xnu-6153.141.1.tar.gz

[apple/xnu.git] / osfmk / x86_64 / machine_routines_asm.s

diff --git a/osfmk/x86_64/machine_routines_asm.s b/osfmk/x86_64/machine_routines_asm.s
index 1d2e3ed3fa18c7391182d987d522263feb385694..c0a1bdc90cde088a4d5a3440406f126ec61ed2ca 100644 (file)
--- a/osfmk/x86_64/machine_routines_asm.s
+++ b/osfmk/x86_64/machine_routines_asm.s
@@ -39,9 +39,7 @@
 /*
 **      ml_get_timebase()
 **
-**      Entry   - %rdi contains pointer to 64 bit structure.
-**
-**      Exit    - 64 bit structure filled in.
+**      Returns TSC in RAX
 **
 */
 ENTRY(ml_get_timebase)
@@ -51,7 +49,6 @@ ENTRY(ml_get_timebase)
        lfence
         shlq   $32,%rdx 
         orq    %rdx,%rax
-       movq    %rax, (%rdi)
                        
        ret
 
@@ -81,10 +78,15 @@ ENTRY(ml_get_timebase)
  *
  */
 ENTRY(tmrCvt)
+       cmpq    $1,%rsi                         /* check for unity fastpath */
+       je      1f
        movq    %rdi,%rax
        mulq    %rsi                            /* result is %rdx:%rax */
        shrdq   $32,%rdx,%rax                   /* %rdx:%rax >>= 32 */
        ret
+1:
+       mov     %rdi,%rax
+       ret
 
  /*
  * void _rtc_nanotime_adjust(
@@ -173,62 +175,45 @@ ENTRY(_rtc_tsc_to_nanoseconds)
        shrdq   $32,%rdx,%rax                   /* %rdx:%rax >>= 32 */
        ret
     
-    
+
+/*
+ *  typedef void (*thread_continue_t)(void *param, wait_result_t)
+ *
+ *     void call_continuation( thread_continue_t continuation,
+ *                                     void *param,
+ *                                         wait_result_t wresult,
+ *                          bool enable interrupts)
+ */
 
 Entry(call_continuation)
-       movq    %rdi,%rcx                       /* get continuation */
-       movq    %rsi,%rdi                       /* continuation param */
-       movq    %rdx,%rsi                       /* wait result */
+
+       movq    %rdi, %r12  /* continuation */
+    movq    %rsi, %r13  /* continuation param */
+    movq    %rdx, %r14  /* wait result */
+
        movq    %gs:CPU_KERNEL_STACK,%rsp       /* set the stack */
        xorq    %rbp,%rbp                       /* zero frame pointer */
+
+    test    %ecx, %ecx
+    jz 1f
+    mov     $1, %edi
+    call   _ml_set_interrupts_enabled
+1:
+
+       movq    %r12,%rcx                       /* continuation */
+       movq    %r13,%rdi                       /* continuation param */
+       movq    %r14,%rsi                       /* wait result */
+
        call    *%rcx                           /* call continuation */
        movq    %gs:CPU_ACTIVE_THREAD,%rdi
        call    EXT(thread_terminate)
 
+
 Entry(x86_init_wrapper)
        xor     %rbp, %rbp
        movq    %rsi, %rsp
        callq   *%rdi
 
-       /*
-       * Generate a 64-bit quantity with possibly random characteristics, intended for use
-       * before the kernel entropy pool is available. The processor's RNG is used if
-       * available, and a value derived from the Time Stamp Counter is returned if not.
-       * Multiple invocations may result in well-correlated values if sourced from the TSC.
-       */
-Entry(ml_early_random)
-       mov     %rbx, %rsi
-       mov     $1, %eax
-       cpuid
-       mov     %rsi, %rbx
-       test    $(1 << 30), %ecx
-       jz      Lnon_rdrand
-       RDRAND_RAX              /* RAX := 64 bits of DRBG entropy */
-       jnc     Lnon_rdrand
-       ret
-Lnon_rdrand:
-       rdtsc /* EDX:EAX := TSC */
-       /* Distribute low order bits */
-       mov     %eax, %ecx
-       xor     %al, %ah
-       shl     $16, %rcx
-       xor     %rcx, %rax
-       xor     %eax, %edx
-
-       /* Incorporate ASLR entropy, if any */
-       lea     (%rip), %rcx
-       shr     $21, %rcx
-       movzbl  %cl, %ecx
-       shl     $16, %ecx
-       xor     %ecx, %edx
-
-       mov     %ah, %cl
-       ror     %cl, %edx /* Right rotate EDX (TSC&0xFF ^ (TSC>>8 & 0xFF))&1F */
-       shl     $32, %rdx
-       xor     %rdx, %rax
-       mov     %cl, %al
-       ret
-       
 #if CONFIG_VMX
 
 /*
@@ -268,3 +253,14 @@ Entry(__vmxoff)
        ret
 
 #endif /* CONFIG_VMX */
+
+/*
+ *     mfence -- Memory Barrier
+ *     Use out-of-line assembly to get
+ *     standard x86-64 ABI guarantees
+ *     about what the caller's codegen
+ *     has in registers vs. memory
+ */
+Entry(do_mfence)
+       mfence
+       ret