh
similarity index 98%
rename from kernel/gen_ikh_data.sh
rename to kernel/gen_kheaders.sh
index 591a94f7b387..581b83534587 100755
--- a/kernel/gen_ikh_data.sh
+++ b/kernel/gen_kheaders.sh
@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 # This script generates an archive consisting of kernel headers
-# for CONFIG_IKHEADERS_PROC.
+# for CONFIG_IKHEADERS.
 set -e
 spath="$(dirname "$(readlink -f "$0")")"
 kroot="$spath/.."
diff --git a/kernel/kheaders.c b/kernel/kheaders.c
index 70ae6052920d..8f69772af77b 100644
--- a/kernel/kheaders.c
+++ b/kernel/kheaders.c
@@ -8,9 +8,8 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/proc_fs.h>
+#include <linux/kobject.h>
 #include <linux/init.h>
-#include <linux/uaccess.h>
 
 /*
  * Define kernel_headers_data and kernel_headers_data_end, within which the
@@ -31,39 +30,32 @@ extern char kernel_headers_data;
 extern char kernel_headers_data_end;
 
 static ssize_t
-ikheaders_read_current(struct file *file, char __user *buf,
-		      size_t len, loff_t *offset)
+ikheaders_read(struct file *file,  struct kobject *kobj,
+	       struct bin_attribute *bin_attr,
+	       char *buf, loff_t off, size_t len)
 {
-	return simple_read_from_buffer(buf, len, offset,
-				       &kernel_headers_data,
-				       &kernel_headers_data_end -
-				       &kernel_headers_data);
+	memcpy(buf, &kernel_headers_data + off, len);
+	return len;
 }
 
-static const struct file_operations ikheaders_file_ops = {
-	.read = ikheaders_read_current,
-	.llseek = default_llseek,
+static struct bin_attribute kheaders_attr __ro_after_init = {
+	.attr = {
+		.name = "kheaders.tar.xz",
+		.mode = 0444,
+	},
+	.read = &ikheaders_read,
 };
 
 static int __init ikheaders_init(void)
 {
-	struct proc_dir_entry *entry;
-
-	/* create the current headers file */
-	entry = proc_create("kheaders.tar.xz", S_IRUGO, NULL,
-			    &ikheaders_file_ops);
-	if (!entry)
-		return -ENOMEM;
-
-	proc_set_size(entry,
-		      &kernel_headers_data_end -
-		      &kernel_headers_data);
-	return 0;
+	kheaders_attr.size = (&kernel_headers_data_end -
+			      &kernel_headers_data);
+	return sysfs_create_bin_file(kernel_kobj, &kheaders_attr);
 }
 
 static void __exit ikheaders_cleanup(void)
 {
-	remove_proc_entry("kheaders.tar.xz", NULL);
+	sysfs_remove_bin_file(kernel_kobj, &kheaders_attr);
 }
 
 module_init(ikheaders_init);
-- 
2.21.0.1020.gf2820cf01a-goog

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v3] kheaders: Move from proc to sysfs
  2019-05-06  1:34 [PATCH v3] kheaders: Move from proc to sysfs Joel Fernandes (Google)
@ 2019-05-08  3:43 ` Masahiro Yamada
  2019-05-09 22:47   ` Joel Fernandes
  0 siblings, 1 reply; 3+ messages in thread
From: Masahiro Yamada @ 2019-05-08  3:43 UTC (permalink / raw)
  To: Joel Fernandes (Google)
  Cc: Linux Kernel Mailing List, Steven Rostedt, Adrian Ratiu,
	Alexei Starovoitov, Andrew Morton, atish patra, bpf,
	Brendan Gregg, Brendan Gregg, Daniel Colascione, Daniel Borkmann,
	Dan Williams, Dietmar Eggemann, duyuchao, Greg Kroah-Hartman,
	Guenter Roeck, Jonathan Corbet, Karim Yaghmour, Kees Cook,
	Cc: Android Kernel, open list:DOCUMENTATION,
	open list:KERNEL SELFTEST FRAMEWORK, linux-trace-devel,
	Manjo Raja Rao, Masami Hiramatsu, Michał Gregorczyk,
	Michal Gregorczyk, Mohammad Husain, Olof Johansson, Qais Yousef,
	Randy Dunlap, Shuah Khan, Srinivas Ramana, Tamir Carmeli,
	Yonghong Song

On Mon, May 6, 2019 at 10:37 AM Joel Fernandes (Google)
<joel@joelfernandes.org> wrote:
>
> The kheaders archive consisting of the kernel headers used for compiling
> bpf programs is in /proc. However there is concern that moving it here
> will make it permanent. Let us move it to /sys/kernel as discussed [1].
>
> [1] https://lore.kernel.org/patchwork/patch/1067310/#1265969
>
> Suggested-by: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> ---
> This patch applies on top of the previous patch that was applied to the
> driver tree:
> https://lore.kernel.org/patchwork/patch/1067310/
>
> v2->v3: Fixed sysfs file mode nit (Greg).
> v1->v2: Fixed some kconfig nits.
>
>  init/Kconfig                                | 16 ++++-----
>  kernel/Makefile                             |  4 +--
>  kernel/{gen_ikh_data.sh => gen_kheaders.sh} |  2 +-
>  kernel/kheaders.c                           | 40 +++++++++------------
>  4 files changed, 26 insertions(+), 36 deletions(-)
>  rename kernel/{gen_ikh_data.sh => gen_kheaders.sh} (98%)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index 26a364a95b57..c3661991b089 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -579,15 +579,13 @@ config IKCONFIG_PROC
>           This option enables access to the kernel configuration file
>           through /proc/config.gz.
>
> -config IKHEADERS_PROC
> -       tristate "Enable kernel header artifacts through /proc/kheaders.tar.xz"
> -       depends on PROC_FS
> -       help
> -         This option enables access to the kernel header and other artifacts that
> -         are generated during the build process. These can be used to build eBPF
> -         tracing programs, or similar programs.  If you build the headers as a
> -         module, a module called kheaders.ko is built which can be loaded on-demand
> -         to get access to the headers.
> +config IKHEADERS
> +       tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"


