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authorHeiko Carstens <hca@linux.ibm.com>2020-11-16 08:06:41 +0100
committerHeiko Carstens <hca@linux.ibm.com>2020-11-23 12:01:13 +0100
commit80f06306240e0ad1c75116111be11950474dfda7 (patch)
tree99ed304a1c6d26ad408145ba98b83d9fbf807b7f /arch/s390/kernel/vdso64
parent062e527956d05fae02f143c0d5ff9e8525c6799f (diff)
downloadlinux-80f06306240e0ad1c75116111be11950474dfda7.tar.gz
s390/vdso: reimplement getcpu vdso syscall
Implement the previously removed getcpu vdso syscall by using the TOD programmable field to pass the cpu number to user space. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel/vdso64')
-rw-r--r--arch/s390/kernel/vdso64/Makefile3
-rw-r--r--arch/s390/kernel/vdso64/getcpu.c20
-rw-r--r--arch/s390/kernel/vdso64/vdso64.lds.S2
-rw-r--r--arch/s390/kernel/vdso64/vdso_user_wrapper.S1
4 files changed, 24 insertions, 2 deletions
diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile
index b0cf58ae82fe..a6e0fb6b91d6 100644
--- a/arch/s390/kernel/vdso64/Makefile
+++ b/arch/s390/kernel/vdso64/Makefile
@@ -7,7 +7,8 @@ ARCH_REL_TYPE_ABS += R_390_GOT|R_390_PLT
include $(srctree)/lib/vdso/Makefile
obj-vdso64 = vdso_user_wrapper.o note.o
-obj-cvdso64 = vdso64_generic.o
+obj-cvdso64 = vdso64_generic.o getcpu.o
+CFLAGS_REMOVE_getcpu.o = -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE)
CFLAGS_REMOVE_vdso64_generic.o = -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE)
# Build rules
diff --git a/arch/s390/kernel/vdso64/getcpu.c b/arch/s390/kernel/vdso64/getcpu.c
new file mode 100644
index 000000000000..a5da7a9eb43d
--- /dev/null
+++ b/arch/s390/kernel/vdso64/getcpu.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright IBM Corp. 2020 */
+
+#include <linux/compiler.h>
+#include <linux/getcpu.h>
+#include <asm/timex.h>
+
+int __s390_vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
+{
+ __u16 todval[8];
+
+ /* CPU number is stored in the programmable field of the TOD clock */
+ get_tod_clock_ext((char *)todval);
+ if (cpu)
+ *cpu = todval[7];
+ /* NUMA node is always zero */
+ if (node)
+ *node = 0;
+ return 0;
+}
diff --git a/arch/s390/kernel/vdso64/vdso64.lds.S b/arch/s390/kernel/vdso64/vdso64.lds.S
index b59006584a9d..7bde3909290f 100644
--- a/arch/s390/kernel/vdso64/vdso64.lds.S
+++ b/arch/s390/kernel/vdso64/vdso64.lds.S
@@ -135,7 +135,7 @@ VERSION
__kernel_gettimeofday;
__kernel_clock_gettime;
__kernel_clock_getres;
-
+ __kernel_getcpu;
local: *;
};
}
diff --git a/arch/s390/kernel/vdso64/vdso_user_wrapper.S b/arch/s390/kernel/vdso64/vdso_user_wrapper.S
index a775d7e52872..f773505c7e63 100644
--- a/arch/s390/kernel/vdso64/vdso_user_wrapper.S
+++ b/arch/s390/kernel/vdso64/vdso_user_wrapper.S
@@ -36,3 +36,4 @@ __kernel_\func:
vdso_func gettimeofday
vdso_func clock_getres
vdso_func clock_gettime
+vdso_func getcpu