[PATCH 4/4] arm64: cpufeature: always log KPTI setting on boot
From: Mark Langsdorf <hidden>
Date: 2018-05-24 19:09:32
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Always log KPTI setting at boot time, whether or not KPTI was forced by a kernel parameter. Signed-off-by: Mark Langsdorf <redacted> --- arch/arm64/kernel/cpufeature.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 697a6ef..e50bf3c 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c@@ -889,16 +889,20 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, __pti_enabled = __kpti_forced > 0; pr_info_once("kernel page table isolation forced %s by %s\n", __pti_enabled ? "ON" : "OFF", str); + } else { + /* Useful for KASLR robustness */ + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) + __pti_enabled = true; + /* Don't force KPTI for CPUs that are not vulnerable */ + else if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list)) + __pti_enabled = false; + /* Defer to CPU feature registers */ + else + __pti_enabled = !has_cpuid_feature(entry, scope); + + pr_info_once("kernel page table isolation %s by %s\n", + __pti_enabled ? "ON" : "OFF", str); } - /* Useful for KASLR robustness */ - else if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) - __pti_enabled = true; - /* Don't force KPTI for CPUs that are not vulnerable */ - else if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list)) - __pti_enabled = false; - /* Defer to CPU feature registers */ - else - __pti_enabled = !has_cpuid_feature(entry, scope); return __pti_enabled; }
--
2.9.5