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authorRussell King <rmk+kernel@armlinux.org.uk>2018-12-06 16:36:38 +0000
committerRussell King <rmk+kernel@armlinux.org.uk>2018-12-06 16:42:05 +0000
commit3a4d0c2172bcf15b7a3d9d498b2b355f9864286b (patch)
tree7523c4e4e64414348d94ac766f8e9ae23df15da5
parent383fb3ee8024d596f488d2dbaf45e572897acbdb (diff)
downloadlinux-3a4d0c2172bcf15b7a3d9d498b2b355f9864286b.tar.gz
ARM: ensure that processor vtables is not lost after boot
Marek Szyprowski reported problems with CPU hotplug in current kernels. This was tracked down to the processor vtables being located in an init section, and therefore discarded after kernel boot, despite being required after boot to properly initialise the non-boot CPUs. Arrange for these tables to end up in .rodata when required. Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Krzysztof Kozlowski <krzk@kernel.org> Fixes: 383fb3ee8024 ("ARM: spectre-v2: per-CPU vtables to work around big.Little systems") Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
-rw-r--r--arch/arm/mm/proc-macros.S10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
index 81d0efb055c6..19516fbc2c55 100644
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -274,6 +274,13 @@
.endm
.macro define_processor_functions name:req, dabort:req, pabort:req, nommu=0, suspend=0, bugs=0
+/*
+ * If we are building for big.Little with branch predictor hardening,
+ * we need the processor function tables to remain available after boot.
+ */
+#if 1 // defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
+ .section ".rodata"
+#endif
.type \name\()_processor_functions, #object
.align 2
ENTRY(\name\()_processor_functions)
@@ -309,6 +316,9 @@ ENTRY(\name\()_processor_functions)
.endif
.size \name\()_processor_functions, . - \name\()_processor_functions
+#if 1 // defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
+ .previous
+#endif
.endm
.macro define_cache_functions name:req