1 files changed, 80 insertions, 0 deletions
diff --git a/src/runtime/os_linux_arm.c b/src/runtime/os_linux_arm.c
new file mode 100644
index 000000000..e3eda7c2d
--- /dev/null
+++ b/src/runtime/os_linux_arm.c
@@ -0,0 +1,80 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "runtime.h"
+#include "defs_GOOS_GOARCH.h"
+#include "os_GOOS.h"
+#include "textflag.h"
+
+#define AT_NULL		0
+#define AT_PLATFORM	15 // introduced in at least 2.6.11
+#define AT_HWCAP	16 // introduced in at least 2.6.11
+#define AT_RANDOM	25 // introduced in 2.6.29
+#define HWCAP_VFP	(1 << 6) // introduced in at least 2.6.11
+#define HWCAP_VFPv3	(1 << 13) // introduced in 2.6.30
+static uint32 runtime·randomNumber;
+uint8  runtime·armArch = 6;	// we default to ARMv6
+uint32 runtime·hwcap;	// set by setup_auxv
+extern uint8  runtime·goarm;	// set by 5l
+
+void
+runtime·checkgoarm(void)
+{
+	if(runtime·goarm > 5 && !(runtime·hwcap & HWCAP_VFP)) {
+		runtime·printf("runtime: this CPU has no floating point hardware, so it cannot run\n");
+		runtime·printf("this GOARM=%d binary. Recompile using GOARM=5.\n", runtime·goarm);
+		runtime·exit(1);
+	}
+	if(runtime·goarm > 6 && !(runtime·hwcap & HWCAP_VFPv3)) {
+		runtime·printf("runtime: this CPU has no VFPv3 floating point hardware, so it cannot run\n");
+		runtime·printf("this GOARM=%d binary. Recompile using GOARM=6.\n", runtime·goarm);
+		runtime·exit(1);
+	}
+}
+
+#pragma textflag NOSPLIT
+void
+runtime·setup_auxv(int32 argc, byte **argv)
+{
+	byte **envp;
+	byte *rnd;
+	uint32 *auxv;
+	uint32 t;
+
+	// skip envp to get to ELF auxiliary vector.
+	for(envp = &argv[argc+1]; *envp != nil; envp++)
+		;
+	envp++;
+	
+	for(auxv=(uint32*)envp; auxv[0] != AT_NULL; auxv += 2) {
+		switch(auxv[0]) {
+		case AT_RANDOM: // kernel provided 16-byte worth of random data
+			if(auxv[1]) {
+				rnd = (byte*)auxv[1];
+				runtime·randomNumber = rnd[4] | rnd[5]<<8 | rnd[6]<<16 | rnd[7]<<24;
+			}
+			break;
+		case AT_PLATFORM: // v5l, v6l, v7l
+			if(auxv[1]) {
+				t = *(uint8*)(auxv[1]+1);
+				if(t >= '5' && t <= '7')
+					runtime·armArch = t - '0';
+			}
+			break;
+		case AT_HWCAP: // CPU capability bit flags
+			runtime·hwcap = auxv[1];
+			break;
+		}
+	}
+}
+
+#pragma textflag NOSPLIT
+int64
+runtime·cputicks(void)
+{
+	// Currently cputicks() is used in blocking profiler and to seed runtime·fastrand1().
+	// runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
+	// runtime·randomNumber provides better seeding of fastrand1.
+	return runtime·nanotime() + runtime·randomNumber;
+}