From 98eb30fe4c69a9b602f29e406317c49b5580352a Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 25 Oct 2023 12:24:52 +1100 Subject: [PATCH] powerpc: Make cpu_spec __ro_after_init The cpu_spec is a struct holding various information about the CPU the kernel is executing on. It's populated early in boot and must not change after that. In particular the cpu_features and mmu_features hold the set of discovered CPU/MMU features and are used to set static keys for each feature, and do binary patching of assembly. So any change to the cpu_features/mmu_features later in boot will not be reflected in the state of the static keys or patched code. There is already logic to check that cpu_features/mmu_features don't change, see check_features() in feature-fixups.c. But as another layer of protection the entire cpu_spec should be read only after init, annotate it as such. Signed-off-by: Michael Ellerman Link: https://msgid.link/20231025012452.1985680-1-mpe@ellerman.id.au --- arch/powerpc/kernel/cputable.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c index e97a0fd0ae905..6f6801da9dc1e 100644 --- a/arch/powerpc/kernel/cputable.c +++ b/arch/powerpc/kernel/cputable.c @@ -20,9 +20,9 @@ #include #include -static struct cpu_spec the_cpu_spec __read_mostly; +static struct cpu_spec the_cpu_spec __ro_after_init; -struct cpu_spec* cur_cpu_spec __read_mostly = NULL; +struct cpu_spec *cur_cpu_spec __ro_after_init = NULL; EXPORT_SYMBOL(cur_cpu_spec); /* The platform string corresponding to the real PVR */ -- 2.30.2