diff mbox series

[kvm-unit-tests,v3,01/11] x86: Share realmode trampoline between i386 and x86_64

Message ID 20220426114352.1262-2-varad.gautam@suse.com (mailing list archive)
State New, archived
Headers show
Series SMP Support for x86 UEFI Tests | expand

Commit Message

Varad Gautam April 26, 2022, 11:43 a.m. UTC 
i386 and x86_64 each maintain their own copy of the realmode trampoline
(sipi_entry). Move the 16-bit SIPI vector and GDT to a new start16.S to
be shared by both.

Signed-off-by: Varad Gautam <varad.gautam@suse.com>
---
 x86/cstart.S   | 20 ++++----------------
 x86/cstart64.S | 18 +++---------------
 x86/start16.S  | 27 +++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 31 deletions(-)
 create mode 100644 x86/start16.S
diff mbox series

Patch

diff --git a/x86/cstart.S b/x86/cstart.S
index 6db6a38..06b5be6 100644
--- a/x86/cstart.S
+++ b/x86/cstart.S
@@ -126,10 +126,10 @@  start32:
 
 ap_init:
 	cld
-	sgdtl ap_gdt_descr // must be close to sipi_entry for real mode access to work
-	lea sipi_entry, %esi
+	sgdtl ap_rm_gdt_descr // must be close to rm_trampoline for real mode access to work
+	lea rm_trampoline, %esi
 	xor %edi, %edi
-	mov $(sipi_end - sipi_entry), %ecx
+	mov $(rm_trampoline_end - rm_trampoline), %ecx
 	rep movsb
 	mov $APIC_DEFAULT_PHYS_BASE, %eax
 	movl $(APIC_DEST_ALLBUT | APIC_DEST_PHYSICAL | APIC_DM_INIT | APIC_INT_ASSERT), APIC_ICR(%eax)
@@ -146,16 +146,4 @@  online_cpus:
 .align 2
 cpu_online_count:	.word 1
 
-.code16
-sipi_entry:
-	mov %cr0, %eax
-	or $1, %eax
-	mov %eax, %cr0
-	lgdtl ap_gdt_descr - sipi_entry
-	ljmpl $8, $ap_start32
-
-ap_gdt_descr:
-	.word 0
-	.long 0
-
-sipi_end:
+#include "start16.S"
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 7272452..cae6f51 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -156,19 +156,7 @@  gdt32:
 	.quad 0x00cf93000000ffff // flat 32-bit data segment
 gdt32_end:
 
-.code16
-sipi_entry:
-	mov %cr0, %eax
-	or $1, %eax
-	mov %eax, %cr0
-	lgdtl gdt32_descr - sipi_entry
-	ljmpl $8, $ap_start32
-
-gdt32_descr:
-	.word gdt32_end - gdt32 - 1
-	.long gdt32
-
-sipi_end:
+#include "start16.S"
 
 .code32
 ap_start32:
@@ -243,9 +231,9 @@  online_cpus:
 
 ap_init:
 	cld
-	lea sipi_entry, %rsi
+	lea rm_trampoline, %rsi
 	xor %rdi, %rdi
-	mov $(sipi_end - sipi_entry), %rcx
+	mov $(rm_trampoline_end - rm_trampoline), %rcx
 	rep movsb
 	mov $APIC_DEFAULT_PHYS_BASE, %eax
 	movl $(APIC_DEST_ALLBUT | APIC_DEST_PHYSICAL | APIC_DM_INIT | APIC_INT_ASSERT), APIC_ICR(%rax)
diff --git a/x86/start16.S b/x86/start16.S
new file mode 100644
index 0000000..e61b22a
--- /dev/null
+++ b/x86/start16.S
@@ -0,0 +1,27 @@ 
+/* Common 16-bit bootstrapping code. */
+
+.code16
+.globl rm_trampoline
+rm_trampoline:
+
+/* Store SIPI vector code at the beginning of trampoline. */
+sipi_entry:
+	mov %cr0, %eax
+	or $1, %eax
+	mov %eax, %cr0
+	lgdtl ap_rm_gdt_descr - sipi_entry
+	ljmpl $8, $ap_start32
+sipi_end:
+
+.globl ap_rm_gdt_descr
+ap_rm_gdt_descr:
+#ifdef __i386__
+	.word 0
+	.long 0
+#else
+	.word gdt32_end - gdt32 - 1
+	.long gdt32
+#endif
+
+.globl rm_trampoline_end
+rm_trampoline_end: