[PATCH v2] All arch: remove system call sys_sysctl

[PATCH v2] All arch: remove system call sys_sysctl

[Xiaoming Ni]

Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
sys_sysctl is actually unavailable: any input can only return an error.

We have been warning about people using the sysctl system call for years
and believe there are no more users.  Even if there are users of this
interface if they have not complained or fixed their code by now they
probably are not going to, so there is no point in warning them any
longer.

So completely remove sys_sysctl on all architectures.

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>

changes in v2:
  According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
  According to Eric W. Biederman's suggestion, update the commit log

V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
  Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
---
 arch/alpha/kernel/syscalls/syscall.tbl             |   2 +-
 arch/arm/configs/am200epdkit_defconfig             |   1 -
 arch/arm/tools/syscall.tbl                         |   2 +-
 arch/arm64/include/asm/unistd32.h                  |   4 +-
 arch/ia64/kernel/syscalls/syscall.tbl              |   2 +-
 arch/m68k/kernel/syscalls/syscall.tbl              |   2 +-
 arch/microblaze/kernel/syscalls/syscall.tbl        |   2 +-
 arch/mips/configs/cu1000-neo_defconfig             |   1 -
 arch/mips/kernel/syscalls/syscall_n32.tbl          |   2 +-
 arch/mips/kernel/syscalls/syscall_n64.tbl          |   2 +-
 arch/mips/kernel/syscalls/syscall_o32.tbl          |   2 +-
 arch/parisc/kernel/syscalls/syscall.tbl            |   2 +-
 arch/powerpc/kernel/syscalls/syscall.tbl           |   2 +-
 arch/s390/kernel/syscalls/syscall.tbl              |   2 +-
 arch/sh/configs/dreamcast_defconfig                |   1 -
 arch/sh/configs/espt_defconfig                     |   1 -
 arch/sh/configs/hp6xx_defconfig                    |   1 -
 arch/sh/configs/landisk_defconfig                  |   1 -
 arch/sh/configs/lboxre2_defconfig                  |   1 -
 arch/sh/configs/microdev_defconfig                 |   1 -
 arch/sh/configs/migor_defconfig                    |   1 -
 arch/sh/configs/r7780mp_defconfig                  |   1 -
 arch/sh/configs/r7785rp_defconfig                  |   1 -
 arch/sh/configs/rts7751r2d1_defconfig              |   1 -
 arch/sh/configs/rts7751r2dplus_defconfig           |   1 -
 arch/sh/configs/se7206_defconfig                   |   1 -
 arch/sh/configs/se7343_defconfig                   |   1 -
 arch/sh/configs/se7619_defconfig                   |   1 -
 arch/sh/configs/se7705_defconfig                   |   1 -
 arch/sh/configs/se7750_defconfig                   |   1 -
 arch/sh/configs/se7751_defconfig                   |   1 -
 arch/sh/configs/secureedge5410_defconfig           |   1 -
 arch/sh/configs/sh03_defconfig                     |   1 -
 arch/sh/configs/sh7710voipgw_defconfig             |   1 -
 arch/sh/configs/sh7757lcr_defconfig                |   1 -
 arch/sh/configs/sh7763rdp_defconfig                |   1 -
 arch/sh/configs/shmin_defconfig                    |   1 -
 arch/sh/configs/titan_defconfig                    |   1 -
 arch/sh/include/uapi/asm/unistd_64.h               |   2 +-
 arch/sh/kernel/syscalls/syscall.tbl                |   2 +-
 arch/sh/kernel/syscalls_64.S                       |   2 +-
 arch/sparc/kernel/syscalls/syscall.tbl             |   2 +-
 arch/x86/entry/syscalls/syscall_32.tbl             |   2 +-
 arch/x86/entry/syscalls/syscall_64.tbl             |   2 +-
 arch/xtensa/kernel/syscalls/syscall.tbl            |   2 +-
 include/linux/compat.h                             |   1 -
 include/linux/syscalls.h                           |   2 -
 include/linux/sysctl.h                             |   6 +-
 include/uapi/linux/sysctl.h                        |  15 --
 kernel/Makefile                                    |   2 +-
 kernel/sys_ni.c                                    |   1 -
 kernel/sysctl_binary.c                             | 171 ---------------------
 tools/perf/arch/powerpc/entry/syscalls/syscall.tbl |   2 +-
 tools/perf/arch/s390/entry/syscalls/syscall.tbl    |   2 +-
 tools/perf/arch/x86/entry/syscalls/syscall_64.tbl  |   2 +-
 55 files changed, 26 insertions(+), 244 deletions(-)
 delete mode 100644 kernel/sysctl_binary.c

