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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v2 2/2] xen: move per-cpu area management into common code
Centralize per-cpu area management to reduce code duplication and
enhance maintainability across architectures.
The per-cpu area management code, which is largely common among
architectures, is moved to a shared implementation in
xen/common/percpu.c. This change includes:
* Remove percpu.c from the X86 and Arm architectures.
* For x86, define INVALID_PERCPU_AREAS and PARK_OFFLINE_CPUS.
* Drop the declaration of __per_cpu_offset[] from stubs.c in
PPC and RISC-V to facilitate the build of the common per-cpu code.
No functional changes for x86.
For Arm add support of CPU_RESUME_FAILED, CPU_REMOVE and freeing of
percpu in the case when system_state != SYS_STATE_suspend.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in V2:
- move definition of park_offline_cpus for Arm, PPC and RISC-V to
<asm-generic/percpu.h>
- add to arm/asm/smp.h inclusion of <xen/percpu.h>
( at least, it is needed as it uses DECLARE_PER_CPU and also
to not break the build because of moved definition of
park_offline_cpus to asm-generic/percpu.h )
- remove x86/percpu.c as all the code was moved to common percpu.c.
- add define PARK_OFFLINE_CPUS to x86/asm/percpu.h as x86 defines it
in own way.
- drop ARCH_PERCPU_AREA_CHECK and ARCH_CPU_PERCPU_CALLBACK as the code
inside this definitions were integrated to common code.
- use park_offline_cpus ? 0 : -EBUSY;
instead of arch_percpu_area_init_status() in init_percpu_area().
- update cpu_percpu_callback() to handle CPU_UP_CANCELED, case CPU_DEAD,
case CPU_RESUME_FAILED and also CPU parking and SYS_STATE_suspend.
- move declaration of percpu_init_areas() to xen/percpu.h.
---
xen/arch/arm/Makefile | 1 -
xen/arch/arm/include/asm/smp.h | 7 +-
xen/arch/arm/percpu.c | 85 -----------------------
xen/arch/ppc/include/asm/smp.h | 6 --
xen/arch/ppc/stubs.c | 1 -
xen/arch/riscv/include/asm/smp.h | 6 --
xen/arch/riscv/stubs.c | 1 -
xen/arch/x86/Makefile | 1 -
xen/arch/x86/include/asm/Makefile | 1 -
xen/arch/x86/include/asm/percpu.h | 16 +++++
xen/arch/x86/percpu.c | 112 ------------------------------
xen/common/Makefile | 1 +
xen/common/percpu.c | 110 +++++++++++++++++++++++++++++
xen/include/asm-generic/percpu.h | 9 ++-
xen/include/xen/percpu.h | 4 ++
15 files changed, 140 insertions(+), 221 deletions(-)
delete mode 100644 xen/arch/arm/percpu.c
create mode 100644 xen/arch/x86/include/asm/percpu.h
delete mode 100644 xen/arch/x86/percpu.c
create mode 100644 xen/common/percpu.c
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 7792bff597..e4ad1ce851 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -39,7 +39,6 @@ obj-$(CONFIG_MEM_ACCESS) += mem_access.o
obj-y += mm.o
obj-y += monitor.o
obj-y += p2m.o
-obj-y += percpu.o
obj-y += platform.o
obj-y += platform_hypercall.o
obj-y += physdev.o
diff --git a/xen/arch/arm/include/asm/smp.h b/xen/arch/arm/include/asm/smp.h
index e99a3a3f53..8f765ed12a 100644
--- a/xen/arch/arm/include/asm/smp.h
+++ b/xen/arch/arm/include/asm/smp.h
@@ -2,6 +2,7 @@
#define __ASM_SMP_H
#ifndef __ASSEMBLY__
+#include <xen/percpu.h>
#include <xen/cpumask.h>
#include <asm/current.h>
#endif
@@ -12,12 +13,6 @@ extern unsigned long smp_up_cpu;
DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_mask);
DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
-/*
- * Do we, for platform reasons, need to actually keep CPUs online when we
- * would otherwise prefer them to be off?
