vdso: Remove struct getcpu_cache

The cache parameter of getcpu() is useless nowadays for various reasons.

  * It is never passed by userspace for either the vDSO or syscalls.
  * It is never used by the kernel.
  * It could not be made to work on the current vDSO architecture.
  * The structure definition is not part of the UAPI headers.
  * vdso_getcpu() is superseded by restartable sequences in any case.

Remove the struct and its header.

As a side-effect this gets rid of an unwanted inclusion of the linux/
header namespace from vDSO code.

[ tglx: Adapt to s390 upstream changes */

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Link: https://patch.msgid.link/20251230-getcpu_cache-v3-1-fb9c5f880ebe@linutronix.de

diff --git a/arch/loongarch/vdso/vgetcpu.c b/arch/loongarch/vdso/vgetcpu.c
index 73af49242ecdc8112007262ff711d14d1f342fa1..6f054ec898c73b1ef30b28cfa89298cfe27d9257 100644 (file)
--- a/arch/loongarch/vdso/vgetcpu.c
+++ b/arch/loongarch/vdso/vgetcpu.c
@@ -4,7 +4,6 @@
  */
 
 #include <asm/vdso.h>
-#include <linux/getcpu.h>
 
 static __always_inline int read_cpu_id(void)
 {
@@ -28,8 +27,8 @@ static __always_inline int read_cpu_id(void)
 }
 
 extern
-int __vdso_getcpu(unsigned int *cpu, unsigned int *node, struct getcpu_cache *unused);
-int __vdso_getcpu(unsigned int *cpu, unsigned int *node, struct getcpu_cache *unused)
+int __vdso_getcpu(unsigned int *cpu, unsigned int *node, void *unused);
+int __vdso_getcpu(unsigned int *cpu, unsigned int *node, void *unused)
 {
        int cpu_id;
 

diff --git a/arch/s390/kernel/vdso/getcpu.c b/arch/s390/kernel/vdso/getcpu.c
index 5c5d4a848b7669436e73df8e3b711e5b876eb3db..1e17665616c5fa766ca66c8de276b212528934bd 100644 (file)
--- a/arch/s390/kernel/vdso/getcpu.c
+++ b/arch/s390/kernel/vdso/getcpu.c
@@ -2,11 +2,10 @@
 /* Copyright IBM Corp. 2020 */
 
 #include <linux/compiler.h>
-#include <linux/getcpu.h>
 #include <asm/timex.h>
 #include "vdso.h"
 
-int __s390_vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
+int __s390_vdso_getcpu(unsigned *cpu, unsigned *node, void *unused)
 {
        union tod_clock clk;
 

diff --git a/arch/s390/kernel/vdso/vdso.h b/arch/s390/kernel/vdso/vdso.h
index 8cff033dd854c1dbeb3bf26ad02ee667288d25b4..1fe52a6f5a564ac381aafb552b34e84003986c74 100644 (file)
--- a/arch/s390/kernel/vdso/vdso.h
+++ b/arch/s390/kernel/vdso/vdso.h
@@ -4,9 +4,7 @@
 
 #include <vdso/datapage.h>
 
-struct getcpu_cache;
-
-int __s390_vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused);
+int __s390_vdso_getcpu(unsigned *cpu, unsigned *node, void *unused);
 int __s390_vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
 int __s390_vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
 int __s390_vdso_clock_getres(clockid_t clock, struct __kernel_timespec *ts);

diff --git a/arch/x86/entry/vdso/vgetcpu.c b/arch/x86/entry/vdso/vgetcpu.c
index e4640306b2e3c95d74d73037ab6b09294b8e1d6c..6381b472b7c52487bccf3cbf0664c3d7a0e59699 100644 (file)
--- a/arch/x86/entry/vdso/vgetcpu.c
+++ b/arch/x86/entry/vdso/vgetcpu.c
@@ -6,17 +6,16 @@
  */
 
