traps: add early boot traps initialization (#68)

This allows to debug issues in PMM and pagetables bootstraping code much easier. Signed-off-by: Pawel Wieczorkiewicz <[email protected]> Co-authored-by: Bjoern Doebel <[email protected]>
KernelTestFramework · Aug 24, 2020 · bc35378 · bc35378
1 parent 41f91aa
commit bc35378
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Showing 6 changed files with 104 additions and 5 deletions.
diff --git a/arch/x86/boot/head.S b/arch/x86/boot/head.S
@@ -100,5 +100,13 @@ _boot_stack:
     .skip BOOT_STACK_SIZE
 GLOBAL(_boot_stack_top)
 
+_boot_stack_ist:
+    .skip BOOT_STACK_SIZE
+GLOBAL(_boot_stack_ist_top)
+
+_boot_stack_df:
+    .skip BOOT_STACK_SIZE
+GLOBAL(_boot_stack_df_top)
+
 #define XEN_ELFNOTE_PHYS32_ENTRY  18
 ELF_NOTE(Xen, XEN_ELFNOTE_PHYS32_ENTRY, .long, _start)
diff --git a/arch/x86/boot/segment.c b/arch/x86/boot/segment.c
@@ -25,9 +25,17 @@
  */
 #include <asm-macros.h>
 #include <ktf.h>
+#include <lib.h>
+#include <processor.h>
 #include <segment.h>
 
-gdt_desc_t boot_gdt[] __aligned(16) __data_init = {
+extern uint8_t *_boot_stack_ist_top;
+extern uint8_t *_boot_stack_df_top;
+
+x86_tss_t __data_init boot_tss __aligned(16);
+x86_tss_t __data_init boot_tss_df __aligned(16);
+
+gdt_desc_t __data_init boot_gdt[NR_BOOT_GDT_ENTRIES] __aligned(16) = {
     /* clang-format off */
     [GDT_NULL].desc      = GDT_ENTRY(0x0, 0x0, 0x0),
     [GDT_KERN_CS32].desc = GDT_ENTRY(DESC_FLAGS(GR, SZ, P, DPL0, S, CODE, R, A), 0x0, 0xfffff),
@@ -36,7 +44,85 @@ gdt_desc_t boot_gdt[] __aligned(16) __data_init = {
     /* clang-format on */
 };
 