- */
-#define park_offline_cpus false
-
extern void noreturn stop_cpu(void);
extern int arch_smp_init(void);
diff --git a/xen/arch/arm/percpu.c b/xen/arch/arm/percpu.c
deleted file mode 100644
index 87fe960330..0000000000
--- a/xen/arch/arm/percpu.c
+++ /dev/null
@@ -1,85 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <xen/percpu.h>
-#include <xen/cpu.h>
-#include <xen/init.h>
-#include <xen/mm.h>
-#include <xen/rcupdate.h>
-
-unsigned long __per_cpu_offset[NR_CPUS];
-#define INVALID_PERCPU_AREA (-(long)__per_cpu_start)
-#define PERCPU_ORDER (get_order_from_bytes(__per_cpu_data_end-__per_cpu_start))
-
-void __init percpu_init_areas(void)
-{
- unsigned int cpu;
- for ( cpu = 1; cpu < NR_CPUS; cpu++ )
- __per_cpu_offset[cpu] = INVALID_PERCPU_AREA;
-}
-
-static int init_percpu_area(unsigned int cpu)
-{
- char *p;
- if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA )
- return -EBUSY;
- if ( (p = alloc_xenheap_pages(PERCPU_ORDER, 0)) == NULL )
- return -ENOMEM;
- memset(p, 0, __per_cpu_data_end - __per_cpu_start);
- __per_cpu_offset[cpu] = p - __per_cpu_start;
- return 0;
-}
-
-struct free_info {
- unsigned int cpu;
- struct rcu_head rcu;
-};
-static DEFINE_PER_CPU(struct free_info, free_info);
-
-static void _free_percpu_area(struct rcu_head *head)
-{
- struct free_info *info = container_of(head, struct free_info, rcu);
- unsigned int cpu = info->cpu;
- char *p = __per_cpu_start + __per_cpu_offset[cpu];
- free_xenheap_pages(p, PERCPU_ORDER);
- __per_cpu_offset[cpu] = INVALID_PERCPU_AREA;
-}
-
-static void free_percpu_area(unsigned int cpu)
-{
- struct free_info *info = &per_cpu(free_info, cpu);
- info->cpu = cpu;
- call_rcu(&info->rcu, _free_percpu_area);
-}
-
-static int cpu_percpu_callback(
- struct notifier_block *nfb, unsigned long action, void *hcpu)
-{
- unsigned int cpu = (unsigned long)hcpu;
- int rc = 0;
-
- switch ( action )
- {
- case CPU_UP_PREPARE:
- rc = init_percpu_area(cpu);
- break;
- case CPU_UP_CANCELED:
- case CPU_DEAD:
- free_percpu_area(cpu);
- break;
- default:
- break;
- }
-
- return notifier_from_errno(rc);
-}
-
-static struct notifier_block cpu_percpu_nfb = {
- .notifier_call = cpu_percpu_callback,
- .priority = 100 /* highest priority */
-};
-
-static int __init percpu_presmp_init(void)
-{
- register_cpu_notifier(&cpu_percpu_nfb);
- return 0;
-}
-presmp_initcall(percpu_presmp_init);
diff --git a/xen/arch/ppc/include/asm/smp.h b/xen/arch/ppc/include/asm/smp.h
index 7b1517ce18..2b872218be 100644
--- a/xen/arch/ppc/include/asm/smp.h
+++ b/xen/arch/ppc/include/asm/smp.h
@@ -7,10 +7,4 @@
DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_mask);
DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
-/*
- * Do we, for platform reasons, need to actually keep CPUs online when we
- * would otherwise prefer them to be off?
