ba05f39d1e
. Check if we have the right number of boot modules . Check if the ELF parsing of VM actually succeeded Both these are root causes of less-than-obvious other errors/asserts a little further down the line; uncovered while experimenting with booting by iPXE, specifically (a) iPXE having a 8-multiboot-modules limit and (b) trying to boot a gzipped VM.
436 lines
13 KiB
C
436 lines
13 KiB
C
/* This file contains code for initialization of protected mode, to initialize
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* code and data segment descriptors, and to initialize global descriptors
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* for local descriptors in the process table.
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*/
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#include <string.h>
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#include <assert.h>
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#include <minix/cpufeature.h>
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#include <machine/multiboot.h>
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#include "kernel/kernel.h"
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#include "archconst.h"
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#include "arch_proto.h"
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#include <libexec.h>
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#define INT_GATE_TYPE (INT_286_GATE | DESC_386_BIT)
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#define TSS_TYPE (AVL_286_TSS | DESC_386_BIT)
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/* This is OK initially, when the 1:1 mapping is still there. */
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char *video_mem = (char *) MULTIBOOT_VIDEO_BUFFER;
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/* Storage for gdt, idt and tss. */
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struct segdesc_s gdt[GDT_SIZE] __aligned(DESC_SIZE);
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struct gatedesc_s idt[IDT_SIZE] __aligned(DESC_SIZE);
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struct tss_s tss[CONFIG_MAX_CPUS];
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u32_t k_percpu_stacks[CONFIG_MAX_CPUS];
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int prot_init_done = 0;
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phys_bytes vir2phys(void *vir)
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{
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extern char _kern_vir_base, _kern_phys_base; /* in kernel.lds */
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u32_t offset = (vir_bytes) &_kern_vir_base -
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(vir_bytes) &_kern_phys_base;
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return (phys_bytes)vir - offset;
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}
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/*===========================================================================*
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* enable_iop *
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*===========================================================================*/
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void enable_iop(struct proc *pp)
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{
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/* Allow a user process to use I/O instructions. Change the I/O Permission
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* Level bits in the psw. These specify least-privileged Current Permission
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* Level allowed to execute I/O instructions. Users and servers have CPL 3.
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* You can't have less privilege than that. Kernel has CPL 0, tasks CPL 1.
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*/
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pp->p_reg.psw |= 0x3000;
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}
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/*===========================================================================*
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* sdesc *
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*===========================================================================*/
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void sdesc(struct segdesc_s *segdp, phys_bytes base, vir_bytes size)
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{
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/* Fill in the size fields (base, limit and granularity) of a descriptor. */
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segdp->base_low = base;
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segdp->base_middle = base >> BASE_MIDDLE_SHIFT;
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segdp->base_high = base >> BASE_HIGH_SHIFT;
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--size; /* convert to a limit, 0 size means 4G */
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if (size > BYTE_GRAN_MAX) {
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segdp->limit_low = size >> PAGE_GRAN_SHIFT;
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segdp->granularity = GRANULAR | (size >>
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(PAGE_GRAN_SHIFT + GRANULARITY_SHIFT));
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} else {
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segdp->limit_low = size;
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segdp->granularity = size >> GRANULARITY_SHIFT;
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}
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segdp->granularity |= DEFAULT; /* means BIG for data seg */
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}
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/*===========================================================================*
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* init_dataseg *
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*===========================================================================*/
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void init_param_dataseg(register struct segdesc_s *segdp,
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phys_bytes base, vir_bytes size, const int privilege)
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{
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/* Build descriptor for a data segment. */
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sdesc(segdp, base, size);
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segdp->access = (privilege << DPL_SHIFT) | (PRESENT | SEGMENT |
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WRITEABLE | ACCESSED);
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/* EXECUTABLE = 0, EXPAND_DOWN = 0, ACCESSED = 0 */
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}
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void init_dataseg(int index, const int privilege)
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{
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init_param_dataseg(&gdt[index], 0, 0xFFFFFFFF, privilege);
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}
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/*===========================================================================*
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* init_codeseg *
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*===========================================================================*/
