1
linux/arch/powerpc/include/asm/cputhreads.h
Nicholas Piggin b350111bf7 powerpc: remove cpu_online_cores_map function
This function builds the cores online map with on-stack cpumasks which
can cause high stack usage with large NR_CPUS.

It is not used in any performance sensitive paths, so instead just check
for first thread sibling.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211105035042.1398309-1-npiggin@gmail.com
2021-11-29 22:48:32 +11:00

116 lines
2.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_CPUTHREADS_H
#define _ASM_POWERPC_CPUTHREADS_H
#ifndef __ASSEMBLY__
#include <linux/cpumask.h>
#include <asm/cpu_has_feature.h>
/*
* Mapping of threads to cores
*
* Note: This implementation is limited to a power of 2 number of
* threads per core and the same number for each core in the system
* (though it would work if some processors had less threads as long
* as the CPU numbers are still allocated, just not brought online).
*
* However, the API allows for a different implementation in the future
* if needed, as long as you only use the functions and not the variables
* directly.
*/
#ifdef CONFIG_SMP
extern int threads_per_core;
extern int threads_per_subcore;
extern int threads_shift;
extern cpumask_t threads_core_mask;
#else
#define threads_per_core 1
#define threads_per_subcore 1
#define threads_shift 0
#define has_big_cores 0
#define threads_core_mask (*get_cpu_mask(0))
#endif
static inline int cpu_nr_cores(void)
{
return nr_cpu_ids >> threads_shift;
}
#ifdef CONFIG_SMP
int cpu_core_index_of_thread(int cpu);
int cpu_first_thread_of_core(int core);
#else
static inline int cpu_core_index_of_thread(int cpu) { return cpu; }
static inline int cpu_first_thread_of_core(int core) { return core; }
#endif
static inline int cpu_thread_in_core(int cpu)
{
return cpu & (threads_per_core - 1);
}
static inline int cpu_thread_in_subcore(int cpu)
{
return cpu & (threads_per_subcore - 1);
}
static inline int cpu_first_thread_sibling(int cpu)
{
return cpu & ~(threads_per_core - 1);
}
static inline int cpu_last_thread_sibling(int cpu)
{
return cpu | (threads_per_core - 1);
}
/*
* tlb_thread_siblings are siblings which share a TLB. This is not
* architected, is not something a hypervisor could emulate and a future
* CPU may change behaviour even in compat mode, so this should only be
* used on PowerNV, and only with care.
*/
static inline int cpu_first_tlb_thread_sibling(int cpu)
{
if (cpu_has_feature(CPU_FTR_ARCH_300) && (threads_per_core == 8))
return cpu & ~0x6; /* Big Core */
else
return cpu_first_thread_sibling(cpu);
}
static inline int cpu_last_tlb_thread_sibling(int cpu)
{
if (cpu_has_feature(CPU_FTR_ARCH_300) && (threads_per_core == 8))
return cpu | 0x6; /* Big Core */
else
return cpu_last_thread_sibling(cpu);
}
static inline int cpu_tlb_thread_sibling_step(void)
{
if (cpu_has_feature(CPU_FTR_ARCH_300) && (threads_per_core == 8))
return 2; /* Big Core */
else
return 1;
}
static inline u32 get_tensr(void)
{
#ifdef CONFIG_BOOKE
if (cpu_has_feature(CPU_FTR_SMT))
return mfspr(SPRN_TENSR);
#endif
return 1;
}
void book3e_start_thread(int thread, unsigned long addr);
void book3e_stop_thread(int thread);
#endif /* __ASSEMBLY__ */
#define INVALID_THREAD_HWID 0x0fff
#endif /* _ASM_POWERPC_CPUTHREADS_H */