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-rw-r--r--src/kernel/dev/v86.c208
-rw-r--r--src/kernel/dev/v86asm.s39
-rw-r--r--src/kernel/dev/vesa.c84
3 files changed, 331 insertions, 0 deletions
diff --git a/src/kernel/dev/v86.c b/src/kernel/dev/v86.c
new file mode 100644
index 0000000..9498eaf
--- /dev/null
+++ b/src/kernel/dev/v86.c
@@ -0,0 +1,208 @@
+#include <string.h>
+#include <paging.h>
+
+#include <dev/v86.h>
+
+#define EFLAGS_VM 0x20000
+#define V86_VALID_FLAGS 0xDFF
+
+// ---- Ugly big static data
+
+STATIC_MUTEX(v86_mutex);
+
+v86_regs_t v86_regs;
+bool v86_if;
+
+pagedir_t *v86_pagedir = 0;
+void* v86_alloc_addr;
+
+bool v86_retval;
+thread_t *v86_caller_thread = 0;
+
+pagedir_t *v86_prev_pagedir = 0;
+
+// ---- Setup code
+
+void v86_run_bios_int(void*);
+void v86_ex_handler(registers_t *regs);
+void v86_pf_handler(void*, registers_t *regs, void* addr);
+void v86_asm_enter_v86(v86_regs_t*);
+
+bool v86_begin_session() {
+ mutex_lock(&v86_mutex);
+
+ if (v86_pagedir == 0) {
+ v86_pagedir = create_pagedir(v86_pf_handler, 0);
+ if (v86_pagedir == 0) return false;
+
+ v86_prev_pagedir = get_current_pagedir();
+ switch_pagedir(v86_pagedir);
+
+ for (void* addr = (void*)V86_ALLOC_ADDR; addr < (void*)V86_STACK_TOP; addr += PAGE_SIZE) {
+ pd_map_page(addr, (uint32_t)addr / PAGE_SIZE, true);
+ }
+ for (void* addr = (void*)V86_BIOS_BEGIN; addr < (void*)V86_BIOS_END; addr += PAGE_SIZE) {
+ pd_map_page(addr, (uint32_t)addr / PAGE_SIZE, true);
+ }
+ pd_map_page(0, 0, true);
+ }
+
+ v86_alloc_addr = (void*)V86_ALLOC_ADDR;
+
+ memset(&v86_regs, 0, sizeof(v86_regs));
+
+ return true;
+}
+
+void v86_end_session() {
+ switch_pagedir(v86_prev_pagedir);
+ v86_prev_pagedir = 0;
+ v86_caller_thread = 0;
+
+ mutex_unlock(&v86_mutex);
+}
+
+void* v86_alloc(size_t size) {
+ void* addr = v86_alloc_addr;
+
+ v86_alloc_addr += size;
+
+ return addr;
+}
+
+bool v86_bios_int(uint8_t int_no) {
+ v86_caller_thread = current_thread;
+
+ uint32_t int_no_32 = int_no;
+
+ thread_t *v86t = new_thread(v86_run_bios_int, (void*)int_no_32);
+ v86t->user_ex_handler = v86_ex_handler;
+
+ int st = enter_critical(CL_NOSWITCH);
+ start_thread(v86t);
+ wait_on(current_thread);
+ exit_critical(st);
+
+ return v86_retval;
+}
+
+void v86_run_bios_int(void* x) {
+ switch_pagedir(v86_pagedir);
+
+ uint32_t int_no = (uint32_t)x;
+
+ uint16_t *ivt = (uint16_t*)0;
+
+ v86_regs.cs = ivt[2 * int_no + 1];
+ v86_regs.ip = ivt[2 * int_no];
+ v86_regs.ss = ((V86_STACK_TOP - 0x10000) >> 4);
+ v86_regs.sp = 0;
+
+ v86_if = true;
+
+ v86_asm_enter_v86(&v86_regs);
+}
+
+void v86_exit_thread(bool status) {
+ v86_retval = status;
+
+ resume_on(v86_caller_thread);
+ exit();
+}
+
+bool v86_gpf_handler(registers_t *regs) {
+ uint8_t* ip = (uint8_t*)V86_LIN_OF_SEG_OFF(regs->cs, regs->eip);
+ uint16_t *stack = (uint16_t*)V86_LIN_OF_SEG_OFF(regs->ss, (regs->esp & 0xFFFF));
+ uint32_t *stack32 = (uint32_t*)stack;
+ bool is_operand32 = false; // bool is_address32 = false;
+
+ while (true) {
+ switch (ip[0]) {
+ case 0x66: // O32
+ is_operand32 = true;
+ ip++; regs->eip = (uint16_t)(regs->eip + 1);
+ break;
+ case 0x67: // A32
+ // is_address32 = true;
+ ip++; regs->eip = (uint16_t)(regs->eip + 1);
+ break;
+ case 0x9C: // PUSHF
+ if (is_operand32) {
+ regs->esp = ((regs->esp & 0xFFFF) - 4) & 0xFFFF;
+ stack32--;
+ *stack32 = regs->eflags & V86_VALID_FLAGS;
+ if (v86_if)
+ *stack32 |= EFLAGS_IF;
+ else
+ *stack32 &= ~EFLAGS_IF;
+ } else {
+ regs->esp = ((regs->esp & 0xFFFF) - 2) & 0xFFFF;
+ stack--;
+ *stack = regs->eflags;
+ if (v86_if)
+ *stack |= EFLAGS_IF;
+ else
+ *stack &= ~EFLAGS_IF;
+ }
+ regs->eip = (uint16_t)(regs->eip + 1);
+ return true;
+ case 0x9D: // POPF
+ if (is_operand32) {
+ regs->eflags = EFLAGS_IF | EFLAGS_VM | (stack32[0] & V86_VALID_FLAGS);
+ v86_if = (stack32[0] & EFLAGS_IF) != 0;
+ regs->esp = ((regs->esp & 0xFFFF) + 4) & 0xFFFF;
+ } else {
+ regs->eflags = EFLAGS_IF | EFLAGS_VM | stack[0];
+ v86_if = (stack[0] & EFLAGS_IF) != 0;
+ regs->esp = ((regs->esp & 0xFFFF) + 2) & 0xFFFF;
+ }
+ regs->eip = (uint16_t)(regs->eip + 1);
+ return true;
+ case 0xCF: // IRET
+ v86_regs.ax = (uint16_t)regs->eax;
+ v86_regs.bx = (uint16_t)regs->ebx;
+ v86_regs.cx = (uint16_t)regs->ecx;
+ v86_regs.dx = (uint16_t)regs->edx;
+ v86_regs.di = (uint16_t)regs->edi;
+ v86_regs.si = (uint16_t)regs->esi;
+
+ v86_exit_thread(true);
+ case 0xFA: // CLI
+ v86_if = false;
+ regs->eip = (uint16_t)(regs->eip + 1);
+ return true;
+ case 0xFB: // STI
+ v86_if = true;
+ regs->eip = (uint16_t)(regs->eip + 1);
+ return true;
+ default:
+ return false;
+ }
+ }
+}
+
+void v86_ex_handler(registers_t *regs) {
+ if (regs->int_no == EX_GENERAL_PROTECTION) {
+ if (!v86_gpf_handler(regs)) v86_exit_thread(false);
+ } else {
+ v86_exit_thread(false);
+ }
+}
+
+void v86_pf_handler(void* zero, registers_t *regs, void* addr) {
+ if (addr < (void*)V86_STACK_TOP) {
+ pd_map_page(addr, (uint32_t)addr / PAGE_SIZE, true);
+ } else {
+ dbg_printf("Unexpected V86 PF at 0x%p\n", addr);
+
+ if (current_thread->user_ex_handler == v86_ex_handler) {
+ // we are in V86 thread
+ v86_exit_thread(false);
+ } else {
+ PANIC("V86 memory access exception.");
+ }
+ }
+}
+
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/dev/v86asm.s b/src/kernel/dev/v86asm.s
new file mode 100644
index 0000000..da5bc38
--- /dev/null
+++ b/src/kernel/dev/v86asm.s
@@ -0,0 +1,39 @@
+
+[BITS 32]
+
+[GLOBAL v86_asm_enter_v86]
+v86_asm_enter_v86:
+ mov eax, [esp + 4]
+
+ xor ebx, ebx
+ mov bx, [eax + 20] ; get GS
+ push ebx
+ mov bx, [eax + 18] ; get FS
+ push ebx
+ mov bx, [eax + 14] ; get DS
+ push ebx
+ mov bx, [eax + 16] ; get ES
+ push ebx
+ mov bx, [eax + 22] ; get SS
+ push ebx
