xnu-4570.71.2.tar.gz

[apple/xnu.git] / libsyscall / custom / __fork.s

diff --git a/libsyscall/custom/__fork.s b/libsyscall/custom/__fork.s
index 5857ab2ad94fc8e1c3a7cac925c36dca46b0597a..dc517a1a28c3cde24d34f7709b0ebbdde8922adc 100644 (file)
--- a/libsyscall/custom/__fork.s
+++ b/libsyscall/custom/__fork.s
@@ -100,6 +100,59 @@ L2:
        addq    $24, %rsp   // restore the stack
        ret
 
+#elif defined(__arm__)
+       
+MI_ENTRY_POINT(___fork)
+       stmfd   sp!, {r4, r7, lr}
+       add     r7, sp, #4
+
+       mov     r1, #1                                  // prime results
+       mov     r12, #SYS_fork
+       swi     #SWI_SYSCALL                            // make the syscall
+       bcs     Lbotch                                  // error?
+
+       cmp     r1, #0                                  // parent (r1=0) or child(r1=1)
+       beq     Lparent
+
+       //child here...
+       MI_GET_ADDRESS(r3, __current_pid)
+       mov     r0, #0
+       str     r0, [r3]                // clear cached pid in child
+       ldmfd   sp!, {r4, r7, pc}
+
+Lbotch:
+       MI_CALL_EXTERNAL(_cerror)                       // jump here on error
+       mov     r0,#-1                                  // set the error
+       // fall thru
+Lparent:       
+       ldmfd   sp!, {r4, r7, pc}                       // pop and return
+
+#elif defined(__arm64__)
+
+#include <mach/arm64/asm.h>
+       
+MI_ENTRY_POINT(___fork)
+       PUSH_FRAME
+       // ARM moves a 1 in to r1 here, but I can't see why.
+       mov             x16, #SYS_fork                          // Syscall code
+       svc             #SWI_SYSCALL                            // Trap to kernel
+       b.cs    Lbotch                                          // Carry bit indicates failure
+       cbz             x1, Lparent                                     // x1 == 0 indicates that we are the parent
+
+       // Child
+       MI_GET_ADDRESS(x9, __current_pid)       // Get address of cached "current pid"
+       mov             w0, #0  
+       str             w0, [x9]                                        // Clear cached current pid                             
+       POP_FRAME                                                       // And done
+       ret
+
+Lbotch:
+       MI_CALL_EXTERNAL(_cerror)                       // Handle error
+       mov             w0, #-1                                         // Return value is -1
+Lparent:
+       POP_FRAME                                                       // Return
+       ret
+
 #else
 #error Unsupported architecture
 #endif