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index b249824..0da7f1c 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -249,7 +249,7 @@
 316	common	mlockall			sys_mlockall
 317	common	munlockall			sys_munlockall
 318	common	sysinfo				sys_sysinfo
-319	common	_sysctl				sys_sysctl
+319	common	_sysctl				sys_ni_syscall
 # 320 was sys_idle
 321	common	oldumount			sys_oldumount
 322	common	swapon				sys_swapon
diff --git a/arch/arm/configs/am200epdkit_defconfig b/arch/arm/configs/am200epdkit_defconfig
index f56ac39..4e49d6c 100644
--- a/arch/arm/configs/am200epdkit_defconfig
+++ b/arch/arm/configs/am200epdkit_defconfig
@@ -3,7 +3,6 @@ CONFIG_LOCALVERSION="gum"
 CONFIG_SYSVIPC=y
 CONFIG_SYSFS_DEPRECATED_V2=y
 CONFIG_EXPERT=y
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_EPOLL is not set
 # CONFIG_SHMEM is not set
 # CONFIG_VM_EVENT_COUNTERS is not set
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 7b3832d..f36fda6 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -162,7 +162,7 @@
 146	common	writev			sys_writev
 147	common	getsid			sys_getsid
 148	common	fdatasync		sys_fdatasync
-149	common	_sysctl			sys_sysctl
+149	common	_sysctl			sys_ni_syscall
 150	common	mlock			sys_mlock
 151	common	munlock			sys_munlock
 152	common	mlockall		sys_mlockall
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index f8dafe9..ca41bb7 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -308,8 +308,8 @@
 __SYSCALL(__NR_getsid, sys_getsid)
 #define __NR_fdatasync 148
 __SYSCALL(__NR_fdatasync, sys_fdatasync)
-#define __NR__sysctl 149
-__SYSCALL(__NR__sysctl, compat_sys_sysctl)
+			/* 149 was sys_sysctl */
+__SYSCALL(149, sys_ni_syscall)
 #define __NR_mlock 150
 __SYSCALL(__NR_mlock, sys_mlock)
 #define __NR_munlock 151
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index 6636a1a..75b880b 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -135,7 +135,7 @@
 123	common	writev				sys_writev
 124	common	pread64				sys_pread64
 125	common	pwrite64			sys_pwrite64
-126	common	_sysctl				sys_sysctl
+126	common	_sysctl				sys_ni_syscall
 127	common	mmap				sys_mmap
 128	common	munmap				sys_munmap
 129	common	mlock				sys_mlock
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 8cd84a7..91b21ad 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -156,7 +156,7 @@
 146	common	writev				sys_writev
 147	common	getsid				sys_getsid
 148	common	fdatasync			sys_fdatasync
-149	common	_sysctl				sys_sysctl
+149	common	_sysctl				sys_ni_syscall
 150	common	mlock				sys_mlock
 151	common	munlock				sys_munlock
 152	common	mlockall			sys_mlockall
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index f581a02..dc5f9fb 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -156,7 +156,7 @@
 146	common	writev				sys_writev
 147	common	getsid				sys_getsid
 148	common	fdatasync			sys_fdatasync
-149	common	_sysctl				sys_sysctl
+149	common	_sysctl				sys_ni_syscall
 150	common	mlock				sys_mlock
 151	common	munlock				sys_munlock
 152	common	mlockall			sys_mlockall
diff --git a/arch/mips/configs/cu1000-neo_defconfig b/arch/mips/configs/cu1000-neo_defconfig
index 9b05a8f..244654c 100644
--- a/arch/mips/configs/cu1000-neo_defconfig
+++ b/arch/mips/configs/cu1000-neo_defconfig
@@ -17,7 +17,6 @@ CONFIG_CGROUP_CPUACCT=y
 CONFIG_NAMESPACES=y
 CONFIG_USER_NS=y
 CONFIG_CC_OPTIMIZE_FOR_SIZE=y
-CONFIG_SYSCTL_SYSCALL=y
 CONFIG_KALLSYMS_ALL=y
 CONFIG_EMBEDDED=y
 # CONFIG_VM_EVENT_COUNTERS is not set
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index c85bdc3..2653b28 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -159,7 +159,7 @@
 149	n32	munlockall			sys_munlockall
 150	n32	vhangup				sys_vhangup
 151	n32	pivot_root			sys_pivot_root
-152	n32	_sysctl				compat_sys_sysctl
+152	n32	_sysctl				sys_ni_syscall
 153	n32	prctl				sys_prctl
 154	n32	adjtimex			sys_adjtimex_time32
 155	n32	setrlimit			compat_sys_setrlimit
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 9e08c40..a4fd3bf 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -159,7 +159,7 @@
 149	n64	munlockall			sys_munlockall
 150	n64	vhangup				sys_vhangup
 151	n64	pivot_root			sys_pivot_root
-152	n64	_sysctl				sys_sysctl
+152	n64	_sysctl				sys_ni_syscall
 153	n64	prctl				sys_prctl
 154	n64	adjtimex			sys_adjtimex
 155	n64	setrlimit			sys_setrlimit
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index a2b591d..a30cfd4 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -164,7 +164,7 @@
 150	o32	unused150			sys_ni_syscall
 151	o32	getsid				sys_getsid
 152	o32	fdatasync			sys_fdatasync
-153	o32	_sysctl				sys_sysctl			compat_sys_sysctl
+153	o32	_sysctl				sys_ni_syscall
 154	o32	mlock				sys_mlock
 155	o32	munlock				sys_munlock
 156	o32	mlockall			sys_mlockall
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 98e7442..a47bc19 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -163,7 +163,7 @@
 146	common	writev			sys_writev			compat_sys_writev
 147	common	getsid			sys_getsid
 148	common	fdatasync		sys_fdatasync
-149	common	_sysctl			sys_sysctl			compat_sys_sysctl
+149	common	_sysctl			sys_ni_syscall
 150	common	mlock			sys_mlock
 151	common	munlock			sys_munlock
 152	common	mlockall		sys_mlockall
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 72fb9dd..a60163f 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -197,7 +197,7 @@
 146	common	writev				sys_writev			compat_sys_writev
 147	common	getsid				sys_getsid
 148	common	fdatasync			sys_fdatasync
-149	nospu	_sysctl				sys_sysctl			compat_sys_sysctl
+149	nospu	_sysctl				sys_ni_syscall
 150	common	mlock				sys_mlock
 151	common	munlock				sys_munlock
 152	common	mlockall			sys_mlockall
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index b731fcb..f17aaf6 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -138,7 +138,7 @@
 146  common	writev			sys_writev			compat_sys_writev
 147  common	getsid			sys_getsid			sys_getsid
 148  common	fdatasync		sys_fdatasync			sys_fdatasync
-149  common	_sysctl			sys_sysctl			compat_sys_sysctl
+149  common	_sysctl			sys_ni_syscall
 150  common	mlock			sys_mlock			sys_mlock
 151  common	munlock			sys_munlock			sys_munlock
 152  common	mlockall		sys_mlockall			sys_mlockall
diff --git a/arch/sh/configs/dreamcast_defconfig b/arch/sh/configs/dreamcast_defconfig
index ae067e0..6a82c7b 100644
--- a/arch/sh/configs/dreamcast_defconfig
+++ b/arch/sh/configs/dreamcast_defconfig
@@ -1,7 +1,6 @@
 CONFIG_SYSVIPC=y
 CONFIG_BSD_PROCESS_ACCT=y
 CONFIG_LOG_BUF_SHIFT=14
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_MODULES=y
diff --git a/arch/sh/configs/espt_defconfig b/arch/sh/configs/espt_defconfig
index a5b865a..9a988c3 100644
--- a/arch/sh/configs/espt_defconfig
+++ b/arch/sh/configs/espt_defconfig
@@ -5,7 +5,6 @@ CONFIG_LOG_BUF_SHIFT=14
 CONFIG_NAMESPACES=y
 CONFIG_UTS_NS=y
 CONFIG_IPC_NS=y
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_OPROFILE=y
diff --git a/arch/sh/configs/hp6xx_defconfig b/arch/sh/configs/hp6xx_defconfig
index a92db66..70e6605 100644
--- a/arch/sh/configs/hp6xx_defconfig
+++ b/arch/sh/configs/hp6xx_defconfig
@@ -3,7 +3,6 @@ CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 # CONFIG_BLK_DEV_BSG is not set
 CONFIG_CPU_SUBTYPE_SH7709=y
diff --git a/arch/sh/configs/landisk_defconfig b/arch/sh/configs/landisk_defconfig
index 567af75..ba6ec04 100644
--- a/arch/sh/configs/landisk_defconfig
+++ b/arch/sh/configs/landisk_defconfig
@@ -1,6 +1,5 @@
 CONFIG_SYSVIPC=y
 CONFIG_LOG_BUF_SHIFT=14
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_KALLSYMS_EXTRA_PASS=y
 CONFIG_SLAB=y
 CONFIG_MODULES=y
diff --git a/arch/sh/configs/lboxre2_defconfig b/arch/sh/configs/lboxre2_defconfig
index 10f6d37..05e4ac6 100644
--- a/arch/sh/configs/lboxre2_defconfig
+++ b/arch/sh/configs/lboxre2_defconfig
@@ -1,6 +1,5 @@
 CONFIG_SYSVIPC=y
 CONFIG_LOG_BUF_SHIFT=14
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_KALLSYMS_EXTRA_PASS=y
 CONFIG_SLAB=y
 CONFIG_MODULES=y
diff --git a/arch/sh/configs/microdev_defconfig b/arch/sh/configs/microdev_defconfig
index ed84d13..c65667d 100644
--- a/arch/sh/configs/microdev_defconfig
+++ b/arch/sh/configs/microdev_defconfig
@@ -2,7 +2,6 @@ CONFIG_BSD_PROCESS_ACCT=y
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 # CONFIG_BLK_DEV_BSG is not set
 CONFIG_CPU_SUBTYPE_SH4_202=y
diff --git a/arch/sh/configs/migor_defconfig b/arch/sh/configs/migor_defconfig
index 494a1675..dec9316 100644
--- a/arch/sh/configs/migor_defconfig
+++ b/arch/sh/configs/migor_defconfig
@@ -4,7 +4,6 @@ CONFIG_IKCONFIG_PROC=y
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_OPROFILE=y
diff --git a/arch/sh/configs/r7780mp_defconfig b/arch/sh/configs/r7780mp_defconfig
index 0a18f80..ff8f8d4 100644
--- a/arch/sh/configs/r7780mp_defconfig
+++ b/arch/sh/configs/r7780mp_defconfig
@@ -3,7 +3,6 @@ CONFIG_BSD_PROCESS_ACCT=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
 CONFIG_LOG_BUF_SHIFT=14
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_FUTEX is not set
 # CONFIG_EPOLL is not set
 CONFIG_SLAB=y
diff --git a/arch/sh/configs/r7785rp_defconfig b/arch/sh/configs/r7785rp_defconfig
index 7226ac5..d9afce5 100644
--- a/arch/sh/configs/r7785rp_defconfig
+++ b/arch/sh/configs/r7785rp_defconfig
@@ -7,7 +7,6 @@ CONFIG_RCU_TRACE=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
 CONFIG_LOG_BUF_SHIFT=14
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_OPROFILE=y
diff --git a/arch/sh/configs/rts7751r2d1_defconfig b/arch/sh/configs/rts7751r2d1_defconfig
index 6a3cfe0..fc9c221 100644
--- a/arch/sh/configs/rts7751r2d1_defconfig
+++ b/arch/sh/configs/rts7751r2d1_defconfig
@@ -1,7 +1,6 @@
 CONFIG_SYSVIPC=y
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_OPROFILE=y
diff --git a/arch/sh/configs/rts7751r2dplus_defconfig b/arch/sh/configs/rts7751r2dplus_defconfig
index 2b3d7d2..ff3fd678 100644
--- a/arch/sh/configs/rts7751r2dplus_defconfig
+++ b/arch/sh/configs/rts7751r2dplus_defconfig
@@ -1,7 +1,6 @@
 CONFIG_SYSVIPC=y
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_OPROFILE=y
diff --git a/arch/sh/configs/se7206_defconfig b/arch/sh/configs/se7206_defconfig
index a93402b..19f0dae 100644
--- a/arch/sh/configs/se7206_defconfig
+++ b/arch/sh/configs/se7206_defconfig
@@ -18,7 +18,6 @@ CONFIG_USER_NS=y
 CONFIG_PID_NS=y
 CONFIG_BLK_DEV_INITRD=y
 # CONFIG_UID16 is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_KALLSYMS_ALL=y
 # CONFIG_ELF_CORE is not set
 # CONFIG_COMPAT_BRK is not set
diff --git a/arch/sh/configs/se7343_defconfig b/arch/sh/configs/se7343_defconfig
index 06d067c..553c7aa 100644
--- a/arch/sh/configs/se7343_defconfig
+++ b/arch/sh/configs/se7343_defconfig
@@ -2,7 +2,6 @@
 CONFIG_SYSVIPC=y
 CONFIG_POSIX_MQUEUE=y
 CONFIG_LOG_BUF_SHIFT=14
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_FUTEX is not set
 # CONFIG_EPOLL is not set
 # CONFIG_SHMEM is not set
diff --git a/arch/sh/configs/se7619_defconfig b/arch/sh/configs/se7619_defconfig
index f54722d..baf1c84 100644
--- a/arch/sh/configs/se7619_defconfig
+++ b/arch/sh/configs/se7619_defconfig
@@ -1,7 +1,6 @@
 # CONFIG_LOCALVERSION_AUTO is not set
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_UID16 is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_KALLSYMS is not set
 # CONFIG_HOTPLUG is not set
 # CONFIG_ELF_CORE is not set
diff --git a/arch/sh/configs/se7705_defconfig b/arch/sh/configs/se7705_defconfig
index ddfc698..805966f 100644
--- a/arch/sh/configs/se7705_defconfig
+++ b/arch/sh/configs/se7705_defconfig
@@ -2,7 +2,6 @@
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_KALLSYMS is not set
 # CONFIG_HOTPLUG is not set
 CONFIG_SLAB=y
diff --git a/arch/sh/configs/se7750_defconfig b/arch/sh/configs/se7750_defconfig
index b23f675..3f1c137 100644
--- a/arch/sh/configs/se7750_defconfig
+++ b/arch/sh/configs/se7750_defconfig
@@ -5,7 +5,6 @@ CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_HOTPLUG is not set
 CONFIG_SLAB=y
 CONFIG_MODULES=y
diff --git a/arch/sh/configs/se7751_defconfig b/arch/sh/configs/se7751_defconfig
index 1623436..4a02406 100644
--- a/arch/sh/configs/se7751_defconfig
+++ b/arch/sh/configs/se7751_defconfig
@@ -3,7 +3,6 @@ CONFIG_BSD_PROCESS_ACCT=y
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_HOTPLUG is not set
 CONFIG_SLAB=y
 CONFIG_MODULES=y
diff --git a/arch/sh/configs/secureedge5410_defconfig b/arch/sh/configs/secureedge5410_defconfig
index 360592d..8422599 100644
--- a/arch/sh/configs/secureedge5410_defconfig
+++ b/arch/sh/configs/secureedge5410_defconfig
@@ -1,7 +1,6 @@
 # CONFIG_SWAP is not set
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_HOTPLUG is not set
 CONFIG_SLAB=y
 # CONFIG_BLK_DEV_BSG is not set
diff --git a/arch/sh/configs/sh03_defconfig b/arch/sh/configs/sh03_defconfig
index 87db9a8..f0073ed 100644
--- a/arch/sh/configs/sh03_defconfig
+++ b/arch/sh/configs/sh03_defconfig
@@ -3,7 +3,6 @@ CONFIG_POSIX_MQUEUE=y
 CONFIG_BSD_PROCESS_ACCT=y
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_OPROFILE=m
diff --git a/arch/sh/configs/sh7710voipgw_defconfig b/arch/sh/configs/sh7710voipgw_defconfig
index c86f284..12a1395 100644
--- a/arch/sh/configs/sh7710voipgw_defconfig
+++ b/arch/sh/configs/sh7710voipgw_defconfig
@@ -2,7 +2,6 @@
 CONFIG_SYSVIPC=y
 CONFIG_POSIX_MQUEUE=y
 CONFIG_LOG_BUF_SHIFT=14
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_FUTEX is not set
 # CONFIG_EPOLL is not set
 # CONFIG_SHMEM is not set
diff --git a/arch/sh/configs/sh7757lcr_defconfig b/arch/sh/configs/sh7757lcr_defconfig
index 9f2aed0..ca327d1 100644
--- a/arch/sh/configs/sh7757lcr_defconfig
+++ b/arch/sh/configs/sh7757lcr_defconfig
@@ -8,7 +8,6 @@ CONFIG_TASK_XACCT=y
 CONFIG_TASK_IO_ACCOUNTING=y
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_BLK_DEV_INITRD=y
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_KALLSYMS_ALL=y
 CONFIG_SLAB=y
 CONFIG_MODULES=y
diff --git a/arch/sh/configs/sh7763rdp_defconfig b/arch/sh/configs/sh7763rdp_defconfig
index d0a0aa7..26c5fd0 100644
--- a/arch/sh/configs/sh7763rdp_defconfig
+++ b/arch/sh/configs/sh7763rdp_defconfig
@@ -5,7 +5,6 @@ CONFIG_LOG_BUF_SHIFT=14
 CONFIG_NAMESPACES=y
 CONFIG_UTS_NS=y
 CONFIG_IPC_NS=y
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_PROFILING=y
 CONFIG_OPROFILE=y
diff --git a/arch/sh/configs/shmin_defconfig b/arch/sh/configs/shmin_defconfig
index d589cfd..5504ca4 100644
--- a/arch/sh/configs/shmin_defconfig
+++ b/arch/sh/configs/shmin_defconfig
@@ -1,7 +1,6 @@
 # CONFIG_SWAP is not set
 CONFIG_LOG_BUF_SHIFT=14
 # CONFIG_UID16 is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 # CONFIG_KALLSYMS is not set
 # CONFIG_HOTPLUG is not set
 # CONFIG_BUG is not set
diff --git a/arch/sh/configs/titan_defconfig b/arch/sh/configs/titan_defconfig
index 4ec961a..ba887f1 100644
--- a/arch/sh/configs/titan_defconfig
+++ b/arch/sh/configs/titan_defconfig
@@ -6,7 +6,6 @@ CONFIG_IKCONFIG_PROC=y
 CONFIG_LOG_BUF_SHIFT=16
 CONFIG_BLK_DEV_INITRD=y
 # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
-# CONFIG_SYSCTL_SYSCALL is not set
 CONFIG_SLAB=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
diff --git a/arch/sh/include/uapi/asm/unistd_64.h b/arch/sh/include/uapi/asm/unistd_64.h
index 75da548..04fe2ef 100644
--- a/arch/sh/include/uapi/asm/unistd_64.h
+++ b/arch/sh/include/uapi/asm/unistd_64.h
@@ -164,7 +164,7 @@
 #define __NR_writev		146
 #define __NR_getsid		147
 #define __NR_fdatasync		148
-#define __NR__sysctl		149
+				/* 149 was sys_sysctl */
 #define __NR_mlock		150
 #define __NR_munlock		151
 #define __NR_mlockall		152
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index e7a4804..7456845 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -156,7 +156,7 @@
 146	common	writev				sys_writev
 147	common	getsid				sys_getsid
 148	common	fdatasync			sys_fdatasync
-149	common	_sysctl				sys_sysctl
+149	common	_sysctl				sys_ni_syscall
 150	common	mlock				sys_mlock
 151	common	munlock				sys_munlock
 152	common	mlockall			sys_mlockall
diff --git a/arch/sh/kernel/syscalls_64.S b/arch/sh/kernel/syscalls_64.S
index 1bcb86f..e4c1d54 100644
--- a/arch/sh/kernel/syscalls_64.S
+++ b/arch/sh/kernel/syscalls_64.S
@@ -166,7 +166,7 @@ sys_call_table:
 	.long sys_writev
 	.long sys_getsid
 	.long sys_fdatasync
-	.long sys_sysctl
+	.long sys_ni_syscall	/* 149: for sys_sysctl */
 	.long sys_mlock			/* 150 */
 	.long sys_munlock
 	.long sys_mlockall
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index d6126ee..74adaeca 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -300,7 +300,7 @@
 249	64	nanosleep		sys_nanosleep
 250	32	mremap			sys_mremap
 250	64	mremap			sys_64_mremap
-251	common	_sysctl			sys_sysctl			compat_sys_sysctl
+251	common	_sysctl			sys_ni_syscall
 252	common	getsid			sys_getsid
 253	common	fdatasync		sys_fdatasync
 254	32	nfsservctl		sys_ni_syscall			sys_nis_syscall
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 686d59d..ef76360 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -160,7 +160,7 @@
 146	i386	writev			sys_writev			compat_sys_writev
 147	i386	getsid			sys_getsid
 148	i386	fdatasync		sys_fdatasync
-149	i386	_sysctl			sys_sysctl			compat_sys_sysctl
+149	i386	_sysctl			sys_ni_syscall
 150	i386	mlock			sys_mlock
 151	i386	munlock			sys_munlock
 152	i386	mlockall		sys_mlockall
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index b345b35..6a3b0b3 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -164,7 +164,7 @@
 153	common	vhangup			sys_vhangup
 154	common	modify_ldt		sys_modify_ldt
 155	common	pivot_root		sys_pivot_root
-156	64	_sysctl			sys_sysctl
+156	64	_sysctl			sys_ni_syscall
 157	common	prctl			sys_prctl
 158	common	arch_prctl		sys_arch_prctl
 159	common	adjtimex		sys_adjtimex
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 96cb070..34cbbf5 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -222,7 +222,7 @@
 204	common	quotactl			sys_quotactl
 # 205 was old nfsservctl
 205	common	nfsservctl			sys_ni_syscall
-206	common	_sysctl				sys_sysctl
+206	common	_sysctl				sys_ni_syscall
 207	common	bdflush				sys_bdflush
 208	common	uname				sys_newuname
 209	common	sysinfo				sys_sysinfo
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 86b61e8..c55d245 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -859,7 +859,6 @@ asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
 asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u32);
 asmlinkage long compat_sys_recv(int fd, void __user *buf, compat_size_t len,
 				unsigned flags);
-asmlinkage long compat_sys_sysctl(struct compat_sysctl_args __user *args);
 
