i386 IDT (#135)

Makefile.am

@@ -47,7 +47,7 @@ endif
 #######
 
 if WITH_ARCH_I386
-libkernaux_la_SOURCES += src/arch/i386.c
+libkernaux_la_SOURCES += src/arch/i386/idt.c
 endif
 
 #######

include/Makefile.am

@@ -17,7 +17,7 @@ nobase_include_HEADERS = \
 ########
 
 if WITH_ARCH_I386
-nobase_include_HEADERS += kernaux/arch/i386.h
+nobase_include_HEADERS += kernaux/arch/i386.h kernaux/arch/i386-idt.h
 endif
 if WITH_ARCH_RISCV64
 nobase_include_HEADERS += kernaux/arch/riscv64.h

include/kernaux/arch/i386-idt.h

@@ -0,0 +1,62 @@
+#ifndef KERNAUX_INCLUDED_ARCH_I386_IDT
+#define KERNAUX_INCLUDED_ARCH_I386_IDT
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <kernaux/macro.h>
+
+#include <stdint.h>
+
+#include <kernaux/macro/packing_start.run>
+
+/**
+ * @brief Interrupt Descriptor Table entry
+ *
+ * @see https://en.wikibooks.org/wiki/X86_Assembly/Advanced_Interrupts#The_Interrupt_Descriptor_Table
+ */
+typedef struct KernAux_Arch_I386_IDTE {
+    uint16_t offset_low;
+    uint16_t selector;
+    uint8_t  _;
+    uint8_t  flags;
+    uint16_t offset_high;
+}
+KERNAUX_PACKED
+KERNAUX_ALIGNED(8)
+*KernAux_Arch_I386_IDTE;
+
+KERNAUX_STATIC_TEST_STRUCT_SIZE(KernAux_Arch_I386_IDTE, 8);
+
+#include <kernaux/macro/packing_end.run>
+
+void KernAux_Arch_I386_IDTE_init_intr(
+    KernAux_Arch_I386_IDTE idte,
+    uint32_t offset,
+    uint16_t cs_selector,
+    uint8_t dpl
+);
+void KernAux_Arch_I386_IDTE_init_task(
+    KernAux_Arch_I386_IDTE idte,
+    uint16_t tss_selector,
+    uint8_t dpl
+);
+void KernAux_Arch_I386_IDTE_init_trap(
+    KernAux_Arch_I386_IDTE idte,
+    uint32_t offset,
+    uint16_t cs_selector,
+    uint8_t dpl
+);
+
+uint32_t KernAux_Arch_I386_IDTE_offset(KernAux_Arch_I386_IDTE idte);
+uint8_t  KernAux_Arch_I386_IDTE_dpl   (KernAux_Arch_I386_IDTE idte);
+
+void
+KernAux_Arch_I386_IDTE_set_offset(KernAux_Arch_I386_IDTE idte, uint32_t offset);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

include/kernaux/arch/i386.h

@@ -5,6 +5,7 @@
 extern "C" {
 #endif
 
+#include <kernaux/arch/i386-idt.h>
 #include <kernaux/arch/x86.h>
 #include <kernaux/macro.h>
 
@@ -91,25 +92,6 @@ KERNAUX_PACKED;
 
 KERNAUX_STATIC_TEST_STRUCT_SIZE(KernAux_Arch_I386_DTE, 8);
 
-// Interrupt descriptor table entry
-// TODO: validate this according to spec
-typedef struct KernAux_Arch_I386_IDTE {
-    uint16_t offset_low;
-    uint16_t selector;
-    uint8_t  _zero0;
-    uint8_t  flags;
-    uint16_t offset_high;
-}
-KERNAUX_PACKED
-*KernAux_Arch_I386_IDTE;
-
-KERNAUX_STATIC_TEST_STRUCT_SIZE(KernAux_Arch_I386_IDTE, 8);
-
-void KernAux_Arch_I386_IDTE_set_offset(
-    KernAux_Arch_I386_IDTE idte,
-    uint32_t address
-);
-
 /**
  * @brief Task state segment
  * @see The manual, page 132, figure 7-1

