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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 12:14:34 -0500
commitd4ab7783c5a390f40787436da9e4e8f558b302d5 (patch)
treeee9d80b5ac0d687571caa38229b5b1206bfba807
parent59dcedd42a346efecf05007aa2ae923bdde915a4 (diff)
downloadlinux-linaro-stable-d4ab7783c5a390f40787436da9e4e8f558b302d5.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 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