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// SPDX-License-Identifier: GPL-2.0
#include <linux/sched/task.h>
#include <linux/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/facility.h>
#include <asm/sections.h>
#include <asm/mem_detect.h>
#include <asm/maccess.h>
#include "decompressor.h"
#include "boot.h"
#define init_mm (*(struct mm_struct *)vmlinux.init_mm_off)
#define swapper_pg_dir vmlinux.swapper_pg_dir_off
#define invalid_pg_dir vmlinux.invalid_pg_dir_off
/*
* Mimic virt_to_kpte() in lack of init_mm symbol. Skip pmd NULL check though.
*/
static inline pte_t *__virt_to_kpte(unsigned long va)
{
return pte_offset_kernel(pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va), va);
}
unsigned long __bootdata_preserved(s390_invalid_asce);
unsigned long __bootdata(pgalloc_pos);
unsigned long __bootdata(pgalloc_end);
unsigned long __bootdata(pgalloc_low);
enum populate_mode {
POPULATE_NONE,
POPULATE_ONE2ONE,
};
static void boot_check_oom(void)
{
if (pgalloc_pos < pgalloc_low)
error("out of memory on boot\n");
}
static void pgtable_populate_begin(unsigned long online_end)
{
unsigned long initrd_end;
unsigned long kernel_end;
kernel_end = vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
pgalloc_low = round_up(kernel_end, PAGE_SIZE);
if (IS_ENABLED(CONFIG_BLK_DEV_INITRD)) {
initrd_end = round_up(initrd_data.start + initrd_data.size, _SEGMENT_SIZE);
pgalloc_low = max(pgalloc_low, initrd_end);
}
pgalloc_end = round_down(online_end, PAGE_SIZE);
pgalloc_pos = pgalloc_end;
boot_check_oom();
}
static void *boot_alloc_pages(unsigned int order)
{
unsigned long size = PAGE_SIZE << order;
pgalloc_pos -= size;
pgalloc_pos = round_down(pgalloc_pos, size);
boot_check_oom();
return (void *)pgalloc_pos;
}
static void *boot_crst_alloc(unsigned long val)
{
unsigned long *table;
table = boot_alloc_pages(CRST_ALLOC_ORDER);
if (table)
crst_table_init(table, val);
return table;
}
static pte_t *boot_pte_alloc(void)
{
static void *pte_leftover;
pte_t *pte;
BUILD_BUG_ON(_PAGE_TABLE_SIZE * 2 != PAGE_SIZE);
if (!pte_leftover) {
pte_leftover = boot_alloc_pages(0);
pte = pte_leftover + _PAGE_TABLE_SIZE;
} else {
pte = pte_leftover;
pte_leftover = NULL;
}
memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
return pte;
}
static unsigned long _pa(unsigned long addr, enum populate_mode mode)
{
switch (mode) {
case POPULATE_NONE:
return -1;
case POPULATE_ONE2ONE:
return addr;
default:
return -1;
}
}
static bool can_large_pud(pud_t *pu_dir, unsigned long addr, unsigned long end)
{
return machine.has_edat2 &&
IS_ALIGNED(addr, PUD_SIZE) && (end - addr) >= PUD_SIZE;
}
static bool can_large_pmd(pmd_t *pm_dir, unsigned long addr, unsigned long end)
{
return machine.has_edat1 &&
IS_ALIGNED(addr, PMD_SIZE) && (end - addr) >= PMD_SIZE;
}
static void pgtable_pte_populate(pmd_t *pmd, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long next;
pte_t *pte, entry;
pte = pte_offset_kernel(pmd, addr);
for (; addr < end; addr += PAGE_SIZE, pte++) {
if (pte_none(*pte)) {
entry = __pte(_pa(addr, mode));
entry = set_pte_bit(entry, PAGE_KERNEL_EXEC);
set_pte(pte, entry);
}
}
}
static void pgtable_pmd_populate(pud_t *pud, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long next;
pmd_t *pmd, entry;
pte_t *pte;
pmd = pmd_offset(pud, addr);
for (; addr < end; addr = next, pmd++) {
next = pmd_addr_end(addr, end);
if (pmd_none(*pmd)) {
if (can_large_pmd(pmd, addr, next)) {
entry = __pmd(_pa(addr, mode));
entry = set_pmd_bit(entry, SEGMENT_KERNEL_EXEC);
set_pmd(pmd, entry);
continue;
}
pte = boot_pte_alloc();
pmd_populate(&init_mm, pmd, pte);
} else if (pmd_large(*pmd)) {
continue;
}
pgtable_pte_populate(pmd, addr, next, mode);
