[PATCH 4/6] x86/smpbppt: Remove early_gdt_descr on 64-bit

Brian Gerst
2023-02-22T22:13:55Z

Build the GDT descriptor on the stack instead.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/kernel/acpi/sleep.c | 2 --
arch/x86/kernel/head_64.S | 19 +++++++------------
2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 008fda8b1982..6538ddb55f28 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -114,8 +114,6 @@ int x86_acpi_suspend_lowlevel(void)
#else /* CONFIG_64BIT */
#ifdef CONFIG_SMP
current->thread.sp = (unsigned long)temp_stack + sizeof(temp_stack);
- early_gdt_descr.address =
- (unsigned long)get_cpu_gdt_rw(smp_processor_id());
initial_gs = per_cpu_offset(smp_processor_id());
/* Force the startup into boot mode */
saved_smpboot_ctrl = xchg(&smpboot_control, 0);
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index f7905ba4b992..0dd57d573a0e 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -245,7 +245,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
#ifdef CONFIG_SMP
/*
* Is this the boot CPU coming up? If so everything is available
- * in initial_gs and early_gdt_descr.
+ * in initial_gs.
*/
movl smpboot_control(%rip), %edx
testl $STARTUP_SECONDARY, %edx
@@ -313,11 +313,6 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
/* Save it for GS BASE setup */
movq %rbx, initial_gs(%rip)

- /* Calculate the GDT address */
- movq $gdt_page, %rcx
- addq %rbx, %rcx
- movq %rcx, early_gdt_descr_base(%rip)
-
movq %rbx, %rdx
#else
xorl %edx, %edx
@@ -339,7 +334,12 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
* addresses where we're currently running on. We have to do that here
* because in 32bit we couldn't load a 64bit linear address.
*/
- lgdt early_gdt_descr(%rip)
+ subq $16, %rsp
+ movw $(GDT_SIZE-1), (%rsp)
+ leaq gdt_page(%rdx), %rax
+ movq %rax, 2(%rsp)
+ lgdt (%rsp)
+ addq $16, %rsp

/* set up data segments */
xorl %eax,%eax
@@ -754,11 +754,6 @@ SYM_DATA_END(level1_fixmap_pgt)

.data
.align 16
-
-SYM_DATA(early_gdt_descr, .word GDT_ENTRIES*8-1)
-SYM_DATA_LOCAL(early_gdt_descr_base, .quad INIT_PER_CPU_VAR(gdt_page))
-
- .align 16
SYM_DATA(smpboot_control, .long 0)

.align 16
--
2.39.2