sravan/system76-edk2
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ArmPkg/ArmSmcLib: Fixed SMC helper functions

Browse Source 
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
This commit is contained in:
Olivier Martin
2014-08-04 14:18:13 +00:00
committed by oliviermartin
parent 9a9dd4e839
commit b4e53e389d
7 changed files with 102 additions and 221 deletions
Download Patch File Download Diff File Expand all files Collapse all files

73
ArmPkg/Library/ArmSmcLib/AArch64/ArmSmc.S
View File

@@ -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