[PATCH v3 12/70] xen: CFI hardening for continue_hypercall_on_cpu()

[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>
---
v3:
 * Fix !CONFIG_PV_SHIM build.  Annotate pv_shim_cpu_{up,down}() stubs.
---
 xen/arch/x86/acpi/power.c          | 2 +-
 xen/arch/x86/cpu/microcode/core.c  | 2 +-
 xen/arch/x86/include/asm/pv/shim.h | 8 ++++----
 xen/arch/x86/include/asm/smp.h     | 6 +++---
 xen/arch/x86/platform_hypercall.c  | 4 ++--
 xen/arch/x86/pv/shim.c             | 4 ++--
 xen/arch/x86/smp.c                 | 4 ++--
 xen/arch/x86/sysctl.c              | 2 +-
 xen/common/core_parking.c          | 2 +-
 xen/common/kexec.c                 | 2 +-
 xen/common/sched/cpupool.c         | 2 +-
 11 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 912d4c4d62f4..c4e7e8698920 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -326,7 +326,7 @@ static int enter_state(u32 state)
     return error;
 }
 
-static long enter_state_helper(void *data)
+static long cf_check enter_state_helper(void *data)
 {
     struct acpi_sleep_info *sinfo = (struct acpi_sleep_info *)data;
     return enter_state(sinfo->sleep_state);
diff --git a/xen/arch/x86/cpu/microcode/core.c 
b/xen/arch/x86/cpu/microcode/core.c
index 46f55fe7f191..9631042190ab 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -558,7 +558,7 @@ struct ucode_buf {
     char buffer[];
 };
 
-static long microcode_update_helper(void *data)
+static long cf_check microcode_update_helper(void *data)
 {
     int ret;
     struct ucode_buf *buffer = data;
diff --git a/xen/arch/x86/include/asm/pv/shim.h 
b/xen/arch/x86/include/asm/pv/shim.h
index 6415f8068e5c..a43c3689b48a 100644
--- a/xen/arch/x86/include/asm/pv/shim.h
+++ b/xen/arch/x86/include/asm/pv/shim.h
@@ -38,8 +38,8 @@ void pv_shim_setup_dom(struct domain *d, l4_pgentry_t 
*l4start,
                        start_info_t *si);
 int pv_shim_shutdown(uint8_t reason);
 void pv_shim_inject_evtchn(unsigned int port);
-long pv_shim_cpu_up(void *data);
-long pv_shim_cpu_down(void *data);
+long cf_check pv_shim_cpu_up(void *data);
+long cf_check pv_shim_cpu_down(void *data);
 void pv_shim_online_memory(unsigned int nr, unsigned int order);
 void pv_shim_offline_memory(unsigned int nr, unsigned int order);
 domid_t get_initial_domain_id(void);
@@ -69,12 +69,12 @@ static inline void pv_shim_inject_evtchn(unsigned int port)
 {
     ASSERT_UNREACHABLE();
 }
-static inline long pv_shim_cpu_up(void *data)
+static inline long cf_check pv_shim_cpu_up(void *data)
 {
     ASSERT_UNREACHABLE();
     return 0;
 }
-static inline long pv_shim_cpu_down(void *data)
+static inline long cf_check pv_shim_cpu_down(void *data)
 {
     ASSERT_UNREACHABLE();
     return 0;
diff --git a/xen/arch/x86/include/asm/smp.h b/xen/arch/x86/include/asm/smp.h
index f7485f602efa..1747772d232e 100644
--- a/xen/arch/x86/include/asm/smp.h
+++ b/xen/arch/x86/include/asm/smp.h
@@ -57,10 +57,10 @@ int cpu_add(uint32_t apic_id, uint32_t acpi_id, uint32_t 
pxm);
 
 void __stop_this_cpu(void);
 
-long cpu_up_helper(void *data);
-long cpu_down_helper(void *data);
+long cf_check cpu_up_helper(void *data);
+long cf_check cpu_down_helper(void *data);
 
-long core_parking_helper(void *data);
+long cf_check core_parking_helper(void *data);
 bool core_parking_remove(unsigned int cpu);
 uint32_t get_cur_idle_nums(void);
 
diff --git a/xen/arch/x86/platform_hypercall.c 
b/xen/arch/x86/platform_hypercall.c
index 84566bbfaa3d..f5d7adc1e802 100644
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -45,7 +45,7 @@ struct resource_access {
     xenpf_resource_entry_t *entries;
 };
 
