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Kernel: Implement software context switching and Processor structure

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Moving certain globals into a new Processor structure for
each CPU allows us to eventually run an instance of the
scheduler on each CPU.
This commit is contained in:
Tom 2020-06-27 13:42:28 -06:00 • committed by Andreas Kling
parent 10407061d2
commit fb41d89384
22 changed files with 1002 additions and 513 deletions
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49
Kernel/Arch/i386/Boot/boot.S
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@ -252,15 +252,6 @@ apic_ap_start:
mov %cs, %ax
mov %ax, %ds
/* Generate a new processor id. This is not the APIC id. We just
need a way to find ourselves a stack without stomping on other
APs that may be doing this concurrently. */
xor %ax, %ax
mov %ax, %bp
inc %ax
lock; xaddw %ax, %ds:(ap_cpu_id - apic_ap_start)(%bp) /* avoid relocation entries */
mov %ax, %bx
xor %ax, %ax
mov %ax, %sp
@ -281,14 +272,18 @@ apic_ap_start32:
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
movl $0x8000, %ebp
/* generate a unique ap cpu id (0 means 1st ap, not bsp!) */
xorl %eax, %eax
incl %eax
lock; xaddl %eax, (ap_cpu_id - apic_ap_start)(%ebp) /* avoid relocation entries */
movl %eax, %esi
/* find our allocated stack based on the generated id */
andl 0x0000FFFF, %ebx
movl %ebx, %esi
movl (ap_cpu_init_stacks - apic_ap_start)(%ebp, %ebx, 4), %esp
movl (ap_cpu_init_stacks - apic_ap_start)(%ebp, %eax, 4), %esp
/* check if we support NX and enable it if we do */
movl $0x80000001, %eax
cpuid
@ -319,8 +314,8 @@ apic_ap_start32:
lgdt (ap_cpu_gdtr_initial2 - apic_ap_start + 0xc0008000)
/* jump above 3GB into our identity mapped area now */
ljmp $8, $(1f - apic_ap_start + 0xc0008000)
1:
ljmp $8, $(apic_ap_start32_2 - apic_ap_start + 0xc0008000)
apic_ap_start32_2:
/* flush the TLB */
movl %cr3, %eax
movl %eax, %cr3
@ -338,13 +333,20 @@ apic_ap_start32:
movl %eax, %cr0
movl (ap_cpu_init_cr4 - apic_ap_start)(%ebp), %eax
movl %eax, %cr4
/* push the Processor pointer this CPU is going to use */
movl (ap_cpu_init_processor_info_array - apic_ap_start)(%ebp), %eax
addl $0xc0000000, %eax
movl 0(%eax, %esi, 4), %eax
push %eax
/* push the cpu id, 0 representing the bsp and call into c++ */
incl %esi
push %esi
xor %ebp, %ebp
cld
/* push the arbitrary cpu id, 0 representing the bsp and call into c++ */
inc %esi
push %esi
/* We are in identity mapped P0x8000 and the BSP will unload this code
once all APs are initialized, so call init_ap but return to our
infinite loop */
@ -356,7 +358,7 @@ apic_ap_start32:
apic_ap_start_size:
.2byte end_apic_ap_start - apic_ap_start
ap_cpu_id:
.2byte 0x0
.4byte 0x0
ap_cpu_gdt:
/* null */
.8byte 0x0
@ -388,6 +390,9 @@ ap_cpu_init_cr3:
.global ap_cpu_init_cr4
ap_cpu_init_cr4:
.4byte 0x0 /* will be set at runtime */
.global ap_cpu_init_processor_info_array
ap_cpu_init_processor_info_array:
.4byte 0x0 /* will be set at runtime */
.global ap_cpu_init_stacks
ap_cpu_init_stacks:
/* array of allocated stack pointers */