forked from Minki/linux
9a2451f186
Currently both order booting and spinwait approach uses a per cpu array to update stack & task pointer. This approach will not work for the following cases. 1. If NR_CPUs are configured to be less than highest hart id. 2. A platform has sparse hartid. This issue can be fixed for ordered booting as the booting cpu brings up one cpu at a time using SBI HSM extension which has opaque parameter that is unused until now. Introduce a common secondary boot data structure that can store the stack and task pointer. Secondary harts will use this data while booting up to setup the sp & tp. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
130 lines
2.8 KiB
C
130 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* HSM extension and cpu_ops implementation.
|
|
*
|
|
* Copyright (c) 2020 Western Digital Corporation or its affiliates.
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/sched/task_stack.h>
|
|
#include <asm/cpu_ops.h>
|
|
#include <asm/cpu_ops_sbi.h>
|
|
#include <asm/sbi.h>
|
|
#include <asm/smp.h>
|
|
|
|
extern char secondary_start_sbi[];
|
|
const struct cpu_operations cpu_ops_sbi;
|
|
|
|
/*
|
|
* Ordered booting via HSM brings one cpu at a time. However, cpu hotplug can
|
|
* be invoked from multiple threads in parallel. Define a per cpu data
|
|
* to handle that.
|
|
*/
|
|
DEFINE_PER_CPU(struct sbi_hart_boot_data, boot_data);
|
|
|
|
static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr,
|
|
unsigned long priv)
|
|
{
|
|
struct sbiret ret;
|
|
|
|
ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
|
|
hartid, saddr, priv, 0, 0, 0);
|
|
if (ret.error)
|
|
return sbi_err_map_linux_errno(ret.error);
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static int sbi_hsm_hart_stop(void)
|
|
{
|
|
struct sbiret ret;
|
|
|
|
ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STOP, 0, 0, 0, 0, 0, 0);
|
|
|
|
if (ret.error)
|
|
return sbi_err_map_linux_errno(ret.error);
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
static int sbi_hsm_hart_get_status(unsigned long hartid)
|
|
{
|
|
struct sbiret ret;
|
|
|
|
ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STATUS,
|
|
hartid, 0, 0, 0, 0, 0);
|
|
if (ret.error)
|
|
return sbi_err_map_linux_errno(ret.error);
|
|
else
|
|
return ret.value;
|
|
}
|
|
#endif
|
|
|
|
static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle)
|
|
{
|
|
unsigned long boot_addr = __pa_symbol(secondary_start_sbi);
|
|
int hartid = cpuid_to_hartid_map(cpuid);
|
|
unsigned long hsm_data;
|
|
struct sbi_hart_boot_data *bdata = &per_cpu(boot_data, cpuid);
|
|
|
|
/* Make sure tidle is updated */
|
|
smp_mb();
|
|
bdata->task_ptr = tidle;
|
|
bdata->stack_ptr = task_stack_page(tidle) + THREAD_SIZE;
|
|
/* Make sure boot data is updated */
|
|
smp_mb();
|
|
hsm_data = __pa(bdata);
|
|
return sbi_hsm_hart_start(hartid, boot_addr, hsm_data);
|
|
}
|
|
|
|
static int sbi_cpu_prepare(unsigned int cpuid)
|
|
{
|
|
if (!cpu_ops_sbi.cpu_start) {
|
|
pr_err("cpu start method not defined for CPU [%d]\n", cpuid);
|
|
return -ENODEV;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static int sbi_cpu_disable(unsigned int cpuid)
|
|
{
|
|
if (!cpu_ops_sbi.cpu_stop)
|
|
return -EOPNOTSUPP;
|
|
return 0;
|
|
}
|
|
|
|
static void sbi_cpu_stop(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = sbi_hsm_hart_stop();
|
|
pr_crit("Unable to stop the cpu %u (%d)\n", smp_processor_id(), ret);
|
|
}
|
|
|
|
static int sbi_cpu_is_stopped(unsigned int cpuid)
|
|
{
|
|
int rc;
|
|
int hartid = cpuid_to_hartid_map(cpuid);
|
|
|
|
rc = sbi_hsm_hart_get_status(hartid);
|
|
|
|
if (rc == SBI_HSM_HART_STATUS_STOPPED)
|
|
return 0;
|
|
return rc;
|
|
}
|
|
#endif
|
|
|
|
const struct cpu_operations cpu_ops_sbi = {
|
|
.name = "sbi",
|
|
.cpu_prepare = sbi_cpu_prepare,
|
|
.cpu_start = sbi_cpu_start,
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
.cpu_disable = sbi_cpu_disable,
|
|
.cpu_stop = sbi_cpu_stop,
|
|
.cpu_is_stopped = sbi_cpu_is_stopped,
|
|
#endif
|
|
};
|