[PATCH 3/3] LoongArch: mm: Add unified function populate_kernel_pte

Bibo Mao
2023-07-12T03:16:31Z

Function pcpu_populate_pte and fixmap_pte are similar, they populate
one page from kernel address space. And there is confusion between
pgd and p4d in function fixmap_pte, such as pgd_none always returns
zero. This patch adds unified function populate_kernel_pte and replaces
pcpu_populate_pte and fixmap_pte.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
arch/loongarch/include/asm/pgalloc.h | 1 +
arch/loongarch/kernel/numa.c | 40 +--------------------
arch/loongarch/mm/init.c | 52 ++++++++++++++++------------
3 files changed, 32 insertions(+), 61 deletions(-)

diff --git a/arch/loongarch/include/asm/pgalloc.h b/arch/loongarch/include/asm/pgalloc.h
index af1d1e4a6965..ca17b573dba6 100644
--- a/arch/loongarch/include/asm/pgalloc.h
+++ b/arch/loongarch/include/asm/pgalloc.h
@@ -91,4 +91,5 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)

#endif /* __PAGETABLE_PUD_FOLDED */

+extern pte_t * __init populate_kernel_pte(unsigned long addr);
#endif /* _ASM_PGALLOC_H */
diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c
index 778e1c20bfb0..24a693b76873 100644
--- a/arch/loongarch/kernel/numa.c
+++ b/arch/loongarch/kernel/numa.c
@@ -67,46 +67,8 @@ static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)

void __init pcpu_populate_pte(unsigned long addr)
{
- pgd_t *pgd = pgd_offset_k(addr);
- p4d_t *p4d = p4d_offset(pgd, addr);
- pud_t *pud;
- pmd_t *pmd;
-
- if (p4d_none(*p4d)) {
- pud = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
- if (!pud)
- goto err_alloc;
- p4d_populate(&init_mm, p4d, pud);
-#ifndef __PAGETABLE_PUD_FOLDED
- pud_init(pud);
-#endif
- }
-
- pud = pud_offset(p4d, addr);
- if (pud_none(*pud)) {
- pmd = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
- if (!pmd)
- goto err_alloc;
- pud_populate(&init_mm, pud, pmd);
-#ifndef __PAGETABLE_PMD_FOLDED
- pmd_init(pmd);
-#endif
- }
-
- pmd = pmd_offset(pud, addr);
- if (!pmd_present(*pmd)) {
- pte_t *pte;
-
- pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
- if (!pte)
- goto err_alloc;
- pmd_populate_kernel(&init_mm, pmd, pte);
- }
-
+ populate_kernel_pte(addr);
return;
-
-err_alloc:
- panic("%s: Failed to allocate memory\n", __func__);
}

void __init setup_per_cpu_areas(void)
diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index 3b7d8129570b..6cd2948373ae 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c
@@ -191,46 +191,49 @@ void vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *al
#endif
#endif

-static pte_t *fixmap_pte(unsigned long addr)
+pte_t * __init populate_kernel_pte(unsigned long addr)
{
- pgd_t *pgd;
- p4d_t *p4d;
+ pgd_t *pgd = pgd_offset_k(addr);
+ p4d_t *p4d = p4d_offset(pgd, addr);
pud_t *pud;
pmd_t *pmd;

- pgd = pgd_offset_k(addr);
- p4d = p4d_offset(pgd, addr);
-
- if (pgd_none(*pgd)) {
- pud_t *new __maybe_unused;
-
- new = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
- pgd_populate(&init_mm, pgd, new);
+ if (p4d_none(*p4d)) {
+ pud = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
+ if (!pud)
+ goto err_alloc;
+ p4d_populate(&init_mm, p4d, pud);
#ifndef __PAGETABLE_PUD_FOLDED
- pud_init(new);
+ pud_init(pud);
#endif
}

pud = pud_offset(p4d, addr);
if (pud_none(*pud)) {
- pmd_t *new __maybe_unused;
-
- new = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
- pud_populate(&init_mm, pud, new);
+ pmd = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
+ if (!pmd)
+ goto err_alloc;
+ pud_populate(&init_mm, pud, pmd);
#ifndef __PAGETABLE_PMD_FOLDED
- pmd_init(new);
+ pmd_init(pmd);
#endif
}

pmd = pmd_offset(pud, addr);
- if (pmd_none(*pmd)) {
- pte_t *new __maybe_unused;
+ if (!pmd_present(*pmd)) {
+ pte_t *pte;

- new = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
- pmd_populate_kernel(&init_mm, pmd, new);
+ pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+ if (!pte)
+ goto err_alloc;
+ pmd_populate_kernel(&init_mm, pmd, pte);
}

return pte_offset_kernel(pmd, addr);
+
+err_alloc:
+ panic("%s: Failed to allocate memory\n", __func__);
+ return NULL;
}

void __init __set_fixmap(enum fixed_addresses idx,
@@ -241,7 +244,12 @@ void __init __set_fixmap(enum fixed_addresses idx,

BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);

- ptep = fixmap_pte(addr);
+ /*
+ * Now only FIX_EARLYCON_MEM_BASE fixed map is used
+ * __set_fixmap must be called before mem_init since function
+ * populate_kernel_pte allocates memory with memblock_alloc method.
+ */
+ ptep = populate_kernel_pte(addr);
if (!pte_none(*ptep)) {
pte_ERROR(*ptep);
return;
--
2.27.0