 #include <linux/kernel.h>
-#include <linux/getcpu.h>
 #include <asm/segment.h>
 #include <vdso/processor.h>
 
 notrace long
-__vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
+__vdso_getcpu(unsigned *cpu, unsigned *node, void *unused)
 {
        vdso_read_cpunode(cpu, node);
 
        return 0;
 }
 
-long getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
+long getcpu(unsigned *cpu, unsigned *node, void *tcache)
        __attribute__((weak, alias("__vdso_getcpu")));

diff --git a/arch/x86/include/asm/vdso/processor.h b/arch/x86/include/asm/vdso/processor.h
index 7000aeb59aa287e2119c3d43ab3eaf82befb59c4..93e0e24e5cb47f7b0056c13f2a7f2304ed4a0595 100644 (file)
--- a/arch/x86/include/asm/vdso/processor.h
+++ b/arch/x86/include/asm/vdso/processor.h
@@ -18,9 +18,7 @@ static __always_inline void cpu_relax(void)
        native_pause();
 }
 
-struct getcpu_cache;
-
-notrace long __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused);
+notrace long __vdso_getcpu(unsigned *cpu, unsigned *node, void *unused);
 
 #endif /* __ASSEMBLER__ */
 

diff --git a/include/linux/getcpu.h b/include/linux/getcpu.h
deleted file mode 100644 (file)
index c304dcd..0000000
--- a/include/linux/getcpu.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _LINUX_GETCPU_H
-#define _LINUX_GETCPU_H 1
-
-/* Cache for getcpu() to speed it up. Results might be a short time
-   out of date, but will be faster.
-
-   User programs should not refer to the contents of this structure.
-   I repeat they should not refer to it. If they do they will break
-   in future kernels.
-
-   It is only a private cache for vgetcpu(). It will change in future kernels.
-   The user program must store this information per thread (__thread)
-   If you want 100% accurate information pass NULL instead. */
-struct getcpu_cache {
-       unsigned long blob[128 / sizeof(long)];
-};
-
-#endif

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index cf84d98964b2f434cfa4946bab54ebf49c71df1c..23704e006afdbe9829a550fe718688e6eb8bdfd9 100644 (file)
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -59,7 +59,6 @@ struct compat_stat;
 struct old_timeval32;
 struct robust_list_head;
 struct futex_waitv;
-struct getcpu_cache;
 struct old_linux_dirent;
 struct perf_event_attr;
 struct file_handle;
@@ -718,7 +717,7 @@ asmlinkage long sys_getrusage(int who, struct rusage __user *ru);
 asmlinkage long sys_umask(int mask);
 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                        unsigned long arg4, unsigned long arg5);
-asmlinkage long sys_getcpu(unsigned __user *cpu, unsigned __user *node, struct getcpu_cache __user *cache);
+asmlinkage long sys_getcpu(unsigned __user *cpu, unsigned __user *node, void __user *cache);
 asmlinkage long sys_gettimeofday(struct __kernel_old_timeval __user *tv,
                                struct timezone __user *tz);
 asmlinkage long sys_settimeofday(struct __kernel_old_timeval __user *tv,

diff --git a/kernel/sys.c b/kernel/sys.c
index 8b58eece4e580b883d19bb1336aff627ae783a4d..f1780ab132a3fbce6aac937ade5b9a35d9837f13 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -31,7 +31,6 @@
 #include <linux/tty.h>
 #include <linux/signal.h>
 #include <linux/cn_proc.h>
-#include <linux/getcpu.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/seccomp.h>
 #include <linux/cpu.h>
@@ -2876,8 +2875,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
        return error;
 }
 
-SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
-               struct getcpu_cache __user *, unused)
+SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep, void __user *, unused)
 {
        int err = 0;
        int cpu = raw_smp_processor_id();

diff --git a/tools/testing/selftests/vDSO/vdso_test_getcpu.c b/tools/testing/selftests/vDSO/vdso_test_getcpu.c
index bea8ad54da11ee0d5597f6c14421afb714693176..3fe49cbdae9885271c80ae3e15b5c1d5c2132c3e 100644 (file)
--- a/tools/testing/selftests/vDSO/vdso_test_getcpu.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getcpu.c
@@ -16,9 +16,7 @@
 #include "vdso_config.h"
 #include "vdso_call.h"
 
-struct getcpu_cache;
-typedef long (*getcpu_t)(unsigned int *, unsigned int *,
-                        struct getcpu_cache *);
+typedef long (*getcpu_t)(unsigned int *, unsigned int *, void *);
 
 int main(int argc, char **argv)
 {