From: Len Brown <len.brown@xxxxxxxxx> In MPS mode, "nosmp" and "maxcpus=0" boot a UP kernel with IOAPIC disabled. However, in ACPI mode, these parameters didn't completely disable the IO APIC initialization code and boot failed. init/main.c: Disable the IO_APIC if "nosmp" or "maxcpus=0" undefine disable_ioapic_setup() when it doesn't apply. i386: delete ioapic_setup(), it was a duplicate of parse_noapic() delete undefinition of disable_ioapic_setup() x86_64: rename disable_ioapic_setup() to parse_noapic() to match i386 define disable_ioapic_setup() in header to match i386 http://bugzilla.kernel.org/show_bug.cgi?id=1641 Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- Documentation/kernel-parameters.txt | 15 ++++++--------- arch/i386/kernel/io_apic.c | 8 -------- arch/x86_64/kernel/io_apic.c | 8 +++----- include/asm-i386/io_apic.h | 1 - include/asm-x86_64/io_apic.h | 6 ++++++ init/main.c | 12 ++++++++++-- 6 files changed, 25 insertions(+), 25 deletions(-) Index: linus/Documentation/kernel-parameters.txt =================================================================== --- linus.orig/Documentation/kernel-parameters.txt +++ linus/Documentation/kernel-parameters.txt @@ -952,14 +952,10 @@ and is between 256 and 4096 characters. Format: <1-256> maxcpus= [SMP] Maximum number of processors that an SMP kernel - should make use of. - Using "nosmp" or "maxcpus=0" will disable SMP - entirely (the MPS table probe still happens, though). - A command-line option of "maxcpus=<NUM>", where <NUM> - is an integer greater than 0, limits the maximum number - of CPUs activated in SMP mode to <NUM>. - Using "maxcpus=1" on an SMP kernel is the trivial - case of an SMP kernel with only one CPU. + should make use of. maxcpus=n : n >= 0 limits the + kernel to using 'n' processors. n=0 is a special case, + it is equivalent to "nosmp", which also disables + the IO APIC. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or equal to this physical address is ignored. @@ -1184,7 +1180,8 @@ and is between 256 and 4096 characters. nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support. - nosmp [SMP] Tells an SMP kernel to act as a UP kernel. + nosmp [SMP] Tells an SMP kernel to act as a UP kernel, + and disable the IO APIC. legacy for "maxcpus=0". nosoftlockup [KNL] Disable the soft-lockup detector. Index: linus/arch/i386/kernel/io_apic.c =================================================================== --- linus.orig/arch/i386/kernel/io_apic.c +++ linus/arch/i386/kernel/io_apic.c @@ -754,14 +754,6 @@ static int pirq_entries [MAX_PIRQS]; static int pirqs_enabled; int skip_ioapic_setup; -static int __init ioapic_setup(char *str) -{ - skip_ioapic_setup = 1; - return 1; -} - -__setup("noapic", ioapic_setup); - static int __init ioapic_pirq_setup(char *str) { int i, max; Index: linus/arch/x86_64/kernel/io_apic.c =================================================================== --- linus.orig/arch/x86_64/kernel/io_apic.c +++ linus/arch/x86_64/kernel/io_apic.c @@ -397,14 +397,12 @@ static void clear_IO_APIC (void) int skip_ioapic_setup; int ioapic_force; -/* dummy parsing: see setup.c */ - -static int __init disable_ioapic_setup(char *str) +static int __init parse_noapic(char *str) { - skip_ioapic_setup = 1; + disable_ioapic_setup(); return 0; } -early_param("noapic", disable_ioapic_setup); +early_param("noapic", parse_noapic); /* Actually the next is obsolete, but keep it for paranoid reasons -AK */ static int __init disable_timer_pin_setup(char *arg) Index: linus/include/asm-i386/io_apic.h =================================================================== --- linus.orig/include/asm-i386/io_apic.h +++ linus/include/asm-i386/io_apic.h @@ -150,7 +150,6 @@ extern int (*ioapic_renumber_irq)(int io #else /* !CONFIG_X86_IO_APIC */ #define io_apic_assign_pci_irqs 0 -static inline void disable_ioapic_setup(void) { } #endif #endif Index: linus/include/asm-x86_64/io_apic.h =================================================================== --- linus.orig/include/asm-x86_64/io_apic.h +++ linus/include/asm-x86_64/io_apic.h @@ -109,6 +109,12 @@ extern int mpc_default_type; /* 1 if "noapic" boot option passed */ extern int skip_ioapic_setup; +static inline void disable_ioapic_setup(void) +{ + skip_ioapic_setup = 1; +} + + /* * If we use the IO-APIC for IRQ routing, disable automatic * assignment of PCI IRQ's. Index: linus/init/main.c =================================================================== --- linus.orig/init/main.c +++ linus/init/main.c @@ -146,9 +146,14 @@ static unsigned int __initdata max_cpus * greater than 0, limits the maximum number of CPUs activated in * SMP mode to <NUM>. */ +#ifndef CONFIG_X86_IO_APIC +static inline void disable_ioapic_setup(void) {}; +#endif + static int __init nosmp(char *str) { max_cpus = 0; + disable_ioapic_setup(); return 0; } @@ -157,10 +162,13 @@ early_param("nosmp", nosmp); static int __init maxcpus(char *str) { get_option(&str, &max_cpus); - return 1; + if (max_cpus == 0) + disable_ioapic_setup(); + + return 0; } -__setup("maxcpus=", maxcpus); +early_param("maxcpus=", maxcpus); #else #define max_cpus NR_CPUS #endif - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
