Damien Zammit, le lun. 29 janv. 2024 10:07:30 +0000, a ecrit:
> - ljmp $BOOT_CS, $M(0f)
> + xorl %eax, %eax
> + mov %cs, %ax
> + shll $4, %eax
> + addl $M(0f), %eax
> + movl %eax, M(ljmp_offset32)
This won't work with pipelined processors, which assume a complete
separation between code and data, and will thus have already loaded
the jmp instruction before your modify it.
Rather either perform the relocation from the C code, or use a variable,
which you can refer from the ljmp instruction.
> + /* ljmpl with relocation */
> + .byte 0x66
> + .byte 0xea
> +ljmp_offset32:
> + .long 0xffffffff
> + .word BOOT_CS
> +
> 0:
> .code32
> + /* Protected mode! */
> movw $BOOT_DS, %ax
> movw %ax, %ds
> movw %ax, %es
> diff --git a/i386/i386/mp_desc.c b/i386/i386/mp_desc.c
> index 467f2728..76b4a79c 100644
> --- a/i386/i386/mp_desc.c
> +++ b/i386/i386/mp_desc.c
> @@ -99,6 +99,7 @@ interrupt_stack_alloc(void)
> */
> int bspdone;
>
> +phys_addr_t apboot_addr;
> extern void *apboot, *apbootend;
> extern volatile ApicLocalUnit* lapic;
>
> @@ -296,7 +297,7 @@ cpu_start(int cpu)
>
> printf("Trying to enable: %d\n", apic_id);
>
> - smp_startup_cpu(apic_id, AP_BOOT_ADDR);
> + smp_startup_cpu(apic_id, apboot_addr);
>
> printf("Started cpu %d (lapic id %04x)\n", cpu, apic_id);
>
> @@ -309,7 +310,7 @@ start_other_cpus(void)
> int ncpus = smp_get_numcpus();
>
> //Copy cpu initialization assembly routine
> - memcpy((void*)phystokv(AP_BOOT_ADDR), (void*) &apboot,
> + memcpy((void*) phystokv(apboot_addr), (void*) &apboot,
> (uint32_t)&apbootend - (uint32_t)&apboot);
>
> #ifndef APIC
> diff --git a/i386/i386/mp_desc.h b/i386/i386/mp_desc.h
> index fea42cd3..bcc68662 100644
> --- a/i386/i386/mp_desc.h
> +++ b/i386/i386/mp_desc.h
> @@ -46,8 +46,6 @@
> #include "gdt.h"
> #include "ldt.h"
>
> -#define AP_BOOT_ADDR 0x7000
> -
> /*
> * The descriptor tables are together in a structure
> * allocated one per processor (except for the boot processor).
> @@ -78,6 +76,11 @@ extern uint8_t solid_intstack[];
>
> extern int bspdone;
>
> +/*
> + * Address to hold AP boot code, held in ASM
> + */
> +extern phys_addr_t apboot_addr;
> +
> /*
> * Each CPU calls this routine to set up its descriptor tables.
> */
> diff --git a/i386/i386at/model_dep.c b/i386/i386at/model_dep.c
> index b0a55754..fb95029f 100644
> --- a/i386/i386at/model_dep.c
> +++ b/i386/i386at/model_dep.c
> @@ -66,6 +66,7 @@
> #include <i386/locore.h>
> #include <i386/model_dep.h>
> #include <i386/smp.h>
> +#include <i386/seg.h>
> #include <i386at/acpi_parse_apic.h>
> #include <i386at/autoconf.h>
> #include <i386at/biosmem.h>
> @@ -125,6 +126,9 @@ char *kernel_cmdline = "";
>
> extern char version[];
>
> +/* Realmode temporary GDT */
> +extern struct pseudo_descriptor gdt_descr_tmp;
> +
> /* If set, reboot the system on ctrl-alt-delete. */
> boolean_t rebootflag = FALSE; /* exported to kdintr */
>
> @@ -201,6 +205,20 @@ void machine_init(void)
> */
> pmap_unmap_page_zero();
> #endif
> +
> +#ifdef APIC
> + /*
> + * Grab an early page for AP boot code
> + */
> + /* FIXME: this may not allocate from below 1MB, if within first 16MB */
> + apboot_addr = vm_page_to_pa(vm_page_grab_contig(PAGE_SIZE,
> VM_PAGE_SEL_DMA));
> + assert (apboot_addr < 0x100000);
> +
> + /*
> + * Patch the realmode gdt with the correct offset
> + */
> + gdt_descr_tmp.linear_base += apboot_addr;
> +#endif
> }
>
> /* Conserve power on processor CPU. */
> --
> 2.43.0
>
>
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