src/arch/i386.c

@@ -1,14 +0,0 @@
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <kernaux/arch/i386.h>
-
-void KernAux_Arch_I386_IDTE_set_offset(
-    const KernAux_Arch_I386_IDTE idte,
-    const uint32_t address
-)
-{
-    idte->offset_low  = 0xFFFF & address;
-    idte->offset_high = 0xFFFF & (address >> 16);
-}

src/arch/i386/idt.c

@@ -0,0 +1,74 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <kernaux/arch/i386.h>
+#include <kernaux/assert.h>
+
+#include <string.h>
+
+#define DPL (0x60u & (dpl << 5))
+
+void KernAux_Arch_I386_IDTE_init_intr(
+    const KernAux_Arch_I386_IDTE idte,
+    const uint32_t offset,
+    const uint16_t cs_selector,
+    const uint8_t dpl
+) {
+    KERNAUX_ASSERT(idte);
+
+    memset(idte, 0, sizeof(*idte));
+    KernAux_Arch_I386_IDTE_set_offset(idte, offset);
+    idte->selector = cs_selector;
+    idte->flags |= 0x80u | DPL | 0xeu; // 1-00-01110
+}
+
+void KernAux_Arch_I386_IDTE_init_task(
+    const KernAux_Arch_I386_IDTE idte,
+    const uint16_t tss_selector,
+    const uint8_t dpl
+) {
+    KERNAUX_ASSERT(idte);
+
+    memset(idte, 0, sizeof(*idte));
+    idte->selector = tss_selector;
+    idte->flags |= 0x80u | DPL | 0x5u; // 1-00-00101
+}
+
+void KernAux_Arch_I386_IDTE_init_trap(
+    const KernAux_Arch_I386_IDTE idte,
+    const uint32_t offset,
+    const uint16_t cs_selector,
+    const uint8_t dpl
+) {
+    KERNAUX_ASSERT(idte);
+
+    memset(idte, 0, sizeof(*idte));
+    KernAux_Arch_I386_IDTE_set_offset(idte, offset);
+    idte->selector = cs_selector;
+    idte->flags |= 0x80u | DPL | 0xfu; // 1-00-01111
+}
+
+uint32_t KernAux_Arch_I386_IDTE_offset(const KernAux_Arch_I386_IDTE idte)
+{
+    KERNAUX_ASSERT(idte);
+
+    return (idte->offset_high << 16) | idte->offset_low;
+}
+
+uint8_t KernAux_Arch_I386_IDTE_dpl(const KernAux_Arch_I386_IDTE idte)
+{
+    KERNAUX_ASSERT(idte);
+
+    return 3 & (idte->flags >> 5);
+}
+
+void KernAux_Arch_I386_IDTE_set_offset(
+    const KernAux_Arch_I386_IDTE idte,
+    const uint32_t offset
+) {
+    KERNAUX_ASSERT(idte);
+
+    idte->offset_low  = 0xffffu & offset;
+    idte->offset_high = 0xffffu & (offset >> 16);
+}

tests/test_arch_i386.c

@@ -7,27 +7,126 @@
 #include <assert.h>
 #include <string.h>
 
-static void test_idte_set_offset();
+static void test_idte_init_intr();
+static void test_idte_init_task();
+static void test_idte_init_trap();
+static void test_idte_get_and_set_offset();
+static void test_idte_get_dpl();
 
 void test_main()
 {
-    test_idte_set_offset();
+    test_idte_init_intr();
+    test_idte_init_task();
+    test_idte_init_trap();
+    test_idte_get_and_set_offset();
+    test_idte_get_dpl();
 }
 
