From: Christoph Hellwig <hch@lst.de>
Date: Wed, 8 Apr 2020 17:27:42 +0200
Subject: x86/mm: Add a x86_has_pat_wp() helper
Git-commit: 1f6f655e01adebf5bd5e6c3da2e843c104ded051
Patch-mainline: v5.8-rc1
References: git-fixes
Abstract the ioremap code away from the caching mode internals.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200408152745.1565832-2-hch@lst.de
Acked-by: Nikolay Borisov <nik.borisov@suse.com>
---
arch/x86/include/asm/pat.h | 2 ++
arch/x86/mm/init.c | 6 ++++++
arch/x86/mm/ioremap.c | 8 ++------
3 files changed, 10 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/pat.h
+++ b/arch/x86/include/asm/pat.h
@@ -23,4 +23,6 @@ void io_free_memtype(resource_size_t sta
bool pat_pfn_immune_to_uc_mtrr(unsigned long pfn);
+bool x86_has_pat_wp(void);
+
#endif /* _ASM_X86_PAT_H */
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -69,6 +69,12 @@ uint8_t __pte2cachemode_tbl[8] = {
};
EXPORT_SYMBOL(__pte2cachemode_tbl);
+/* Check that the write-protect PAT entry is set for write-protect */
+bool x86_has_pat_wp(void)
+{
+ return __pte2cachemode_tbl[_PAGE_CACHE_MODE_WP] == _PAGE_CACHE_MODE_WP;
+}
+
static unsigned long __initdata pgt_buf_start;
static unsigned long __initdata pgt_buf_end;
static unsigned long __initdata pgt_buf_top;
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -740,10 +740,8 @@ void __init *early_memremap_encrypted(re
void __init *early_memremap_encrypted_wp(resource_size_t phys_addr,
unsigned long size)
{
- /* Be sure the write-protect PAT entry is set for write-protect */
- if (__pte2cachemode_tbl[_PAGE_CACHE_MODE_WP] != _PAGE_CACHE_MODE_WP)
+ if (!x86_has_pat_wp())
return NULL;
-
return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_ENC_WP);
}
@@ -761,10 +759,8 @@ void __init *early_memremap_decrypted(re
void __init *early_memremap_decrypted_wp(resource_size_t phys_addr,
unsigned long size)
{
- /* Be sure the write-protect PAT entry is set for write-protect */
- if (__pte2cachemode_tbl[_PAGE_CACHE_MODE_WP] != _PAGE_CACHE_MODE_WP)
+ if (!x86_has_pat_wp())
return NULL;
-
return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_NOENC_WP);
}
#endif /* CONFIG_ARCH_USE_MEMREMAP_PROT */