diff mbox series

[kvm-unit-tests,8/9] x86: Provide a common 64-bit AP entrypoint for EFI and non-EFI

Message ID 20220408103127.19219-9-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 8, 2022, 10:31 a.m. UTC
ap_start64() currently serves as the 64-bit entrypoint for non-EFI
tests.

Having ap_start64() and save_id() written in asm prevents sharing these
routines between EFI and non-EFI tests.

Rewrite them in C and use ap_start64 as the 64-bit entrypoint in the EFI
boot flow.

With this, EFI tests support -smp > 1. smptest.efi now passes.

Signed-off-by: Varad Gautam <varad.gautam@suse.com>
---
 lib/x86/asm/setup.h  |  3 +++
 lib/x86/setup.c      | 57 +++++++++++++++++++++++++++++++++-----------
 lib/x86/smp.c        |  1 +
 x86/cstart64.S       | 30 -----------------------
 x86/efi/efistart64.S |  5 ----
 5 files changed, 47 insertions(+), 49 deletions(-)
diff mbox series

Patch

diff --git a/lib/x86/asm/setup.h b/lib/x86/asm/setup.h
index 24d4fa9..8502e7d 100644
--- a/lib/x86/asm/setup.h
+++ b/lib/x86/asm/setup.h
@@ -16,4 +16,7 @@  efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo);
 void setup_5level_page_table(void);
 #endif /* CONFIG_EFI */
 
+void save_id(void);
+void ap_start64(void);
+
 #endif /* _X86_ASM_SETUP_H_ */
diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index e5a690a..261fd9b 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -14,8 +14,12 @@ 
 #include "apic.h"
 #include "apic-defs.h"
 #include "asm/setup.h"
+#include "processor.h"
+#include "atomic.h"
 
 extern char edata;
+extern unsigned char online_cpus[(MAX_TEST_CPUS + 7) / 8];
+extern unsigned cpu_online_count;
 
 struct mbi_bootinfo {
 	u32 flags;
@@ -170,10 +174,27 @@  void setup_multiboot(struct mbi_bootinfo *bi)
 #ifdef CONFIG_EFI
 
 /* From x86/efi/efistart64.S */
+
 extern void update_cs(void);
 extern void setup_segments64(u64 gs_base);
 extern u8 stacktop;
+#endif
+
+static void setup_gdt_tss(void)
+{
+	size_t tss_offset;
+
+	/* 64-bit setup_tss does not use the stacktop argument.  */
+	tss_offset = setup_tss(NULL);
+	load_gdt_tss(tss_offset);
+#ifdef CONFIG_EFI
+	update_cs();
+	u64 gs_base = (u64)(&stacktop) - (PAGE_SIZE * (apic_id() + 1));
+	setup_segments64(gs_base);
+#endif
+}
 
+#ifdef CONFIG_EFI
 static efi_status_t setup_memory_allocator(efi_bootinfo_t *efi_bootinfo)
 {
 	int i;
@@ -270,20 +291,6 @@  static void setup_page_table(void)
 	write_cr3((ulong)&ptl4);
 }
 
-static void setup_gdt_tss(void)
-{
-	size_t tss_offset;
-	u64 gs_base;
-
-	/* 64-bit setup_tss does not use the stacktop argument.  */
-	tss_offset = setup_tss(NULL);
-	load_gdt_tss(tss_offset);
-
-	update_cs();
-	gs_base = (u64)(&stacktop) - (PAGE_SIZE * (apic_id() + 1));
-	setup_segments64(gs_base);
-}
-
 efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo)
 {
 	efi_status_t status;
@@ -330,6 +337,7 @@  efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo)
 	mask_pic_interrupts();
 	setup_page_table();
 	enable_apic();
+	save_id();
 	ap_init();
 	enable_x2apic();
 	smp_init();
@@ -352,3 +360,24 @@  void setup_libcflat(void)
 			add_setup_arg("bootloader");
 	}
 }
+
+void save_id(void)
+{
+	u32 id = apic_id();
+
+	/* atomic_fetch_or() emits `lock or %dl, (%eax)` */
+	atomic_fetch_or(&online_cpus[id / 8], (1 << (id % 8)));
+}
+
+void ap_start64(void)
+{
+	reset_apic();
+	load_idt();
+	setup_gdt_tss();
+	save_id();
+	enable_apic();
+	enable_x2apic();
+	sti();
+	atomic_fetch_inc(&cpu_online_count);
+	asm volatile("1: hlt; jmp 1b");
+}
diff --git a/lib/x86/smp.c b/lib/x86/smp.c
index 4ddb459..eec8d2b 100644
--- a/lib/x86/smp.c
+++ b/lib/x86/smp.c
@@ -22,6 +22,7 @@  static atomic_t active_cpus;
 extern u8 sipi_entry;
 extern u8 sipi_end;
 volatile unsigned cpu_online_count = 1;
+unsigned char online_cpus[(MAX_TEST_CPUS + 7) / 8];
 
 static __attribute__((used)) void ipi(void)
 {
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 45009d4..e0d4ab5 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -126,33 +126,6 @@  gdt32_descr:
 sipi_end:
 
 .code64
-save_id:
-	movl $(APIC_DEFAULT_PHYS_BASE + APIC_ID), %eax
-	movl (%rax), %eax
-	shrl $24, %eax
-	lock btsl %eax, online_cpus
-	retq
-
-ap_start64:
-.retry:
-	xor %eax, %eax
-	lock btsl %eax, ap_lock
-	jc .retry
-	call reset_apic
-	call load_idt
-	load_tss
-	call enable_apic
-	call save_id
-	call enable_x2apic
-	sti
-	xor %eax, %eax
-	lock btr %eax, ap_lock
-	nop
-	lock incw cpu_online_count
-
-1:	hlt
-	jmp 1b
-
 start64:
 	call reset_apic
 	call load_idt
@@ -191,6 +164,3 @@  setup_5level_page_table:
 	lretq
 lvl5:
 	retq
-
-online_cpus:
-	.fill (max_cpus + 7) / 8, 1, 0
diff --git a/x86/efi/efistart64.S b/x86/efi/efistart64.S
index c8fd3a2..99a3802 100644
--- a/x86/efi/efistart64.S
+++ b/x86/efi/efistart64.S
@@ -102,8 +102,3 @@  sipi_end:
 .code32
 
 #include "../start32.S"
-
-.code64:
-
-ap_start64:
-	jmp ap_start64