Add set_direct_map_*() functions for setting the direct map alias for
the page to its default permissions and to an invalid state that cannot
be cached in a TLB. (See d253ca0c3 ("x86/mm/cpa: Add set_direct_map_*()
functions")) Add a similar implementation for LoongArch.
This fixes the KFENCE warnings during hibernation:
==================================================================
BUG: KFENCE: invalid read in swsusp_save+0x368/0x4d8
Invalid read at 0x00000000f7b89a3c:
swsusp_save+0x368/0x4d8
hibernation_snapshot+0x3f0/0x4e0
hibernate+0x20c/0x440
state_store+0x128/0x140
kernfs_fop_write_iter+0x160/0x260
vfs_write+0x2c0/0x520
ksys_write+0x74/0x160
do_syscall+0xb0/0x160
CPU: 0 UID: 0 PID: 812 Comm: bash Tainted: G B 6.11.0-rc1+ #1566
Tainted: [B]=BAD_PAGE
Hardware name: Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0 10/21/2022
==================================================================
Note: We can only set permissions for KVRANGE/XKVRANGE kernel addresses.
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/set_memory.h | 4 ++
arch/loongarch/mm/pageattr.c | 60 +++++++++++++++++++++++++
3 files changed, 65 insertions(+)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 49efa0470e16..727dc80d0477 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -26,6 +26,7 @@ config LOONGARCH
select ARCH_HAS_PTE_DEVMAP
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_SET_MEMORY
+ select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_INLINE_READ_LOCK if !PREEMPTION
select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
diff --git a/arch/loongarch/include/asm/set_memory.h b/arch/loongarch/include/asm/set_memory.h
index 64c7f942e8ec..d70505b6676c 100644
--- a/arch/loongarch/include/asm/set_memory.h
+++ b/arch/loongarch/include/asm/set_memory.h
@@ -14,4 +14,8 @@ int set_memory_nx(unsigned long addr, int numpages);
int set_memory_ro(unsigned long addr, int numpages);
int set_memory_rw(unsigned long addr, int numpages);
+bool kernel_page_present(struct page *page);
+int set_direct_map_default_noflush(struct page *page);
+int set_direct_map_invalid_noflush(struct page *page);
+
#endif /* _ASM_LOONGARCH_SET_MEMORY_H */
diff --git a/arch/loongarch/mm/pageattr.c b/arch/loongarch/mm/pageattr.c
index d11c8f4b8248..5ca25481b275 100644
--- a/arch/loongarch/mm/pageattr.c
+++ b/arch/loongarch/mm/pageattr.c
@@ -157,3 +157,63 @@ int set_memory_rw(unsigned long addr, int numpages)
return __set_memory(addr, numpages, __pgprot(_PAGE_WRITE | _PAGE_DIRTY), __pgprot(0));
}
+
+bool kernel_page_present(struct page *page)
+{
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long addr = (unsigned long)page_address(page);
+
+ if (addr < vm_map_base)
+ return true;
+
+ pgd = pgd_offset_k(addr);
+ if (pgd_none(pgdp_get(pgd)))
+ return false;
+ if (pgd_leaf(pgdp_get(pgd)))
+ return true;
+
+ p4d = p4d_offset(pgd, addr);
+ if (p4d_none(p4dp_get(p4d)))
+ return false;
+ if (p4d_leaf(p4dp_get(p4d)))
+ return true;
+
+ pud = pud_offset(p4d, addr);
+ if (pud_none(pudp_get(pud)))
+ return false;
+ if (pud_leaf(pudp_get(pud)))
+ return true;
+
+ pmd = pmd_offset(pud, addr);
+ if (pmd_none(pmdp_get(pmd)))
+ return false;
+ if (pmd_leaf(pmdp_get(pmd)))
+ return true;
+
+ pte = pte_offset_kernel(pmd, addr);
+ return pte_present(ptep_get(pte));
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+ unsigned long addr = (unsigned long)page_address(page);
+
+ if (addr < vm_map_base)
+ return 0;
+
+ return __set_memory(addr, 1, PAGE_KERNEL, __pgprot(0));
+}
+
+int set_direct_map_invalid_noflush(struct page *page)
+{
+ unsigned long addr = (unsigned long)page_address(page);
+
+ if (addr < vm_map_base)
+ return 0;
+
+ return __set_memory(addr, 1, __pgprot(0), __pgprot(_PAGE_PRESENT | _PAGE_VALID));
+}
--
2.43.5