- */
-#define park_offline_cpus false
-
#endif
diff --git a/xen/arch/ppc/stubs.c b/xen/arch/ppc/stubs.c
index bdb5f8c66d..fff82f5cf3 100644
--- a/xen/arch/ppc/stubs.c
+++ b/xen/arch/ppc/stubs.c
@@ -141,7 +141,6 @@ void smp_send_state_dump(unsigned int cpu)
/* domain.c */
DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
-unsigned long __per_cpu_offset[NR_CPUS];
void context_switch(struct vcpu *prev, struct vcpu *next)
{
diff --git a/xen/arch/riscv/include/asm/smp.h b/xen/arch/riscv/include/asm/smp.h
index b1ea91b1eb..c63c499d12 100644
--- a/xen/arch/riscv/include/asm/smp.h
+++ b/xen/arch/riscv/include/asm/smp.h
@@ -8,12 +8,6 @@
DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_mask);
DECLARE_PER_CPU(cpumask_var_t, cpu_core_mask);
-/*
- * Do we, for platform reasons, need to actually keep CPUs online when we
- * would otherwise prefer them to be off?
- */
-#define park_offline_cpus false
-
#endif
/*
diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
index 2aa245f272..5951b0ce91 100644
--- a/xen/arch/riscv/stubs.c
+++ b/xen/arch/riscv/stubs.c
@@ -133,7 +133,6 @@ void smp_send_state_dump(unsigned int cpu)
/* domain.c */
DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
-unsigned long __per_cpu_offset[NR_CPUS];
void context_switch(struct vcpu *prev, struct vcpu *next)
{
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 00ab091634..bf68f38c0e 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -54,7 +54,6 @@ obj-y += mpparse.o
obj-y += nmi.o
obj-y += numa.o
obj-y += pci.o
-obj-y += percpu.o
obj-y += physdev.o
obj-$(CONFIG_COMPAT) += x86_64/physdev.o
obj-y += psr.o
diff --git a/xen/arch/x86/include/asm/Makefile
b/xen/arch/x86/include/asm/Makefile
index daab34ff0a..2c27787d31 100644
--- a/xen/arch/x86/include/asm/Makefile
+++ b/xen/arch/x86/include/asm/Makefile
@@ -1,3 +1,2 @@
# SPDX-License-Identifier: GPL-2.0-only
generic-y += div64.h
-generic-y += percpu.h
diff --git a/xen/arch/x86/include/asm/percpu.h
b/xen/arch/x86/include/asm/percpu.h
new file mode 100644
index 0000000000..b892dc2f00
--- /dev/null
+++ b/xen/arch/x86/include/asm/percpu.h
@@ -0,0 +1,16 @@
+#ifndef __X86_PERCPU_H__
+#define __X86_PERCPU_H__
+
+#define PARK_OFFLINE_CPUS
+
+#include <asm-generic/percpu.h>
+
+/*
+ * Force uses of per_cpu() with an invalid area to attempt to access the
+ * middle of the non-canonical address space resulting in a #GP, rather than a
+ * possible #PF at (NULL + a little) which has security implications in the
+ * context of PV guests.
+ */
+#define INVALID_PERCPU_AREA (0x8000000000000000UL - (unsigned
long)__per_cpu_start)
+
+#endif /* __X86_PERCPU_H__ */
diff --git a/xen/arch/x86/percpu.c b/xen/arch/x86/percpu.c
deleted file mode 100644
index 3205eacea6..0000000000
--- a/xen/arch/x86/percpu.c
+++ /dev/null
@@ -1,112 +0,0 @@
-#include <xen/percpu.h>
-#include <xen/cpu.h>
-#include <xen/init.h>
-#include <xen/mm.h>
-#include <xen/rcupdate.h>
-
-unsigned long __per_cpu_offset[NR_CPUS];
-
-/*
- * Force uses of per_cpu() with an invalid area to attempt to access the
- * middle of the non-canonical address space resulting in a #GP, rather than a
- * possible #PF at (NULL + a little) which has security implications in the
- * context of PV guests.
