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| author | Alex Auvolat <alex.auvolat@ens.fr> | 2015-02-13 18:53:36 +0100 |
|---|---|---|
| committer | Alex Auvolat <alex.auvolat@ens.fr> | 2015-02-13 18:53:36 +0100 |
| commit | 0ea68568372b7b7b20bca6985ae4b36e8c99c0e9 (patch) | |
| tree | 832f7f4ac8e2537cf5aee531634d01499bb4a318 /src/kernel/core | |
| parent | 7aafc22a01de5cabb99aed76782f6c0999b7de05 (diff) | |
| download | kogata-0ea68568372b7b7b20bca6985ae4b36e8c99c0e9.tar.gz kogata-0ea68568372b7b7b20bca6985ae4b36e8c99c0e9.zip | |
Implement switching to usermode.
Diffstat (limited to 'src/kernel/core')
| -rw-r--r-- | src/kernel/core/gdt.c | 23 | ||||
| -rw-r--r-- | src/kernel/core/thread.c | 3 |
2 files changed, 24 insertions, 2 deletions
diff --git a/src/kernel/core/gdt.c b/src/kernel/core/gdt.c index eadde5f..97e6661 100644 --- a/src/kernel/core/gdt.c +++ b/src/kernel/core/gdt.c @@ -60,6 +60,7 @@ typedef struct tss_entry tss_entry_t; static gdt_entry_t gdt_entries[GDT_ENTRIES]; static gdt_ptr_t gdt_ptr; +static tss_entry_t tss_entry; /* For internal use only. Writes one entry of the GDT with given parameters. */ static void gdt_set_gate(int num, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran) { @@ -84,7 +85,27 @@ void gdt_init() { gdt_set_gate(3, 0, 0xFFFFFFFF, 0xFA, 0xCF); //User code segment 0x18 gdt_set_gate(4, 0, 0xFFFFFFFF, 0xF2, 0xCF); //User data segment 0x20 - asm volatile ("lgdt %0"::"m"(gdt_ptr):"memory"); + // Write TSS + memset(&tss_entry, 0, sizeof(tss_entry)); + + tss_entry.ss0 = 0x10; + tss_entry.esp0 = 0; + + tss_entry.cs = 0x0b; + tss_entry.ss = tss_entry.ds = tss_entry.es = tss_entry.fs = tss_entry.gs = 0x13; + + uint32_t tss_base = (uint32_t)&tss_entry; + uint32_t tss_limit = tss_base + sizeof(tss_entry_t); + + gdt_set_gate(5, tss_base, tss_limit, 0xE9, 0x00); + + asm volatile("lgdt %0"::"m"(gdt_ptr):"memory"); + + asm volatile("movw $0x2b, %%ax; ltr %%ax":::"%eax"); +} + +void set_kernel_stack(void* addr) { + tss_entry.esp0 = (uint32_t)addr; } /* vim: set ts=4 sw=4 tw=0 noet :*/ diff --git a/src/kernel/core/thread.c b/src/kernel/core/thread.c index 9d11da2..519ba41 100644 --- a/src/kernel/core/thread.c +++ b/src/kernel/core/thread.c @@ -2,6 +2,7 @@ #include <malloc.h> #include <dbglog.h> #include <idt.h> +#include <gdt.h> #include <frame.h> #include <paging.h> @@ -88,6 +89,7 @@ void run_scheduler() { current_thread = dequeue_thread(); if (current_thread != 0) { + set_kernel_stack(current_thread->stack_region->addr + current_thread->stack_region->size); resume_context(¤t_thread->ctx); } else { // Wait for an IRQ @@ -146,7 +148,6 @@ thread_t *new_thread(entry_t entry, void* data) { // used by user processes t->proc = 0; - t->usermem_pf_handler = 0; t->kmem_violation_handler = 0; return t; |