[PATCH v2 17/70] xen: CFI hardening for open_softirq()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Control Flow Integrity schemes use toolchain and optionally hardware support
to help protect against call/jump/return oriented programming attacks.

Use cf_check to annotate function pointer targets for the toolchain.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/cpu/mcheck/mce.c       | 2 +-
 xen/arch/x86/domain.c               | 2 +-
 xen/arch/x86/include/asm/flushtlb.h | 2 +-
 xen/arch/x86/pv/traps.c             | 2 +-
 xen/arch/x86/smp.c                  | 2 +-
 xen/arch/x86/time.c                 | 2 +-
 xen/common/rcupdate.c               | 2 +-
 xen/common/sched/core.c             | 6 +++---
 xen/common/tasklet.c                | 2 +-
 xen/common/timer.c                  | 2 +-
 xen/drivers/passthrough/x86/hvm.c   | 2 +-
 11 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
index 43f6c8471a90..3467e0f1a315 100644
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -1837,7 +1837,7 @@ static int mce_delayed_action(mctelem_cookie_t mctc)
 }
 
 /* Softirq Handler for this MCE# processing */
-static void mce_softirq(void)
+static void cf_check mce_softirq(void)
 {
     static DEFINE_MCE_BARRIER(mce_inside_bar);
     static DEFINE_MCE_BARRIER(mce_severity_bar);
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index f943283b2a88..1c3a1ec2a080 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -2523,7 +2523,7 @@ void vcpu_mark_events_pending(struct vcpu *v)
         vcpu_kick(v);
 }
 
-static void vcpu_kick_softirq(void)
+static void cf_check vcpu_kick_softirq(void)
 {
     /*
      * Nothing to do here: we merely prevent notifiers from racing with checks
diff --git a/xen/arch/x86/include/asm/flushtlb.h 
b/xen/arch/x86/include/asm/flushtlb.h
index 0be2273387ed..18777f1d4c00 100644
--- a/xen/arch/x86/include/asm/flushtlb.h
+++ b/xen/arch/x86/include/asm/flushtlb.h
@@ -87,7 +87,7 @@ static inline void tlbflush_filter(cpumask_t *mask, uint32_t 
page_timestamp)
             __cpumask_clear_cpu(cpu, mask);
 }
 
-void new_tlbflush_clock_period(void);
+void cf_check new_tlbflush_clock_period(void);
 
 /* Read pagetable base. */
 static inline unsigned long read_cr3(void)
diff --git a/xen/arch/x86/pv/traps.c b/xen/arch/x86/pv/traps.c
index 170e1030982b..97fe54b5ee5a 100644
--- a/xen/arch/x86/pv/traps.c
+++ b/xen/arch/x86/pv/traps.c
@@ -130,7 +130,7 @@ bool set_guest_nmi_trapbounce(void)
 
 static DEFINE_PER_CPU(struct vcpu *, softirq_nmi_vcpu);
 
-static void nmi_softirq(void)
+static void cf_check nmi_softirq(void)
 {
     struct vcpu **v_ptr = &this_cpu(softirq_nmi_vcpu);
 
diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c
index f6fd7f95df58..b9a696f61963 100644
--- a/xen/arch/x86/smp.c
+++ b/xen/arch/x86/smp.c
@@ -290,7 +290,7 @@ void flush_area_mask(const cpumask_t *mask, const void *va, 
unsigned int flags)
 }
 
 /* Call with no locks held and interrupts enabled (e.g., softirq context). */
-void new_tlbflush_clock_period(void)
+void cf_check new_tlbflush_clock_period(void)
 {
     cpumask_t allbutself;
 
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index b444d6344e79..5a72b66800e4 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -1455,7 +1455,7 @@ int cpu_frequency_change(u64 freq)
 static DEFINE_PER_CPU(struct cpu_time_stamp, cpu_calibration);
 
 /* Softirq handler for per-CPU time calibration. */
-static void local_time_calibration(void)
+static void cf_check local_time_calibration(void)
 {
     struct cpu_time *t = &this_cpu(cpu_time);
     const struct cpu_time_stamp *c = &this_cpu(cpu_calibration);
diff --git a/xen/common/rcupdate.c b/xen/common/rcupdate.c
index 423d6b1d6d02..212a99acd8c8 100644
--- a/xen/common/rcupdate.c
+++ b/xen/common/rcupdate.c
@@ -466,7 +466,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,
         rcu_do_batch(rdp);
 }
 
-static void rcu_process_callbacks(void)
+static void cf_check rcu_process_callbacks(void)
 {
     struct rcu_data *rdp = &this_cpu(rcu_data);
 
diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c
index 285de9ee2a19..b1836b591c0a 100644
--- a/xen/common/sched/core.c
+++ b/xen/common/sched/core.c
@@ -2568,7 +2568,7 @@ static struct sched_unit *sched_wait_rendezvous_in(struct 
sched_unit *prev,
     return prev->next_task;
 }
 
-static void sched_slave(void)
+static void cf_check sched_slave(void)
 {
     struct vcpu          *v, *vprev = current;
     struct sched_unit    *prev = vprev->sched_unit, *next;
@@ -2632,7 +2632,7 @@ static void sched_slave(void)
  * - deschedule the current domain (scheduler independent).
  * - pick a new domain (scheduler dependent).
  */
-static void schedule(void)
+static void cf_check schedule(void)
 {
     struct vcpu          *vnext, *vprev = current;
     struct sched_unit    *prev = vprev->sched_unit, *next = NULL;
@@ -2928,7 +2928,7 @@ const cpumask_t *sched_get_opt_cpumask(enum sched_gran 
opt, unsigned int cpu)
     return mask;
 }
 
-static void schedule_dummy(void)
+static void cf_check schedule_dummy(void)
 {
     sched_tasklet_check_cpu(smp_processor_id());
 }
diff --git a/xen/common/tasklet.c b/xen/common/tasklet.c
index 1b16bbcdeb0b..3ad67b5c2493 100644
--- a/xen/common/tasklet.c
+++ b/xen/common/tasklet.c
@@ -135,7 +135,7 @@ void do_tasklet(void)
 }
 
 /* Softirq context work */
-static void tasklet_softirq_action(void)
+static void cf_check tasklet_softirq_action(void)
 {
     unsigned int cpu = smp_processor_id();
     struct list_head *list = &per_cpu(softirq_tasklet_list, cpu);
diff --git a/xen/common/timer.c b/xen/common/timer.c
index b788050ea1d8..700f191a70b4 100644
--- a/xen/common/timer.c
+++ b/xen/common/timer.c
@@ -450,7 +450,7 @@ static void execute_timer(struct timers *ts, struct timer 
*t)
 }
 
 
-static void timer_softirq_action(void)
+static void cf_check timer_softirq_action(void)
 {
     struct timer  *t, **heap, *next;
     struct timers *ts;
diff --git a/xen/drivers/passthrough/x86/hvm.c 
b/xen/drivers/passthrough/x86/hvm.c
index 527bd6a56d83..0e3c0f6aeed3 100644
--- a/xen/drivers/passthrough/x86/hvm.c
+++ b/xen/drivers/passthrough/x86/hvm.c
@@ -1003,7 +1003,7 @@ int arch_pci_clean_pirqs(struct domain *d)
  * Note: 'pt_pirq_softirq_reset' can clear the STATE_SCHED before we get to
  * doing it. If that is the case we let 'pt_pirq_softirq_reset' do 
ref-counting.
  */
-static void dpci_softirq(void)
+static void cf_check dpci_softirq(void)
 {
     unsigned int cpu = smp_processor_id();
     LIST_HEAD(our_list);
-- 
2.11.0