 /* obsolete: fs/readdir.c */
 asmlinkage long compat_sys_old_readdir(unsigned int fd,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 63ffa6d..915233a 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -48,7 +48,6 @@
 struct statfs64;
 struct statx;
 struct fsinfo_params;
-struct __sysctl_args;
 struct sysinfo;
 struct timespec;
 struct __kernel_old_timeval;
@@ -1125,7 +1124,6 @@ asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events,
 asmlinkage long sys_bdflush(int func, long data);
 asmlinkage long sys_oldumount(char __user *name);
 asmlinkage long sys_uselib(const char __user *library);
-asmlinkage long sys_sysctl(struct __sysctl_args __user *args);
 asmlinkage long sys_sysfs(int option,
 				unsigned long arg1, unsigned long arg2);
 asmlinkage long sys_fork(void);
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 8112c15..299f9cb 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -90,15 +90,13 @@ int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
  * sysctl names can be mirrored automatically under /proc/sys.  The
  * procname supplied controls /proc naming.
  *
- * The table's mode will be honoured both for sys_sysctl(2) and
- * proc-fs access.
+ * The table's mode will be honoured for proc-fs access.
  *
  * Leaf nodes in the sysctl tree will be represented by a single file
  * under /proc; non-leaf nodes will be represented by directories.  A
  * null procname disables /proc mirroring at this node.
  *
- * sysctl(2) can automatically manage read and write requests through
- * the sysctl table.  The data and maxlen fields of the ctl_table
+ * The data and maxlen fields of the ctl_table
  * struct enable minimal validation of the values being written to be
  * performed, and the mode field allows minimal authentication.
  * 
diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
index 27c1ed2..84b44c3 100644
--- a/include/uapi/linux/sysctl.h
+++ b/include/uapi/linux/sysctl.h
@@ -27,21 +27,6 @@
 #include <linux/types.h>
 #include <linux/compiler.h>
 
