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authorMichael Ellerman <mpe@ellerman.id.au>2023-10-25 12:24:52 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2023-11-27 22:01:14 +1100
commit98eb30fe4c69a9b602f29e406317c49b5580352a (patch)
treef0329c322c988c7f6d8432404fb821d72d7382ce
parent183bc0c640c785a710885a10b614193f114fe760 (diff)
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 <mpe@ellerman.id.au> Link: https://msgid.link/20231025012452.1985680-1-mpe@ellerman.id.au
-rw-r--r--arch/powerpc/kernel/cputable.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index e97a0fd0ae90..6f6801da9dc1 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -20,9 +20,9 @@
#include <asm/setup.h>
#include <asm/cpu_setup.h>
-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 */