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[PATCH 1/3 gnumach] apic: Use cpuid to read the apic id for speed
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From: |
Damien Zammit |
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Subject: |
[PATCH 1/3 gnumach] apic: Use cpuid to read the apic id for speed |
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Date: |
Fri, 11 Aug 2023 08:34:44 +0000 |
---
i386/i386/apic.c | 11 +++++------
i386/i386/cpu_number.h | 20 +++++++++++++++++++-
i386/i386/locore.S | 2 +-
i386/i386/mp_desc.c | 3 +--
x86_64/locore.S | 10 +++++-----
5 files changed, 31 insertions(+), 15 deletions(-)
diff --git a/i386/i386/apic.c b/i386/i386/apic.c
index 2bb8e3f1..3a51f506 100644
--- a/i386/i386/apic.c
+++ b/i386/i386/apic.c
@@ -185,7 +185,11 @@ apic_get_num_ioapics(void)
int
apic_get_current_cpu(void)
{
- return (lapic->apic_id.r >> 24) & 0xff;
+ unsigned int eax, ebx, ecx, edx;
+ eax = 1;
+ ecx = 0;
+ cpuid(eax, ebx, ecx, edx);
+ return (ebx >> 24);
}
@@ -295,11 +299,6 @@ lapic_enable(void)
cpu_intr_save(&flags);
apic_id = apic_get_current_cpu();
- if (apic_id < 0)
- {
- printf("apic_get_current_cpu() failed, assuming BSP\n");
- apic_id = 0;
- }
dummy = lapic->dest_format.r;
lapic->dest_format.r = 0xffffffff; /* flat model */
diff --git a/i386/i386/cpu_number.h b/i386/i386/cpu_number.h
index c00896e8..df086370 100644
--- a/i386/i386/cpu_number.h
+++ b/i386/i386/cpu_number.h
@@ -39,12 +39,30 @@
#define CX(addr, reg) addr(,reg,8)
#endif
-#define CPU_NUMBER(reg) \
+#define CPU_NUMBER_NO_STACK(reg) \
movl %cs:lapic, reg ;\
movl %cs:APIC_ID(reg), reg ;\
shrl $24, reg ;\
movl %cs:CX(cpu_id_lut, reg), reg ;\
+/* Never call CPU_NUMBER(%esi) */
+#define CPU_NUMBER(reg) \
+ pushl %esi ;\
+ pushl %eax ;\
+ pushl %ebx ;\
+ pushl %ecx ;\
+ pushl %edx ;\
+ movl $1, %eax ;\
+ cpuid ;\
+ shrl $24, %ebx ;\
+ movl %cs:CX(cpu_id_lut, %ebx), %esi ;\
+ popl %edx ;\
+ popl %ecx ;\
+ popl %ebx ;\
+ popl %eax ;\
+ movl %esi, reg ;\
+ popl %esi ;\
+
#ifndef __ASSEMBLER__
#include "kern/cpu_number.h"
int cpu_number(void);
diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index 55add6e4..67fe4257 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -1054,7 +1054,7 @@ syscall_entry_2:
movl %edx,R_CS(%esp) /* fix cs */
movl %ebx,R_EFLAGS(%esp) /* fix eflags */
- CPU_NUMBER(%edx)
+ CPU_NUMBER_NO_STACK(%edx)
TIME_TRAP_SENTRY
movl CX(EXT(kernel_stack),%edx),%ebx
diff --git a/i386/i386/mp_desc.c b/i386/i386/mp_desc.c
index fa66aa44..c6af8fc6 100644
--- a/i386/i386/mp_desc.c
+++ b/i386/i386/mp_desc.c
@@ -267,8 +267,7 @@ cpu_setup(int cpu)
void
cpu_ap_main()
{
- unsigned apic_id = (((ApicLocalUnit*)phystokv(lapic_addr))->apic_id.r >>
24) & 0xff;
- int cpu = apic_get_cpu_kernel_id(apic_id);
+ int cpu = cpu_number();
do {
cpu_pause();
diff --git a/x86_64/locore.S b/x86_64/locore.S
index 271a9071..402b9c85 100644
--- a/x86_64/locore.S
+++ b/x86_64/locore.S
@@ -905,7 +905,7 @@ ast_from_interrupt:
pusha /* save general registers */
PUSH_SEGMENTS_ISR(%rdx)
SET_KERNEL_SEGMENTS
- CPU_NUMBER(%edx)
+ CPU_NUMBER_NO_STACK(%edx)
TIME_TRAP_UENTRY
movq CX(EXT(kernel_stack),%edx),%rsp
@@ -1155,7 +1155,7 @@ syscall_entry_2:
movq %rdx,R_CS(%rsp) /* fix cs */
movq %rbx,R_EFLAGS(%rsp) /* fix eflags */
- CPU_NUMBER(%edx)
+ CPU_NUMBER_NO_STACK(%edx)
TIME_TRAP_SENTRY
movq CX(EXT(kernel_stack),%edx),%rbx
@@ -1355,7 +1355,7 @@ ENTRY(syscall64)
* save only the callee-preserved status according to the C ABI,
* plus RIP and EFLAGS for sysret
*/
- CPU_NUMBER(%r11)
+ CPU_NUMBER_NO_STACK(%r11)
movq CX(EXT(active_threads),%r11),%r11 /* point to current thread */
movq TH_PCB(%r11),%r11 /* point to pcb */
addq $ PCB_ISS,%r11 /* point to saved state */
@@ -1389,7 +1389,7 @@ ENTRY(syscall64)
mov %r10,%rcx /* fix arg3 location according to C ABI
*/
/* switch to kernel stack, then we can enable interrupts */
- CPU_NUMBER(%r11)
+ CPU_NUMBER_NO_STACK(%r11)
movq CX(EXT(kernel_stack),%r11),%rsp
sti
@@ -1428,7 +1428,7 @@ _syscall64_call:
_syscall64_check_for_ast:
/* Check for ast. */
- CPU_NUMBER(%r11)
+ CPU_NUMBER_NO_STACK(%r11)
cmpl $0,CX(EXT(need_ast),%r11)
jz _syscall64_restore_state
--
2.40.1