[Minios-devel] [PATCH v3 22/43] arm64: implement the __arch_switch_threads

[Huang Shijie <shijie.huang@xxxxxxx>]

The __arch_switch_threads is used for switching the threads.
This patch implements it.

Signed-off-by: Huang Shijie <shijie.huang@xxxxxxx>
---
 arch/arm/arm64/arm64.S | 38 ++++++++++++++++++++++++++++++++++++++
 include/arm/arm64/os.h |  4 ++++
 2 files changed, 42 insertions(+)

diff --git a/arch/arm/arm64/arm64.S b/arch/arm/arm64/arm64.S
index fa3406f..5f55f99 100644
--- a/arch/arm/arm64/arm64.S
+++ b/arch/arm/arm64/arm64.S
@@ -1,5 +1,6 @@
 #include "asm.h"
 #include <arch_limits.h>
+#include <arm64/os.h>
 #include <arm64/pagetable.h>
 #include <arm64/traps.h>
 #include <xen/xen.h>
@@ -434,3 +435,40 @@ ENTRY(vector_table)
     vector_entry el0_fiq_invalid          /* FIQ 32-bit EL0         */
     vector_entry el0_error_invalid        /* Error 32-bit EL0       */
 END(vector_table)
+
+/*
+ * => x0 = &prev->sp
+ *    x1 = &next->sp
+ * <= switch to the next thread
+ */
+ENTRY(__arch_switch_threads)
+    /* Store the callee-saved registers to prev's struct thread */
+    mov   x2, sp
+
+    sub   x2, x2, #(CALLEE_SAVED_REGISTERS * 8)
+    stp   x19, x20, [x2, #16 * 0]
+    stp   x21, x22, [x2, #16 * 1]
+    stp   x23, x24, [x2, #16 * 2]
+    stp   x25, x26, [x2, #16 * 3]
+    stp   x27, x28, [x2, #16 * 4]
+    str   x29, [x2, #16 * 5]
+
+    /* Store current sp/ip to prev's struct thread */
+    stp   x2, x30, [x0]
+
+    /* Load the sp/ip from next's struct thread */
+    ldp   x2, x30, [x1]
+
+    /* Restore the callee-saved registers */
+    ldp   x19, x20, [x2, #16 * 0]
+    ldp   x21, x22, [x2, #16 * 1]
+    ldp   x23, x24, [x2, #16 * 2]
+    ldp   x25, x26, [x2, #16 * 3]
+    ldp   x27, x28, [x2, #16 * 4]
+    ldr   x29, [x2, #16 * 5]
+
+    add   x2, x2, #(CALLEE_SAVED_REGISTERS * 8)
+    mov   sp, x2
+
+    br    x30
+ENDPROC(__arch_switch_threads)
diff --git a/include/arm/arm64/os.h b/include/arm/arm64/os.h
index 89b4002..2d55023 100644
--- a/include/arm/arm64/os.h
+++ b/include/arm/arm64/os.h
@@ -1,6 +1,8 @@
 #ifndef _ARM64_OS_H_
 #define _ARM64_OS_H_
 
+#ifndef __ASSEMBLY__
+
 #define BUG()           __asm__ __volatile("wfi" ::: "memory")
 
 static inline void local_irq_disable(void)
@@ -25,6 +27,8 @@ static inline void local_irq_enable(void)
     __asm__ __volatile__("mrs %0, daif":"=r"(x)::"memory"); \
 }
 
+#endif
+
 /* The Callee-saved registers : x19 ~ x29 */
 #define CALLEE_SAVED_REGISTERS 11
 
-- 
2.7.4


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