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

diff --git a/arch/x86/boot/pm.c b/arch/x86/boot/pm.c
index ab35b52d2c4b04ca84058ae6f7785da6229a6e86..5941f930f6c5a80037b0a94cac3874aec30a9f2e 100644 (file)
--- a/arch/x86/boot/pm.c
+++ b/arch/x86/boot/pm.c
@@ -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. */

diff --git a/arch/x86/include/asm/desc_defs.h b/arch/x86/include/asm/desc_defs.h
index 33d229ed96dcf748a5e05b9f08132f18c0aa7a3e..d440a65af8f394c52244ea15e6621a758c12874a 100644 (file)
--- a/arch/x86/include/asm/desc_defs.h
+++ b/arch/x86/include/asm/desc_defs.h
@@ -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)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 32934a0656af6ce4a7397a31157cdf51213eaedd..6184488a7d77d3a3cfb42c4181d2bd9753c02899 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -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),

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 00dbddfdfecec64fbf1d3b2aaf402d7076629a69..dc0956067944dc6332dc52a50756460e5b3ff69f 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -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),
 };
 
 /*

diff --git a/arch/x86/realmode/rm/reboot.S b/arch/x86/realmode/rm/reboot.S
index 5bc068b9acdd574004ad8a6b45075938cad35491..e714b4624e3676d9c7b4d40ed512e088d2c22d62 100644 (file)
--- a/arch/x86/realmode/rm/reboot.S
+++ b/arch/x86/realmode/rm/reboot.S
@@ -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)

diff --git a/drivers/firmware/efi/libstub/x86-5lvl.c b/drivers/firmware/efi/libstub/x86-5lvl.c
index 005dd9b14f95b0647e405d813f0c16de984bea8b..77359e802181fd82b6a624cf74183e6a318cec9b 100644 (file)
--- a/drivers/firmware/efi/libstub/x86-5lvl.c
+++ b/drivers/firmware/efi/libstub/x86-5lvl.c
@@ -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),
 };
 
 /*