-long cpu_frequency_change_helper(void *);
+long cf_check cpu_frequency_change_helper(void *);
 void check_resource_access(struct resource_access *);
 void resource_access(void *);
 
@@ -59,7 +59,7 @@ DEFINE_SPINLOCK(xenpf_lock);
 # undef guest_from_compat_handle
 # define guest_from_compat_handle(x,y) ((x)=(y))
 
-long cpu_frequency_change_helper(void *data)
+long cf_check cpu_frequency_change_helper(void *data)
 {
     return cpu_frequency_change((uint64_t)data);
 }
diff --git a/xen/arch/x86/pv/shim.c b/xen/arch/x86/pv/shim.c
index ae4d8913faa1..2ee290a3920d 100644
--- a/xen/arch/x86/pv/shim.c
+++ b/xen/arch/x86/pv/shim.c
@@ -845,7 +845,7 @@ int cf_check compat_grant_table_op(
 #endif
 #endif
 
-long pv_shim_cpu_up(void *data)
+long cf_check pv_shim_cpu_up(void *data)
 {
     struct vcpu *v = data;
     struct domain *d = v->domain;
@@ -883,7 +883,7 @@ long pv_shim_cpu_up(void *data)
     return 0;
 }
 
-long pv_shim_cpu_down(void *data)
+long cf_check pv_shim_cpu_down(void *data)
 {
     struct vcpu *v = data;
     long rc;
diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c
index eef0f9c6cbf4..f4952a6bf9a5 100644
--- a/xen/arch/x86/smp.c
+++ b/xen/arch/x86/smp.c
@@ -399,7 +399,7 @@ void call_function_interrupt(struct cpu_user_regs *regs)
     smp_call_function_interrupt();
 }
 
-long cpu_up_helper(void *data)
+long cf_check cpu_up_helper(void *data)
 {
     unsigned int cpu = (unsigned long)data;
     int ret = cpu_up(cpu);
@@ -422,7 +422,7 @@ long cpu_up_helper(void *data)
     return ret;
 }
 
-long cpu_down_helper(void *data)
+long cf_check cpu_down_helper(void *data)
 {
     int cpu = (unsigned long)data;
     int ret = cpu_down(cpu);
diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c
index aff52a13f373..1772f51f8f6e 100644
--- a/xen/arch/x86/sysctl.c
+++ b/xen/arch/x86/sysctl.c
@@ -79,7 +79,7 @@ static void l3_cache_get(void *arg)
         l3_info->size = info.size / 1024; /* in KB unit */
 }
 
-static long smt_up_down_helper(void *data)
+static long cf_check smt_up_down_helper(void *data)
 {
     bool up = (bool)data;
     unsigned int cpu, sibling_mask = boot_cpu_data.x86_num_siblings - 1;
diff --git a/xen/common/core_parking.c b/xen/common/core_parking.c
index 44a907abfd7f..4afad04f2f68 100644
--- a/xen/common/core_parking.c
+++ b/xen/common/core_parking.c
@@ -169,7 +169,7 @@ static unsigned int core_parking_power(unsigned int event)
     return cpu;
 }
 
-long core_parking_helper(void *data)
+long cf_check core_parking_helper(void *data)
 {
     uint32_t idle_nums = (unsigned long)data;
     unsigned int cpu;
diff --git a/xen/common/kexec.c b/xen/common/kexec.c
index 3b223cd03d75..b222a5fd782e 100644
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -395,7 +395,7 @@ void kexec_crash(enum crash_reason reason)
     BUG();
 }
 
-static long kexec_reboot(void *_image)
+static long cf_check kexec_reboot(void *_image)
 {
     struct kexec_image *image = _image;
 
diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c
index e5cfb03b857e..b9d4babd0d8a 100644
--- a/xen/common/sched/cpupool.c
+++ b/xen/common/sched/cpupool.c
@@ -544,7 +544,7 @@ static int cpupool_unassign_cpu_start(struct cpupool *c, 
unsigned int cpu)
     return ret;
 }
 
-static long cpupool_unassign_cpu_helper(void *info)
+static long cf_check cpupool_unassign_cpu_helper(void *info)
 {
     struct cpupool *c = info;
     long ret;
-- 
2.11.0