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author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2017-02-22 09:38:18 +0000 |
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committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2017-02-22 13:22:41 +0000 |
commit | 91231b55d5302065fac71bf5040809aec65bb2f7 (patch) | |
tree | 89fa4a1e535c8aca08e2181e69c1234ae9d0f7e9 /ArmPlatformPkg | |
parent | 88dab294d249f2cc22a72a0c2aa307d8432492b9 (diff) | |
download | edk2-platforms-91231b55d5302065fac71bf5040809aec65bb2f7.tar.xz |
ArmPlatformPkg/ArmPlatformStackLib: use callee preserved registers
The entry code in ArmPlatformStackSet () is a 1:1 transliteration of the
ARM version, which uses the callee preserved registers r3 - r7 (*) to
preserve the function arguments and the link register across a call to
ArmPlatformIsPrimaryCore ().
However, x3 - x7 are not callee preserved on AARCH64, and so we should use
registers >= x19 instead. While we're at it, drop an unnecessary preserve
of the link register, and simplify/deobfuscate the calculation of the
secondary stack position.
(*) Note that r3 is not actually a callee saved register even on ARM.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Diffstat (limited to 'ArmPlatformPkg')
-rw-r--r-- | ArmPlatformPkg/Library/ArmPlatformStackLib/AArch64/ArmPlatformStackLib.S | 43 |
1 files changed, 19 insertions, 24 deletions
diff --git a/ArmPlatformPkg/Library/ArmPlatformStackLib/AArch64/ArmPlatformStackLib.S b/ArmPlatformPkg/Library/ArmPlatformStackLib/AArch64/ArmPlatformStackLib.S index 65d7d6c6d6..e219d53cb7 100644 --- a/ArmPlatformPkg/Library/ArmPlatformStackLib/AArch64/ArmPlatformStackLib.S +++ b/ArmPlatformPkg/Library/ArmPlatformStackLib/AArch64/ArmPlatformStackLib.S @@ -22,13 +22,13 @@ // );
ASM_FUNC(ArmPlatformStackSet)
// Save parameters
- mov x6, x3
- mov x5, x2
- mov x4, x1
- mov x3, x0
+ mov x26, x3
+ mov x25, x2
+ mov x24, x1
+ mov x23, x0
// Save the Link register
- mov x7, x30
+ mov x27, x30
// Identify Stack
mov x0, x1
@@ -36,13 +36,13 @@ ASM_FUNC(ArmPlatformStackSet) cmp x0, #1
// Restore parameters
- mov x0, x3
- mov x1, x4
- mov x2, x5
- mov x3, x6
+ mov x0, x23
+ mov x1, x24
+ mov x2, x25
+ mov x3, x26
// Restore the Link register
- mov x30, x7
+ mov x30, x27
b.ne 0f
@@ -57,10 +57,7 @@ ASM_FUNC(ArmPlatformStackSet) // IN UINTN SecondaryStackSize
// );
ASM_FUNC(ArmPlatformStackSetPrimary)
- // Save the Link register
- mov x4, x30
-
- // Add stack of primary stack to StackBase
+ // Add size of primary stack to StackBase
add x0, x0, x2
// Compute SecondaryCoresCount * SecondaryCoreStackSize
@@ -70,7 +67,7 @@ ASM_FUNC(ArmPlatformStackSetPrimary) // Set Primary Stack ((StackBase + PrimaryStackSize) + (SecondaryCoresCount * SecondaryCoreStackSize))
add sp, x0, x3
- br x4
+ ret
//VOID
//ArmPlatformStackSetSecondary (
@@ -81,30 +78,28 @@ ASM_FUNC(ArmPlatformStackSetPrimary) // );
ASM_FUNC(ArmPlatformStackSetSecondary)
// Save the Link register
- mov x4, x30
+ mov x24, x30
mov sp, x0
// Get Core Position
mov x0, x1
bl ASM_PFX(ArmPlatformGetCorePosition)
- mov x5, x0
+ mov x25, x0
// Get Primary Core Position
bl ASM_PFX(ArmPlatformGetPrimaryCoreMpId)
bl ASM_PFX(ArmPlatformGetCorePosition)
// Get Secondary Core Position. We should get consecutive secondary stack number from 1...(CoreCount-1)
- cmp x5, x0
- b.ls 1f
+ cmp x25, x0
+
// Decrement the position if after the primary core
- sub x5, x5, #1
-1:
- add x5, x5, #1
+ cinc x25, x25, ls
// Compute top of the secondary stack
- mul x3, x3, x5
+ mul x3, x3, x25
// Set stack
add sp, sp, x3
- br x4
+ ret x24
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