ArmPkg/ArmSmcLib: Fixed SMC helper functions

The SMC helper functions were buggy as they were assuming that
the values in x1-x7 registers were preserved across an SMC call,
which is not the case.  This patch fixes this issue.

It also simplifies the code by providing only 1 version of the SMC
helper function.  We used to have 4 versions depending on the number
of arguments.  The problem with this approach was that the number of
arguments also dictated the number of return values, which is
completely unrelated.  E.g. you can have an SMC call that takes
1 argument but returns 4 values.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>



git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15748 6f19259b-4bc3-4df7-8a09-765794883524

6 files changed, 77 insertions, 198 deletions

diff --git a/ArmPkg/Library/ArmSmcLib/AArch64/ArmSmc.S b/ArmPkg/Library/ArmSmcLib/AArch64/ArmSmc.S
index 579a73e96c..f73c98cfc3 100644
--- a/ArmPkg/Library/ArmSmcLib/AArch64/ArmSmc.S
+++ b/ArmPkg/Library/ArmSmcLib/AArch64/ArmSmc.S
@@ -1,5 +1,5 @@
 //

-//  Copyright (c) 2012-2013, ARM Limited. All rights reserved.

+//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.

 //

 //  This program and the accompanying materials

 //  are licensed and made available under the terms and conditions of the BSD License

@@ -15,64 +15,27 @@
 .align 3

 

 GCC_ASM_EXPORT(ArmCallSmc)

-GCC_ASM_EXPORT(ArmCallSmcArg1)

-GCC_ASM_EXPORT(ArmCallSmcArg2)

-GCC_ASM_EXPORT(ArmCallSmcArg3)

 

 ASM_PFX(ArmCallSmc):

-  str   x1, [sp, #-0x10]!

-  mov   x1, x0

-  ldr   x0,[x1]

-  smc   #0

-  str   x0,[x1]

-  ldr   x1, [sp], #0x10

-  ret

+  // Push x0 on the stack

+  str   x0, [sp, #-8]!

 

-ASM_PFX(ArmCallSmcArg1):

-  stp   x2, x3, [sp, #-0x10]!

-  mov   x2, x0

-  mov   x3, x1

-  ldr   x0,[x2]

-  ldr   x1,[x3]

-  smc   #0

-  str   x0,[x2]

-  str   x1,[x3]

-  ldp   x2, x3, [sp], #0x10

-  ret

+  // Load the SMC arguments values into the appropriate registers

+  ldp   x6, x7, [x0, #48]

+  ldp   x4, x5, [x0, #32]

+  ldp   x2, x3, [x0, #16]

+  ldp   x0, x1, [x0, #0]

 

-ASM_PFX(ArmCallSmcArg2):

-  stp   x3, x4, [sp, #-0x10]!

-  str   x5, [sp, #-8]!

-  mov   x3, x0

-  mov   x4, x1

-  mov   x5, x2

-  ldr   x0,[x3]

-  ldr   x1,[x4]

-  ldr   x2,[x5]

   smc   #0

-  str   x0,[x3]

-  str   x1,[x4]

-  str   x2,[x5]

-  ldr   x5, [sp], #8

-  ldp   x3, x4, [sp], #0x10

-  ret

 

-ASM_PFX(ArmCallSmcArg3):

-  stp   x4, x5, [sp, #-0x10]!

-  stp   x6, x7, [sp, #-0x10]!

-  mov   x4, x0

-  mov   x5, x1

-  mov   x6, x2

-  mov   x7, x3

-  ldr   x0,[x4]

-  ldr   x1,[x5]

-  ldr   x2,[x6]

-  ldr   x3,[x7]

-  smc   #0

-  str   x0,[x4]

-  str   x1,[x5]

-  str   x2,[x6]

-  str   x3,[x7]

-  ldp   x4, x5, [sp], #0x10

-  ldp   x6, x7, [sp], #0x10

+  // Pop the ARM_SMC_ARGS structure address from the stack into x9

+  ldr   x9, [sp], #8

+

+  // Store the SMC returned values into the appropriate registers

+  // A SMC call can return up to 4 values - we do not need to store back x4-x7.

+  stp   x2, x3, [x9, #16]

+  stp   x0, x1, [x9, #0]

+

+  mov   x0, x9

+

   ret

diff --git a/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S b/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S
index c9c0740feb..260fb10fe8 100644
--- a/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S
+++ b/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.S
@@ -1,5 +1,5 @@
 //

-//  Copyright (c) 2012, ARM Limited. All rights reserved.

+//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.

