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authorRussell King <rmk+kernel@armlinux.org.uk>2019-01-09 13:20:56 -0500
committerDavid A. Long <dave.long@linaro.org>2019-02-13 12:08:56 -0500
commitf762b665bef0c435998d5c6ae271c1ed1daeb7e8 (patch)
tree649cbc3fc7f74313801ab00c9a56cc086342273f
parentb991f790c4824b7e13b400429f9c485f10e6aa13 (diff)
downloadlinux-linaro-stable-f762b665bef0c435998d5c6ae271c1ed1daeb7e8.tar.gz
ARM: ensure that processor vtables is not lost after boot
Commit 3a4d0c2172bcf15b7a3d9d498b2b355f9864286b upstream. 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> Signed-off-by: David A. Long <dave.long@linaro.org>
-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 7d9176c4a21d..7be1d7921342 100644
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -275,6 +275,13 @@
.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)
@@ -310,6 +317,9 @@ 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