From 3a4d0c2172bcf15b7a3d9d498b2b355f9864286b Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 6 Dec 2018 16:36:38 +0000 Subject: [PATCH] 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 Tested-by: Krzysztof Kozlowski Fixes: 383fb3ee8024 ("ARM: spectre-v2: per-CPU vtables to work around big.Little systems") Signed-off-by: Russell King --- arch/arm/mm/proc-macros.S | 10 ++++++++++ 1 file changed, 10 insertions(+) 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 -- 2.30.2