-#define CTL_MAXNAME 10		/* how many path components do we allow in a
-				   call to sysctl?   In other words, what is
-				   the largest acceptable value for the nlen
-				   member of a struct __sysctl_args to have? */
-
-struct __sysctl_args {
-	int __user *name;
-	int nlen;
-	void __user *oldval;
-	size_t __user *oldlenp;
-	void __user *newval;
-	size_t newlen;
-	unsigned long __unused[4];
-};
-
 /* Define sysctl names first */
 
 /* Top-level names: */
diff --git a/kernel/Makefile b/kernel/Makefile
index 0bd4ed7..a3f7c08 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -5,7 +5,7 @@
 
 obj-y     = fork.o exec_domain.o panic.o \
 	    cpu.o exit.o softirq.o resource.o \
-	    sysctl.o sysctl_binary.o capability.o ptrace.o user.o \
+	    sysctl.o capability.o ptrace.o user.o \
 	    signal.o sys.o umh.o workqueue.o pid.o task_work.o \
 	    extable.o params.o \
 	    kthread.o sys_ni.o nsproxy.o \
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index fad48ac..c935c18 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -373,7 +373,6 @@ asmlinkage long sys_ni_syscall(void)
 COND_SYSCALL_COMPAT(socketcall);
 
 /* compat syscalls for arm64, x86, ... */
-COND_SYSCALL_COMPAT(sysctl);
 COND_SYSCALL_COMPAT(fanotify_mark);
 