I suggested "depends on SYSFS" twice, both in v1 and v2.

https://lore.kernel.org/patchwork/patch/1069806/#1266147
https://lore.kernel.org/patchwork/patch/1070005/#1266279



> +       help
> +         This option enables access to the in-kernel headers that are generated during
> +         the build process. These can be used to build eBPF tracing programs,
> +         or similar programs.  If you build the headers as a module, a module called
> +         kheaders.ko is built which can be loaded on-demand to get access to headers.
>
>  config LOG_BUF_SHIFT
>         int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"


-- 
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v3] kheaders: Move from proc to sysfs
  2019-05-08  3:43 ` Masahiro Yamada
@ 2019-05-09 22:47   ` Joel Fernandes
  0 siblings, 0 replies; 3+ messages in thread
From: Joel Fernandes @ 2019-05-09 22:47 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Linux Kernel Mailing List, Steven Rostedt, Adrian Ratiu,
	Alexei Starovoitov, Andrew Morton, atish patra, bpf,
	Brendan Gregg, Brendan Gregg, Daniel Colascione, Daniel Borkmann,
	Dan Williams, Dietmar Eggemann, duyuchao, Greg Kroah-Hartman,
	Guenter Roeck, Jonathan Corbet, Karim Yaghmour, Kees Cook,
	Cc: Android Kernel, open list:DOCUMENTATION,
	open list:KERNEL SELFTEST FRAMEWORK, linux-trace-devel,
	Manjo Raja Rao, Masami Hiramatsu, Michał Gregorczyk,
	Michal Gregorczyk, Mohammad Husain, Olof Johansson, Qais Yousef,
	Randy Dunlap, Shuah Khan, Srinivas Ramana, Tamir Carmeli,
	Yonghong Song

On Wed, May 08, 2019 at 12:43:34PM +0900, Masahiro Yamada wrote:
> On Mon, May 6, 2019 at 10:37 AM Joel Fernandes (Google)
> <joel@joelfernandes.org> wrote:
> >
> > The kheaders archive consisting of the kernel headers used for compiling
> > bpf programs is in /proc. However there is concern that moving it here
> > will make it permanent. Let us move it to /sys/kernel as discussed [1].
> >
> > [1] https://lore.kernel.org/patchwork/patch/1067310/#1265969
> >
> > Suggested-by: Steven Rostedt <rostedt@goodmis.org>
> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > ---
> > This patch applies on top of the previous patch that was applied to the
> > driver tree:
> > https://lore.kernel.org/patchwork/patch/1067310/
> >
> > v2->v3: Fixed sysfs file mode nit (Greg).
> > v1->v2: Fixed some kconfig nits.
> >
> >  init/Kconfig                                | 16 ++++-----
> >  kernel/Makefile                             |  4 +--
> >  kernel/{gen_ikh_data.sh => gen_kheaders.sh} |  2 +-
> >  kernel/kheaders.c                           | 40 +++++++++------------
> >  4 files changed, 26 insertions(+), 36 deletions(-)
> >  rename kernel/{gen_ikh_data.sh => gen_kheaders.sh} (98%)
> >
> > diff --git a/init/Kconfig b/init/Kconfig
> > index 26a364a95b57..c3661991b089 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -579,15 +579,13 @@ config IKCONFIG_PROC
> >           This option enables access to the kernel configuration file
> >           through /proc/config.gz.
> >
> > -config IKHEADERS_PROC
> > -       tristate "Enable kernel header artifacts through /proc/kheaders.tar.xz"
> > -       depends on PROC_FS
> > -       help
> > -         This option enables access to the kernel header and other artifacts that
> > -         are generated during the build process. These can be used to build eBPF
> > -         tracing programs, or similar programs.  If you build the headers as a
> > -         module, a module called kheaders.ko is built which can be loaded on-demand
> > -         to get access to the headers.
> > +config IKHEADERS
> > +       tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz"
> 
> 
> I suggested "depends on SYSFS" twice, both in v1 and v2.
> 
> https://lore.kernel.org/patchwork/patch/1069806/#1266147
> https://lore.kernel.org/patchwork/patch/1070005/#1266279

Sorry about missing that. I have made a note of this, and can address it in a
later patch. There is a more pressing issue with allmodconfig regression
times so I will look into that first. Also a vacation is taking up some of my
time.

Needless to say I will get to it soon and the point has been duly noted!

thanks,

 - Joel

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2019-05-06  1:34 [PATCH v3] kheaders: Move from proc to sysfs Joel Fernandes (Google)
2019-05-08  3:43 ` Masahiro Yamada
2019-05-09 22:47   ` Joel Fernandes

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