config COMPILE_IN_THUMB_MODE
bool "Build using Thumb mode"
select USE_BX
+ select USE_LDREXSTREX
help
Say 'y' here to force building uClibc in thumb mode.
Say 'n' to use your compiler's default mode.
Say 'y' to use BX to return from functions on your thumb-aware
processor. Say 'y' if you need to use interworking. Say 'n' if not.
It is safe to say 'y' even if you're not doing interworking.
+
+config USE_LDREXSTREX
+ bool "Use load-store exclusive ASM ops (not supported in SmartFusion)"
+ depends on COMPILE_IN_THUMB_MODE
+ default n
+ help
+ Say 'y' to use LDREX/STREX ASM ops.
#include <sys/syscall.h>
#include <bits/arm_asm.h>
#include <bits/arm_bx.h>
+
+#if defined __UCLIBC_HAS_THREADS__ && !defined __LINUXTHREADS_OLD__
#include <sysdep-cancel.h>
+#endif
#define CLONE_VM 0x00000100
#define CLONE_THREAD 0x00010000
@ get flags
mov r0, r2
@ new sp is already in r1
- @ load remaining arguments off the stack
- stmfd sp!, {r4}
- ldr r2, [sp, #4]
- ldr r3, [sp, #8]
- ldr r4, [sp, #12]
DO_CALL (clone)
movs a1, a1
blt __error
- ldmnefd sp!, {r4}
beq 1f
bx lr
1:
@ pick the function arg and call address off the stack and execute
ldr r0, [sp, #4]
+#if defined(__USE_BX__)
ldr r1, [sp]
bl 2f @ blx r1
+#else
+ mov lr, pc
+ ldr pc, [sp]
+#endif
@ and we are done, passing the return value through r0
bl HIDDEN_JUMPTARGET(_exit)
#ifndef _PT_MACHINE_H
#define _PT_MACHINE_H 1
-#include <features.h>
+#include <sys/syscall.h>
+#include <unistd.h>
#ifndef PT_EI
# define PT_EI __extern_always_inline
#endif
+#if defined(__thumb__)
+#if defined(__USE_LDREXSTREX__)
+PT_EI long int ldrex(int *spinlock)
+{
+ long int ret;
+ __asm__ __volatile__(
+ "ldrex %0, [%1]\n"
+ : "=r"(ret)
+ : "r"(spinlock) : "memory");
+ return ret;
+}
+
+PT_EI long int strex(int val, int *spinlock)
+{
+ long int ret;
+ __asm__ __volatile__(
+ "strex %0, %1, [%2]\n"
+ : "=r"(ret)
+ : "r" (val), "r"(spinlock) : "memory");
+ return ret;
+}
+
+/* Spinlock implementation; required. */
+PT_EI long int
+testandset (int *spinlock)
+{
+ register unsigned int ret;
+
+ do {
+ ret = ldrex(spinlock);
+ } while (strex(1, spinlock));
+
+ return ret;
+}
+
+#else /* __USE_LDREXSTREX__ */
+
/* This will not work on ARM1 or ARM2 because SWP is lacking on those
machines. Unfortunately we have no way to detect this at compile
time; let's hope nobody tries to use one. */
PT_EI long int testandset (int *spinlock)
{
register unsigned int ret;
-
-#if defined(__thumb__)
void *pc;
__asm__ __volatile__(
".align 0\n"
"\t.force_thumb"
: "=r"(ret), "=r"(pc)
: "0"(1), "r"(spinlock));
-#else
+ return ret;
+}
+#endif
+#else /* __thumb__ */
+
+PT_EI long int testandset (int *spinlock);
+PT_EI long int testandset (int *spinlock)
+{
+ register unsigned int ret;
__asm__ __volatile__("swp %0, %1, [%2]"
: "=r"(ret)
: "0"(1), "r"(spinlock));
-#endif
-
return ret;
}
-
+#endif
/* Get some notion of the current stack. Need not be exactly the top
of the stack, just something somewhere in the current frame. */