CPU number initialization in vDSO is now a bit cleaned up by
the new helper functions. The helper functions will take
care of combing CPU and node number and reading each from
the combined value.
Suggested-by: Andy Lutomirski <l...@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok....@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@kernel.org>
---
arch/x86/entry/vdso/vgetcpu.c | 4 ++--
arch/x86/entry/vdso/vma.c | 16 ++++++++--------
arch/x86/include/asm/segment.h | 28 ++++++++++++++++++++++++++++
arch/x86/include/asm/vgtod.h | 2 --
4 files changed, 38 insertions(+), 12 deletions(-)
diff --git a/arch/x86/entry/vdso/vgetcpu.c b/arch/x86/entry/vdso/vgetcpu.c
index 8ec3d1f..3284069 100644
--- a/arch/x86/entry/vdso/vgetcpu.c
+++ b/arch/x86/entry/vdso/vgetcpu.c
@@ -18,9 +18,9 @@ __vdso_getcpu(unsigned *cpu, unsigned *node, struct
getcpu_cache *unused)
p = __getcpu();
if (cpu)
- *cpu = p & VGETCPU_CPU_MASK;
+ *cpu = lsl_tscp_to_cpu(p);
if (node)
- *node = p >> 12;
+ *node = lsl_tscp_to_node(p);
return 0;
}
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 833e229..1fc93da 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -340,19 +340,19 @@ static void vgetcpu_cpu_init(void *arg)
int cpu = smp_processor_id();
struct desc_struct d = { };
unsigned long node = 0;
+ unsigned long cpu_number = 0;
#ifdef CONFIG_NUMA
node = cpu_to_node(cpu);
#endif
+ cpu_number = make_lsl_tscp(cpu, node);
+
if (static_cpu_has(X86_FEATURE_RDTSCP))
- write_rdtscp_aux((node << 12) | cpu);
+ write_rdtscp_aux(cpu_number);
+
+ /* Store cpu number in limit */
+ d.limit0 = cpu_number;
+ d.limit1 = cpu_number >> 16;
- /*
- * Store cpu number in limit so that it can be loaded
- * quickly in user space in vgetcpu. (12 bits for the CPU
- * and 8 bits for the node)
- */
- d.limit0 = cpu | ((node & 0xf) << 12);
- d.limit1 = node >> 4;
d.type = 5; /* RO data, expand down, accessed */
d.dpl = 3; /* Visible to user code */
d.s = 1; /* Not a system segment */
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 492e3d1..2169a24 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -224,6 +224,34 @@
#define GDT_ENTRY_TLS_ENTRIES 3
#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8)
+#ifdef CONFIG_X86_64
+
+/* Bit size and mask of CPU number stored in the per CPU data (and TSC_AUX) */
+#define LSL_TSCP_CPU_SIZE 12
+#define LSL_TSCP_CPU_MASK 0xfff
+
+#ifndef __ASSEMBLY__
+
+/* Helper functions to store/load CPU and node numbers */
+
+static inline unsigned long make_lsl_tscp(int cpu, unsigned long node)
+{
+ return ((node << LSL_TSCP_CPU_SIZE) | cpu);
+}
+
+static inline unsigned int lsl_tscp_to_cpu(unsigned long x)
+{
+ return (x & LSL_TSCP_CPU_MASK);
+}
+
+static inline unsigned int lsl_tscp_to_node(unsigned long x)
+{
+ return (x >> LSL_TSCP_CPU_SIZE);
+}
+
+#endif /* !__ASSEMBLY__ */
+#endif /* CONFIG_X86_64 */
+
#ifdef __KERNEL__
/*
diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index 9cd9036..24e69b3 100644
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -79,8 +79,6 @@ static inline void gtod_write_end(struct vsyscall_gtod_data
*s)
#ifdef CONFIG_X86_64
-#define VGETCPU_CPU_MASK 0xfff
-
static inline unsigned int __getcpu(void)
{
unsigned int p;
--
2.7.4
