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authorMarc Zyngier <marc.zyngier@arm.com>2015-06-03 14:36:23 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2015-06-05 10:38:52 +0100
commitb0dd9c02d476162340ad60fc96befa817fa8fe9f (patch)
treeda38aa4858c587ef098f1097bcfb8796eefdfbcd /arch/arm64/kernel/entry.S
parent10b48f7ef2a765452a583dbc256ed7da7fe7f1fc (diff)
downloadop-kernel-dev-b0dd9c02d476162340ad60fc96befa817fa8fe9f.zip
op-kernel-dev-b0dd9c02d476162340ad60fc96befa817fa8fe9f.tar.gz
arm64: Rework alternate sequence for ARM erratum 845719
The workaround for erratum 845719 is currently using a branch between two alternate sequences, which is quite fragile, and that we are going to break as we rework the alternative code. This patch reworks the workaround to fit in a single alternative sequence. The generated code itself is unchanged. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/entry.S')
-rw-r--r--arch/arm64/kernel/entry.S27
1 files changed, 15 insertions, 12 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 959fe87..9fe1a85 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -124,21 +124,24 @@
msr sp_el0, x23
#ifdef CONFIG_ARM64_ERRATUM_845719
- alternative_insn \
- "nop", \
- "tbz x22, #4, 1f", \
- ARM64_WORKAROUND_845719
+
+#undef SEQUENCE_ORG
+#undef SEQUENCE_ALT
+
#ifdef CONFIG_PID_IN_CONTEXTIDR
- alternative_insn \
- "nop; nop", \
- "mrs x29, contextidr_el1; msr contextidr_el1, x29; 1:", \
- ARM64_WORKAROUND_845719
+
+#define SEQUENCE_ORG "nop ; nop ; nop"
+#define SEQUENCE_ALT "tbz x22, #4, 1f ; mrs x29, contextidr_el1; msr contextidr_el1, x29; 1:"
+
#else
- alternative_insn \
- "nop", \
- "msr contextidr_el1, xzr; 1:", \
- ARM64_WORKAROUND_845719
+
+#define SEQUENCE_ORG "nop ; nop"
+#define SEQUENCE_ALT "tbz x22, #4, 1f ; msr contextidr_el1, xzr; 1:"
+
#endif
+
+ alternative_insn SEQUENCE_ORG, SEQUENCE_ALT, ARM64_WORKAROUND_845719
+
#endif
.endif
msr elr_el1, x21 // set up the return data
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