Messages in this thread Patch in this message | | | Date | Wed, 13 Apr 2022 16:54:00 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v5 2/2] x86/mce: Add support for Extended Physical Address MCA changes |
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On Wed, Apr 13, 2022 at 02:10:30PM +0000, Yazen Ghannam wrote: > This function gets called from __mcheck_cpu_init_early() so that the info is > available before the MCA banks are polled in __mcheck_cpu_init_generic().
Would that work?
I've moved first bank polling into __mcheck_cpu_init_clear_banks() because, well, this function is clearing the banks so it might as well poll them first. First bank polling in a init_generic function doesn't make too much sense anyway.
And __mcheck_cpu_check_banks() functionality is moved into __mcheck_cpu_init_clear_banks() because, well, silly.
On a quick scan, I don't see problems with such move but the devil is in the detail.
Hmm?
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diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 99e3ff9607a3..345e068215c4 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -1732,21 +1732,8 @@ static void __mcheck_cpu_cap_init(void) static void __mcheck_cpu_init_generic(void) { - enum mcp_flags m_fl = 0; - mce_banks_t all_banks; u64 cap; - if (!mca_cfg.bootlog) - m_fl = MCP_DONTLOG; - - /* - * Log the machine checks left over from the previous reset. Log them - * only, do not start processing them. That will happen in mcheck_late_init() - * when all consumers have been registered on the notifier chain. - */ - bitmap_fill(all_banks, MAX_NR_BANKS); - machine_check_poll(MCP_UC | MCP_QUEUE_LOG | m_fl, &all_banks); - cr4_set_bits(X86_CR4_MCE); rdmsrl(MSR_IA32_MCG_CAP, cap); @@ -1757,33 +1744,21 @@ static void __mcheck_cpu_init_generic(void) static void __mcheck_cpu_init_clear_banks(void) { struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + enum mcp_flags m_fl = 0; + mce_banks_t all_banks; + u64 msrval; int i; - for (i = 0; i < this_cpu_read(mce_num_banks); i++) { - struct mce_bank *b = &mce_banks[i]; - - if (!b->init) - continue; - wrmsrl(mca_msr_reg(i, MCA_CTL), b->ctl); - wrmsrl(mca_msr_reg(i, MCA_STATUS), 0); - } -} + if (!mca_cfg.bootlog) + m_fl = MCP_DONTLOG; -/* - * Do a final check to see if there are any unused/RAZ banks. - * - * This must be done after the banks have been initialized and any quirks have - * been applied. - * - * Do not call this from any user-initiated flows, e.g. CPU hotplug or sysfs. - * Otherwise, a user who disables a bank will not be able to re-enable it - * without a system reboot. - */ -static void __mcheck_cpu_check_banks(void) -{ - struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); - u64 msrval; - int i; + /* + * Log the machine checks left over from the previous reset. Log them + * only, do not start processing them. That will happen in mcheck_late_init() + * when all consumers have been registered on the notifier chain. + */ + bitmap_fill(all_banks, MAX_NR_BANKS); + machine_check_poll(MCP_UC | MCP_QUEUE_LOG | m_fl, &all_banks); for (i = 0; i < this_cpu_read(mce_num_banks); i++) { struct mce_bank *b = &mce_banks[i]; @@ -1791,6 +1766,9 @@ static void __mcheck_cpu_check_banks(void) if (!b->init) continue; + wrmsrl(mca_msr_reg(i, MCA_CTL), b->ctl); + wrmsrl(mca_msr_reg(i, MCA_STATUS), 0); + rdmsrl(mca_msr_reg(i, MCA_CTL), msrval); b->init = !!msrval; } @@ -2159,7 +2137,6 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c) __mcheck_cpu_init_generic(); __mcheck_cpu_init_vendor(c); __mcheck_cpu_init_clear_banks(); - __mcheck_cpu_check_banks(); __mcheck_cpu_setup_timer(); } -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
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