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