From 80f06306240e0ad1c75116111be11950474dfda7 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 16 Nov 2020 08:06:41 +0100 Subject: [PATCH] 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 Signed-off-by: Heiko Carstens --- arch/s390/include/asm/timex.h | 7 +++++++ arch/s390/include/asm/vdso.h | 2 ++ arch/s390/kernel/smp.c | 2 ++ arch/s390/kernel/vdso.c | 7 +++++++ arch/s390/kernel/vdso64/Makefile | 3 ++- arch/s390/kernel/vdso64/getcpu.c | 20 ++++++++++++++++++++ arch/s390/kernel/vdso64/vdso64.lds.S | 2 +- arch/s390/kernel/vdso64/vdso_user_wrapper.S | 1 + 8 files changed, 42 insertions(+), 2 deletions(-) create mode 100644 arch/s390/kernel/vdso64/getcpu.c diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h index 289aaff4d365..c8e244ecdfde 100644 --- a/arch/s390/include/asm/timex.h +++ b/arch/s390/include/asm/timex.h @@ -49,6 +49,13 @@ static inline void set_clock_comparator(__u64 time) asm volatile("sckc %0" : : "Q" (time)); } +static inline void set_tod_programmable_field(u16 val) +{ + register unsigned long reg0 asm("0") = val; + + asm volatile("sckpf" : : "d" (reg0)); +} + void clock_comparator_work(void); void __init time_early_init(void); diff --git a/arch/s390/include/asm/vdso.h b/arch/s390/include/asm/vdso.h index 9b299c05abf1..f65590889054 100644 --- a/arch/s390/include/asm/vdso.h +++ b/arch/s390/include/asm/vdso.h @@ -14,5 +14,7 @@ extern struct vdso_data *vdso_data; +void vdso_getcpu_init(void); + #endif /* __ASSEMBLY__ */ #endif /* __S390_VDSO_H__ */ diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 7f7d81f19292..647226e50c80 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -54,6 +54,7 @@ #include #include #include +#include #include "entry.h" enum { @@ -858,6 +859,7 @@ static void smp_init_secondary(void) preempt_disable(); init_cpu_timer(); vtime_init(); + vdso_getcpu_init(); pfault_init(); notify_cpu_starting(cpu); if (topology_cpu_dedicated(cpu)) diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c index 53c983f1ea51..aef2edff9959 100644 --- a/arch/s390/kernel/vdso.c +++ b/arch/s390/kernel/vdso.c @@ -29,6 +29,7 @@ #include #include #include +#include extern char vdso64_start, vdso64_end; static void *vdso64_kbase = &vdso64_start; @@ -100,6 +101,11 @@ static union { } vdso_data_store __page_aligned_data; struct vdso_data *vdso_data = (struct vdso_data *)&vdso_data_store.data; +void vdso_getcpu_init(void) +{ + set_tod_programmable_field(smp_processor_id()); +} + /* * This is called from binfmt_elf, we create the special vma for the * vDSO and insert it into the mm struct tree @@ -170,6 +176,7 @@ static int __init vdso_init(void) { int i; + vdso_getcpu_init(); /* Calculate the size of the 64 bit vDSO */ vdso64_pages = ((&vdso64_end - &vdso64_start + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1; 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 +#include +#include + +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 -- 2.20.1