-void test_idte_set_offset()
+void test_idte_init_intr()
+{
+    struct KernAux_Arch_I386_IDTE idte;
+    memset(&idte, 0xff, sizeof(idte));
+
+    KernAux_Arch_I386_IDTE_init_intr(&idte, 0x12345678, 0xcafe, 0);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0x12345678);
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 0);
+    assert(idte.selector == 0xcafe);
+    assert(idte._ == 0);
+    assert(idte.flags == 0x8e); // 1-00-01110
+
+    KernAux_Arch_I386_IDTE_init_intr(&idte, 0x12345678, 0xcafe, 3);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0x12345678);
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 3);
+    assert(idte.selector == 0xcafe);
+    assert(idte._ == 0);
+    assert(idte.flags == 0xee); // 1-11-01110
+}
+
+void test_idte_init_task()
+{
+    struct KernAux_Arch_I386_IDTE idte;
+    memset(&idte, 0xff, sizeof(idte));
+
+    KernAux_Arch_I386_IDTE_init_task(&idte, 0xcafe, 0);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0);
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 0);
+    assert(idte.selector == 0xcafe);
+    assert(idte._ == 0);
+    assert(idte.flags == 0x85); // 1-00-00101
+
+    KernAux_Arch_I386_IDTE_init_task(&idte, 0xcafe, 3);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0);
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 3);
+    assert(idte.selector == 0xcafe);
+    assert(idte._ == 0);
+    assert(idte.flags == 0xe5); // 1-11-00101
+}
+
+void test_idte_init_trap()
+{
+    struct KernAux_Arch_I386_IDTE idte;
+    memset(&idte, 0xff, sizeof(idte));
+
+    KernAux_Arch_I386_IDTE_init_trap(&idte, 0x12345678, 0xcafe, 0);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0x12345678);
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 0);
+    assert(idte.selector == 0xcafe);
+    assert(idte._ == 0);
+    assert(idte.flags == 0x8f); // 1-00-01111
+
+    KernAux_Arch_I386_IDTE_init_trap(&idte, 0x12345678, 0xcafe, 3);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0x12345678);
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 3);
+    assert(idte.selector == 0xcafe);
+    assert(idte._ == 0);
+    assert(idte.flags == 0xef); // 1-11-01111
+}
+
+void test_idte_get_and_set_offset()
+{
+    struct KernAux_Arch_I386_IDTE idte;
+
+    memset(&idte, 0xff, sizeof(idte));
+    KernAux_Arch_I386_IDTE_set_offset(&idte, 0);
+    assert(idte.offset_high == 0);
+    assert(idte.offset_low  == 0);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0);
+
+    memset(&idte, 0, sizeof(idte));
+    KernAux_Arch_I386_IDTE_set_offset(&idte, 0xffffffff);
+    assert(idte.offset_high == 0xffff);
+    assert(idte.offset_low  == 0xffff);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0xffffffff);
+
+    memset(&idte, 0, sizeof(idte));
+    KernAux_Arch_I386_IDTE_set_offset(&idte, 0x12345678);
+    assert(idte.offset_high == 0x1234);
+    assert(idte.offset_low  == 0x5678);
+    assert(KernAux_Arch_I386_IDTE_offset(&idte) == 0x12345678);
+}
+
+void test_idte_get_dpl()
 {
     struct KernAux_Arch_I386_IDTE idte;
     memset(&idte, 0, sizeof(idte));
 
-    KernAux_Arch_I386_IDTE_set_offset(&idte, 0);
-    assert(idte.offset_high == 0);
-    assert(idte.offset_low  == 0);
+    idte.flags = 0; // 0-00-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 0);
+    idte.flags = 0x80; // 1-00-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 0);
 
-    KernAux_Arch_I386_IDTE_set_offset(&idte, 0xFFFFFFFF);
-    assert(idte.offset_high == 0xFFFF);
-    assert(idte.offset_low  == 0xFFFF);
+    idte.flags = 0x20; // 0-01-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 1);
+    idte.flags = 0xa0; // 1-01-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 1);
 
-    KernAux_Arch_I386_IDTE_set_offset(&idte, 0x12345678);
-    assert(idte.offset_high == 0x1234);
-    assert(idte.offset_low  == 0x5678);
+    idte.flags = 0x40; // 0-10-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 2);
+    idte.flags = 0xc0; // 1-10-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 2);
+
+    idte.flags = 0x60; // 0-11-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 3);
+    idte.flags = 0xe0; // 1-11-00000
+    assert(KernAux_Arch_I386_IDTE_dpl(&idte) == 3);
 }