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linux/arch/powerpc/include/asm/smp.h
Nicholas Piggin dc222fa773 powerpc/64: Move paca allocation to early_setup() 
The early paca and boot cpuid dance is complicated and currently does
not quite work as expected for boot cpuid != 0 cases.

early_init_devtree() currently allocates the paca_ptrs and boot cpuid
paca, but until that returns and early_setup() calls setup_paca(), this
thread is currently still executing with smp_processor_id() == 0.

One problem this causes is the paca_ptrs[smp_processor_id()] pointer is
poisoned, so valid_emergency_stack() (any backtrace) and any similar
users will crash.

Another is that the hardware id which is set here will not be returned
by get_hard_smp_processor_id(smp_processor_id()), but it would work
correctly for boot_cpuid == 0, which could lead to difficult to
reproduce or find bugs. The hard id does not seem to be used by the rest
of early_init_devtree(), it just looks like all this code might have
been put here to allocate somewhere to store boot CPU hardware id while
scanning the devtree.

Rearrange things so the hwid is put in a global variable like
boot_cpuid, and do all the paca allocation and boot paca setup in the
64-bit early_setup() after we have everything ready to go.

The paca_ptrs[0] re-poisoning code in early_setup does not seem to have
ever worked, because paca_ptrs[0] was never not-poisoned when boot_cpuid
is not 0.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix build error on 32-bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221216115930.2667772-4-npiggin@gmail.com
2023-02-10 22:19:56 +11:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* smp.h: PowerPC-specific SMP code.
*
* Original was a copy of sparc smp.h. Now heavily modified
* for PPC.
*
* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1996-2001 Cort Dougan <cort@fsmlabs.com>
*/
#ifndef _ASM_POWERPC_SMP_H
#define _ASM_POWERPC_SMP_H
#ifdef __KERNEL__
#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/kernel.h>
#include <linux/irqreturn.h>
#ifndef __ASSEMBLY__
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#endif
#include <asm/percpu.h>
extern int boot_cpuid;
extern int boot_cpu_hwid; /* PPC64 only */
extern int spinning_secondaries;
extern u32 *cpu_to_phys_id;
extern bool coregroup_enabled;
extern int cpu_to_chip_id(int cpu);
extern int *chip_id_lookup_table;
DECLARE_PER_CPU(cpumask_var_t, thread_group_l1_cache_map);
DECLARE_PER_CPU(cpumask_var_t, thread_group_l2_cache_map);
DECLARE_PER_CPU(cpumask_var_t, thread_group_l3_cache_map);
#ifdef CONFIG_SMP
struct smp_ops_t {
void (*message_pass)(int cpu, int msg);
#ifdef CONFIG_PPC_SMP_MUXED_IPI
void (*cause_ipi)(int cpu);
#endif
int (*cause_nmi_ipi)(int cpu);
void (*probe)(void);
int (*kick_cpu)(int nr);
int (*prepare_cpu)(int nr);
void (*setup_cpu)(int nr);
void (*bringup_done)(void);
void (*take_timebase)(void);
void (*give_timebase)(void);
int (*cpu_disable)(void);
void (*cpu_die)(unsigned int nr);
int (*cpu_bootable)(unsigned int nr);
#ifdef CONFIG_HOTPLUG_CPU
void (*cpu_offline_self)(void);
#endif
};
extern struct task_struct *secondary_current;
void start_secondary(void *unused);
extern int smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us);
extern int smp_send_safe_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 delay_us);
extern void smp_send_debugger_break(void);
extern void start_secondary_resume(void);
extern void smp_generic_give_timebase(void);
extern void smp_generic_take_timebase(void);
DECLARE_PER_CPU(unsigned int, cpu_pvr);
#ifdef CONFIG_HOTPLUG_CPU
int generic_cpu_disable(void);
void generic_cpu_die(unsigned int cpu);
void generic_set_cpu_dead(unsigned int cpu);
void generic_set_cpu_up(unsigned int cpu);
int generic_check_cpu_restart(unsigned int cpu);
int is_cpu_dead(unsigned int cpu);
#else
#define generic_set_cpu_up(i) do { } while (0)
#endif
#ifdef CONFIG_PPC64
#define raw_smp_processor_id() (local_paca->paca_index)
#define hard_smp_processor_id() (get_paca()->hw_cpu_id)
#else
/* 32-bit */
extern int smp_hw_index[];
#define raw_smp_processor_id() (current_thread_info()->cpu)
#define hard_smp_processor_id() (smp_hw_index[smp_processor_id()])
static inline int get_hard_smp_processor_id(int cpu)
{
return smp_hw_index[cpu];
}
static inline void set_hard_smp_processor_id(int cpu, int phys)
