arm: rewrite shuffle_scno in a bit more readable way
* linux/arm/syscallent.h: Define ARM_FIRST_SHUFFLED_SYSCALL instead of
ARM_LAST_ORDINARY_SYSCALL.
* syscall.c [ARM || AARCH64] (shuffle_scno): Update.
diff --git a/syscall.c b/syscall.c
index 091626c..343fa30 100644
--- a/syscall.c
+++ b/syscall.c
@@ -930,34 +930,35 @@
#endif /* architecture */
}
-/* Shuffle syscall numbers so that we don't have huge gaps in syscall table.
- * The shuffling should be reversible: shuffle_scno(shuffle_scno(n)) == n.
+/*
+ * Shuffle syscall numbers so that we don't have huge gaps in syscall table.
+ * The shuffling should be an involution: shuffle_scno(shuffle_scno(n)) == n.
*/
#if defined(ARM) || defined(AARCH64) /* So far only 32-bit ARM needs this */
static long
shuffle_scno(unsigned long scno)
{
- if (scno <= ARM_LAST_ORDINARY_SYSCALL)
+ if (scno < ARM_FIRST_SHUFFLED_SYSCALL)
return scno;
/* __ARM_NR_cmpxchg? Swap with LAST_ORDINARY+1 */
- if (scno == 0x000ffff0)
- return ARM_LAST_ORDINARY_SYSCALL+1;
- if (scno == ARM_LAST_ORDINARY_SYSCALL+1)
+ if (scno == ARM_FIRST_SHUFFLED_SYSCALL)
return 0x000ffff0;
+ if (scno == 0x000ffff0)
+ return ARM_FIRST_SHUFFLED_SYSCALL;
- /* Is it ARM specific syscall?
- * Swap with [LAST_ORDINARY+2, LAST_ORDINARY+2 + LAST_SPECIAL] range.
+#define ARM_SECOND_SHUFFLED_SYSCALL (ARM_FIRST_SHUFFLED_SYSCALL + 1)
+ /*
+ * Is it ARM specific syscall?
+ * Swap [0x000f0000, 0x000f0000 + LAST_SPECIAL] range
+ * with [SECOND_SHUFFLED, SECOND_SHUFFLED + LAST_SPECIAL] range.
*/
- if (scno >= 0x000f0000
- && scno <= 0x000f0000 + ARM_LAST_SPECIAL_SYSCALL
- ) {
- return scno - 0x000f0000 + (ARM_LAST_ORDINARY_SYSCALL+2);
+ if (scno >= 0x000f0000 &&
+ scno <= 0x000f0000 + ARM_LAST_SPECIAL_SYSCALL) {
+ return scno - 0x000f0000 + ARM_SECOND_SHUFFLED_SYSCALL;
}
- if (/* scno >= ARM_LAST_ORDINARY_SYSCALL+2 - always true */ 1
- && scno <= (ARM_LAST_ORDINARY_SYSCALL+2) + ARM_LAST_SPECIAL_SYSCALL
- ) {
- return scno + 0x000f0000 - (ARM_LAST_ORDINARY_SYSCALL+2);
+ if (scno <= ARM_SECOND_SHUFFLED_SYSCALL + ARM_LAST_SPECIAL_SYSCALL) {
+ return scno + 0x000f0000 - ARM_SECOND_SHUFFLED_SYSCALL;
}
return scno;