cregit-Linux how code gets into the kernel

Release 4.14 arch/arm64/kernel/acpi_parking_protocol.c

/*
 * ARM64 ACPI Parking Protocol implementation
 *
 * Authors: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
 *          Mark Salter <msalter@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <linux/acpi.h>
#include <linux/mm.h>
#include <linux/types.h>

#include <asm/cpu_ops.h>


struct parking_protocol_mailbox {
	
__le32 cpu_id;
	
__le32 reserved;
	
__le64 entry_point;
};


struct cpu_mailbox_entry {
	
struct parking_protocol_mailbox __iomem *mailbox;
	
phys_addr_t mailbox_addr;
	
u8 version;
	
u8 gic_cpu_id;
};


static struct cpu_mailbox_entry cpu_mailbox_entries[NR_CPUS];


void __init acpi_set_mailbox_entry(int cpu, struct acpi_madt_generic_interrupt *p) { struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; cpu_entry->mailbox_addr = p->parked_address; cpu_entry->version = p->parking_version; cpu_entry->gic_cpu_id = p->cpu_interface_number; }

Contributors

PersonTokensPropCommitsCommitProp
Lorenzo Pieralisi49100.00%1100.00%
Total49100.00%1100.00%


bool acpi_parking_protocol_valid(int cpu) { struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; return cpu_entry->mailbox_addr && cpu_entry->version; }

Contributors

PersonTokensPropCommitsCommitProp
Lorenzo Pieralisi28100.00%1100.00%
Total28100.00%1100.00%


static int acpi_parking_protocol_cpu_init(unsigned int cpu) { pr_debug("%s: ACPI parked addr=%llx\n", __func__, cpu_mailbox_entries[cpu].mailbox_addr); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Lorenzo Pieralisi27100.00%1100.00%
Total27100.00%1100.00%


static int acpi_parking_protocol_cpu_prepare(unsigned int cpu) { return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Lorenzo Pieralisi13100.00%1100.00%
Total13100.00%1100.00%


static int acpi_parking_protocol_cpu_boot(unsigned int cpu) { struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; struct parking_protocol_mailbox __iomem *mailbox; u32 cpu_id; /* * Map mailbox memory with attribute device nGnRE (ie ioremap - * this deviates from the parking protocol specifications since * the mailboxes are required to be mapped nGnRnE; the attribute * discrepancy is harmless insofar as the protocol specification * is concerned). * If the mailbox is mistakenly allocated in the linear mapping * by FW ioremap will fail since the mapping will be prevented * by the kernel (it clashes with the linear mapping attributes * specifications). */ mailbox = ioremap(cpu_entry->mailbox_addr, sizeof(*mailbox)); if (!mailbox) return -EIO; cpu_id = readl_relaxed(&mailbox->cpu_id); /* * Check if firmware has set-up the mailbox entry properly * before kickstarting the respective cpu. */ if (cpu_id != ~0U) { iounmap(mailbox); return -ENXIO; } /* * stash the mailbox address mapping to use it for further FW * checks in the postboot method */ cpu_entry->mailbox = mailbox; /* * We write the entry point and cpu id as LE regardless of the * native endianness of the kernel. Therefore, any boot-loaders * that read this address need to convert this address to the * Boot-Loader's endianness before jumping. */ writeq_relaxed(__pa_symbol(secondary_entry), &mailbox->entry_point); writel_relaxed(cpu_entry->gic_cpu_id, &mailbox->cpu_id); arch_send_wakeup_ipi_mask(cpumask_of(cpu)); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Lorenzo Pieralisi12698.44%250.00%
Laura Abbott10.78%125.00%
Luc Van Oostenryck10.78%125.00%
Total128100.00%4100.00%


static void acpi_parking_protocol_cpu_postboot(void) { int cpu = smp_processor_id(); struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu]; struct parking_protocol_mailbox __iomem *mailbox = cpu_entry->mailbox; u64 entry_point; entry_point = readq_relaxed(&mailbox->entry_point); /* * Check if firmware has cleared the entry_point as expected * by the protocol specification. */ WARN_ON(entry_point); }

Contributors

PersonTokensPropCommitsCommitProp
Lorenzo Pieralisi5296.30%250.00%
Luc Van Oostenryck23.70%250.00%
Total54100.00%4100.00%

const struct cpu_operations acpi_parking_protocol_ops = { .name = "parking-protocol", .cpu_init = acpi_parking_protocol_cpu_init, .cpu_prepare = acpi_parking_protocol_cpu_prepare, .cpu_boot = acpi_parking_protocol_cpu_boot, .cpu_postboot = acpi_parking_protocol_cpu_postboot };

Overall Contributors

PersonTokensPropCommitsCommitProp
Lorenzo Pieralisi37998.19%240.00%
Laura Abbott41.04%120.00%
Luc Van Oostenryck30.78%240.00%
Total386100.00%5100.00%
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