[Xen-devel] [PATCH v11 5/9] xen/x86: use DECLARE_BOUNDS as required

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Use DECLARE_BOUNDS and the two static inline functions that come with it
for comparisons and subtractions of:

__2M_rwdata_start, __2M_rwdata_end, __end_vpci_array,
__start_vpci_array, _stextentry, _etextentry, __trampoline_rel_start,
__trampoline_rel_stop, __trampoline_seg_start, __trampoline_seg_stop
__per_cpu_start, __per_cpu_data_end

possible to use the provided static inline functions.
M3CM: Rule-18.2: Subtraction between pointers shall only be applied to
pointers that address elements of the same array.

https://wiki.sei.cmu.edu/confluence/display/c/ARR36-C.+Do+not+subtract+or+compare+two+pointers+that+do+not+refer+to+the+same+array

QAVerify: 2761
Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
CC: JBeulich@xxxxxxxx
CC: andrew.cooper3@xxxxxxxxxx
---
Changes in v11:
- change p type to struct abstract_per_cpu *
- move changes to alternative.c to a new patch
- use DECLARE_BOUNDS

Changes in v10:
- use DEFINE_SYMBOL
- move changes for _start, _end, _stext, _etext, _srodata, _erodata,
  _sinittext, _einittext to a different patch

Changes in v9:
- use SYMBOLS_SUBTRACT and SYMBOLS_COMPARE
---
 xen/arch/x86/efi/efi-boot.h  | 10 ++++++----
 xen/arch/x86/percpu.c        | 11 ++++++-----
 xen/arch/x86/setup.c         |  8 ++++++--
 xen/arch/x86/smpboot.c       |  6 ++++--
 xen/drivers/vpci/vpci.c      |  6 +++---
 xen/include/asm-x86/percpu.h |  6 +++++-
 6 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 5789d2c..a674e98 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -98,8 +98,10 @@ static void __init efi_arch_relocate_image(unsigned long 
delta)
     }
 }
 
-extern const s32 __trampoline_rel_start[], __trampoline_rel_stop[];
-extern const s32 __trampoline_seg_start[], __trampoline_seg_stop[];
+typedef s32 trampoline_rel_t;
+DECLARE_BOUNDS(trampoline_rel, __trampoline_rel_start, __trampoline_rel_stop);
+typedef s32 trampoline_seg_t;
+DECLARE_BOUNDS(trampoline_seg, __trampoline_seg_start, __trampoline_seg_stop);
 
 static void __init relocate_trampoline(unsigned long phys)
 {
@@ -112,11 +114,11 @@ static void __init relocate_trampoline(unsigned long phys)
 
     /* Apply relocations to trampoline. */
     for ( trampoline_ptr = __trampoline_rel_start;
-          trampoline_ptr < __trampoline_rel_stop;
+          trampoline_rel_lt(trampoline_ptr, __trampoline_rel_stop);
           ++trampoline_ptr )
         *(u32 *)(*trampoline_ptr + (long)trampoline_ptr) += phys;
     for ( trampoline_ptr = __trampoline_seg_start;
-          trampoline_ptr < __trampoline_seg_stop;
+          trampoline_seg_lt(trampoline_ptr, __trampoline_seg_stop);
           ++trampoline_ptr )
         *(u16 *)(*trampoline_ptr + (long)trampoline_ptr) = phys >> 4;
 }
diff --git a/xen/arch/x86/percpu.c b/xen/arch/x86/percpu.c
index 8be4ebd..82ed5a2 100644
--- a/xen/arch/x86/percpu.c
+++ b/xen/arch/x86/percpu.c
@@ -13,7 +13,8 @@ unsigned long __per_cpu_offset[NR_CPUS];
  * context of PV guests.
  */
 #define INVALID_PERCPU_AREA (0x8000000000000000L - (long)__per_cpu_start)
-#define PERCPU_ORDER get_order_from_bytes(__per_cpu_data_end - __per_cpu_start)
+#define PERCPU_ORDER get_order_from_bytes(per_cpu_diff(__per_cpu_start,     \
+                                                       __per_cpu_data_end))
 
