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Message-Id: <1d982a2883cd807668fad9575ea1c285ae7c272b.1684137557.git.houwenlong.hwl@antgroup.com>
Date: Mon, 15 May 2023 16:19:34 +0800
From: "Hou Wenlong" <houwenlong.hwl@...group.com>
To: linux-kernel@...r.kernel.org
Cc: "Lai Jiangshan" <jiangshan.ljs@...group.com>,
"Hou Wenlong" <houwenlong.hwl@...group.com>,
"Andy Lutomirski" <luto@...nel.org>,
"Thomas Gleixner" <tglx@...utronix.de>,
"Ingo Molnar" <mingo@...hat.com>, "Borislav Petkov" <bp@...en8.de>,
"Dave Hansen" <dave.hansen@...ux.intel.com>, <x86@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
"Peter Zijlstra" <peterz@...radead.org>,
"Suren Baghdasaryan" <surenb@...gle.com>,
"Andrew Morton" <akpm@...ux-foundation.org>,
"Mike Rapoport (IBM)" <rppt@...nel.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
"David Woodhouse" <dwmw@...zon.co.uk>,
"Usama Arif" <usama.arif@...edance.com>,
"Josh Poimboeuf" <jpoimboe@...nel.org>,
"Brian Gerst" <brgerst@...il.com>
Subject: [PATCH RFC 3/4] x86/fixmap: Move vsyscall page out of fixmap area
After mapping vsyscall page individually, the vsyscall page could be
moved out of fixmap area.
Suggested-by: Lai Jiangshan <jiangshan.ljs@...group.com>
Signed-off-by: Hou Wenlong <houwenlong.hwl@...group.com>
---
arch/x86/entry/vsyscall/vsyscall_64.c | 4 ----
arch/x86/include/asm/fixmap.h | 17 +++++------------
arch/x86/kernel/head_64.S | 6 +++---
arch/x86/mm/fault.c | 1 -
arch/x86/mm/init_64.c | 2 +-
5 files changed, 9 insertions(+), 21 deletions(-)
diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index 4373460ebbde..f469f8dc36d4 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -35,7 +35,6 @@
#include <asm/vsyscall.h>
#include <asm/unistd.h>
-#include <asm/fixmap.h>
#include <asm/traps.h>
#include <asm/paravirt.h>
@@ -391,7 +390,4 @@ void __init map_vsyscall(void)
if (vsyscall_mode == XONLY)
vm_flags_init(&gate_vma, VM_EXEC);
-
- BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
- (unsigned long)VSYSCALL_ADDR);
}
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index d0dcefb5cc59..eeb152ad9682 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -23,13 +23,13 @@
* covered fully.
*/
#ifndef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP
-# define FIXMAP_PMD_NUM 2
+# define FIXMAP_PMD_NUM 1
#else
# define KM_PMDS (KM_MAX_IDX * ((CONFIG_NR_CPUS + 511) / 512))
-# define FIXMAP_PMD_NUM (KM_PMDS + 2)
+# define FIXMAP_PMD_NUM (KM_PMDS + 1)
#endif
-/* fixmap starts downwards from the 507th entry in level2_fixmap_pgt */
-#define FIXMAP_PMD_TOP 507
+/* fixmap starts downwards from the 506th entry in level2_fixmap_pgt */
+#define FIXMAP_PMD_TOP 506
#ifndef __ASSEMBLY__
#include <linux/kernel.h>
@@ -38,8 +38,6 @@
#include <asm/pgtable_types.h>
#ifdef CONFIG_X86_32
#include <linux/threads.h>
-#else
-#include <uapi/asm/vsyscall.h>
#endif
/*
@@ -55,8 +53,7 @@
extern unsigned long __FIXADDR_TOP;
#define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
#else
-#define FIXADDR_TOP (round_up(VSYSCALL_ADDR + PAGE_SIZE, 1<<PMD_SHIFT) - \
- PAGE_SIZE)
+#define FIXADDR_TOP (0xffffffffff600000UL - PAGE_SIZE)
#endif
/*
@@ -81,10 +78,6 @@ extern unsigned long __FIXADDR_TOP;
enum fixed_addresses {
#ifdef CONFIG_X86_32
FIX_HOLE,
-#else
-#ifdef CONFIG_X86_VSYSCALL_EMULATION
- VSYSCALL_PAGE = (FIXADDR_TOP - VSYSCALL_ADDR) >> PAGE_SHIFT,
-#endif
#endif
FIX_DBGP_BASE,
FIX_EARLYCON_MEM_BASE,
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index a5df3e994f04..8a0714bc52db 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -639,15 +639,15 @@ SYM_DATA_START_PAGE_ALIGNED(level2_kernel_pgt)
SYM_DATA_END(level2_kernel_pgt)
SYM_DATA_START_PAGE_ALIGNED(level2_fixmap_pgt)
- .fill (512 - 4 - FIXMAP_PMD_NUM),8,0
+ .fill (512 - 5 - FIXMAP_PMD_NUM),8,0
pgtno = 0
.rept (FIXMAP_PMD_NUM)
.quad level1_fixmap_pgt + (pgtno << PAGE_SHIFT) - __START_KERNEL_map \
+ _PAGE_TABLE_NOENC;
pgtno = pgtno + 1
.endr
- /* 6 MB reserved space + a 2MB hole */
- .fill 4,8,0
+ /* 2MB (with 4KB vsyscall page inside) + 6 MB reserved space + a 2MB hole */
+ .fill 5,8,0
SYM_DATA_END(level2_fixmap_pgt)
SYM_DATA_START_PAGE_ALIGNED(level1_fixmap_pgt)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index e4399983c50c..988478e7ef1f 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -23,7 +23,6 @@
#include <asm/cpufeature.h> /* boot_cpu_has, ... */
#include <asm/traps.h> /* dotraplinkage, ... */
-#include <asm/fixmap.h> /* VSYSCALL_ADDR */
#include <asm/vsyscall.h> /* emulate_vsyscall */
#include <asm/vm86.h> /* struct vm86 */
#include <asm/mmu_context.h> /* vma_pkey() */
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a190aae8ceaf..b7fd05a1ba1d 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -40,7 +40,7 @@
#include <linux/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
-#include <asm/fixmap.h>
+#include <asm/vsyscall.h>
#include <asm/e820/api.h>
#include <asm/apic.h>
#include <asm/tlb.h>
--
2.31.1
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