The LEON3_Boot_Cpu global object is only used by start.S. Move the definition
of this object to start.S and use a local symbol .Lbootcpuindex for it.
Use a compare-and-swap instruction to assign the boot CPU. This allows a
concurrent initialization.
Close #4845.
---
bsps/sparc/leon3/start/bspstart.c | 5 -----
bsps/sparc/shared/start/start.S | 35 +++++++++++++++++++++----------
2 files changed, 24 insertions(+), 16 deletions(-)
diff --git a/bsps/sparc/leon3/start/bspstart.c
b/bsps/sparc/leon3/start/bspstart.c
index d93d73aca8..61f888247f 100644
--- a/bsps/sparc/leon3/start/bspstart.c
+++ b/bsps/sparc/leon3/start/bspstart.c
@@ -59,11 +59,6 @@ int CPU_SPARC_HAS_SNOOPING;
/* Index of CPU, in an AMP system CPU-index may be non-zero */
uint32_t LEON3_Cpu_Index = 0;
-#if defined(RTEMS_SMP)
-/* Index of the boot CPU. Set by the first CPU at boot to its CPU ID. */
-int LEON3_Boot_Cpu = -1;
-#endif
-
/*
* set_snooping
*
diff --git a/bsps/sparc/shared/start/start.S b/bsps/sparc/shared/start/start.S
index a67c6bc163..01f1353758 100644
--- a/bsps/sparc/shared/start/start.S
+++ b/bsps/sparc/shared/start/start.S
@@ -493,17 +493,13 @@ SYM(hard_reset):
mov %sp, %fp ! set frame pointer
#if defined(START_LEON3_ENABLE_SMP)
- /* If LEON3_Boot_Cpu < 0 then assign us as boot CPU and continue. */
- set SYM(LEON3_Boot_Cpu), %l0
- ld [%l0], %l1
- tst %l1
- bneg .Lbootcpu
- nop
-
- call SYM(bsp_start_on_secondary_processor) ! does not return
- mov %g6, %o0
-.Lbootcpu:
- st %l7, [%l0]
+ /* If .Lbootcpuindex < 0 then assign us as boot CPU and continue. */
+ set SYM(.Lbootcpuindex), %l0
+ mov -1, %l1
+ casa [ %l0 ] (10), %l1, %l7
+ cmp %l1, %l7
+ bne .Lbootsecondarycpu
+ nop
#endif
/* clear the bss */
@@ -527,4 +523,21 @@ SYM(hard_reset):
call SYM(boot_card) ! does not return
mov %g0, %o0 ! command line
+#if defined(START_LEON3_ENABLE_SMP)
+.Lbootsecondarycpu:
+ call SYM(bsp_start_on_secondary_processor) ! does not return
+ mov %g6, %o0
+
+ /*
+ * This is the index of the boot CPU. Set by the first CPU at boot to
+ * its CPU index.
+ */
+ .section .data, "aw"
+ .align 4
+ .type .Lbootcpuindex, #object
+ .size .Lbootcpuindex, 4
+.Lbootcpuindex:
+ .long -1
+#endif
+
/* end of file */
--
2.35.3
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