 /* x86 */
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
deleted file mode 100644
index 7d550cc..00000000
--- a/kernel/sysctl_binary.c
+++ /dev/null
@@ -1,171 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/stat.h>
-#include <linux/sysctl.h>
-#include "../fs/xfs/xfs_sysctl.h"
-#include <linux/sunrpc/debug.h>
-#include <linux/string.h>
-#include <linux/syscalls.h>
-#include <linux/namei.h>
-#include <linux/mount.h>
-#include <linux/fs.h>
-#include <linux/nsproxy.h>
-#include <linux/pid_namespace.h>
-#include <linux/file.h>
-#include <linux/ctype.h>
-#include <linux/netdevice.h>
-#include <linux/kernel.h>
-#include <linux/uuid.h>
-#include <linux/slab.h>
-#include <linux/compat.h>
-
-static ssize_t binary_sysctl(const int *name, int nlen,
-	void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)
-{
-	return -ENOSYS;
-}
-
-static void deprecated_sysctl_warning(const int *name, int nlen)
-{
-	int i;
-
-	/*
-	 * CTL_KERN/KERN_VERSION is used by older glibc and cannot
-	 * ever go away.
-	 */
-	if (nlen >= 2 && name[0] == CTL_KERN && name[1] == KERN_VERSION)
-		return;
-
-	if (printk_ratelimit()) {
-		printk(KERN_INFO
-			"warning: process `%s' used the deprecated sysctl "
-			"system call with ", current->comm);
-		for (i = 0; i < nlen; i++)
-			printk(KERN_CONT "%d.", name[i]);
-		printk(KERN_CONT "\n");
-	}
-	return;
-}
-
-#define WARN_ONCE_HASH_BITS 8
-#define WARN_ONCE_HASH_SIZE (1<<WARN_ONCE_HASH_BITS)
-
-static DECLARE_BITMAP(warn_once_bitmap, WARN_ONCE_HASH_SIZE);
-
-#define FNV32_OFFSET 2166136261U
-#define FNV32_PRIME 0x01000193
-
-/*
- * Print each legacy sysctl (approximately) only once.
- * To avoid making the tables non-const use a external
- * hash-table instead.
- * Worst case hash collision: 6, but very rarely.
- * NOTE! We don't use the SMP-safe bit tests. We simply
- * don't care enough.
- */
-static void warn_on_bintable(const int *name, int nlen)
-{
-	int i;
-	u32 hash = FNV32_OFFSET;
-
-	for (i = 0; i < nlen; i++)
-		hash = (hash ^ name[i]) * FNV32_PRIME;
-	hash %= WARN_ONCE_HASH_SIZE;
-	if (__test_and_set_bit(hash, warn_once_bitmap))
-		return;
-	deprecated_sysctl_warning(name, nlen);
-}
-
-static ssize_t do_sysctl(int __user *args_name, int nlen,
-	void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)
-{
-	int name[CTL_MAXNAME];
-	int i;
-
-	/* Check args->nlen. */
-	if (nlen < 0 || nlen > CTL_MAXNAME)
-		return -ENOTDIR;
-	/* Read in the sysctl name for simplicity */
-	for (i = 0; i < nlen; i++)
-		if (get_user(name[i], args_name + i))
-			return -EFAULT;
-
-	warn_on_bintable(name, nlen);
-
-	return binary_sysctl(name, nlen, oldval, oldlen, newval, newlen);
-}
-
-SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
-{
-	struct __sysctl_args tmp;
-	size_t oldlen = 0;
-	ssize_t result;
-
-	if (copy_from_user(&tmp, args, sizeof(tmp)))
-		return -EFAULT;
-
-	if (tmp.oldval && !tmp.oldlenp)
-		return -EFAULT;
-
-	if (tmp.oldlenp && get_user(oldlen, tmp.oldlenp))
-		return -EFAULT;
-
-	result = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, oldlen,
-			   tmp.newval, tmp.newlen);
-
-	if (result >= 0) {
-		oldlen = result;
-		result = 0;
-	}
-
-	if (tmp.oldlenp && put_user(oldlen, tmp.oldlenp))
-		return -EFAULT;
-
-	return result;
-}
-
-
-#ifdef CONFIG_COMPAT
-
-struct compat_sysctl_args {
-	compat_uptr_t	name;
-	int		nlen;
-	compat_uptr_t	oldval;
-	compat_uptr_t	oldlenp;
-	compat_uptr_t	newval;
-	compat_size_t	newlen;
-	compat_ulong_t	__unused[4];
-};
-
-COMPAT_SYSCALL_DEFINE1(sysctl, struct compat_sysctl_args __user *, args)
-{
-	struct compat_sysctl_args tmp;
-	compat_size_t __user *compat_oldlenp;
-	size_t oldlen = 0;
-	ssize_t result;
-
-	if (copy_from_user(&tmp, args, sizeof(tmp)))
-		return -EFAULT;
-
-	if (tmp.oldval && !tmp.oldlenp)
-		return -EFAULT;
-
-	compat_oldlenp = compat_ptr(tmp.oldlenp);
-	if (compat_oldlenp && get_user(oldlen, compat_oldlenp))
-		return -EFAULT;
-
-	result = do_sysctl(compat_ptr(tmp.name), tmp.nlen,
-			   compat_ptr(tmp.oldval), oldlen,
-			   compat_ptr(tmp.newval), tmp.newlen);
-
-	if (result >= 0) {
-		oldlen = result;
-		result = 0;
-	}
-
-	if (compat_oldlenp && put_user(oldlen, compat_oldlenp))
-		return -EFAULT;
-
-	return result;
-}
-
-#endif /* CONFIG_COMPAT */
diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
index 35b61bf..6d29d9a 100644
--- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
@@ -193,7 +193,7 @@
 146	common	writev				sys_writev			compat_sys_writev
 147	common	getsid				sys_getsid
 148	common	fdatasync			sys_fdatasync
-149	nospu	_sysctl				sys_sysctl			compat_sys_sysctl
+149	nospu	_sysctl				sys_ni_syscall
 150	common	mlock				sys_mlock
 151	common	munlock				sys_munlock
 152	common	mlockall			sys_mlockall
diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
index b38d484..0193f9b 100644
--- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
@@ -138,7 +138,7 @@
 146  common	writev			sys_writev			compat_sys_writev
 147  common	getsid			sys_getsid			sys_getsid
 148  common	fdatasync		sys_fdatasync			sys_fdatasync
-149  common	_sysctl			sys_sysctl			compat_sys_sysctl
+149  common	_sysctl			sys_ni_syscall
 150  common	mlock			sys_mlock			compat_sys_mlock
 151  common	munlock			sys_munlock			compat_sys_munlock
 152  common	mlockall		sys_mlockall			sys_mlockall
diff --git a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
index 37b844f..4e50062 100644
--- a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
@@ -164,7 +164,7 @@
 153	common	vhangup			sys_vhangup
 154	common	modify_ldt		sys_modify_ldt
 155	common	pivot_root		sys_pivot_root
-156	64	_sysctl			sys_sysctl
+156	64	_sysctl			sys_ni_syscall
 157	common	prctl			sys_prctl
 158	common	arch_prctl		sys_arch_prctl
 159	common	adjtimex		sys_adjtimex
-- 
1.8.5.6

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Stephen Rothwell]

[-- Attachment #1: Type: text/plain, Size: 1962 bytes --]

Hi Xiaoming,

On Thu, 11 Jun 2020 11:54:00 +0800 Xiaoming Ni <nixiaoming@huawei.com> wrote:
>
>  arch/sh/configs/dreamcast_defconfig                |   1 -
>  arch/sh/configs/espt_defconfig                     |   1 -
>  arch/sh/configs/hp6xx_defconfig                    |   1 -
>  arch/sh/configs/landisk_defconfig                  |   1 -
>  arch/sh/configs/lboxre2_defconfig                  |   1 -
>  arch/sh/configs/microdev_defconfig                 |   1 -
>  arch/sh/configs/migor_defconfig                    |   1 -
>  arch/sh/configs/r7780mp_defconfig                  |   1 -
>  arch/sh/configs/r7785rp_defconfig                  |   1 -
>  arch/sh/configs/rts7751r2d1_defconfig              |   1 -
>  arch/sh/configs/rts7751r2dplus_defconfig           |   1 -
>  arch/sh/configs/se7206_defconfig                   |   1 -
>  arch/sh/configs/se7343_defconfig                   |   1 -
>  arch/sh/configs/se7619_defconfig                   |   1 -
>  arch/sh/configs/se7705_defconfig                   |   1 -
>  arch/sh/configs/se7750_defconfig                   |   1 -
>  arch/sh/configs/se7751_defconfig                   |   1 -
>  arch/sh/configs/secureedge5410_defconfig           |   1 -
>  arch/sh/configs/sh03_defconfig                     |   1 -
>  arch/sh/configs/sh7710voipgw_defconfig             |   1 -
>  arch/sh/configs/sh7757lcr_defconfig                |   1 -
>  arch/sh/configs/sh7763rdp_defconfig                |   1 -
>  arch/sh/configs/shmin_defconfig                    |   1 -
>  arch/sh/configs/titan_defconfig                    |   1 -
>  arch/sh/include/uapi/asm/unistd_64.h               |   2 +-
>  arch/sh/kernel/syscalls/syscall.tbl                |   2 +-
>  arch/sh/kernel/syscalls_64.S                       |   2 +-

You might want to rebase this onto v5.8-rc1 when it is released this
weekend as the 64bit sh code (sh5) has been removed.