 //

 //  This program and the accompanying materials

 //  are licensed and made available under the terms and conditions of the BSD License

@@ -16,60 +16,37 @@
 .arch_extension sec

 

 GCC_ASM_EXPORT(ArmCallSmc)

-GCC_ASM_EXPORT(ArmCallSmcArg1)

-GCC_ASM_EXPORT(ArmCallSmcArg2)

-GCC_ASM_EXPORT(ArmCallSmcArg3)

 

 ASM_PFX(ArmCallSmc):

-    push    {r1}

-    mov     r1, r0

-    ldr     r0,[r1]

-    smc     #0

-    str     r0,[r1]

-    pop     {r1}

-    bx      lr

+    push    {r4-r8}

+    // r0 will be popped just after the SMC call

+    push    {r0}

 

-ASM_PFX(ArmCallSmcArg1):

-    push    {r2-r3}

-    mov     r2, r0

-    mov     r3, r1

-    ldr     r0,[r2]

-    ldr     r1,[r3]

-    smc     #0

-    str     r0,[r2]

-    str     r1,[r3]

-    pop     {r2-r3}

-    bx      lr

+    // Load the SMC arguments values into the appropriate registers

+    ldr     r7, [r0, #28]

+    ldr     r6, [r0, #24]

+    ldr     r5, [r0, #20]

+    ldr     r4, [r0, #16]

+    ldr     r3, [r0, #12]

+    ldr     r2, [r0, #8]

+    ldr     r1, [r0, #4]

+    ldr     r0, [r0, #0]

 

-ASM_PFX(ArmCallSmcArg2):

-    push    {r3-r5}

-    mov     r3, r0

-    mov     r4, r1

-    mov     r5, r2

-    ldr     r0,[r3]

-    ldr     r1,[r4]

-    ldr     r2,[r5]

     smc     #0

-    str     r0,[r3]

-    str     r1,[r4]

-    str     r2,[r5]

-    pop     {r3-r5}

-    bx      lr

 

-ASM_PFX(ArmCallSmcArg3):

-    push    {r4-r7}

-    mov     r4, r0

-    mov     r5, r1

-    mov     r6, r2

-    mov     r7, r3

-    ldr     r0,[r4]

-    ldr     r1,[r5]

-    ldr     r2,[r6]

-    ldr     r3,[r7]

-    smc     #0

-    str     r0,[r4]

-    str     r1,[r5]

-    str     r2,[r6]

-    str     r3,[r7]

-    pop     {r4-r7}

+    // Pop the ARM_SMC_ARGS structure address from the stack into r8

+    pop     {r8}

+

+    // Load the SMC returned values into the appropriate registers

+    // A SMC call can return up to 4 values - we do not need to store back r4-r7.

+    str     r3, [r8, #12]

+    str     r2, [r8, #8]

+    str     r1, [r8, #4]

+    str     r0, [r8, #0]

+

+    mov     r0, r8

+

+    // Restore the registers r4-r8

+    pop     {r4-r8}

+

     bx      lr

diff --git a/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm b/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm
index f46bd7ecd4..ad55ae7752 100644
--- a/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm
+++ b/ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm
@@ -1,5 +1,5 @@
 //

-//  Copyright (c) 2012, ARM Limited. All rights reserved.

+//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.

 //

 //  This program and the accompanying materials

 //  are licensed and made available under the terms and conditions of the BSD License

@@ -12,64 +12,41 @@
 //

 

     EXPORT ArmCallSmc

-    EXPORT ArmCallSmcArg1

-    EXPORT ArmCallSmcArg2

-    EXPORT ArmCallSmcArg3

 

     AREA   ArmSmc, CODE, READONLY

 

 ArmCallSmc

-    push    {r1}

-    mov     r1, r0

-    ldr     r0,[r1]

-    smc     #0

-    str     r0,[r1]

-    pop     {r1}

-    bx      lr

+    push    {r4-r8}

+    // r0 will be popped just after the SMC call

+    pop     {r0}

 

-ArmCallSmcArg1

-    push    {r2-r3}

-    mov     r2, r0

-    mov     r3, r1

-    ldr     r0,[r2]

-    ldr     r1,[r3]

-    smc     #0

-    str     r0,[r2]

-    str     r1,[r3]

-    pop     {r2-r3}

-    bx      lr

+    // Load the SMC arguments values into the appropriate registers

+    ldr     r7, [r0, #28]

+    ldr     r6, [r0, #24]

+    ldr     r5, [r0, #20]

+    ldr     r4, [r0, #16]

+    ldr     r3, [r0, #12]

+    ldr     r2, [r0, #8]

+    ldr     r1, [r0, #4]

+    ldr     r0, [r0, #0]

 

-ArmCallSmcArg2

-    push    {r3-r5}

-    mov     r3, r0

-    mov     r4, r1

-    mov     r5, r2

-    ldr     r0,[r3]

