96 lines
2.2 KiB
C
96 lines
2.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/pgtable.h>
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#include <asm/abs_lowcore.h>
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#define ABS_LOWCORE_UNMAPPED 1
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#define ABS_LOWCORE_LAP_ON 2
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#define ABS_LOWCORE_IRQS_ON 4
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unsigned long __bootdata_preserved(__abs_lowcore);
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bool __ro_after_init abs_lowcore_mapped;
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int abs_lowcore_map(int cpu, struct lowcore *lc, bool alloc)
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{
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unsigned long addr = __abs_lowcore + (cpu * sizeof(struct lowcore));
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unsigned long phys = __pa(lc);
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int rc, i;
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for (i = 0; i < LC_PAGES; i++) {
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rc = __vmem_map_4k_page(addr, phys, PAGE_KERNEL, alloc);
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if (rc) {
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/*
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* Do not unmap allocated page tables in case the
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* allocation was not requested. In such a case the
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* request is expected coming from an atomic context,
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* while the unmap attempt might sleep.
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*/
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if (alloc) {
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for (--i; i >= 0; i--) {
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addr -= PAGE_SIZE;
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vmem_unmap_4k_page(addr);
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}
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}
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return rc;
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}
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addr += PAGE_SIZE;
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phys += PAGE_SIZE;
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}
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return 0;
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}
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void abs_lowcore_unmap(int cpu)
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{
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unsigned long addr = __abs_lowcore + (cpu * sizeof(struct lowcore));
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int i;
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for (i = 0; i < LC_PAGES; i++) {
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vmem_unmap_4k_page(addr);
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addr += PAGE_SIZE;
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}
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}
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struct lowcore *get_abs_lowcore(unsigned long *flags)
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{
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unsigned long irq_flags;
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union ctlreg0 cr0;
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int cpu;
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*flags = 0;
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cpu = get_cpu();
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if (abs_lowcore_mapped) {
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return ((struct lowcore *)__abs_lowcore) + cpu;
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} else {
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if (cpu != 0)
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panic("Invalid unmapped absolute lowcore access\n");
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local_irq_save(irq_flags);
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if (!irqs_disabled_flags(irq_flags))
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*flags |= ABS_LOWCORE_IRQS_ON;
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__ctl_store(cr0.val, 0, 0);
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if (cr0.lap) {
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*flags |= ABS_LOWCORE_LAP_ON;
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__ctl_clear_bit(0, 28);
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}
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*flags |= ABS_LOWCORE_UNMAPPED;
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return lowcore_ptr[0];
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}
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}
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void put_abs_lowcore(struct lowcore *lc, unsigned long flags)
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{
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if (abs_lowcore_mapped) {
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if (flags)
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panic("Invalid mapped absolute lowcore release\n");
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} else {
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if (smp_processor_id() != 0)
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panic("Invalid mapped absolute lowcore access\n");
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if (!(flags & ABS_LOWCORE_UNMAPPED))
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panic("Invalid unmapped absolute lowcore release\n");
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if (flags & ABS_LOWCORE_LAP_ON)
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__ctl_set_bit(0, 28);
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if (flags & ABS_LOWCORE_IRQS_ON)
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local_irq_enable();
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}
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put_cpu();
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}
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