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5685d7fcb5
In the current code, SMP is selected in Kconfig for LoongArch, the users
can not unset it, this is reasonable for a multi-processor machine. But
as the help info of config SMP said, if you have a system with only one
CPU, say N. On a uni-processor machine, the kernel will run faster if you
say N here.
Loongson-2K0500 is a single-core CPU for applications like industrial
control, printing terminals, and BMC (Baseboard Management Controller),
there are many development boards, products and solutions on the market,
so it is better and necessary to give a chance to build with !CONFIG_SMP
for a uni-processor machine.
First of all, do not select SMP for config LOONGARCH in Kconfig to make
it possible to unset CONFIG_SMP. Then, do some changes to fix warnings
and errors if CONFIG_SMP is not set.
(1) Define get_ipi_irq() only if CONFIG_SMP is set to fix the warning:
arch/loongarch/kernel/irq.c:90:19: warning: 'get_ipi_irq' defined but not used [-Wunused-function]
(2) Add "#ifdef CONFIG_SMP" in asm/smp.h to fix the warning:
./arch/loongarch/include/asm/smp.h:49:9: warning: "raw_smp_processor_id" redefined
49 | #define raw_smp_processor_id raw_smp_processor_id
| ^~~~~~~~~~~~~~~~~~~~
./include/linux/smp.h:198:9: note: this is the location of the previous definition
198 | #define raw_smp_processor_id() 0
(3) Define machine_shutdown() as empty under !CONFIG_SMP to fix the error:
arch/loongarch/kernel/machine_kexec.c: In function 'machine_shutdown':
arch/loongarch/kernel/machine_kexec.c:233:25: error: implicit declaration of function 'cpu_device_up'; did you mean 'put_device'? [-Wimplicit-function-declaration]
(4) Make config SCHED_SMT depends on SMP to fix many errors such as:
kernel/sched/core.c: In function 'sched_core_find':
kernel/sched/core.c:310:43: error: 'struct rq' has no member named 'cpu'
(5) Define cpu_logical_map(cpu) as 0 under !CONFIG_SMP in asm/smp.h,
then include asm/smp.h in asm/acpi.h (because acpi.h is included in
linux/irq.h indirectly) to fix many build errors under drivers/irqchip
such as:
drivers/irqchip/irq-loongson-eiointc.c: In function 'cpu_to_eio_node':
drivers/irqchip/irq-loongson-eiointc.c:59:16: error: implicit declaration of function 'cpu_logical_map' [-Wimplicit-function-declaration]
(6) Do not write per_cpu_offset(0) to PERCPU_BASE_KS when resume because
the per_cpu_offset(x) macro is defined as (__per_cpu_offset[x]) only
under CONFIG_SMP in include/asm-generic/percpu.h. Just save the value of
PERCPU_BASE_KS when suspend and restore it when resume to fix the error:
arch/loongarch/power/suspend.c: In function 'loongarch_common_resume':
arch/loongarch/power/suspend.c:47:21: error: implicit declaration of function 'per_cpu_offset' [-Wimplicit-function-declaration]
(7) Fix huge page handling under !CONFIG_SMP in tlbex.S.
When running the UnixBench tests with "-c 1" single-streamed pass, the
improvement of performance is about 9 percent with this patch.
By the way, it is helpful to debug and analysis the kernel issues of
multi-processor system under !CONFIG_SMP.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Author: Jianmin Lv <lvjianmin@loongson.cn>
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* Huacai Chen <chenhuacai@loongson.cn>
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* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
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*/
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#ifndef _ASM_LOONGARCH_ACPI_H
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#define _ASM_LOONGARCH_ACPI_H
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#include <asm/smp.h>
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#include <asm/suspend.h>
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#ifdef CONFIG_ACPI
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extern int acpi_strict;
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extern int acpi_disabled;
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extern int acpi_pci_disabled;
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extern int acpi_noirq;
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extern int pptt_enabled;
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#define acpi_os_ioremap acpi_os_ioremap
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void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size);
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static inline void disable_acpi(void)
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{
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acpi_disabled = 1;
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acpi_pci_disabled = 1;
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acpi_noirq = 1;
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}
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static inline bool acpi_has_cpu_in_madt(void)
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{
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return true;
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}
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#define MAX_CORE_PIC 256
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extern struct list_head acpi_wakeup_device_list;
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extern struct acpi_madt_core_pic acpi_core_pic[MAX_CORE_PIC];
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extern int __init parse_acpi_topology(void);
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static inline u32 get_acpi_id_for_cpu(unsigned int cpu)
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{
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return acpi_core_pic[cpu_logical_map(cpu)].processor_id;
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}
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#endif /* !CONFIG_ACPI */
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#define ACPI_TABLE_UPGRADE_MAX_PHYS ARCH_LOW_ADDRESS_LIMIT
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extern int loongarch_acpi_suspend(void);
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extern int (*acpi_suspend_lowlevel)(void);
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static inline unsigned long acpi_get_wakeup_address(void)
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{
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#ifdef CONFIG_SUSPEND
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return (unsigned long)loongarch_wakeup_start;
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#endif
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return 0UL;
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}
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#endif /* _ASM_LOONGARCH_ACPI_H */
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