From 593f4a788e5d09e9f00182561437461b0b564de4 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Wed, 16 Jul 2008 19:15:30 +0100 Subject: x86: APIC: remove apic_write_around(); use alternatives Use alternatives to select the workaround for the 11AP Pentium erratum for the affected steppings on the fly rather than build time. Remove the X86_GOOD_APIC configuration option and replace all the calls to apic_write_around() with plain apic_write(), protecting accesses to the ESR as appropriate due to the 3AP Pentium erratum. Remove apic_read_around() and all its invocations altogether as not needed. Remove apic_write_atomic() and all its implementing backends. The use of ASM_OUTPUT2() is not strictly needed for input constraints, but I have used it for readability's sake. I had the feeling no one else was brave enough to do it, so I went ahead and here it is. Verified by checking the generated assembly and tested with both a 32-bit and a 64-bit configuration, also with the 11AP "feature" forced on and verified with gdb on /proc/kcore to work as expected (as an 11AP machines are quite hard to get hands on these days). Some script complained about the use of "volatile", but apic_write() needs it for the same reason and is effectively a replacement for writel(), so I have disregarded it. I am not sure what the policy wrt defconfig files is, they are generated and there is risk of a conflict resulting from an unrelated change, so I have left changes to them out. The option will get removed from them at the next run. Some testing with machines other than mine will be needed to avoid some stupid mistake, but despite its volume, the change is not really that intrusive, so I am fairly confident that because it works for me, it will everywhere. Signed-off-by: Maciej W. Rozycki Signed-off-by: Ingo Molnar --- arch/x86/kernel/nmi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/nmi.c') diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index ec024b3baad..384b49fed59 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -263,7 +263,7 @@ late_initcall(init_lapic_nmi_sysfs); static void __acpi_nmi_enable(void *__unused) { - apic_write_around(APIC_LVT0, APIC_DM_NMI); + apic_write(APIC_LVT0, APIC_DM_NMI); } /* @@ -277,7 +277,7 @@ void acpi_nmi_enable(void) static void __acpi_nmi_disable(void *__unused) { - apic_write_around(APIC_LVT0, APIC_DM_NMI | APIC_LVT_MASKED); + apic_write(APIC_LVT0, APIC_DM_NMI | APIC_LVT_MASKED); } /* -- cgit v1.2.3 From e3a61b0a8c0e342e700a61cd554b01050f333a36 Mon Sep 17 00:00:00 2001 From: Simon Arlott Date: Sat, 19 Jul 2008 23:32:54 +0100 Subject: x86: add unknown_nmi_panic kernel parameter It's not possible to enable the unknown_nmi_panic sysctl option until init is run. It's useful to be able to panic the kernel during boot too, this adds a parameter to enable this option. Signed-off-by: Simon Arlott Signed-off-by: Ingo Molnar --- arch/x86/kernel/nmi.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/x86/kernel/nmi.c') diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index ec024b3baad..e0b44b7b717 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -448,6 +448,13 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason) #ifdef CONFIG_SYSCTL +static int __init setup_unknown_nmi_panic(char *str) +{ + unknown_nmi_panic = 1; + return 1; +} +__setup("unknown_nmi_panic", setup_unknown_nmi_panic); + static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu) { unsigned char reason = get_nmi_reason(); -- cgit v1.2.3