[edk2-devel] [PATCH v2 2/2] ArmPkg/ArmMmuLib: Fix ArmReplaceLiveTranslationEntry() alignment

[Marvin Häuser]

As the ASM_FUNC() macro performs a section switch, the preceding
.balign directive applies the alignment constraint to the current
location in the previous section. As the linker may not merge the
sections in-order, ArmReplaceLiveTranslationEntry() may be left
unaligned.

Replace the explicit invocation of .balign with the ASM_FUNC_ALIGN()
macro, which guarantees the alignment constraint is applied correctly.

Reviewed-by: Leif Lindholm <quic_llindhol at quicinc.com>
Signed-off-by: Marvin Häuser <mhaeuser at posteo.de>
Cc: Leif Lindholm <quic_llindhol at quicinc.com>
Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
Cc: Sami Mujawar <sami.mujawar at arm.com>
Cc: Vitaly Cheptsov <vit9696 at protonmail.com>
---
 ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibReplaceEntry.S | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibReplaceEntry.S b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibReplaceEntry.S
index e936a5be4e11..7627aeb95464 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibReplaceEntry.S
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibReplaceEntry.S
@@ -69,17 +69,16 @@
 .L2_\@:
   .endm
 
-  // Align this routine to a log2 upper bound of its size, so that it is
-  // guaranteed not to cross a page or block boundary.
-  .balign 0x200
-
 //VOID
 //ArmReplaceLiveTranslationEntry (
 //  IN  UINT64  *Entry,
 //  IN  UINT64  Value,
 //  IN  UINT64  Address
 //  )
-ASM_FUNC(ArmReplaceLiveTranslationEntry)
+//
+// Align this routine to a log2 upper bound of its size, so that it is
+// guaranteed not to cross a page or block boundary.
+ASM_FUNC_ALIGN(ArmReplaceLiveTranslationEntry, 0x200)
 
   // disable interrupts
   mrs   x4, daif
-- 
2.40.0



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