dc2bc768a0
This is a the first of a series of patch-sets aiming at making kdump more robust against stack overflows. This patch set does the following: * Add safe_smp_processor_id function to i386 architecture (this function was inspired by the x86_64 function of the same name). * Substitute "smp_processor_id" with the stack overflow-safe "safe_smp_processor_id" in the reboot path to the second kernel. This patch: On the event of a stack overflow critical data that usually resides at the bottom of the stack is likely to be stomped and, consequently, its use should be avoided. In particular, in the i386 and IA64 architectures the macro smp_processor_id ultimately makes use of the "cpu" member of struct thread_info which resides at the bottom of the stack. x86_64, on the other hand, is not affected by this problem because it benefits from the use of the PDA infrastructure. To circumvent this problem I suggest implementing "safe_smp_processor_id()" (it already exists in x86_64) for i386 and IA64 and use it as a replacement for smp_processor_id in the reboot path to the dump capture kernel. This is a possible implementation for i386. Signed-off-by: Fernando Vazquez <fernando@intellilink.co.jp> Looks-reasonable-to: Andi Kleen <ak@muc.de> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Cc: James Bottomley <James.Bottomley@steeleye.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
114 lines
2.5 KiB
C
114 lines
2.5 KiB
C
#ifndef __ASM_SMP_H
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#define __ASM_SMP_H
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/*
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* We need the APIC definitions automatically as part of 'smp.h'
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*/
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#ifndef __ASSEMBLY__
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#include <linux/kernel.h>
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#include <linux/threads.h>
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#include <linux/cpumask.h>
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#endif
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#ifdef CONFIG_X86_LOCAL_APIC
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#ifndef __ASSEMBLY__
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#include <asm/fixmap.h>
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#include <asm/bitops.h>
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#include <asm/mpspec.h>
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#ifdef CONFIG_X86_IO_APIC
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#include <asm/io_apic.h>
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#endif
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#include <asm/apic.h>
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#endif
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#endif
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#define BAD_APICID 0xFFu
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#ifdef CONFIG_SMP
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#ifndef __ASSEMBLY__
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/*
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* Private routines/data
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*/
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extern void smp_alloc_memory(void);
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extern int pic_mode;
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extern int smp_num_siblings;
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extern cpumask_t cpu_sibling_map[];
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extern cpumask_t cpu_core_map[];
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extern void (*mtrr_hook) (void);
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extern void zap_low_mappings (void);
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extern void lock_ipi_call_lock(void);
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extern void unlock_ipi_call_lock(void);
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#define MAX_APICID 256
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extern u8 x86_cpu_to_apicid[];
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#define cpu_physical_id(cpu) x86_cpu_to_apicid[cpu]
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extern u8 apicid_2_node[];
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#ifdef CONFIG_HOTPLUG_CPU
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extern void cpu_exit_clear(void);
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extern void cpu_uninit(void);
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#endif
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/*
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* This function is needed by all SMP systems. It must _always_ be valid
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* from the initial startup. We map APIC_BASE very early in page_setup(),
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* so this is correct in the x86 case.
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*/
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#define raw_smp_processor_id() (current_thread_info()->cpu)
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extern cpumask_t cpu_callout_map;
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extern cpumask_t cpu_callin_map;
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extern cpumask_t cpu_possible_map;
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/* We don't mark CPUs online until __cpu_up(), so we need another measure */
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static inline int num_booting_cpus(void)
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{
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return cpus_weight(cpu_callout_map);
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}
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#ifdef CONFIG_X86_LOCAL_APIC
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#ifdef APIC_DEFINITION
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extern int hard_smp_processor_id(void);
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#else
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#include <mach_apicdef.h>
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static inline int hard_smp_processor_id(void)
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{
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/* we don't want to mark this access volatile - bad code generation */
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return GET_APIC_ID(*(unsigned long *)(APIC_BASE+APIC_ID));
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}
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#endif
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#endif
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extern int safe_smp_processor_id(void);
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extern int __cpu_disable(void);
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extern void __cpu_die(unsigned int cpu);
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extern unsigned int num_processors;
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#endif /* !__ASSEMBLY__ */
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#else /* CONFIG_SMP */
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#define safe_smp_processor_id() 0
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#define cpu_physical_id(cpu) boot_cpu_physical_apicid
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#define NO_PROC_ID 0xFF /* No processor magic marker */
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#endif
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#ifndef __ASSEMBLY__
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#ifdef CONFIG_X86_LOCAL_APIC
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static __inline int logical_smp_processor_id(void)
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{
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/* we don't want to mark this access volatile - bad code generation */
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return GET_APIC_LOGICAL_ID(*(unsigned long *)(APIC_BASE+APIC_LDR));
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}
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#endif
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#endif
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#endif
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