/*
* Copyright (c) 2006 Jakub Jermar
* Copyright (c) 2009 Pavel Rimsky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup kernel_sparc64
* @{
*/
/** @file
*/
#include <smp/smp.h>
#include <smp/ipi.h>
#include <genarch/ofw/ofw_tree.h>
#include <cpu.h>
#include <arch/cpu.h>
#include <arch/boot/boot.h>
#include <arch.h>
#include <config.h>
#include <macros.h>
#include <halt.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <synch/waitq.h>
#include <stdio.h>
#include <arch/sun4v/hypercall.h>
#include <arch/sun4v/md.h>
#include <arch/sun4v/ipi.h>
#include <time/delay.h>
#include <arch/smp/sun4v/smp.h>
#include <str.h>
#include <errno.h>
/** hypervisor code of the "running" state of the CPU */
#define CPU_STATE_RUNNING 2
/** maximum possible number of processor cores */
#define MAX_NUM_CORES 8
/** needed in the CPU_START hypercall */
extern void kernel_image_start(void);
/** needed in the CPU_START hypercall */
extern void *trap_table;
/** number of execution units detected */
uint8_t exec_unit_count = 0;
/** execution units (processor cores) */
exec_unit_t exec_units[MAX_NUM_CORES];
/** CPU structures */
extern cpu_t *cpus;
/** maximum number of strands per a physical core detected */
unsigned int max_core_strands = 0;
#if 0
/**
* Proposes the optimal number of ready threads for each virtual processor
* in the given processor core so that the processor core is as busy as the
* average processor core. The proposed number of ready threads will be
* stored to the proposed_nrdy variable of the cpu_arch_t struture.
*/
bool calculate_optimal_nrdy(exec_unit_t *exec_unit)
{
/* calculate the number of threads the core will steal */
int avg = atomic_load(&nrdy) / exec_unit_count;
int to_steal = avg - atomic_load(&(exec_units->nrdy));
if (to_steal < 0) {
return true;
} else if (to_steal == 0) {
return false;
}
/* initialize the proposals with the real numbers of ready threads */
unsigned int k;
for (k = 0; k < exec_unit->strand_count; k++) {
exec_units->cpus[k]->arch.proposed_nrdy =
atomic_load(&(exec_unit->cpus[k]->nrdy));
}
/* distribute the threads to be stolen to the core's CPUs */
int j;
for (j = to_steal; j > 0; j--) {
unsigned int k;
unsigned int least_busy = 0;
unsigned int least_busy_nrdy =
exec_unit->cpus[0]->arch.proposed_nrdy;
/* for each stolen thread, give it to the least busy CPU */
for (k = 0; k < exec_unit->strand_count; k++) {
if (exec_unit->cpus[k]->arch.proposed_nrdy < least_busy_nrdy) {
least_busy = k;
least_busy_nrdy =
exec_unit->cpus[k]->arch.proposed_nrdy;
}
}
exec_unit->cpus[least_busy]->arch.proposed_nrdy++;
}
return false;
}
#endif
/**
* Finds out which execution units belong to particular CPUs. By execution unit
* we mean the physical core the logical processor is backed by. Since each
* Niagara physical core has just one integer execution unit and we will
* ignore other execution units than the integer ones, we will use the terms
* "integer execution unit", "execution unit" and "physical core"
* interchangeably.
*
* The physical cores are detected by browsing the children of the CPU node
* in the machine description and looking for a node representing an integer
* execution unit. Once the integer execution unit of a particular CPU is
* known, the ID of the CPU is added to the list of cpuids of the corresponding
* execution unit structure (exec_unit_t). If an execution unit is encountered
* for the first time, a new execution unit structure (exec_unit_t) must be
* created first and added to the execution units array (exec_units).
*
* If the function fails to find an execution unit for a CPU (this may happen
* on machines with older firmware or on Simics), it performs a fallback code
* which pretends there exists just one execution unit and all CPUs belong to
* it.
*
* Finally, the array of all execution units is reordered such that its element
* which represents the physical core of the the bootstrap CPU is at index 0.
