[Xen-devel] [PATCH v8 4/7] xen: use initcall_start_, ctors_start_, and more

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Start making use of the following uintptr_t variables:

initcall_start_, presmp_initcall_end_, initcall_end_, ctors_start_,
ctors_end_, start_schedulers_array_, end_schedulers_array_,
lock_profile_start_, lock_profile_end_, note_gnu_build_id_start_,
note_gnu_build_id_end_

Replacing the corresponding linker symbols. It is done to avoid
comparing and subtracting pointers pointing to different objects.

The separation is a bit arbitrary, but all these symbols are used only
within the C source file where they are declared.

One meaningful change is in the calculation of NUM_SCHEDULERS.

Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
---
Changes in v8:
- remove SYMBOL_HIDE
- use new symbol names
- changes are split differently across the patches
---
 xen/common/kernel.c   | 11 +++++++----
 xen/common/lib.c      |  7 +++++--
 xen/common/schedule.c |  7 ++++---
 xen/common/spinlock.c |  8 +++++---
 xen/common/version.c  | 10 +++++-----
 5 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 5766a0f..7eea266 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -306,20 +306,23 @@ void add_taint(unsigned int flag)
     tainted |= flag;
 }
 
-extern const initcall_t __initcall_start[], __presmp_initcall_end[],
-    __initcall_end[];
+extern uintptr_t initcall_start_, presmp_initcall_end_, initcall_end_;
 
 void __init do_presmp_initcalls(void)
 {
     const initcall_t *call;
-    for ( call = __initcall_start; call < __presmp_initcall_end; call++ )
+    for ( call = (const initcall_t *)initcall_start_;
+          (uintptr_t)call < presmp_initcall_end_;
+          call++ )
         (*call)();
 }
 
 void __init do_initcalls(void)
 {
     const initcall_t *call;
-    for ( call = __presmp_initcall_end; call < __initcall_end; call++ )
+    for ( call = (const initcall_t *)presmp_initcall_end_;
+          (uintptr_t)call < initcall_end_;
+          call++ )
         (*call)();
 }
 
diff --git a/xen/common/lib.c b/xen/common/lib.c
index 8ebec81..e228b18 100644
--- a/xen/common/lib.c
+++ b/xen/common/lib.c
@@ -492,12 +492,15 @@ unsigned long long parse_size_and_unit(const char *s, 
const char **ps)
 }
 
 typedef void (*ctor_func_t)(void);
-extern const ctor_func_t __ctors_start[], __ctors_end[];
+extern uintptr_t ctors_start_, ctors_end_;
 
 void __init init_constructors(void)
 {
     const ctor_func_t *f;
-    for ( f = __ctors_start; f < __ctors_end; ++f )
+
+    for ( f = (const ctor_func_t *)ctors_start_;
+          (uintptr_t)f < ctors_end_;
+          ++f )
         (*f)();
 
     /* Putting this here seems as good (or bad) as any other place. */
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index a957c5e..13b9558 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -67,9 +67,10 @@ DEFINE_PER_CPU(struct scheduler *, scheduler);
 /* Scratch space for cpumasks. */
 DEFINE_PER_CPU(cpumask_t, cpumask_scratch);
 
-extern const struct scheduler *__start_schedulers_array[], 
*__end_schedulers_array[];
-#define NUM_SCHEDULERS (__end_schedulers_array - __start_schedulers_array)
-#define schedulers __start_schedulers_array
+extern uintptr_t start_schedulers_array_, end_schedulers_array_;
+#define NUM_SCHEDULERS ((end_schedulers_array_ - start_schedulers_array_) \
+                        / sizeof(const struct scheduler *))
+#define schedulers ((struct scheduler **)start_schedulers_array_)
 
 static struct scheduler __read_mostly ops;
 
diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 6bc52d7..766cdc1 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -318,8 +318,8 @@ struct lock_profile_anc {
 typedef void lock_profile_subfunc(
     struct lock_profile *, int32_t, int32_t, void *);
 
-extern struct lock_profile *__lock_profile_start;
-extern struct lock_profile *__lock_profile_end;
+extern uintptr_t lock_profile_start_;
+extern uintptr_t lock_profile_end_;
 
 static s_time_t lock_profile_start;
 static struct lock_profile_anc lock_profile_ancs[LOCKPROF_TYPE_N];
@@ -474,7 +474,9 @@ static int __init lock_prof_init(void)
 {
     struct lock_profile **q;
 
-    for ( q = &__lock_profile_start; q < &__lock_profile_end; q++ )
+    for ( q = (struct lock_profile **)lock_profile_start_;
+          (uintptr_t)q < lock_profile_end_;
+          q++ )
     {
         (*q)->next = lock_profile_glb_q.elem_q;
         lock_profile_glb_q.elem_q = *q;
diff --git a/xen/common/version.c b/xen/common/version.c
index 223cb52..246c96b 100644
--- a/xen/common/version.c
+++ b/xen/common/version.c
@@ -86,7 +86,7 @@ int xen_build_id(const void **p, unsigned int *len)
 
 #ifdef BUILD_ID
 /* Defined in linker script. */
-extern const Elf_Note __note_gnu_build_id_start[], __note_gnu_build_id_end[];
+extern uintptr_t note_gnu_build_id_start_, note_gnu_build_id_end_;
 
 int xen_build_id_check(const Elf_Note *n, unsigned int n_sz,
                        const void **p, unsigned int *len)
@@ -142,19 +142,19 @@ struct cv_info_pdb70
 
 static int __init xen_build_init(void)
 {
-    const Elf_Note *n = __note_gnu_build_id_start;
+    const Elf_Note *n = (const Elf_Note *)note_gnu_build_id_start_;
     unsigned int sz;
     int rc;
 
     /* --build-id invoked with wrong parameters. */
-    if ( __note_gnu_build_id_end <= &n[0] )
+    if ( note_gnu_build_id_end_ <= (uintptr_t)&n[0] )
         return -ENODATA;
 
     /* Check for full Note header. */
-    if ( &n[1] >= __note_gnu_build_id_end )
+    if ( (uintptr_t)&n[1] >= note_gnu_build_id_end_ )
         return -ENODATA;
 
-    sz = (void *)__note_gnu_build_id_end - (void *)n;
+    sz = note_gnu_build_id_end_ - (uintptr_t)n;
 
     rc = xen_build_id_check(n, sz, &build_id_p, &build_id_len);
 
-- 
1.9.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel