Make futex syscalls directly on aarch64
This saves ~1% CPU.
Change-Id: I56c20dce4655ac13c0339f9305799bd6424ada46
Signed-off-by: Austin Schuh <austin.schuh@bluerivertech.com>
diff --git a/aos/ipc_lib/aos_sync.cc b/aos/ipc_lib/aos_sync.cc
index 39ea4c6..6407a57 100644
--- a/aos/ipc_lib/aos_sync.cc
+++ b/aos/ipc_lib/aos_sync.cc
@@ -115,17 +115,24 @@
// result or a negated errno value. -1..-4095 mean errors and not successful
// results, which is guaranteed by the kernel.
//
-// They each have optimized versions for ARM EABI (the syscall interface is
-// different for non-EABI ARM, so that is the right thing to test for) that
-// don't go through syscall(2) or errno.
-// These use register variables to get the values in the right registers to
-// actually make the syscall.
+// They each have optimized versions for some architectures which don't go
+// through syscall(2) or errno. These use register variables to get the values
+// in the right registers to actually make the syscall.
-// The actual macro that we key off of to use the inline versions or not.
+// The actual macros that we key off of to use the inline versions or not.
#if defined(__ARM_EABI__)
+// The syscall interface is different for non-EABI ARM, so we test specifically
+// for EABI.
#define ARM_EABI_INLINE_SYSCALL 1
+#define AARCH64_INLINE_SYSCALL 0
+#elif defined(__aarch64__)
+// Linux only has one supported syscall ABI on aarch64, which is the one we
+// support.
+#define ARM_EABI_INLINE_SYSCALL 0
+#define AARCH64_INLINE_SYSCALL 1
#else
#define ARM_EABI_INLINE_SYSCALL 0
+#define AARCH64_INLINE_SYSCALL 0
#endif
// Used for FUTEX_WAIT, FUTEX_LOCK_PI, and FUTEX_TRYLOCK_PI.
@@ -144,6 +151,19 @@
"r"(timeout_reg), "r"(syscall_number)
: "memory");
return result;
+#elif AARCH64_INLINE_SYSCALL
+ register aos_futex *addr1_reg __asm__("x0") = addr1;
+ register int op_reg __asm__("x1") = op;
+ register int val1_reg __asm__("x2") = val1;
+ register const struct timespec *timeout_reg __asm__("x3") = timeout;
+ register int syscall_number __asm__("x8") = SYS_futex;
+ register int result __asm__("x0");
+ __asm__ volatile("svc #0"
+ : "=r"(result)
+ : "r"(addr1_reg), "r"(op_reg), "r"(val1_reg),
+ "r"(timeout_reg), "r"(syscall_number)
+ : "memory");
+ return result;
#else
const int r = syscall(SYS_futex, addr1, op, val1, timeout);
if (r == -1) return -errno;
@@ -164,6 +184,18 @@
"r"(syscall_number)
: "memory");
return result;
+#elif AARCH64_INLINE_SYSCALL
+ register aos_futex *addr1_reg __asm__("x0") = addr1;
+ register int op_reg __asm__("x1") = FUTEX_WAKE;
+ register int val1_reg __asm__("x2") = val1;
+ register int syscall_number __asm__("x8") = SYS_futex;
+ register int result __asm__("x0");
+ __asm__ volatile("svc #0"
+ : "=r"(result)
+ : "r"(addr1_reg), "r"(op_reg), "r"(val1_reg),
+ "r"(syscall_number)
+ : "memory");
+ return result;
#else
const int r = syscall(SYS_futex, addr1, FUTEX_WAKE, val1);
if (r == -1) return -errno;
@@ -190,6 +222,22 @@
"r"(syscall_number)
: "memory");
return result;
+#elif AARCH64_INLINE_SYSCALL
+ register aos_futex *addr1_reg __asm__("x0") = addr1;
+ register int op_reg __asm__("x1") = FUTEX_CMP_REQUEUE_PI;
+ register int num_wake_reg __asm__("x2") = num_wake;
+ register int num_requeue_reg __asm__("x3") = num_requeue;
+ register aos_futex *m_reg __asm__("x4") = m;
+ register uint32_t val_reg __asm__("x5") = val;
+ register int syscall_number __asm__("x8") = SYS_futex;
+ register int result __asm__("x0");
+ __asm__ volatile("svc #0"
+ : "=r"(result)
+ : "r"(addr1_reg), "r"(op_reg), "r"(num_wake_reg),
+ "r"(num_requeue_reg), "r"(m_reg), "r"(val_reg),
+ "r"(syscall_number)
+ : "memory");
+ return result;
#else
const int r = syscall(SYS_futex, addr1, FUTEX_CMP_REQUEUE_PI, num_wake,
num_requeue, m, val);
@@ -215,6 +263,20 @@
"r"(timeout_reg), "r"(m_reg), "r"(syscall_number)
: "memory");
return result;
+#elif AARCH64_INLINE_SYSCALL
+ register aos_condition *addr1_reg __asm__("x0") = addr1;
+ register int op_reg __asm__("x1") = FUTEX_WAIT_REQUEUE_PI;
+ register uint32_t start_val_reg __asm__("x2") = start_val;
+ register const struct timespec *timeout_reg __asm__("x3") = timeout;
+ register aos_futex *m_reg __asm__("x4") = m;
+ register int syscall_number __asm__("x8") = SYS_futex;
+ register int result __asm__("x0");
+ __asm__ volatile("svc #0"
+ : "=r"(result)
+ : "r"(addr1_reg), "r"(op_reg), "r"(start_val_reg),
+ "r"(timeout_reg), "r"(m_reg), "r"(syscall_number)
+ : "memory");
+ return result;
#else
const int r =
syscall(SYS_futex, addr1, FUTEX_WAIT_REQUEUE_PI, start_val, timeout, m);
@@ -234,6 +296,16 @@
: "r"(addr1_reg), "r"(op_reg), "r"(syscall_number)
: "memory");
return result;
+#elif AARCH64_INLINE_SYSCALL
+ register aos_futex *addr1_reg __asm__("x0") = addr1;
+ register int op_reg __asm__("x1") = FUTEX_UNLOCK_PI;
+ register int syscall_number __asm__("x8") = SYS_futex;
+ register int result __asm__("x0");
+ __asm__ volatile("svc #0"
+ : "=r"(result)
+ : "r"(addr1_reg), "r"(op_reg), "r"(syscall_number)
+ : "memory");
+ return result;
#else
const int r = syscall(SYS_futex, addr1, FUTEX_UNLOCK_PI);
if (r == -1) return -errno;