ap_init() copies the SIPI vector to lowmem, sends INIT/SIPI to APs
and waits on the APs to come up.
Port this routine to C from asm and move it to smp.c to allow sharing
this functionality between the EFI (-fPIC) and non-EFI builds.
Call ap_init() from the EFI setup path to reset the APs to a known
location.
Signed-off-by: Varad Gautam <varad.gautam@xxxxxxxx>
---
lib/x86/setup.c | 1 +
lib/x86/smp.c | 28 ++++++++++++++++++++++++++--
lib/x86/smp.h | 1 +
x86/cstart64.S | 20 ++------------------
x86/efi/efistart64.S | 9 +++++++++
5 files changed, 39 insertions(+), 20 deletions(-)
diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index 2d63a44..86ba6de 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -323,6 +323,7 @@ efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo)
load_idt();
mask_pic_interrupts();
enable_apic();
+ ap_init();
enable_x2apic();
smp_init();
setup_page_table();
diff --git a/lib/x86/smp.c b/lib/x86/smp.c
index 683b25d..d7f5aba 100644
--- a/lib/x86/smp.c
+++ b/lib/x86/smp.c
@@ -18,6 +18,9 @@ static volatile int ipi_done;
static volatile bool ipi_wait;
static int _cpu_count;
static atomic_t active_cpus;
+extern u8 sipi_entry;
+extern u8 sipi_end;
+volatile unsigned cpu_online_count = 1;
static __attribute__((used)) void ipi(void)
{
@@ -114,8 +117,6 @@ void smp_init(void)
int i;
void ipi_entry(void);
- _cpu_count = fwcfg_get_nb_cpus();
-
setup_idt();
init_apic_map();
set_idt_entry(IPI_VECTOR, ipi_entry, 0);
@@ -142,3 +143,26 @@ void smp_reset_apic(void)
atomic_inc(&active_cpus);
}
+
+void ap_init(void)
+{
+ u8 *dst_addr = 0;
+ size_t sipi_sz = (&sipi_end - &sipi_entry) + 1;
+
+ asm volatile("cld");
+
+ /* Relocate SIPI vector to dst_addr so it can run in 16-bit mode. */
+ memcpy(dst_addr, &sipi_entry, sipi_sz);
+
+ /* INIT */
+ apic_icr_write(APIC_DEST_ALLBUT | APIC_DEST_PHYSICAL | APIC_DM_INIT | APIC_INT_ASSERT, 0);
+
+ /* SIPI */
+ apic_icr_write(APIC_DEST_ALLBUT | APIC_DEST_PHYSICAL | APIC_DM_STARTUP, 0);
+
+ _cpu_count = fwcfg_get_nb_cpus();
+
+ while (_cpu_count != cpu_online_count) {
+ ;
+ }
+}
diff --git a/lib/x86/smp.h b/lib/x86/smp.h
index bd303c2..9c92853 100644
--- a/lib/x86/smp.h
+++ b/lib/x86/smp.h
@@ -78,5 +78,6 @@ void on_cpu(int cpu, void (*function)(void *data), void *data);
void on_cpu_async(int cpu, void (*function)(void *data), void *data);
void on_cpus(void (*function)(void *data), void *data);
void smp_reset_apic(void);
+void ap_init(void);
#endif
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 7272452..f371d06 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -157,6 +157,7 @@ gdt32:
gdt32_end:
.code16
+.globl sipi_entry
sipi_entry:
mov %cr0, %eax
or $1, %eax
@@ -168,6 +169,7 @@ gdt32_descr:
.word gdt32_end - gdt32 - 1
.long gdt32
+.globl sipi_end
sipi_end:
.code32
@@ -240,21 +242,3 @@ lvl5:
online_cpus:
.fill (max_cpus + 7) / 8, 1, 0
-
-ap_init:
- cld
- lea sipi_entry, %rsi
- xor %rdi, %rdi
- mov $(sipi_end - sipi_entry), %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)
- movl $(APIC_DEST_ALLBUT | APIC_DEST_PHYSICAL | APIC_DM_STARTUP), APIC_ICR(%rax)
- call fwcfg_get_nb_cpus
-1: pause
- cmpw %ax, cpu_online_count
- jne 1b
- ret
-
-.align 2
-cpu_online_count: .word 1
diff --git a/x86/efi/efistart64.S b/x86/efi/efistart64.S
index 017abba..0425153 100644
--- a/x86/efi/efistart64.S
+++ b/x86/efi/efistart64.S
@@ -57,3 +57,12 @@ load_gdt_tss:
pushq $0x08 /* 2nd entry in gdt64: 64-bit code segment */
pushq %rdi
lretq
+
+.code16
+
+.globl sipi_entry
+sipi_entry:
+ jmp sipi_entry
+
+.globl sipi_end
+sipi_end:
--
2.35.1