-- 
Cheers,
Stephen Rothwell

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Will Deacon]

On Thu, Jun 11, 2020 at 11:54:00AM +0800, Xiaoming Ni wrote:
> Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
> sys_sysctl is actually unavailable: any input can only return an error.
> 
> We have been warning about people using the sysctl system call for years
> and believe there are no more users.  Even if there are users of this
> interface if they have not complained or fixed their code by now they
> probably are not going to, so there is no point in warning them any
> longer.
> 
> So completely remove sys_sysctl on all architectures.
> 
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> 
> changes in v2:
>   According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
>   According to Eric W. Biederman's suggestion, update the commit log
> 
> V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
>   Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
> ---
>  arch/alpha/kernel/syscalls/syscall.tbl             |   2 +-
>  arch/arm/configs/am200epdkit_defconfig             |   1 -
>  arch/arm/tools/syscall.tbl                         |   2 +-
>  arch/arm64/include/asm/unistd32.h                  |   4 +-

For the arm/arm64 parts:

Acked-by: Will Deacon <will@kernel.org>

Will

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Eric W. Biederman]

Xiaoming Ni <nixiaoming@huawei.com> writes:

> Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
> sys_sysctl is actually unavailable: any input can only return an error.
>
> We have been warning about people using the sysctl system call for years
> and believe there are no more users.  Even if there are users of this
> interface if they have not complained or fixed their code by now they
> probably are not going to, so there is no point in warning them any
> longer.
>
> So completely remove sys_sysctl on all architectures.



>
> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>
> changes in v2:
>   According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
>   According to Eric W. Biederman's suggestion, update the commit log
>
> V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
>   Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
> ---
>  include/uapi/linux/sysctl.h                        |  15 --
[snip]

> diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
> index 27c1ed2..84b44c3 100644
> --- a/include/uapi/linux/sysctl.h
> +++ b/include/uapi/linux/sysctl.h
> @@ -27,21 +27,6 @@
>  #include <linux/types.h>
>  #include <linux/compiler.h>
>  
> -#define CTL_MAXNAME 10		/* how many path components do we allow in a
> -				   call to sysctl?   In other words, what is
> -				   the largest acceptable value for the nlen
> -				   member of a struct __sysctl_args to have? */
> -
> -struct __sysctl_args {
> -	int __user *name;
> -	int nlen;
> -	void __user *oldval;
> -	size_t __user *oldlenp;
> -	void __user *newval;
> -	size_t newlen;
> -	unsigned long __unused[4];
> -};
> -
>  /* Define sysctl names first */
>  
>  /* Top-level names: */
[snip]

The uapi header change does not make sense.  The entire point of the
header is to allow userspace programs to be able to call sys_sysctl.
It either needs to all stay or all go.

As the concern with the uapi header is about userspace programs being
able to compile please leave the header for now.

We should leave auditing userspace and seeing if userspace code will
still compile if we remove this header for a separate patch.  The
concerns and justifications for the uapi header are completely different
then for the removing the sys_sysctl implementation.

Otherwise
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>


Eric

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Rich Felker]

On Thu, Jun 11, 2020 at 06:43:00AM -0500, Eric W. Biederman wrote:
> Xiaoming Ni <nixiaoming@huawei.com> writes:
> 
> > Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
> > sys_sysctl is actually unavailable: any input can only return an error.
> >
> > We have been warning about people using the sysctl system call for years
> > and believe there are no more users.  Even if there are users of this
> > interface if they have not complained or fixed their code by now they
> > probably are not going to, so there is no point in warning them any
> > longer.
> >
> > So completely remove sys_sysctl on all architectures.
> 
> 
> 
> >
> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> >
> > changes in v2:
> >   According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
> >   According to Eric W. Biederman's suggestion, update the commit log
> >
> > V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
> >   Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
> > ---
> >  include/uapi/linux/sysctl.h                        |  15 --
> [snip]
> 
> > diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
> > index 27c1ed2..84b44c3 100644
> > --- a/include/uapi/linux/sysctl.h
> > +++ b/include/uapi/linux/sysctl.h
> > @@ -27,21 +27,6 @@
> >  #include <linux/types.h>
> >  #include <linux/compiler.h>
> >  
> > -#define CTL_MAXNAME 10		/* how many path components do we allow in a
> > -				   call to sysctl?   In other words, what is
> > -				   the largest acceptable value for the nlen
> > -				   member of a struct __sysctl_args to have? */
> > -
> > -struct __sysctl_args {
> > -	int __user *name;
> > -	int nlen;
> > -	void __user *oldval;
> > -	size_t __user *oldlenp;
> > -	void __user *newval;
> > -	size_t newlen;
> > -	unsigned long __unused[4];
> > -};
> > -
> >  /* Define sysctl names first */
> >  
> >  /* Top-level names: */
> [snip]
> 
> The uapi header change does not make sense.  The entire point of the
> header is to allow userspace programs to be able to call sys_sysctl.
> It either needs to all stay or all go.
> 
> As the concern with the uapi header is about userspace programs being
> able to compile please leave the header for now.
> 
> We should leave auditing userspace and seeing if userspace code will
> still compile if we remove this header for a separate patch.  The
> concerns and justifications for the uapi header are completely different
> then for the removing the sys_sysctl implementation.
> 
> Otherwise
> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>

The UAPI header should be kept because it's defining an API not just
for the kernel the headers are supplied with, but for all past
kernels. In particular programs needing a failsafe CSPRNG source that
works on old kernels may (do) use this as a fallback only if modern
syscalls are missing. Removing the syscall is no problem since it
won't be used, but if you remove the types/macros from the UAPI
headers, they'll have to copy that into their own sources.

Rich

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Eric W. Biederman]

Rich Felker <dalias@libc.org> writes:

> On Thu, Jun 11, 2020 at 06:43:00AM -0500, Eric W. Biederman wrote:
>> Xiaoming Ni <nixiaoming@huawei.com> writes:
>> 
>> > Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
>> > sys_sysctl is actually unavailable: any input can only return an error.
>> >
>> > We have been warning about people using the sysctl system call for years
>> > and believe there are no more users.  Even if there are users of this
>> > interface if they have not complained or fixed their code by now they
>> > probably are not going to, so there is no point in warning them any
>> > longer.
>> >
>> > So completely remove sys_sysctl on all architectures.
>> 
>> 
>> 
>> >
>> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>> >
>> > changes in v2:
>> >   According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
>> >   According to Eric W. Biederman's suggestion, update the commit log
>> >
>> > V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
>> >   Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
>> > ---
>> >  include/uapi/linux/sysctl.h                        |  15 --
>> [snip]
>> 
>> > diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
>> > index 27c1ed2..84b44c3 100644
>> > --- a/include/uapi/linux/sysctl.h
>> > +++ b/include/uapi/linux/sysctl.h
>> > @@ -27,21 +27,6 @@
>> >  #include <linux/types.h>
>> >  #include <linux/compiler.h>
>> >  
>> > -#define CTL_MAXNAME 10		/* how many path components do we allow in a
>> > -				   call to sysctl?   In other words, what is
>> > -				   the largest acceptable value for the nlen
>> > -				   member of a struct __sysctl_args to have? */
>> > -
>> > -struct __sysctl_args {
>> > -	int __user *name;
>> > -	int nlen;
>> > -	void __user *oldval;
>> > -	size_t __user *oldlenp;
>> > -	void __user *newval;
>> > -	size_t newlen;
>> > -	unsigned long __unused[4];
>> > -};
>> > -
>> >  /* Define sysctl names first */
>> >  
>> >  /* Top-level names: */
>> [snip]
>> 
>> The uapi header change does not make sense.  The entire point of the
>> header is to allow userspace programs to be able to call sys_sysctl.
>> It either needs to all stay or all go.
>> 
>> As the concern with the uapi header is about userspace programs being
>> able to compile please leave the header for now.
>> 
>> We should leave auditing userspace and seeing if userspace code will
>> still compile if we remove this header for a separate patch.  The
>> concerns and justifications for the uapi header are completely different
>> then for the removing the sys_sysctl implementation.
>> 
>> Otherwise
>> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
>
> The UAPI header should be kept because it's defining an API not just
> for the kernel the headers are supplied with, but for all past
> kernels. In particular programs needing a failsafe CSPRNG source that
> works on old kernels may (do) use this as a fallback only if modern
> syscalls are missing. Removing the syscall is no problem since it
> won't be used, but if you remove the types/macros from the UAPI
> headers, they'll have to copy that into their own sources.

