Hi folks, This series fixes __ro_after_init keys used in modules (courtesy of PeterZ) and flags more keys as __ro_after_init. Further context for why I'm looking into this here: http://lore.kernel.org/r/20230720163056.2564824-1-vschneid@xxxxxxxxxx Compile & boot tested for x86_64_defconfig and i386_defconfig. @Peter, regarding making __use_tsc x86_32, I hit a few snags. Currently, for the static key to be enabled, we (mostly) need: o X86_FEATURE_TSC is in CPUID o determine_cpu_tsc_frequencies passes All X86_64 systems have a TSC, so the CPUID feature is a given there. Calibrating the TSC can end up depending on different things: o CPUID accepting 0x16 as eax input (cf. cpu_khz_from_cpuid()) o MSR_FSB_FREQ being available (cf. cpu_khz_from_msr()) o pit_hpet_ptimer_calibrate_cpu() doesn't mess up I couldn't find any guarantees for X86_64 on having the processor frequency information CPUID leaf, nor for the FSB_FREQ MSR (both tsc_msr_cpu_ids and the SDM seem to point at only a handful of models). pit_hpet_ptimer_calibrate_cpu() relies on having either HPET or the ACPI PM timer, the latter being widely available, though X86_PM_TIMER can be disabled via EXPERT. The question here is: are there any guarantees that at least one of these can be relied upon for x86_64? And with all of that, there is still the "apicpmtimer" cmdline option which currently invokes notsc_setup() on x86_64. The justification I found for it was in 0c3749c41f5e ("[PATCH] x86_64: Calibrate APIC timer using PM timer"): """ On some broken motherboards (at least one NForce3 based AMD64 laptop) the PIT timer runs at a incorrect frequency. This patch adds a new option "apicpmtimer" that allows to use the APIC timer and calibrate it using the PMTimer. """ Revisions ========= v1 -> v2 ++++++++ - Collected tags (Josh, Sean) - Fixed CONFIG_JUMP_LABEL=n compile fail (lkp) Cheers, Valentin Peter Zijlstra (1): jump_label,module: Don't alloc static_key_mod for __ro_after_init keys Valentin Schneider (4): context_tracking: Make context_tracking_key __ro_after_init x86/kvm: Make kvm_async_pf_enabled __ro_after_init x86/speculation: Make mds_user_clear __ro_after_init x86/tsc: Make __use_tsc __ro_after_init arch/x86/kernel/cpu/bugs.c | 2 +- arch/x86/kernel/kvm.c | 2 +- arch/x86/kernel/tsc.c | 2 +- include/asm-generic/sections.h | 5 ++++ include/linux/jump_label.h | 3 +++ init/main.c | 1 + kernel/context_tracking.c | 2 +- kernel/jump_label.c | 49 ++++++++++++++++++++++++++++++++++ 8 files changed, 62 insertions(+), 4 deletions(-) -- 2.43.0