- */
-#define INVALID_PERCPU_AREA (0x8000000000000000UL - (unsigned
long)__per_cpu_start)
-#define PERCPU_ORDER get_order_from_bytes(__per_cpu_data_end - __per_cpu_start)
-
-void __init percpu_init_areas(void)
-{
- unsigned int cpu;
-
- for ( cpu = 1; cpu < NR_CPUS; cpu++ )
- __per_cpu_offset[cpu] = INVALID_PERCPU_AREA;
-}
-
-static int init_percpu_area(unsigned int cpu)
-{
- char *p;
-
- if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA )
- return 0;
-
- if ( (p = alloc_xenheap_pages(PERCPU_ORDER, 0)) == NULL )
- return -ENOMEM;
-
- memset(p, 0, __per_cpu_data_end - __per_cpu_start);
- __per_cpu_offset[cpu] = p - __per_cpu_start;
-
- return 0;
-}
-
-struct free_info {
- unsigned int cpu;
- struct rcu_head rcu;
-};
-static DEFINE_PER_CPU(struct free_info, free_info);
-
-static void cf_check _free_percpu_area(struct rcu_head *head)
-{
- struct free_info *info = container_of(head, struct free_info, rcu);
- unsigned int cpu = info->cpu;
- char *p = __per_cpu_start + __per_cpu_offset[cpu];
-
- free_xenheap_pages(p, PERCPU_ORDER);
- __per_cpu_offset[cpu] = INVALID_PERCPU_AREA;
-}
-
-static void free_percpu_area(unsigned int cpu)
-{
- struct free_info *info = &per_cpu(free_info, cpu);
-
- info->cpu = cpu;
- call_rcu(&info->rcu, _free_percpu_area);
-}
-
-static int cf_check cpu_percpu_callback(
- struct notifier_block *nfb, unsigned long action, void *hcpu)
-{
- unsigned int cpu = (unsigned long)hcpu;
- int rc = 0;
-
- switch ( action )
- {
- case CPU_UP_PREPARE:
- rc = init_percpu_area(cpu);
- break;
- case CPU_UP_CANCELED:
- case CPU_DEAD:
- case CPU_RESUME_FAILED:
- if ( !park_offline_cpus && system_state != SYS_STATE_suspend )
- free_percpu_area(cpu);
- break;
- case CPU_REMOVE:
- if ( park_offline_cpus )
- free_percpu_area(cpu);
- break;
- }
-
- return notifier_from_errno(rc);
-}
-
-static struct notifier_block cpu_percpu_nfb = {
- .notifier_call = cpu_percpu_callback,
- .priority = 100 /* highest priority */
-};
-
-static int __init cf_check percpu_presmp_init(void)
-{
- register_cpu_notifier(&cpu_percpu_nfb);
-
- return 0;
-}
-presmp_initcall(percpu_presmp_init);
-
-/*
- * Local variables:
- * mode: C
- * c-file-style: "BSD"
- * c-basic-offset: 4
- * indent-tabs-mode: nil
- * End:
- */
diff --git a/xen/common/Makefile b/xen/common/Makefile
index fc52e0857d..f90bb00d23 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -31,6 +31,7 @@ obj-y += notifier.o
obj-$(CONFIG_NUMA) += numa.o
obj-y += page_alloc.o
obj-y += pdx.o
+obj-y += percpu.o
obj-$(CONFIG_PERF_COUNTERS) += perfc.o
obj-bin-$(CONFIG_HAS_PMAP) += pmap.init.o
obj-y += preempt.o
diff --git a/xen/common/percpu.c b/xen/common/percpu.c
new file mode 100644
index 0000000000..58a774154d
--- /dev/null
+++ b/xen/common/percpu.c
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <xen/percpu.h>
+#include <xen/cpu.h>
+#include <xen/init.h>
+#include <xen/mm.h>
+#include <xen/rcupdate.h>
+
+#ifndef INVALID_PERCPU_AREA
+#define INVALID_PERCPU_AREA (-(long)__per_cpu_start)
+#endif
+
+#define PERCPU_ORDER get_order_from_bytes(__per_cpu_data_end - __per_cpu_start)