* Moreover, the array of CPU IDs within the BSP's physical core structure is
* reordered such that the element which represents the ID of the BSP is at
* index 0. This is done because we would like the CPUs to be woken up
* such that the 0-index CPU of the 0-index execution unit is
* woken up first. And since the BSP is already woken up, we would like it to be
* at 0-th position of the 0-th execution unit structure.
*
* Apart from that, the code also counts the total number of CPUs and stores
* it to the global config.cpu_count variable.
*/
static void detect_execution_units(void)
{
/* ID of the bootstrap processor */
uint64_t myid;
/* total number of CPUs detected */
size_t cpu_count = 0;
/* will be set to 1 if detecting the physical cores fails */
bool exec_unit_assign_error = 0;
/* index of the bootstrap physical core in the array of cores */
unsigned int bsp_exec_unit_index = 0;
/* index of the BSP ID inside the array of bootstrap core's cpuids */
unsigned int bsp_core_strand_index = 0;
__hypercall_fast_ret1(0, 0, 0, 0, 0, CPU_MYID, &myid);
md_node_t node = md_get_root();
/* walk through all the CPU nodes in the MD */
while (md_next_node(&node, "cpu")) {
uint64_t cpuid;
md_get_integer_property(node, "id", &cpuid);
cpu_count++;
/*
* if failed in previous CPUs, don't try
* to detect physical cores any more
*/
if (exec_unit_assign_error)
continue;
/* detect exec. unit for the CPU represented by current node */
uint64_t exec_unit_id = 0;
md_child_iter_t it = md_get_child_iterator(node);
while (md_next_child(&it)) {
md_node_t child = md_get_child_node(it);
const char *exec_unit_type = "";
md_get_string_property(child, "type", &exec_unit_type);
/* each physical core has just 1 integer exec. unit */
if (str_cmp(exec_unit_type, "integer") == 0) {
exec_unit_id = child;
break;
}
}
/* execution unit detected successfully */
if (exec_unit_id != 0) {
/* find the exec. unit in array of existing units */
unsigned int i = 0;
for (i = 0; i < exec_unit_count; i++) {
if (exec_units[i].exec_unit_id == exec_unit_id)
break;
}
/*
* execution unit just met has not been met before, so
* create a new entry in array of all execution units
*/
if (i == exec_unit_count) {
exec_units[i].exec_unit_id = exec_unit_id;
exec_units[i].strand_count = 0;
atomic_store(&(exec_units[i].nrdy), 0);
spinlock_initialize(&(exec_units[i].proposed_nrdy_lock), "exec_units[].proposed_nrdy_lock");
exec_unit_count++;
}
/*
* remember the exec. unit and strand of the BSP
*/
if (cpuid == myid) {
bsp_exec_unit_index = i;
bsp_core_strand_index = exec_units[i].strand_count;
}
/* add the CPU just met to the exec. unit's list */
exec_units[i].cpuids[exec_units[i].strand_count] = cpuid;
exec_units[i].strand_count++;
max_core_strands =
exec_units[i].strand_count > max_core_strands ?
exec_units[i].strand_count : max_core_strands;
/* detecting execution unit failed */
} else {
exec_unit_assign_error = 1;
}
}
/* save the number of CPUs to a globally accessible variable */
config.cpu_count = cpu_count;
/*
* A fallback code which will be executed if finding out which
* execution units belong to particular CPUs fails. Pretend there
* exists just one execution unit and all CPUs belong to it.
*/
if (exec_unit_assign_error) {
bsp_exec_unit_index = 0;
exec_unit_count = 1;
exec_units[0].strand_count = cpu_count;
exec_units[0].exec_unit_id = 1;
spinlock_initialize(&(exec_units[0].proposed_nrdy_lock), "exec_units[0].proposed_nrdy_lock");
atomic_store(&(exec_units[0].nrdy), 0);
max_core_strands = cpu_count;
/* browse CPUs again, assign them the fictional exec. unit */
node = md_get_root();
unsigned int i = 0;
while (md_next_node(&node, "cpu")) {
uint64_t cpuid;
md_get_integer_property(node, "id", &cpuid);
if (cpuid == myid) {
bsp_core_strand_index = i;
}
exec_units[0].cpuids[i++] = cpuid;
}
}
/*
* Reorder the execution units array elements and the cpuid array
* elements so that the BSP will always be the very first CPU of
* the very first execution unit.