{
smp_hw_index[cpu] = phys;
}
#endif
DECLARE_PER_CPU(cpumask_var_t, cpu_sibling_map);
DECLARE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
DECLARE_PER_CPU(cpumask_var_t, cpu_core_map);
DECLARE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
static inline struct cpumask *cpu_sibling_mask(int cpu)
{
return per_cpu(cpu_sibling_map, cpu);
}
static inline struct cpumask *cpu_core_mask(int cpu)
{
return per_cpu(cpu_core_map, cpu);
}
static inline struct cpumask *cpu_l2_cache_mask(int cpu)
{
return per_cpu(cpu_l2_cache_map, cpu);
}
static inline struct cpumask *cpu_smallcore_mask(int cpu)
{
return per_cpu(cpu_smallcore_map, cpu);
}
extern int cpu_to_core_id(int cpu);
extern bool has_big_cores;
extern bool thread_group_shares_l2;
extern bool thread_group_shares_l3;
#define cpu_smt_mask cpu_smt_mask
#ifdef CONFIG_SCHED_SMT
static inline const struct cpumask *cpu_smt_mask(int cpu)
{
if (has_big_cores)
return per_cpu(cpu_smallcore_map, cpu);
return per_cpu(cpu_sibling_map, cpu);
}
#endif /* CONFIG_SCHED_SMT */
/* Since OpenPIC has only 4 IPIs, we use slightly different message numbers.
*
* Make sure this matches openpic_request_IPIs in open_pic.c, or what shows up
* in /proc/interrupts will be wrong!!! --Troy */
#define PPC_MSG_CALL_FUNCTION 0
#define PPC_MSG_RESCHEDULE 1
#define PPC_MSG_TICK_BROADCAST 2
#define PPC_MSG_NMI_IPI 3
/* This is only used by the powernv kernel */
#define PPC_MSG_RM_HOST_ACTION 4
#define NMI_IPI_ALL_OTHERS -2
#ifdef CONFIG_NMI_IPI
extern int smp_handle_nmi_ipi(struct pt_regs *regs);
#else
static inline int smp_handle_nmi_ipi(struct pt_regs *regs) { return 0; }
#endif
/* for irq controllers that have dedicated ipis per message (4) */
extern int smp_request_message_ipi(int virq, int message);
extern const char *smp_ipi_name[];
/* for irq controllers with only a single ipi */
extern void smp_muxed_ipi_message_pass(int cpu, int msg);
extern void smp_muxed_ipi_set_message(int cpu, int msg);
extern irqreturn_t smp_ipi_demux(void);
extern irqreturn_t smp_ipi_demux_relaxed(void);
void smp_init_pSeries(void);
void smp_init_cell(void);
void smp_setup_cpu_maps(void);
extern int __cpu_disable(void);
extern void __cpu_die(unsigned int cpu);
#else
/* for UP */
#define hard_smp_processor_id() get_hard_smp_processor_id(0)
#define smp_setup_cpu_maps()
#define thread_group_shares_l2 0
#define thread_group_shares_l3 0
static inline const struct cpumask *cpu_sibling_mask(int cpu)
{
return cpumask_of(cpu);
}
static inline const struct cpumask *cpu_smallcore_mask(int cpu)
{
return cpumask_of(cpu);
}
static inline const struct cpumask *cpu_l2_cache_mask(int cpu)
{
return cpumask_of(cpu);
}
#endif /* CONFIG_SMP */
#ifdef CONFIG_PPC64
static inline int get_hard_smp_processor_id(int cpu)
{
return paca_ptrs[cpu]->hw_cpu_id;
}
static inline void set_hard_smp_processor_id(int cpu, int phys)
{
paca_ptrs[cpu]->hw_cpu_id = phys;
}
#else
/* 32-bit */
#ifndef CONFIG_SMP
extern int boot_cpuid_phys;
static inline int get_hard_smp_processor_id(int cpu)
{
return boot_cpuid_phys;
}
static inline void set_hard_smp_processor_id(int cpu, int phys)
{
boot_cpuid_phys = phys;
}
#endif /* !CONFIG_SMP */
#endif /* !CONFIG_PPC64 */
#if defined(CONFIG_PPC64) && (defined(CONFIG_SMP) || defined(CONFIG_KEXEC_CORE))
extern void smp_release_cpus(void);
#else
static inline void smp_release_cpus(void) { }
#endif
extern int smt_enabled_at_boot;
extern void smp_mpic_probe(void);
extern void smp_mpic_setup_cpu(int cpu);
extern int smp_generic_kick_cpu(int nr);
extern int smp_generic_cpu_bootable(unsigned int nr);
extern void smp_generic_give_timebase(void);
extern void smp_generic_take_timebase(void);
extern struct smp_ops_t *smp_ops;
extern void arch_send_call_function_single_ipi(int cpu);
extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
/* Definitions relative to the secondary CPU spin loop
* and entry point. Not all of them exist on both 32 and
* 64-bit but defining them all here doesn't harm
*/
extern void generic_secondary_smp_init(void);
extern unsigned long __secondary_hold_spinloop;
extern unsigned long __secondary_hold_acknowledge;
extern char __secondary_hold;
extern unsigned int booting_thread_hwid;
extern void __early_start(void);
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_SMP_H) */
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