May we assume you know of a least one piece of userspace that will fail
to compile if this header file is removed?

Eric

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Rich Felker]

On Thu, Jun 11, 2020 at 12:01:11PM -0500, Eric W. Biederman wrote:
> Rich Felker <dalias@libc.org> writes:
> 
> > On Thu, Jun 11, 2020 at 06:43:00AM -0500, Eric W. Biederman wrote:
> >> Xiaoming Ni <nixiaoming@huawei.com> writes:
> >> 
> >> > Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
> >> > sys_sysctl is actually unavailable: any input can only return an error.
> >> >
> >> > We have been warning about people using the sysctl system call for years
> >> > and believe there are no more users.  Even if there are users of this
> >> > interface if they have not complained or fixed their code by now they
> >> > probably are not going to, so there is no point in warning them any
> >> > longer.
> >> >
> >> > So completely remove sys_sysctl on all architectures.
> >> 
> >> 
> >> 
> >> >
> >> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> >> >
> >> > changes in v2:
> >> >   According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
> >> >   According to Eric W. Biederman's suggestion, update the commit log
> >> >
> >> > V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
> >> >   Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
> >> > ---
> >> >  include/uapi/linux/sysctl.h                        |  15 --
> >> [snip]
> >> 
> >> > diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
> >> > index 27c1ed2..84b44c3 100644
> >> > --- a/include/uapi/linux/sysctl.h
> >> > +++ b/include/uapi/linux/sysctl.h
> >> > @@ -27,21 +27,6 @@
> >> >  #include <linux/types.h>
> >> >  #include <linux/compiler.h>
> >> >  
> >> > -#define CTL_MAXNAME 10		/* how many path components do we allow in a
> >> > -				   call to sysctl?   In other words, what is
> >> > -				   the largest acceptable value for the nlen
> >> > -				   member of a struct __sysctl_args to have? */
> >> > -
> >> > -struct __sysctl_args {
> >> > -	int __user *name;
> >> > -	int nlen;
> >> > -	void __user *oldval;
> >> > -	size_t __user *oldlenp;
> >> > -	void __user *newval;
> >> > -	size_t newlen;
> >> > -	unsigned long __unused[4];
> >> > -};
> >> > -
> >> >  /* Define sysctl names first */
> >> >  
> >> >  /* Top-level names: */
> >> [snip]
> >> 
> >> The uapi header change does not make sense.  The entire point of the
> >> header is to allow userspace programs to be able to call sys_sysctl.
> >> It either needs to all stay or all go.
> >> 
> >> As the concern with the uapi header is about userspace programs being
> >> able to compile please leave the header for now.
> >> 
> >> We should leave auditing userspace and seeing if userspace code will
> >> still compile if we remove this header for a separate patch.  The
> >> concerns and justifications for the uapi header are completely different
> >> then for the removing the sys_sysctl implementation.
> >> 
> >> Otherwise
> >> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
> >
> > The UAPI header should be kept because it's defining an API not just
> > for the kernel the headers are supplied with, but for all past
> > kernels. In particular programs needing a failsafe CSPRNG source that
> > works on old kernels may (do) use this as a fallback only if modern
> > syscalls are missing. Removing the syscall is no problem since it
> > won't be used, but if you remove the types/macros from the UAPI
> > headers, they'll have to copy that into their own sources.
> 
> May we assume you know of a least one piece of userspace that will fail
> to compile if this header file is removed?

I know at least one piece of software is using SYS_sysctl for a
fallback CSPRNG source. I'm not 100% sure that they're using the
kernel headers; they might have copied it already. I'm also not sure
how many there are.

Regardless, I think the principle stands. There's no need to remove
definitions that are essentially maintenance-free now that the
interface is no longer available in new kernels, and doing so
contributes to the myth that you're supposed to use kernel headers
matching runtime kernel rather than it always being safe to use latest
headers.

Rich

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Eric W. Biederman]

Rich Felker <dalias@libc.org> writes:

> On Thu, Jun 11, 2020 at 12:01:11PM -0500, Eric W. Biederman wrote:
>> Rich Felker <dalias@libc.org> writes:
>> 
>> > On Thu, Jun 11, 2020 at 06:43:00AM -0500, Eric W. Biederman wrote:
>> >> Xiaoming Ni <nixiaoming@huawei.com> writes:
>> >> 
>> >> > Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
>> >> > sys_sysctl is actually unavailable: any input can only return an error.
>> >> >
>> >> > We have been warning about people using the sysctl system call for years
>> >> > and believe there are no more users.  Even if there are users of this
>> >> > interface if they have not complained or fixed their code by now they
>> >> > probably are not going to, so there is no point in warning them any
>> >> > longer.
>> >> >
>> >> > So completely remove sys_sysctl on all architectures.
>> >> 
>> >> 
>> >> 
>> >> >
>> >> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>> >> >
>> >> > changes in v2:
>> >> >   According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
>> >> >   According to Eric W. Biederman's suggestion, update the commit log
>> >> >
>> >> > V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
>> >> >   Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
>> >> > ---
>> >> >  include/uapi/linux/sysctl.h                        |  15 --
>> >> [snip]
>> >> 
>> >> > diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
>> >> > index 27c1ed2..84b44c3 100644
>> >> > --- a/include/uapi/linux/sysctl.h
>> >> > +++ b/include/uapi/linux/sysctl.h
>> >> > @@ -27,21 +27,6 @@
>> >> >  #include <linux/types.h>
>> >> >  #include <linux/compiler.h>
>> >> >  
>> >> > -#define CTL_MAXNAME 10		/* how many path components do we allow in a
>> >> > -				   call to sysctl?   In other words, what is
>> >> > -				   the largest acceptable value for the nlen
>> >> > -				   member of a struct __sysctl_args to have? */
>> >> > -
>> >> > -struct __sysctl_args {
>> >> > -	int __user *name;
>> >> > -	int nlen;
>> >> > -	void __user *oldval;
>> >> > -	size_t __user *oldlenp;
>> >> > -	void __user *newval;
>> >> > -	size_t newlen;
>> >> > -	unsigned long __unused[4];
>> >> > -};
>> >> > -
>> >> >  /* Define sysctl names first */
>> >> >  
>> >> >  /* Top-level names: */
>> >> [snip]
>> >> 
>> >> The uapi header change does not make sense.  The entire point of the
>> >> header is to allow userspace programs to be able to call sys_sysctl.
>> >> It either needs to all stay or all go.
>> >> 
>> >> As the concern with the uapi header is about userspace programs being
>> >> able to compile please leave the header for now.
>> >> 
>> >> We should leave auditing userspace and seeing if userspace code will
>> >> still compile if we remove this header for a separate patch.  The
>> >> concerns and justifications for the uapi header are completely different
>> >> then for the removing the sys_sysctl implementation.
>> >> 
>> >> Otherwise
>> >> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
>> >
>> > The UAPI header should be kept because it's defining an API not just
>> > for the kernel the headers are supplied with, but for all past
>> > kernels. In particular programs needing a failsafe CSPRNG source that
>> > works on old kernels may (do) use this as a fallback only if modern
>> > syscalls are missing. Removing the syscall is no problem since it
>> > won't be used, but if you remove the types/macros from the UAPI
>> > headers, they'll have to copy that into their own sources.
>> 
>> May we assume you know of a least one piece of userspace that will fail
>> to compile if this header file is removed?
>
> I know at least one piece of software is using SYS_sysctl for a
> fallback CSPRNG source. I'm not 100% sure that they're using the
> kernel headers; they might have copied it already. I'm also not sure
> how many there are.
>
> Regardless, I think the principle stands. There's no need to remove
> definitions that are essentially maintenance-free now that the
> interface is no longer available in new kernels, and doing so
> contributes to the myth that you're supposed to use kernel headers
> matching runtime kernel rather than it always being safe to use latest
> headers.