+ mov bx, [eax + 26] ; get SP
+ push ebx
+ pushf
+ pop ebx
+ or ebx, 20200h
+ push ebx
+ xor ebx, ebx
+ mov bx, [eax + 12] ; get CS
+ push ebx
+ mov bx, [eax + 24] ; get IP
+ push ebx
+
+ mov bx, [eax + 2]
+ mov cx, [eax + 4]
+ mov dx, [eax + 6]
+ mov di, [eax + 8]
+ mov si, [eax + 10]
+ mov ax, [eax]
+
+ iret
+
diff --git a/src/kernel/dev/vesa.c b/src/kernel/dev/vesa.c
new file mode 100644
index 0000000..6b23a34
--- /dev/null
+++ b/src/kernel/dev/vesa.c
@@ -0,0 +1,84 @@
+#include <string.h>
+
+#include <dev/vesa.h>
+#include <dev/v86.h>
+
+// ---- VESA data structures
+
+typedef struct {
+ char vbe_signature[4]; // == "VESA"
+ uint16_t vbe_version;
+ v86_farptr_t oem_string_ptr;
+ uint8_t capabilities[4];
+ v86_farptr_t video_mode_ptr;
+ uint16_t total_memory; // as # of 64KB blocks
+} __attribute__((packed)) vbe_info_block_t;
+
+typedef struct {
+ uint16_t attributes;
+ uint8_t winA, winB;
+ uint16_t granularity;
+ uint16_t winsize;
+ uint16_t segmentA, segmentB;
+ v86_farptr_t real_fct_ptr;
+ uint16_t pitch; // bytes per scanline
+
+ uint16_t Xres, Yres;
+ uint8_t Wchar, Ychar, planes, bpp, banks;
+ uint8_t memory_model, bank_size, image_pages;
+ uint8_t reserved0;
+
+ uint8_t red_mask, red_position;
+ uint8_t green_mask, green_position;
+ uint8_t blue_mask, blue_position;
+ uint8_t rsv_mask, rsv_position;
+ uint8_t directcolor_attributes;
+
+ uint32_t physbase; // the offset of the framebuffer in physical memory!
+ uint32_t reserved1;
+ uint16_t reserved2;
+} __attribute__((packed)) vbe_mode_info_block_t;
+
+// ---- VESA code
+
+void vesa_detect(fs_t *iofs) {
+ if (!v86_begin_session()) return;
+
+ vbe_info_block_t *i = (vbe_info_block_t*)v86_alloc(512);
+ memset(i, 0, 512);
+ strncpy(i->vbe_signature, "VBE2", 4);
+
+ v86_regs.ax = 0x4F00;
+ v86_regs.es = V86_SEG_OF_LIN(i);
+ v86_regs.di = V86_OFF_OF_LIN(i);
+
+ if (v86_bios_int(0x10)) {
+ if (v86_regs.ax == 0x004F) {
+ dbg_printf("Detected VESA (sig %s, ver 0x%x, oem %s) with %d kb ram.\n",
+ i->vbe_signature, i->vbe_version, v86_lin_of_fp(i->oem_string_ptr), 64 * i->total_memory);
+
+ vbe_mode_info_block_t *mi = (vbe_mode_info_block_t*)v86_alloc(256);
+
+ uint16_t *modes = (uint16_t*)v86_lin_of_fp(i->video_mode_ptr);
+ for (int n = 0; modes[n] != 0xFFFF; n++) {
+ v86_regs.ax = 0x4F01;
+ v86_regs.cx = modes[n];
+ v86_regs.es = V86_SEG_OF_LIN(mi);
+ v86_regs.di = V86_OFF_OF_LIN(mi);
+ if (v86_bios_int(0x10) && v86_regs.ax == 0x004F) {
+ dbg_printf("Mode 0x%x : %dx%dx%d at 0x%p\n", modes[n], mi->Xres, mi->Yres, mi->bpp, mi->physbase);
+ } else {
+ dbg_printf("Mode 0x%x : could not get info\n", modes[n]);
+ }
+ }
+ } else {
+ dbg_printf("Error in BIOS int 0x10/0x4F00.\n");
+ }
+ } else {
+ dbg_printf("Could not call BIOS int 0x10.\n");
+ }
+
+ v86_end_session();
+}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-22 07:05:06 +0000