 void __init percpu_init_areas(void)
 {
@@ -25,7 +26,7 @@ void __init percpu_init_areas(void)
 
 static int init_percpu_area(unsigned int cpu)
 {
-    char *p;
+    struct abstract_per_cpu *p;
 
     if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA )
         return 0;
@@ -33,8 +34,8 @@ static int init_percpu_area(unsigned int cpu)
     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;
+    memset(p, 0, per_cpu_diff(__per_cpu_start, __per_cpu_data_end));
+    __per_cpu_offset[cpu] = per_cpu_lt(__per_cpu_start, p);
 
     return 0;
 }
@@ -49,7 +50,7 @@ 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];
+    char *p = (char *)__per_cpu_start + __per_cpu_offset[cpu];
 
     free_xenheap_pages(p, PERCPU_ORDER);
     __per_cpu_offset[cpu] = INVALID_PERCPU_AREA;
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 06eb483..3264328 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -252,7 +252,9 @@ void __init discard_initial_images(void)
     initial_images = NULL;
 }
 
-extern char __init_begin[], __init_end[], __bss_start[], __bss_end[];
+typedef char init_t;
+DECLARE_BOUNDS(init, __init_begin, __init_end);
+extern char __bss_start[], __bss_end[];
 
 static void __init init_idle_domain(void)
 {
@@ -600,7 +602,9 @@ static void noinline init_done(void)
     unregister_init_virtual_region();
 
     /* Zero the .init code and data. */
-    for ( va = __init_begin; va < _p(__init_end); va += PAGE_SIZE )
+    for ( va = (char *)__init_begin;
+          init_lt(va, __init_end);
+          va += PAGE_SIZE )
         clear_page(va);
 
     /* Destroy Xen's mappings, and reuse the pages. */
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 7d1226d..114c953 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -782,7 +782,8 @@ DEFINE_PER_CPU(root_pgentry_t *, root_pgt);
 
 static root_pgentry_t common_pgt;
 
-extern const char _stextentry[], _etextentry[];
+typedef char textentry_t;
+DECLARE_BOUNDS(textentry, _stextentry, _etextentry);
 
 static int setup_cpu_root_pgt(unsigned int cpu)
 {
@@ -811,7 +812,8 @@ static int setup_cpu_root_pgt(unsigned int cpu)
         const char *ptr;
 
         for ( rc = 0, ptr = _stextentry;
-              !rc && ptr < _etextentry; ptr += PAGE_SIZE )
+              !rc && textentry_lt(ptr, _etextentry);
+              ptr += PAGE_SIZE )
             rc = clone_mapping(ptr, rpt);
 
         if ( rc )
diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index 82607bd..a1d6817 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -31,9 +31,9 @@ struct vpci_register {
 };
 
 #ifdef __XEN__
-extern vpci_register_init_t *const __start_vpci_array[];
-extern vpci_register_init_t *const __end_vpci_array[];
-#define NUM_VPCI_INIT (__end_vpci_array - __start_vpci_array)
+typedef vpci_register_init_t *const vpci_array_t;
+DECLARE_BOUNDS(vpci_array, __start_vpci_array, __end_vpci_array);
+#define NUM_VPCI_INIT (vpci_array_diff(__start_vpci_array, __end_vpci_array))
 
 void vpci_remove_device(struct pci_dev *pdev)
 {
diff --git a/xen/include/asm-x86/percpu.h b/xen/include/asm-x86/percpu.h
index 51562b9..67982de 100644
--- a/xen/include/asm-x86/percpu.h
+++ b/xen/include/asm-x86/percpu.h
@@ -2,7 +2,11 @@
 #define __X86_PERCPU_H__
 
 #ifndef __ASSEMBLY__
-extern char __per_cpu_start[], __per_cpu_data_end[];
+#include <xen/lib.h>
+#include <xen/types.h>
+
+typedef char per_cpu_t;
+DECLARE_BOUNDS(per_cpu, __per_cpu_start, __per_cpu_data_end);
 extern unsigned long __per_cpu_offset[NR_CPUS];
 void percpu_init_areas(void);
 #endif
-- 
1.9.1


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