If there is no one using the definitions removing them saves people
having to remember what they are there for.

The big rule is don't break userspace.  The goal is to allow people to
upgrade their kernel without needing to worry about userspace breaking,
and to be able to downgrade to the extent possible to help in tracking
bugs.

Not being able to compile userspace seems like a pretty clear cut case.
Although there are some fuzzy edges given the history of the kernel
headers.  Things like your libc requiring kernel headers to be processed
before they can be used.  I think there are still some kernel headers
that have that restriction when used with glibc as glibc uses different
sizes for types like dev_t.

The bottom line is we can't do it casually so that any work in the
direction of removing from or deleting uapi headers needs to be it's own
separate patch.

Given how much effort it can be to show that userspace is not using
something I don't expect us to be mucking with the uapi headers any time
soon.

Eric

Re: [PATCH v2] All arch: remove system call sys_sysctl

[Xiaoming Ni]

On 2020/6/12 2:23, Eric W. Biederman wrote:
> Rich Felker <dalias@libc.org> writes:
> 
>> On Thu, Jun 11, 2020 at 12:01:11PM -0500, Eric W. Biederman wrote:
>>> Rich Felker <dalias@libc.org> writes:
>>>
>>>> On Thu, Jun 11, 2020 at 06:43:00AM -0500, Eric W. Biederman wrote:
>>>>> Xiaoming Ni <nixiaoming@huawei.com> writes:
>>>>>
>>>>>> Since the commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
>>>>>> sys_sysctl is actually unavailable: any input can only return an error.
>>>>>>
>>>>>> We have been warning about people using the sysctl system call for years
>>>>>> and believe there are no more users.  Even if there are users of this
>>>>>> interface if they have not complained or fixed their code by now they
>>>>>> probably are not going to, so there is no point in warning them any
>>>>>> longer.
>>>>>>
>>>>>> So completely remove sys_sysctl on all architectures.
>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>> Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
>>>>>>
>>>>>> changes in v2:
>>>>>>    According to Kees Cook's suggestion, completely remove sys_sysctl on all arch
>>>>>>    According to Eric W. Biederman's suggestion, update the commit log
>>>>>>
>>>>>> V1: https://lore.kernel.org/lkml/1591683605-8585-1-git-send-email-nixiaoming@huawei.com/
>>>>>>    Delete the code of sys_sysctl and return -ENOSYS directly at the function entry
>>>>>> ---
>>>>>>   include/uapi/linux/sysctl.h                        |  15 --
>>>>> [snip]
>>>>>
>>>>>> diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
>>>>>> index 27c1ed2..84b44c3 100644
>>>>>> --- a/include/uapi/linux/sysctl.h
>>>>>> +++ b/include/uapi/linux/sysctl.h
>>>>>> @@ -27,21 +27,6 @@
>>>>>>   #include <linux/types.h>
>>>>>>   #include <linux/compiler.h>
>>>>>>   
>>>>>> -#define CTL_MAXNAME 10		/* how many path components do we allow in a
>>>>>> -				   call to sysctl?   In other words, what is
>>>>>> -				   the largest acceptable value for the nlen
>>>>>> -				   member of a struct __sysctl_args to have? */
>>>>>> -
>>>>>> -struct __sysctl_args {
>>>>>> -	int __user *name;
>>>>>> -	int nlen;
>>>>>> -	void __user *oldval;
>>>>>> -	size_t __user *oldlenp;
>>>>>> -	void __user *newval;
>>>>>> -	size_t newlen;
>>>>>> -	unsigned long __unused[4];
>>>>>> -};
>>>>>> -
>>>>>>   /* Define sysctl names first */
>>>>>>   
>>>>>>   /* Top-level names: */
>>>>> [snip]
>>>>>
>>>>> The uapi header change does not make sense.  The entire point of the
>>>>> header is to allow userspace programs to be able to call sys_sysctl.
>>>>> It either needs to all stay or all go.
>>>>>
>>>>> As the concern with the uapi header is about userspace programs being
>>>>> able to compile please leave the header for now.
>>>>>
>>>>> We should leave auditing userspace and seeing if userspace code will
>>>>> still compile if we remove this header for a separate patch.  The
>>>>> concerns and justifications for the uapi header are completely different
>>>>> then for the removing the sys_sysctl implementation.
>>>>>
>>>>> Otherwise
>>>>> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
>>>>
>>>> The UAPI header should be kept because it's defining an API not just
>>>> for the kernel the headers are supplied with, but for all past
>>>> kernels. In particular programs needing a failsafe CSPRNG source that
>>>> works on old kernels may (do) use this as a fallback only if modern
>>>> syscalls are missing. Removing the syscall is no problem since it
>>>> won't be used, but if you remove the types/macros from the UAPI
>>>> headers, they'll have to copy that into their own sources.
>>>
>>> May we assume you know of a least one piece of userspace that will fail
>>> to compile if this header file is removed?
>>
>> I know at least one piece of software is using SYS_sysctl for a
>> fallback CSPRNG source. I'm not 100% sure that they're using the
>> kernel headers; they might have copied it already. I'm also not sure
>> how many there are.
>>
>> Regardless, I think the principle stands. There's no need to remove
>> definitions that are essentially maintenance-free now that the
>> interface is no longer available in new kernels, and doing so
>> contributes to the myth that you're supposed to use kernel headers
>> matching runtime kernel rather than it always being safe to use latest
>> headers.
> 
> If there is no one using the definitions removing them saves people
> having to remember what they are there for.
> 
> The big rule is don't break userspace.  The goal is to allow people to
> upgrade their kernel without needing to worry about userspace breaking,
> and to be able to downgrade to the extent possible to help in tracking
> bugs.
> 
> Not being able to compile userspace seems like a pretty clear cut case.
> Although there are some fuzzy edges given the history of the kernel
> headers.  Things like your libc requiring kernel headers to be processed
> before they can be used.  I think there are still some kernel headers
> that have that restriction when used with glibc as glibc uses different
> sizes for types like dev_t.
> 
> The bottom line is we can't do it casually so that any work in the
> direction of removing from or deleting uapi headers needs to be it's own
> separate patch.
> 
> Given how much effort it can be to show that userspace is not using
> something I don't expect us to be mucking with the uapi headers any time
> soon.
> 
> Eric
> 

Thanks everyone for your guidance, I will delete the update of uapi file 
in v3 version.

But here I am still a bit confused: how to modify include/uapi?

Before commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
most of the enumeration variables defined in include/uapi/linux/sysctl.h
were used in kernel/sysctl_binary.c,
After commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"),
the code for enumerating variables in include/uapi/linux/sysctl.h cannot
be found in the current git repository

 From the management of a single git repository, we can immediately 
delete include/uapi/linux/sysctl.h for the reason of deleting unused 
code. But from the complex cooperation of linux/libc/ltp/man/xxxx, it 
may take a long time to modify uapi.

Is there any example for the update of uapi? How to control the rhythm?
How to update uapi?

Thanks
Xiaoming Ni