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static void init_codeseg(int index, int privilege)
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{
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/* Build descriptor for a code segment. */
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sdesc(&gdt[index], 0, 0xFFFFFFFF);
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gdt[index].access = (privilege << DPL_SHIFT)
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| (PRESENT | SEGMENT | EXECUTABLE | READABLE);
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/* CONFORMING = 0, ACCESSED = 0 */
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}
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static struct gate_table_s gate_table_pic[] = {
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{ hwint00, VECTOR( 0), INTR_PRIVILEGE },
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{ hwint01, VECTOR( 1), INTR_PRIVILEGE },
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{ hwint02, VECTOR( 2), INTR_PRIVILEGE },
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{ hwint03, VECTOR( 3), INTR_PRIVILEGE },
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{ hwint04, VECTOR( 4), INTR_PRIVILEGE },
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{ hwint05, VECTOR( 5), INTR_PRIVILEGE },
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{ hwint06, VECTOR( 6), INTR_PRIVILEGE },
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{ hwint07, VECTOR( 7), INTR_PRIVILEGE },
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{ hwint08, VECTOR( 8), INTR_PRIVILEGE },
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{ hwint09, VECTOR( 9), INTR_PRIVILEGE },
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{ hwint10, VECTOR(10), INTR_PRIVILEGE },
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{ hwint11, VECTOR(11), INTR_PRIVILEGE },
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{ hwint12, VECTOR(12), INTR_PRIVILEGE },
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{ hwint13, VECTOR(13), INTR_PRIVILEGE },
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{ hwint14, VECTOR(14), INTR_PRIVILEGE },
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{ hwint15, VECTOR(15), INTR_PRIVILEGE },
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{ NULL, 0, 0}
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};
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static struct gate_table_s gate_table_exceptions[] = {
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{ divide_error, DIVIDE_VECTOR, INTR_PRIVILEGE },
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{ single_step_exception, DEBUG_VECTOR, INTR_PRIVILEGE },
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{ nmi, NMI_VECTOR, INTR_PRIVILEGE },
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{ breakpoint_exception, BREAKPOINT_VECTOR, USER_PRIVILEGE },
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{ overflow, OVERFLOW_VECTOR, USER_PRIVILEGE },
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{ bounds_check, BOUNDS_VECTOR, INTR_PRIVILEGE },
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{ inval_opcode, INVAL_OP_VECTOR, INTR_PRIVILEGE },
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{ copr_not_available, COPROC_NOT_VECTOR, INTR_PRIVILEGE },
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{ double_fault, DOUBLE_FAULT_VECTOR, INTR_PRIVILEGE },
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{ copr_seg_overrun, COPROC_SEG_VECTOR, INTR_PRIVILEGE },
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{ inval_tss, INVAL_TSS_VECTOR, INTR_PRIVILEGE },
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{ segment_not_present, SEG_NOT_VECTOR, INTR_PRIVILEGE },
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{ stack_exception, STACK_FAULT_VECTOR, INTR_PRIVILEGE },
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{ general_protection, PROTECTION_VECTOR, INTR_PRIVILEGE },
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{ page_fault, PAGE_FAULT_VECTOR, INTR_PRIVILEGE },
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{ copr_error, COPROC_ERR_VECTOR, INTR_PRIVILEGE },
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{ alignment_check, ALIGNMENT_CHECK_VECTOR, INTR_PRIVILEGE },
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{ machine_check, MACHINE_CHECK_VECTOR, INTR_PRIVILEGE },
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{ simd_exception, SIMD_EXCEPTION_VECTOR, INTR_PRIVILEGE },
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{ ipc_entry_softint_orig, IPC_VECTOR_ORIG, USER_PRIVILEGE },
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{ kernel_call_entry_orig, KERN_CALL_VECTOR_ORIG, USER_PRIVILEGE },
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{ ipc_entry_softint_um, IPC_VECTOR_UM, USER_PRIVILEGE },
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{ kernel_call_entry_um, KERN_CALL_VECTOR_UM, USER_PRIVILEGE },
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{ NULL, 0, 0}
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};
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int tss_init(unsigned cpu, void * kernel_stack)
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{
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struct tss_s * t = &tss[cpu];
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int index = TSS_INDEX(cpu);
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struct segdesc_s *tssgdt;
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tssgdt = &gdt[index];
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init_param_dataseg(tssgdt, (phys_bytes) t,
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sizeof(struct tss_s), INTR_PRIVILEGE);
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tssgdt->access = PRESENT | (INTR_PRIVILEGE << DPL_SHIFT) | TSS_TYPE;
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/* Build TSS. */
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memset(t, 0, sizeof(*t));
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t->ds = t->es = t->fs = t->gs = t->ss0 = KERN_DS_SELECTOR;
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t->cs = KERN_CS_SELECTOR;
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t->iobase = sizeof(struct tss_s); /* empty i/o permissions map */
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/*
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* make space for process pointer and cpu id and point to the first
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* usable word
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*/
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k_percpu_stacks[cpu] = t->sp0 = ((unsigned) kernel_stack) - X86_STACK_TOP_RESERVED;
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/*
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* set the cpu id at the top of the stack so we know on which cpu is
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* this stak in use when we trap to kernel
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*/
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*((reg_t *)(t->sp0 + 1 * sizeof(reg_t))) = cpu;
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/* Set up Intel SYSENTER support if available. */
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if(minix_feature_flags & MKF_I386_INTEL_SYSENTER) {
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ia32_msr_write(INTEL_MSR_SYSENTER_CS, 0, KERN_CS_SELECTOR);
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ia32_msr_write(INTEL_MSR_SYSENTER_ESP, 0, t->sp0);