}
}
static void pgtable_pud_populate(p4d_t *p4d, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long next;
pud_t *pud, entry;
pmd_t *pmd;
pud = pud_offset(p4d, addr);
for (; addr < end; addr = next, pud++) {
next = pud_addr_end(addr, end);
if (pud_none(*pud)) {
if (can_large_pud(pud, addr, next)) {
entry = __pud(_pa(addr, mode));
entry = set_pud_bit(entry, REGION3_KERNEL_EXEC);
set_pud(pud, entry);
continue;
}
pmd = boot_crst_alloc(_SEGMENT_ENTRY_EMPTY);
pud_populate(&init_mm, pud, pmd);
} else if (pud_large(*pud)) {
continue;
}
pgtable_pmd_populate(pud, addr, next, mode);
}
}
static void pgtable_p4d_populate(pgd_t *pgd, unsigned long addr, unsigned long end,
enum populate_mode mode)
{
unsigned long next;
p4d_t *p4d;
pud_t *pud;
p4d = p4d_offset(pgd, addr);
for (; addr < end; addr = next, p4d++) {
next = p4d_addr_end(addr, end);
if (p4d_none(*p4d)) {
pud = boot_crst_alloc(_REGION3_ENTRY_EMPTY);
p4d_populate(&init_mm, p4d, pud);
}
pgtable_pud_populate(p4d, addr, next, mode);
}
}
static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode)
{
unsigned long next;
pgd_t *pgd;
p4d_t *p4d;
pgd = pgd_offset(&init_mm, addr);
for (; addr < end; addr = next, pgd++) {
next = pgd_addr_end(addr, end);
if (pgd_none(*pgd)) {
p4d = boot_crst_alloc(_REGION2_ENTRY_EMPTY);
pgd_populate(&init_mm, pgd, p4d);
}
pgtable_p4d_populate(pgd, addr, next, mode);
}
}
/*
* The pgtables are located in the range [pgalloc_pos, pgalloc_end).
* That range must stay intact and is later reserved in the memblock.
* Therefore pgtable_populate(pgalloc_pos, pgalloc_end) is needed to
* finalize pgalloc_pos pointer. However that call can decrease the
* value of pgalloc_pos pointer itself. Therefore, pgtable_populate()
* needs to be called repeatedly until pgtables are complete and
* pgalloc_pos does not grow left anymore.
*/
static void pgtable_populate_end(void)
{
unsigned long pgalloc_end_curr = pgalloc_end;
unsigned long pgalloc_pos_prev;
do {
pgalloc_pos_prev = pgalloc_pos;
pgtable_populate(pgalloc_pos, pgalloc_end_curr, POPULATE_ONE2ONE);
pgalloc_end_curr = pgalloc_pos_prev;
} while (pgalloc_pos < pgalloc_pos_prev);
}
void setup_vmem(unsigned long online_end, unsigned long asce_limit)
{
unsigned long asce_type;
unsigned long asce_bits;
if (asce_limit == _REGION1_SIZE) {
asce_type = _REGION2_ENTRY_EMPTY;
asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
} else {
asce_type = _REGION3_ENTRY_EMPTY;
asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
}
s390_invalid_asce = invalid_pg_dir | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
crst_table_init((unsigned long *)swapper_pg_dir, asce_type);
crst_table_init((unsigned long *)invalid_pg_dir, _REGION3_ENTRY_EMPTY);
/*
* To allow prefixing the lowcore must be mapped with 4KB pages.
* To prevent creation of a large page at address 0 first map
* the lowcore and create the identity mapping only afterwards.
*
* No further pgtable_populate() calls are allowed after the value
* of pgalloc_pos finalized with a call to pgtable_populate_end().
*/
pgtable_populate_begin(online_end);
pgtable_populate(0, sizeof(struct lowcore), POPULATE_ONE2ONE);
pgtable_populate(0, online_end, POPULATE_ONE2ONE);
pgtable_populate(__memcpy_real_area, __memcpy_real_area + PAGE_SIZE,
POPULATE_NONE);
memcpy_real_ptep = __virt_to_kpte(__memcpy_real_area);
pgtable_populate_end();
S390_lowcore.kernel_asce = swapper_pg_dir | asce_bits;
S390_lowcore.user_asce = s390_invalid_asce;
__ctl_load(S390_lowcore.kernel_asce, 1, 1);
__ctl_load(S390_lowcore.user_asce, 7, 7);
__ctl_load(S390_lowcore.kernel_asce, 13, 13);
init_mm.context.asce = S390_lowcore.kernel_asce;
}
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