diff options
| author | Olivier Martin <olivier.martin@arm.com> | 2014-08-04 14:18:13 +0000 |
|---|---|---|
| committer | oliviermartin <oliviermartin@6f19259b-4bc3-4df7-8a09-765794883524> | 2014-08-04 14:18:13 +0000 |
| commit | b4e53e389d2a04678fb28bc445cd5b554bb175e0 (patch) | |
| tree | 02f998bd9cc6b4be7b903943872c0c5a5cbeda6f /ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm | |
| parent | 9a9dd4e8393177a48e5d8a773ce8aa42566045b9 (diff) | |
| download | edk2-platforms-b4e53e389d2a04678fb28bc445cd5b554bb175e0.tar.xz | |
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
Diffstat (limited to 'ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm')
| -rw-r--r-- | ArmPkg/Library/ArmSmcLib/Arm/ArmSmc.asm | 79 |
1 files changed, 28 insertions, 51 deletions
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
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