linux-kernel - [PATCH V5 10/50] x86: Replace PTI_PGTABLE_SWITCH_BIT with PTI_USER_PGTABLE

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Date:   Wed, 10 Nov 2021 19:56:56 +0800
From:   Lai Jiangshan <jiangshanlai@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     x86@...nel.org, Lai Jiangshan <laijs@...ux.alibaba.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
Subject: [PATCH V5 10/50] x86: Replace PTI_PGTABLE_SWITCH_BIT with PTI_USER_PGTABLE_BIT

From: Lai Jiangshan <laijs@...ux.alibaba.com>

They are the same in meaning and value.

Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com>
---
 arch/x86/include/asm/pgtable.h | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 65542106464b..c8909457574a 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -5,6 +5,7 @@
 #include <linux/mem_encrypt.h>
 #include <asm/page.h>
 #include <asm/pgtable_types.h>
+#include <asm/processor-flags.h>
 
 /*
  * Macro to mark a page protection value as UC-
@@ -1164,14 +1165,6 @@ static inline bool pgdp_maps_userspace(void *__ptr)
 static inline int pgd_large(pgd_t pgd) { return 0; }
 
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
-/*
- * All top-level PAGE_TABLE_ISOLATION page tables are order-1 pages
- * (8k-aligned and 8k in size).  The kernel one is at the beginning 4k and
- * the user one is in the last 4k.  To switch between them, you
- * just need to flip the 12th bit in their addresses.
- */
-#define PTI_PGTABLE_SWITCH_BIT	PAGE_SHIFT
-
 /*
  * This generates better code than the inline assembly in
  * __set_bit().
@@ -1193,12 +1186,12 @@ static inline void *ptr_clear_bit(void *ptr, int bit)
 
 static inline pgd_t *kernel_to_user_pgdp(pgd_t *pgdp)
 {
-	return ptr_set_bit(pgdp, PTI_PGTABLE_SWITCH_BIT);
+	return ptr_set_bit(pgdp, PTI_USER_PGTABLE_BIT);
 }
 
 static inline pgd_t *user_to_kernel_pgdp(pgd_t *pgdp)
 {
-	return ptr_clear_bit(pgdp, PTI_PGTABLE_SWITCH_BIT);
+	return ptr_clear_bit(pgdp, PTI_USER_PGTABLE_BIT);
 }
 #endif /* CONFIG_PAGE_TABLE_ISOLATION */
 
-- 
2.19.1.6.gb485710b