Re: [PATCH v2] kheaders: Move from proc to sysfs

On Sat, May 04, 2019 at 08:12:13AM -0400, Joel Fernandes (Google) 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/

v1->v2: Fixed some kconfig nits (Masami).

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

Good in changing the config name, I hadn't thought of that.

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

Same here, nice.

-static const struct file_operations ikheaders_file_ops = {

• .read = ikheaders_read_current,
• .llseek = default_llseek,

+static struct bin_attribute kheaders_attr __ro_after_init = {

Minor nit, are you sure about __ro_after_init for an attribute structure? Is it even needed?

• .attr = {

• .name = "kheaders.tar.xz",
  

• .mode = S_IRUGO,
  

• },
• .read = &ikheaders_read,

};

BIN_ATTR_RO? Ah, no, that will not work with the name of the file, nevermind.

But, you should change S_IRUGO to the correct octal number, checkpatch should have barfed on this change.

thanks,

greg k-h