*/
exec_unit_t temp_exec_unit = exec_units[0];
exec_units[0] = exec_units[bsp_exec_unit_index];
exec_units[bsp_exec_unit_index] = temp_exec_unit;
uint64_t temp_cpuid = exec_units[0].cpuids[0];
exec_units[0].cpuids[0] = exec_units[0].cpuids[bsp_exec_unit_index];
exec_units[0].cpuids[bsp_core_strand_index] = temp_cpuid;
}
/**
* Determine number of processors and detect physical cores. On Simics
* copy the code which will be executed by the AP when the BSP sends an
* IPI to it in order to make it execute HelenOS code.
*/
void smp_init(void)
{
detect_execution_units();
}
/**
* For each CPU sets the value of cpus[i].arch.id, where i is the
* index of the CPU in the cpus variable, to the cpuid of the i-th processor
* to be run. The CPUs are run such that the CPU represented by cpus[0]
* is run first, cpus[1] is run after it, and cpus[cpu_count - 1] is run as the
* last one.
*
* The CPU IDs are set such that during waking the CPUs up the
* processor cores will be alternated, i.e. first one CPU from the first core
* will be run, after that one CPU from the second CPU core will be run,...
* then one CPU from the last core will be run, after that another CPU
* from the first core will be run, then another CPU from the second core
* will be run,... then another CPU from the last core will be run, and so on.
*/
static void init_cpuids(void)
{
unsigned int cur_core_strand;
unsigned int cur_core;
unsigned int cur_cpu = 0;
for (cur_core_strand = 0; cur_core_strand < max_core_strands; cur_core_strand++) {
for (cur_core = 0; cur_core < exec_unit_count; cur_core++) {
if (cur_core_strand > exec_units[cur_core].strand_count)
continue;
cpus[cur_cpu].arch.exec_unit = &(exec_units[cur_core]);
atomic_add(&(exec_units[cur_core].nrdy), atomic_load(&(cpus[cur_cpu].nrdy)));
cpus[cur_cpu].arch.id = exec_units[cur_core].cpuids[cur_core_strand];
exec_units[cur_core].cpus[cur_core_strand] = &(cpus[cur_cpu]);
cur_cpu++;
}
}
}
/**
* Wakes up a single CPU.
*
* @param cpuid ID of the CPU to be woken up
*/
static bool wake_cpu(uint64_t cpuid)
{
#ifdef CONFIG_SIMICS_SMP_HACK
ipi_unicast_to((void (*)(void)) 1234, cpuid);
#else
/* stop the CPU before making it execute our code */
if (__hypercall_fast1(CPU_STOP, cpuid) != EOK)
return false;
/* wait for the CPU to stop */
uint64_t state;
__hypercall_fast_ret1(cpuid, 0, 0, 0, 0, CPU_STATE, &state);
while (state == CPU_STATE_RUNNING)
__hypercall_fast_ret1(cpuid, 0, 0, 0, 0, CPU_STATE, &state);
/* make the CPU run again and execute HelenOS code */
if (__hypercall_fast4(CPU_START, cpuid,
(uint64_t) KA2PA(kernel_image_start), KA2PA(trap_table),
physmem_base) != EOK)
return false;
#endif
if (semaphore_down_timeout(&ap_completion_semaphore, 10000000) != EOK)
printf("%s: waiting for processor (cpuid = %" PRIu64 ") timed out\n",
__func__, cpuid);
return true;
}
/** Wake application processors up. */
void kmp(void *arg)
{
init_cpuids();
unsigned int i;
for (i = 1; i < config.cpu_count; i++) {
wake_cpu(cpus[i].arch.id);
}
}
/** @}
*/