diff mbox series

[4.9,15/16] ARM: ensure that processor vtables is not lost after boot

Message ID 20190214144930.27539-16-dave.long@linaro.org
State New
Headers show
Series V4.9 backport of more 32-bit arm spectre patches | expand

Commit Message

David Long Feb. 14, 2019, 2:49 p.m. UTC 
From: Russell King <rmk+kernel@armlinux.org.uk>


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>

---
 arch/arm/mm/proc-macros.S | 10 ++++++++++
 1 file changed, 10 insertions(+)

-- 
2.17.1
diff mbox series

Patch

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