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s390/mm: allocate Real Memory Copy Area in decompressor

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Move Real Memory Copy Area allocation to the decompressor.
As result, memcpy_real() and memcpy_real_iter() movers
become usable since the very moment the kernel starts.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Alexander Gordeev 2022-12-11 08:18:57 +01:00 committed by Heiko Carstens
parent e0e0a87b4b
commit 8e9205d2a5
5 changed files with 20 additions and 10 deletions
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2
arch/s390/boot/startup.c
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@ -3,6 +3,7 @@
#include <linux/elf.h>
#include <asm/boot_data.h>
#include <asm/sections.h>
#include <asm/maccess.h>
#include <asm/cpu_mf.h>
#include <asm/setup.h>
#include <asm/kasan.h>
@ -19,6 +20,7 @@
unsigned long __bootdata_preserved(__kaslr_offset);
unsigned long __bootdata_preserved(__abs_lowcore);
unsigned long __bootdata_preserved(__memcpy_real_area);
pte_t *__bootdata_preserved(memcpy_real_ptep);
unsigned long __bootdata(__amode31_base);
unsigned long __bootdata_preserved(VMALLOC_START);
unsigned long __bootdata_preserved(VMALLOC_END);

15
arch/s390/boot/vmem.c
View File

@ -5,6 +5,7 @@
#include <asm/facility.h>
#include <asm/sections.h>
#include <asm/mem_detect.h>
#include <asm/maccess.h>
#include "decompressor.h"
#include "boot.h"
@ -12,12 +13,21 @@
#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,
};
@ -88,6 +98,8 @@ static pte_t *boot_pte_alloc(void)
static unsigned long _pa(unsigned long addr, enum populate_mode mode)
{
switch (mode) {
case POPULATE_NONE:
return -1;
case POPULATE_ONE2ONE:
return addr;
default:
@ -259,6 +271,9 @@ void setup_vmem(unsigned long online_end, unsigned long asce_limit)
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;

2
arch/s390/include/asm/maccess.h
View File

@ -7,7 +7,7 @@
struct iov_iter;
extern unsigned long __memcpy_real_area;
void memcpy_real_init(void);
extern pte_t *memcpy_real_ptep;
size_t memcpy_real_iter(struct iov_iter *iter, unsigned long src, size_t count);
int memcpy_real(void *dest, unsigned long src, size_t count);
#ifdef CONFIG_CRASH_DUMP

2
arch/s390/kernel/setup.c
View File

@ -1046,7 +1046,7 @@ void __init setup_arch(char **cmdline_p)
* Create kernel page tables.
*/
paging_init();
memcpy_real_init();
/*
* After paging_init created the kernel page table, the new PSWs
* in lowcore can now run with DAT enabled.

9
arch/s390/mm/maccess.c
View File

@ -21,7 +21,7 @@
#include <asm/maccess.h>
unsigned long __bootdata_preserved(__memcpy_real_area);
static __ro_after_init pte_t *memcpy_real_ptep;
pte_t *__bootdata_preserved(memcpy_real_ptep);
static DEFINE_MUTEX(memcpy_real_mutex);
static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t size)
@ -79,13 +79,6 @@ notrace void *s390_kernel_write(void *dst, const void *src, size_t size)
return dst;
}
void __init memcpy_real_init(void)
{
memcpy_real_ptep = vmem_get_alloc_pte(__memcpy_real_area, true);
if (!memcpy_real_ptep)
panic("Couldn't setup memcpy real area");
}
size_t memcpy_real_iter(struct iov_iter *iter, unsigned long src, size_t count)
{
size_t len, copied, res = 0;