Re: [PATCH 1/4] LoongArch: Set pte entry with PAGE_GLOBAL for kernel space
From: maobibo
Date: Fri Oct 11 2024 - 22:40:37 EST
Huacai,
On 2024/10/12 上午10:15, Huacai Chen wrote:
Hi, Bibo,
On Thu, Oct 10, 2024 at 11:50 AM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
Unlike general architectures, there are two pages for one TLB entry
on LoongArch system. For kernel space, it requires both two pte
entries with PAGE_GLOBAL set, else HW treats it as non-global tlb,
there will be potential problems if tlb entry for kernel space is
not global. Such as fail to flush kernel tlb with function
local_flush_tlb_kernel_range() which only flush tlb with global bit.
Here function kernel_pte_init() is added, it can be used to init
pte table when it is created, so the default inital pte is
PAGE_GLOBAL rather than zero at beginning.
I think kernel_pte_init() is also needed in zero_pmd_populate() in
mm/kasan/init.c. And moreover, the second patch should be squashed in
yes, it is needed in zero_pmd_populate() in mm/kasan/init.c, will add it
in next version.
this one because they should be as a whole. Though the second one
touches the common code, I can merge it with mm maintainer's acked-by.
Sure, will merge it with the second one into one patch.
Regards
Bibo Mao
Huacai
Kernel space areas includes fixmap, percpu, vmalloc and kasan areas
set default pte entry with PAGE_GLOBAL set.
Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
arch/loongarch/include/asm/pgalloc.h | 13 +++++++++++++
arch/loongarch/include/asm/pgtable.h | 1 +
arch/loongarch/mm/init.c | 4 +++-
arch/loongarch/mm/kasan_init.c | 4 +++-
arch/loongarch/mm/pgtable.c | 22 ++++++++++++++++++++++
5 files changed, 42 insertions(+), 2 deletions(-)
diff --git a/arch/loongarch/include/asm/pgalloc.h b/arch/loongarch/include/asm/pgalloc.h
index 4e2d6b7ca2ee..b2698c03dc2c 100644
--- a/arch/loongarch/include/asm/pgalloc.h
+++ b/arch/loongarch/include/asm/pgalloc.h
@@ -10,8 +10,21 @@
#define __HAVE_ARCH_PMD_ALLOC_ONE
#define __HAVE_ARCH_PUD_ALLOC_ONE
+#define __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
#include <asm-generic/pgalloc.h>
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
+{
+ pte_t *pte;
+
+ pte = (pte_t *) __get_free_page(GFP_KERNEL);
+ if (!pte)
+ return NULL;
+
+ kernel_pte_init(pte);
+ return pte;
+}
+
static inline void pmd_populate_kernel(struct mm_struct *mm,
pmd_t *pmd, pte_t *pte)
{
diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index 9965f52ef65b..22e3a8f96213 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -269,6 +269,7 @@ extern void set_pmd_at(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp, pm
extern void pgd_init(void *addr);
extern void pud_init(void *addr);
extern void pmd_init(void *addr);
+extern void kernel_pte_init(void *addr);
/*
* Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index 8a87a482c8f4..9f26e933a8a3 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c
@@ -198,9 +198,11 @@ pte_t * __init populate_kernel_pte(unsigned long addr)
if (!pmd_present(pmdp_get(pmd))) {
pte_t *pte;
- pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+ pte = memblock_alloc_raw(PAGE_SIZE, PAGE_SIZE);
if (!pte)
panic("%s: Failed to allocate memory\n", __func__);
+
+ kernel_pte_init(pte);
pmd_populate_kernel(&init_mm, pmd, pte);
}
diff --git a/arch/loongarch/mm/kasan_init.c b/arch/loongarch/mm/kasan_init.c
index 427d6b1aec09..34988573b0d5 100644
--- a/arch/loongarch/mm/kasan_init.c
+++ b/arch/loongarch/mm/kasan_init.c
@@ -152,6 +152,8 @@ static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
phys_addr_t page_phys = early ?
__pa_symbol(kasan_early_shadow_page)
: kasan_alloc_zeroed_page(node);
+ if (!early)
+ kernel_pte_init(__va(page_phys));
next = addr + PAGE_SIZE;
set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
} while (ptep++, addr = next, addr != end && __pte_none(early, ptep_get(ptep)));
@@ -287,7 +289,7 @@ void __init kasan_init(void)
set_pte(&kasan_early_shadow_pte[i],
pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO));
- memset(kasan_early_shadow_page, 0, PAGE_SIZE);
+ kernel_pte_init(kasan_early_shadow_page);
csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
local_flush_tlb_all();
diff --git a/arch/loongarch/mm/pgtable.c b/arch/loongarch/mm/pgtable.c
index eb6a29b491a7..228ffc1db0a3 100644
--- a/arch/loongarch/mm/pgtable.c
+++ b/arch/loongarch/mm/pgtable.c
@@ -38,6 +38,28 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
}
EXPORT_SYMBOL_GPL(pgd_alloc);
+void kernel_pte_init(void *addr)
+{
+ unsigned long *p, *end;
+ unsigned long entry;
+
+ entry = (unsigned long)_PAGE_GLOBAL;
+ p = (unsigned long *)addr;
+ end = p + PTRS_PER_PTE;
+
+ do {
+ p[0] = entry;
+ p[1] = entry;
+ p[2] = entry;
+ p[3] = entry;
+ p[4] = entry;
+ p += 8;
+ p[-3] = entry;
+ p[-2] = entry;
+ p[-1] = entry;
+ } while (p != end);
+}
+
void pgd_init(void *addr)
{
unsigned long *p, *end;
--
2.39.3