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ia32_msr_write(INTEL_MSR_SYSENTER_EIP, 0, (u32_t) ipc_entry_sysenter);
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}
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/* Set up AMD SYSCALL support if available. */
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if(minix_feature_flags & MKF_I386_AMD_SYSCALL) {
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u32_t msr_lo, msr_hi;
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/* set SYSCALL ENABLE bit in EFER MSR */
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ia32_msr_read(AMD_MSR_EFER, &msr_hi, &msr_lo);
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msr_lo |= AMD_EFER_SCE;
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ia32_msr_write(AMD_MSR_EFER, msr_hi, msr_lo);
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/* set STAR register value */
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#define set_star_cpu(forcpu) if(cpu == forcpu) { \
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ia32_msr_write(AMD_MSR_STAR, \
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((u32_t)USER_CS_SELECTOR << 16) | (u32_t)KERN_CS_SELECTOR, \
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(u32_t) ipc_entry_syscall_cpu ## forcpu); }
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set_star_cpu(0);
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set_star_cpu(1);
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set_star_cpu(2);
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set_star_cpu(3);
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set_star_cpu(4);
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set_star_cpu(5);
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set_star_cpu(6);
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set_star_cpu(7);
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assert(CONFIG_MAX_CPUS <= 8);
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}
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return SEG_SELECTOR(index);
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}
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phys_bytes init_segdesc(int gdt_index, void *base, int size)
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{
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struct desctableptr_s *dtp = (struct desctableptr_s *) &gdt[gdt_index];
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dtp->limit = size - 1;
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dtp->base = (phys_bytes) base;
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return (phys_bytes) dtp;
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}
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void int_gate(struct gatedesc_s *tab,
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unsigned vec_nr, vir_bytes offset, unsigned dpl_type)
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{
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/* Build descriptor for an interrupt gate. */
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register struct gatedesc_s *idp;
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idp = &tab[vec_nr];
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idp->offset_low = offset;
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idp->selector = KERN_CS_SELECTOR;
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idp->p_dpl_type = dpl_type;
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idp->offset_high = offset >> OFFSET_HIGH_SHIFT;
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}
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void int_gate_idt(unsigned vec_nr, vir_bytes offset, unsigned dpl_type)
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{
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int_gate(idt, vec_nr, offset, dpl_type);
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}
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void idt_copy_vectors(struct gate_table_s * first)
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{
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struct gate_table_s *gtp;
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for (gtp = first; gtp->gate; gtp++) {
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int_gate(idt, gtp->vec_nr, (vir_bytes) gtp->gate,
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PRESENT | INT_GATE_TYPE |
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(gtp->privilege << DPL_SHIFT));
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}
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}
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void idt_copy_vectors_pic(void)
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{
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idt_copy_vectors(gate_table_pic);
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}
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void idt_init(void)
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{
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idt_copy_vectors_pic();
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idt_copy_vectors(gate_table_exceptions);
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}
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struct desctableptr_s gdt_desc, idt_desc;
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void idt_reload(void)
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{
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x86_lidt(&idt_desc);
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}
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multiboot_module_t *bootmod(int pnr)
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{
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int i;
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assert(pnr >= 0);
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/* Search for desired process in boot process
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* list. The first NR_TASKS ones do not correspond
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* to a module, however, so we don't search those.
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*/
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for(i = NR_TASKS; i < NR_BOOT_PROCS; i++) {
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int p;
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p = i - NR_TASKS;
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if(image[i].proc_nr == pnr) {
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assert(p < MULTIBOOT_MAX_MODS);
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assert(p < kinfo.mbi.mods_count);
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return &kinfo.module_list[p];
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}
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}
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panic("boot module %d not found", pnr);
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}
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int booting_cpu = 0;
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void prot_load_selectors(void)
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{
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/* this function is called by both prot_init by the BSP and
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* the early AP booting code in mpx.S by secondary CPU's.
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* everything is set up the same except for the TSS that is per-CPU.