-    ldr     r1,[r4]

-    ldr     r2,[r5]

     smc     #0

-    str     r0,[r3]

-    str     r1,[r4]

-    str     r2,[r5]

-    pop     {r3-r5}

-    bx      lr

 

-ArmCallSmcArg3

-    push    {r4-r7}

-    mov     r4, r0

-    mov     r5, r1

-    mov     r6, r2

-    mov     r7, r3

-    ldr     r0,[r4]

-    ldr     r1,[r5]

-    ldr     r2,[r6]

-    ldr     r3,[r7]

-    smc     #0

-    str     r0,[r4]

-    str     r1,[r5]

-    str     r2,[r6]

-    str     r3,[r7]

-    pop     {r4-r7}

+    // Pop the ARM_SMC_ARGS structure address from the stack into r8

+    pop     {r8}

+

+    // Load the SMC returned values into the appropriate registers

+    // A SMC call can return up to 4 values - we do not need to store back r4-r7.

+    str     r3, [r8, #12]

+    str     r2, [r8, #8]

+    str     r1, [r8, #4]

+    str     r0, [r8, #0]

+

+    mov     r0, r8

+

+    // Restore the registers r4-r8

+    pop     {r4-r8}

+

     bx      lr

 

     END

diff --git a/ArmPkg/Library/ArmSmcLibNull/AArch64/ArmSmcNull.S b/ArmPkg/Library/ArmSmcLibNull/AArch64/ArmSmcNull.S
index ec6e067ac3..a6ef0e04da 100644
--- a/ArmPkg/Library/ArmSmcLibNull/AArch64/ArmSmcNull.S
+++ b/ArmPkg/Library/ArmSmcLibNull/AArch64/ArmSmcNull.S
@@ -1,5 +1,5 @@
 //

-//  Copyright (c) 2012-2013, ARM Limited. All rights reserved.

+//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.

 //

 //  This program and the accompanying materials

 //  are licensed and made available under the terms and conditions of the BSD License

@@ -15,18 +15,6 @@
 .align 3

 

 GCC_ASM_EXPORT(ArmCallSmc)

-GCC_ASM_EXPORT(ArmCallSmcArg1)

-GCC_ASM_EXPORT(ArmCallSmcArg2)

-GCC_ASM_EXPORT(ArmCallSmcArg3)

 

 ASM_PFX(ArmCallSmc):

   ret

-

-ASM_PFX(ArmCallSmcArg1):

-  ret

-

-ASM_PFX(ArmCallSmcArg2):

-  ret

-

-ASM_PFX(ArmCallSmcArg3):

-  ret

diff --git a/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.S b/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.S
index 4896dd0c9b..9eaefd30cf 100644
--- a/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.S
+++ b/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.S
@@ -1,5 +1,5 @@
 //

-//  Copyright (c) 2012-2013, ARM Limited. All rights reserved.

+//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.

 //

 //  This program and the accompanying materials

 //  are licensed and made available under the terms and conditions of the BSD License

@@ -15,19 +15,6 @@
 .align 3

 

 GCC_ASM_EXPORT(ArmCallSmc)

-GCC_ASM_EXPORT(ArmCallSmcArg1)

-GCC_ASM_EXPORT(ArmCallSmcArg2)

-GCC_ASM_EXPORT(ArmCallSmcArg3)

 

 ASM_PFX(ArmCallSmc):

   bx     lr

-

-// Arg1 in R1

-ASM_PFX(ArmCallSmcArg1):

-  bx     lr

-

-ASM_PFX(ArmCallSmcArg2):

-  bx     lr

-

-ASM_PFX(ArmCallSmcArg3):

-  bx     lr

diff --git a/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.asm b/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.asm
index 24c20752e3..3d3f554554 100644
--- a/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.asm
+++ b/ArmPkg/Library/ArmSmcLibNull/Arm/ArmSmcNull.asm
@@ -1,5 +1,5 @@
 //

-//  Copyright (c) 2012-2013, ARM Limited. All rights reserved.

+//  Copyright (c) 2012-2014, ARM Limited. All rights reserved.

 //

 //  This program and the accompanying materials

 //  are licensed and made available under the terms and conditions of the BSD License

@@ -12,23 +12,10 @@
 //

 

     EXPORT ArmCallSmc

-    EXPORT ArmCallSmcArg1

-    EXPORT ArmCallSmcArg2

-    EXPORT ArmCallSmcArg3

 

     AREA   ArmSmc, CODE, READONLY

 

 ArmCallSmc

   bx     lr

 

-// Arg1 in R1

-ArmCallSmcArg1

-  bx     lr

-

-ArmCallSmcArg2

-  bx     lr

-

-ArmCallSmcArg3

-  bx     lr

-

   END