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x86/asm: Always set A (accessed) flag in GDT descriptors 

We have no known use for having the CPU track whether GDT descriptors
have been accessed or not.

Simplify the code by adding the flag to the common flags and removing
it everywhere else.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231219151200.2878271-5-vegard.nossum@oracle.com
This commit is contained in:
Vegard Nossum 2023-12-19 16:11:59 +01:00 committed by Ingo Molnar
parent 1445f6e15f
commit 3b184b71df
6 changed files with 16 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/x86/boot/pm.c
View File

@ -68,9 +68,9 @@ static void setup_gdt(void)
being 8-byte unaligned. Intel recommends 16 byte alignment. */
static const u64 boot_gdt[] __attribute__((aligned(16))) = {
/* CS: code, read/execute, 4 GB, base 0 */
[GDT_ENTRY_BOOT_CS] = GDT_ENTRY(DESC_CODE32 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_BOOT_CS] = GDT_ENTRY(DESC_CODE32, 0, 0xfffff),
/* DS: data, read/write, 4 GB, base 0 */
[GDT_ENTRY_BOOT_DS] = GDT_ENTRY(DESC_DATA32 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_BOOT_DS] = GDT_ENTRY(DESC_DATA32, 0, 0xfffff),
/* TSS: 32-bit tss, 104 bytes, base 4096 */
/* We only have a TSS here to keep Intel VT happy;
we don't actually use it for anything. */

4
arch/x86/include/asm/desc_defs.h
View File

@ -37,9 +37,9 @@
* of flags
*/
#define _DESC_DATA (_DESC_S | _DESC_PRESENT | \
#define _DESC_DATA (_DESC_S | _DESC_PRESENT | _DESC_ACCESSED | \
_DESC_DATA_WRITABLE)
#define _DESC_CODE (_DESC_S | _DESC_PRESENT | \
#define _DESC_CODE (_DESC_S | _DESC_PRESENT | _DESC_ACCESSED | \
_DESC_CODE_READABLE | _DESC_CODE_EXECUTABLE)
#define DESC_DATA16 (_DESC_DATA)

12
arch/x86/kernel/cpu/common.c
View File

@ -188,12 +188,12 @@ DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
* TLS descriptors are currently at a different place compared to i386.
* Hopefully nobody expects them at a fixed place (Wine?)
*/
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA64 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER32_CS] = GDT_ENTRY_INIT(DESC_CODE32 | DESC_USER | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(DESC_DATA64 | DESC_USER | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(DESC_CODE64 | DESC_USER | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA64, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER32_CS] = GDT_ENTRY_INIT(DESC_CODE32 | DESC_USER, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(DESC_DATA64 | DESC_USER, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(DESC_CODE64 | DESC_USER, 0, 0xfffff),
#else
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA32, 0, 0xfffff),

6
arch/x86/kernel/head64.c
View File

@ -71,9 +71,9 @@ EXPORT_SYMBOL(vmemmap_base);
* GDT used on the boot CPU before switching to virtual addresses.
*/
static struct desc_struct startup_gdt[GDT_ENTRIES] __initdata = {
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA64 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA64, 0, 0xfffff),
};
/*

2
arch/x86/realmode/rm/reboot.S
View File

@ -154,5 +154,5 @@ SYM_DATA_START(machine_real_restart_gdt)
* base value 0x100; since this is consistent with real mode
* semantics we don't have to reload the segments once CR0.PE = 0.
*/
.quad GDT_ENTRY(DESC_DATA16 | _DESC_ACCESSED, 0x100, 0xffff)
.quad GDT_ENTRY(DESC_DATA16, 0x100, 0xffff)
SYM_DATA_END(machine_real_restart_gdt)

4
drivers/firmware/efi/libstub/x86-5lvl.c
View File

@ -13,8 +13,8 @@ bool efi_no5lvl;
static void (*la57_toggle)(void *cr3);
static const struct desc_struct gdt[] = {
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64 | _DESC_ACCESSED, 0, 0xfffff),
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64, 0, 0xfffff),
};
/*