Commit 4b5f9254 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'topic/kcmp-kconfig-2021-02-22' of git://anongit.freedesktop.org/drm/drm 

Pull kcmp kconfig update from Daniel Vetter:
 "Make the kcmp syscall available independently of checkpoint/restore.

  drm userspaces uses this, systemd uses this, so makes sense to pull it
  out from the checkpoint-restore bundle.

  Kees reviewed this from security pov and is happy with the final
  version"

Link: https://lwn.net/Articles/845448/

* tag 'topic/kcmp-kconfig-2021-02-22' of git://anongit.freedesktop.org/drm/drm:
  kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE
parents 7b0b78df bfe3911a

drivers/gpu/drm/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -15,6 +15,9 @@ menuconfig DRM 
	select I2C_ALGOBIT

	select DMA_SHARED_BUFFER

	select SYNC_FILE

# gallium uses SYS_kcmp for os_same_file_description() to de-duplicate

# device and dmabuf fd. Let's make sure that is available for our userspace.

	select KCMP

	help

	  Kernel-level support for the Direct Rendering Infrastructure (DRI)

	  introduced in XFree86 4.0. If you say Y here, you need to select

fs/eventpoll.c

+2 −2
Original line number Diff line number Diff line
@@ -979,7 +979,7 @@ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd) 
	return epir;

}



#ifdef CONFIG_CHECKPOINT_RESTORE

#ifdef CONFIG_KCMP

static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff)

{

	struct rb_node *rbp;
@@ -1021,7 +1021,7 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, 


	return file_raw;

}

#endif /* CONFIG_CHECKPOINT_RESTORE */

#endif /* CONFIG_KCMP */



/**

 * Adds a new entry to the tail of the list in a lockless way, i.e.

include/linux/eventpoll.h

+1 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ struct file; 


#ifdef CONFIG_EPOLL



#ifdef CONFIG_CHECKPOINT_RESTORE

#ifdef CONFIG_KCMP

struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);

#endif

init/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -1193,6 +1193,7 @@ endif # NAMESPACES 
config CHECKPOINT_RESTORE

	bool "Checkpoint/restore support"

	select PROC_CHILDREN

	select KCMP

	default n

	help

	  Enables additional kernel features in a sake of checkpoint/restore.
@@ -1736,6 +1737,16 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS 
config ARCH_HAS_MEMBARRIER_SYNC_CORE

	bool



config KCMP

	bool "Enable kcmp() system call" if EXPERT

	help

	  Enable the kernel resource comparison system call. It provides

	  user-space with the ability to compare two processes to see if they

	  share a common resource, such as a file descriptor or even virtual

	  memory space.



	  If unsure, say N.



config RSEQ

	bool "Enable rseq() system call" if EXPERT

	default y

kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ obj-y += livepatch/ 
obj-y += dma/

obj-y += entry/



obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o

obj-$(CONFIG_KCMP) += kcmp.o

obj-$(CONFIG_FREEZER) += freezer.o

obj-$(CONFIG_PROFILING) += profile.o

obj-$(CONFIG_STACKTRACE) += stacktrace.o