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*/
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x86_lgdt(&gdt_desc); /* Load gdt */
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idt_init();
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idt_reload();
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x86_lldt(LDT_SELECTOR); /* Load bogus ldt */
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x86_ltr(TSS_SELECTOR(booting_cpu));
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x86_load_kerncs();
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x86_load_ds(KERN_DS_SELECTOR);
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x86_load_es(KERN_DS_SELECTOR);
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x86_load_fs(KERN_DS_SELECTOR);
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x86_load_gs(KERN_DS_SELECTOR);
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x86_load_ss(KERN_DS_SELECTOR);
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}
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/*===========================================================================*
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* prot_init *
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*===========================================================================*/
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void prot_init()
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{
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extern char k_boot_stktop;
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if(_cpufeature(_CPUF_I386_SYSENTER))
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minix_feature_flags |= MKF_I386_INTEL_SYSENTER;
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if(_cpufeature(_CPUF_I386_SYSCALL))
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minix_feature_flags |= MKF_I386_AMD_SYSCALL;
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memset(gdt, 0, sizeof(gdt));
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memset(idt, 0, sizeof(idt));
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/* Build GDT, IDT, IDT descriptors. */
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gdt_desc.base = (u32_t) gdt;
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gdt_desc.limit = sizeof(gdt)-1;
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idt_desc.base = (u32_t) idt;
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idt_desc.limit = sizeof(idt)-1;
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tss_init(0, &k_boot_stktop);
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/* Build GDT */
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init_param_dataseg(&gdt[LDT_INDEX],
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(phys_bytes) 0, 0, INTR_PRIVILEGE); /* unusable LDT */
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gdt[LDT_INDEX].access = PRESENT | LDT;
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init_codeseg(KERN_CS_INDEX, INTR_PRIVILEGE);
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init_dataseg(KERN_DS_INDEX, INTR_PRIVILEGE);
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init_codeseg(USER_CS_INDEX, USER_PRIVILEGE);
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init_dataseg(USER_DS_INDEX, USER_PRIVILEGE);
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/* Currently the multiboot segments are loaded; which is fine, but
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* let's replace them with the ones from our own GDT so we test
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* right away whether they work as expected.
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*/
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prot_load_selectors();
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/* Set up a new post-relocate bootstrap pagetable so that
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* we can map in VM, and we no longer rely on pre-relocated
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* data.
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*/
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pg_clear();
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pg_identity(&kinfo); /* Still need 1:1 for lapic and video mem and such. */
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pg_mapkernel();
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pg_load();
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prot_init_done = 1;
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}
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static int alloc_for_vm = 0;
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void arch_post_init(void)
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{
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/* Let memory mapping code know what's going on at bootstrap time */
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struct proc *vm;
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vm = proc_addr(VM_PROC_NR);
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get_cpulocal_var(ptproc) = vm;
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pg_info(&vm->p_seg.p_cr3, &vm->p_seg.p_cr3_v);
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}
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int libexec_pg_alloc(struct exec_info *execi, off_t vaddr, size_t len)
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{
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pg_map(PG_ALLOCATEME, vaddr, vaddr+len, &kinfo);
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pg_load();
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memset((char *) vaddr, 0, len);
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alloc_for_vm += len;
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return OK;
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}
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void arch_boot_proc(struct boot_image *ip, struct proc *rp)
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{
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multiboot_module_t *mod;
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if(rp->p_nr < 0) return;
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mod = bootmod(rp->p_nr);
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/* Important special case: we put VM in the bootstrap pagetable
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* so it can run.
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*/
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if(rp->p_nr == VM_PROC_NR) {
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struct exec_info execi;
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memset(&execi, 0, sizeof(execi));
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/* exec parameters */
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execi.stack_high = kinfo.user_sp;
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execi.stack_size = 16 * 1024; /* not too crazy as it must be preallocated */
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execi.proc_e = ip->endpoint;
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execi.hdr = (char *) mod->mod_start; /* phys mem direct */
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execi.hdr_len = mod->mod_end - mod->mod_start;
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strlcpy(execi.progname, ip->proc_name, sizeof(execi.progname));
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execi.frame_len = 0;
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/* callbacks for use in the kernel */
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execi.copymem = libexec_copy_memcpy;
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execi.clearmem = libexec_clear_memset;
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execi.allocmem_prealloc = libexec_pg_alloc;
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execi.allocmem_ondemand = libexec_pg_alloc;
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execi.clearproc = NULL;
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/* parse VM ELF binary and alloc/map it into bootstrap pagetable */
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if(libexec_load_elf(&execi) != OK)
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panic("VM loading failed");
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/* Initialize the server stack pointer. Take it down three words
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* to give startup code something to use as "argc", "argv" and "envp".
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*/
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arch_proc_init(rp, execi.pc, kinfo.user_sp - 3*4, ip->proc_name);
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/* Free VM blob that was just copied into existence. */
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cut_memmap(&kinfo, mod->mod_start, mod->mod_end);
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/* Remember them */
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kinfo.vm_allocated_bytes = alloc_for_vm;
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}
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}
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