ArmPkg/ArmSmcLib: Fixed SMC helper functions

[mirror_edk2.git] / ArmPkg / Library / ArmSmcLib / Arm / ArmSmc.S

diff --git a/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S b/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S
index c9c0740febe8707e77174861d685fbf017a4619e..260fb10fe86b9bf696b8908967f48f51a7414892 100644 (file)
--- a/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S
+++ b/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S
@@ -1,5 +1,5 @@
 //\r
-//  Copyright (c) 2012, ARM Limited. All rights reserved.\r
+//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.\r
 //\r
 //  This program and the accompanying materials\r
 //  are licensed and made available under the terms and conditions of the BSD License\r
@@ -16,60 +16,37 @@
 .arch_extension sec\r
 \r
 GCC_ASM_EXPORT(ArmCallSmc)\r
-GCC_ASM_EXPORT(ArmCallSmcArg1)\r
-GCC_ASM_EXPORT(ArmCallSmcArg2)\r
-GCC_ASM_EXPORT(ArmCallSmcArg3)\r
 \r
 ASM_PFX(ArmCallSmc):\r
-    push    {r1}\r
-    mov     r1, r0\r
-    ldr     r0,[r1]\r
-    smc     #0\r
-    str     r0,[r1]\r
-    pop     {r1}\r
-    bx      lr\r
+    push    {r4-r8}\r
+    // r0 will be popped just after the SMC call\r
+    push    {r0}\r
 \r
-ASM_PFX(ArmCallSmcArg1):\r
-    push    {r2-r3}\r
-    mov     r2, r0\r
-    mov     r3, r1\r
-    ldr     r0,[r2]\r
-    ldr     r1,[r3]\r
-    smc     #0\r
-    str     r0,[r2]\r
-    str     r1,[r3]\r
-    pop     {r2-r3}\r
-    bx      lr\r
+    // Load the SMC arguments values into the appropriate registers\r
+    ldr     r7, [r0, #28]\r
+    ldr     r6, [r0, #24]\r
+    ldr     r5, [r0, #20]\r
+    ldr     r4, [r0, #16]\r
+    ldr     r3, [r0, #12]\r
+    ldr     r2, [r0, #8]\r
+    ldr     r1, [r0, #4]\r
+    ldr     r0, [r0, #0]\r
 \r
-ASM_PFX(ArmCallSmcArg2):\r
-    push    {r3-r5}\r
-    mov     r3, r0\r
-    mov     r4, r1\r
-    mov     r5, r2\r
-    ldr     r0,[r3]\r
-    ldr     r1,[r4]\r
-    ldr     r2,[r5]\r
     smc     #0\r
-    str     r0,[r3]\r
-    str     r1,[r4]\r
-    str     r2,[r5]\r
-    pop     {r3-r5}\r
-    bx      lr\r
 \r
-ASM_PFX(ArmCallSmcArg3):\r
-    push    {r4-r7}\r
-    mov     r4, r0\r
-    mov     r5, r1\r
-    mov     r6, r2\r
-    mov     r7, r3\r
-    ldr     r0,[r4]\r
-    ldr     r1,[r5]\r
-    ldr     r2,[r6]\r
-    ldr     r3,[r7]\r
-    smc     #0\r
-    str     r0,[r4]\r
-    str     r1,[r5]\r
-    str     r2,[r6]\r
-    str     r3,[r7]\r
-    pop     {r4-r7}\r
+    // Pop the ARM_SMC_ARGS structure address from the stack into r8\r
+    pop     {r8}\r
+\r
+    // Load the SMC returned values into the appropriate registers\r
+    // A SMC call can return up to 4 values - we do not need to store back r4-r7.\r
+    str     r3, [r8, #12]\r
+    str     r2, [r8, #8]\r
+    str     r1, [r8, #4]\r
+    str     r0, [r8, #0]\r
+\r
+    mov     r0, r8\r
+\r
+    // Restore the registers r4-r8\r
+    pop     {r4-r8}\r
+\r
     bx      lr\r