+
+unsigned long __per_cpu_offset[NR_CPUS];
+
+void __init percpu_init_areas(void)
+{
+ unsigned int cpu;
+
+ for ( cpu = 1; cpu < NR_CPUS; cpu++ )
+ __per_cpu_offset[cpu] = INVALID_PERCPU_AREA;
+}
+
+static int init_percpu_area(unsigned int cpu)
+{
+ char *p;
+
+ if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA )
+ return park_offline_cpus ? 0 : -EBUSY;
+
+ if ( (p = alloc_xenheap_pages(PERCPU_ORDER, 0)) == NULL )
+ return -ENOMEM;
+
+ memset(p, 0, __per_cpu_data_end - __per_cpu_start);
+ __per_cpu_offset[cpu] = p - __per_cpu_start;
+
+ return 0;
+}
+
+struct free_info {
+ unsigned int cpu;
+ struct rcu_head rcu;
+};
+static DEFINE_PER_CPU(struct free_info, free_info);
+
+static void cf_check _free_percpu_area(struct rcu_head *head)
+{
+ struct free_info *info = container_of(head, struct free_info, rcu);
+ unsigned int cpu = info->cpu;
+ char *p = __per_cpu_start + __per_cpu_offset[cpu];
+
+ free_xenheap_pages(p, PERCPU_ORDER);
+ __per_cpu_offset[cpu] = INVALID_PERCPU_AREA;
+}
+
+static void free_percpu_area(unsigned int cpu)
+{
+ struct free_info *info = &per_cpu(free_info, cpu);
+
+ info->cpu = cpu;
+ call_rcu(&info->rcu, _free_percpu_area);
+}
+
+static int cf_check cpu_percpu_callback(
+ struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+ int rc = 0;
+
+ switch ( action )
+ {
+ case CPU_UP_PREPARE:
+ rc = init_percpu_area(cpu);
+ break;
+ case CPU_UP_CANCELED:
+ case CPU_DEAD:
+ case CPU_RESUME_FAILED:
+ if ( !park_offline_cpus && system_state != SYS_STATE_suspend )
+ free_percpu_area(cpu);
+ break;
+ case CPU_REMOVE:
+ if ( park_offline_cpus )
+ free_percpu_area(cpu);
+ break;
+ }
+
+ return notifier_from_errno(rc);
+}
+
+static struct notifier_block cpu_percpu_nfb = {
+ .notifier_call = cpu_percpu_callback,
+ .priority = 100 /* highest priority */
+};
+
+static int __init cf_check percpu_presmp_init(void)
+{
+ register_cpu_notifier(&cpu_percpu_nfb);
+
+ return 0;
+}
+presmp_initcall(percpu_presmp_init);
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-generic/percpu.h b/xen/include/asm-generic/percpu.h
index 60af4f9ff9..d36afda2dd 100644
--- a/xen/include/asm-generic/percpu.h
+++ b/xen/include/asm-generic/percpu.h
@@ -10,7 +10,14 @@
extern char __per_cpu_start[];
extern const char __per_cpu_data_end[];
extern unsigned long __per_cpu_offset[NR_CPUS];
-void percpu_init_areas(void);
+
+#ifndef PARK_OFFLINE_CPUS
+/*
+ * Do we, for platform reasons, need to actually keep CPUs online when we
+ * would otherwise prefer them to be off?
+ */
+#define park_offline_cpus false
+#endif
#define per_cpu(var, cpu) \
(*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]))
diff --git a/xen/include/xen/percpu.h b/xen/include/xen/percpu.h
index 57522f346b..90c4e120ec 100644
--- a/xen/include/xen/percpu.h
+++ b/xen/include/xen/percpu.h
@@ -33,4 +33,8 @@
#define get_cpu_var(var) this_cpu(var)
#define put_cpu_var(var)
+#ifndef __ASSEMBLY__
+void percpu_init_areas(void);
+#endif
+
#endif /* __XEN_PERCPU_H__ */
--
2.46.1
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