-gdt_ptr_t boot_gdt_ptr __data_init = {
+gdt_ptr_t __data_init boot_gdt_ptr = {
     .size = sizeof(boot_gdt) - 1,
     .addr = _ul(&boot_gdt),
 };
+
+idt_entry_t __data_init boot_idt[256];
+
+idt_ptr_t boot_idt_ptr __data_init = {
+    .size = sizeof(boot_idt) - 1,
+    .addr = _ul(&boot_idt),
+};
+
+static void __text_init init_boot_tss(void) {
+#if defined(__i386__)
+    boot_tss_df.iopb = sizeof(boot_tss_df);
+    boot_tss_df.esp0 = _ul(_boot_stack_df_top);
+    boot_tss_df.ss = __KERN_DS;
+    boot_tss_df.ds = __KERN_DS;
+    boot_tss_df.es = __KERN_DS;
+    boot_tss_df.fs = __KERN_DS;
+    boot_tss_df.gs = __KERN_DS;
+    boot_tss_df.eip = _ul(entry_DF);
+    boot_tss_df.cs = __KERN_CS;
+    boot_tss_df.cr3 = read_cr3();
+
+    /* Assign identity mapping of the tss_df, because GDT has only 32-bit base. */
+    boot_gdt[GDT_BOOT_TSS_DF].desc =
+        GDT_ENTRY(DESC_FLAGS(SZ, P, CODE, A), _ul(&boot_tss_df), sizeof(boot_tss_df) - 1);
+
+    /* FIXME */
+    boot_tss.esp0 = _ul(_boot_stack_ist_top);
+    boot_tss.ss0 = __KERN_DS;
+    boot_tss.cr3 = read_cr3();
+#elif defined(__x86_64__)
+    boot_tss.rsp0 = _ul(_boot_stack_ist_top);
+    boot_tss.ist[0] = _ul(_boot_stack_df_top);
+#endif
+    boot_tss.iopb = sizeof(boot_tss);
+
+    /* Assign identity mapping of the tss, because GDT has only 32-bit base. */
+    boot_gdt[GDT_BOOT_TSS].desc =
+        GDT_ENTRY(DESC_FLAGS(SZ, P, CODE, A), _ul(&boot_tss), sizeof(boot_tss) - 1);
+#if defined(__x86_64__)
+    boot_gdt[GDT_BOOT_TSS + 1].desc = GDT_ENTRY(0x0, 0x0, 0x0);
+#endif
+
+    barrier();
+    ltr(GDT_BOOT_TSS << 3);
+}
+
+void __text_init init_boot_traps(void) {
+    /* clang-format off */
+    set_intr_gate(&boot_idt[X86_EX_DE],  __KERN_CS, _ul(entry_DE),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_DB],  __KERN_CS, _ul(entry_DB),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_NMI], __KERN_CS, _ul(entry_NMI), GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_BP],  __KERN_CS, _ul(entry_BP),  GATE_DPL3, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_OF],  __KERN_CS, _ul(entry_OF),  GATE_DPL3, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_BR],  __KERN_CS, _ul(entry_BR),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_UD],  __KERN_CS, _ul(entry_UD),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_NM],  __KERN_CS, _ul(entry_NM),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_CS],  __KERN_CS, _ul(entry_CS),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_TS],  __KERN_CS, _ul(entry_TS),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_NP],  __KERN_CS, _ul(entry_NP),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_SS],  __KERN_CS, _ul(entry_SS),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_GP],  __KERN_CS, _ul(entry_GP),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_PF],  __KERN_CS, _ul(entry_PF),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_MF],  __KERN_CS, _ul(entry_MF),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_AC],  __KERN_CS, _ul(entry_AC),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_MC],  __KERN_CS, _ul(entry_MC),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_XM],  __KERN_CS, _ul(entry_XM),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_VE],  __KERN_CS, _ul(entry_VE),  GATE_DPL0, GATE_PRESENT, 0);
+    set_intr_gate(&boot_idt[X86_EX_SE],  __KERN_CS, _ul(entry_SE),  GATE_DPL0, GATE_PRESENT, 0);
+#if defined(__x86_64__)
+    set_intr_gate(&boot_idt[X86_EX_DF],  __KERN_CS, _ul(entry_DF),  GATE_DPL0, GATE_PRESENT, 1);
+#endif
+    /* clang-format on */
+
+    barrier();
+    lidt(&boot_idt_ptr);
+
+    init_boot_tss();
+}
diff --git a/common/setup.c b/common/setup.c
@@ -88,6 +88,8 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic,
     /* Initialize console early */
     init_console();
 
+    init_boot_traps();
+
     if (multiboot_magic == MULTIBOOT_BOOTLOADER_MAGIC) {
         /* Indentity mapping is still on, so fill in multiboot structures */
         init_multiboot(mbi, &kernel_cmdline);

diff --git a/include/arch/x86/segment.h b/include/arch/x86/segment.h
@@ -34,6 +34,9 @@
 #define GDT_KERN_DS32 0x2
 #define GDT_KERN_CS64 0x3
 
+#define GDT_BOOT_TSS    0x4
+#define GDT_BOOT_TSS_DF 0x5
+
 #define GDT_USER_CS32 0x4
 #define GDT_USER_DS32 0x5
 #define GDT_USER_CS64 0x6
@@ -43,7 +46,8 @@
 
 #define GDT_PERCPU 0x9
 
-#define NR_GDT_ENTRIES 10
+#define NR_BOOT_GDT_ENTRIES 6
+#define NR_GDT_ENTRIES      10
 
 #define __KERN_CS32 (GDT_KERN_CS32 << 3)
 #define __KERN_DS32 (GDT_KERN_DS32 << 3)

diff --git a/include/arch/x86/traps.h b/include/arch/x86/traps.h
@@ -33,6 +33,7 @@
 #ifndef __ASSEMBLY__
 
 extern void init_traps(unsigned int cpu);
+extern void init_boot_traps(void);
 
 #endif /* __ASSEMBLY__ */
 

diff --git a/include/setup.h b/include/setup.h
@@ -25,8 +25,6 @@
 #ifndef KTF_SETUP_H
 #define KTF_SETUP_H
 
-#define KERN_STACK_SIZE (5 * PAGE_SIZE)
-
 #ifndef __ASSEMBLY__
 #include <page.h>
 #include <string.h>