Move user exception support into userprog.

[pintos-anon] / src / threads / gdt.c

diff --git a/src/threads/gdt.c b/src/threads/gdt.c
deleted file mode 100644 (file)
index 7a6005f..0000000
--- a/src/threads/gdt.c
+++ /dev/null
@@ -1,133 +0,0 @@
-#include "gdt.h"
-#include "debug.h"
-#include "mmu.h"
-#include "palloc.h"
-#include "tss.h"
-
-/* The Global Descriptor Table (GDT).
-
-   The GDT, an x86-specific structure, defines segments that can
-   potentially be used by all processes in a system, subject to
-   their permissions.  There is also a per-process Local
-   Descriptor Table (LDT) but that is not used by modern
-   operating systems.
-
-   Each entry in the GDT, which is known by its byte offset in
-   the table, identifies a segment.  For our purposes only three
-   types of segments are of interest: code, data, and TSS or
-   Task-State Segment descriptors.  The former two types are
-   exactly what they sound like.  The TSS is used primarily for
-   stack switching on interrupts.
-
-   For more information on the GDT as used here, refer to
-   [IA32-v3] sections 3.2 through 3.5. */
-static uint64_t gdt[SEL_CNT];
-
-/* Creating descriptors. */
-static uint64_t make_code_desc (int dpl);
-static uint64_t make_data_desc (int dpl);
-static uint64_t make_tss_desc (void *laddr);
-
-/* Sets up a proper GDT.  The bootstrap loader's GDT didn't
-   include user-mode selectors or a TSS, but we need both now. */
-void
-gdt_init (void)
-{
-  uint64_t gdtr_operand;
-
-  /* Initialize GDT. */
-  gdt[SEL_NULL / sizeof *gdt] = 0;
-  gdt[SEL_KCSEG / sizeof *gdt] = make_code_desc (0);
-  gdt[SEL_KDSEG / sizeof *gdt] = make_data_desc (0);
-  gdt[SEL_UCSEG / sizeof *gdt] = make_code_desc (3);
-  gdt[SEL_UDSEG / sizeof *gdt] = make_data_desc (3);
-  gdt[SEL_TSS / sizeof *gdt] = make_tss_desc (tss_get ());
-
-  /* Load GDTR, TR. */
-  gdtr_operand = make_dtr_operand (sizeof gdt - 1, gdt);
-  asm volatile ("lgdt %0" :: "m" (gdtr_operand));
-  asm volatile ("ltr %w0" :: "r" (SEL_TSS));
-}
-\f
-/* System segment or code/data segment? */
-enum seg_class
-  {
-    CLS_SYSTEM = 0,             /* System segment. */
-    CLS_CODE_DATA = 1           /* Code or data segment. */
-  };
-
-/* Limit has byte or 4 kB page granularity? */
-enum seg_granularity
-  {
-    GRAN_BYTE = 0,              /* Limit has 1-byte granularity. */
-    GRAN_PAGE = 1               /* Limit has 4 kB granularity. */
-  };
-
-/* Returns a segment descriptor with the given 32-bit BASE and
-   20-bit LIMIT (whose interpretation depends on GRANULARITY).
-   The descriptor represents a system or code/data segment
-   according to CLASS, and TYPE is its type (whose interpretation
-   depends on the class).
-
-   The segment has descriptor privilege level DPL, meaning that
-   it can be used in rings numbered DPL or lower.  In practice,
-   DPL==3 means that user processes can use the segment and
-   DPL==0 means that only the kernel can use the segment.  See
-   [IA32-v3] section 4.5 for further discussion. */
-static uint64_t
-make_seg_desc (uint32_t base,
-               uint32_t limit,
-               enum seg_class class,
-               int type,
-               int dpl,
-               enum seg_granularity granularity)
-{
-  uint32_t e0, e1;
-
-  ASSERT (limit <= 0xfffff);
-  ASSERT (class == CLS_SYSTEM || class == CLS_CODE_DATA);
-  ASSERT (type >= 0 && type <= 15);
-  ASSERT (dpl >= 0 && dpl <= 3);
-  ASSERT (granularity == GRAN_BYTE || granularity == GRAN_PAGE);
-
-  e0 = ((limit & 0xffff)             /* Limit 15:0. */
-        | (base << 16));             /* Base 15:0. */
-
-  e1 = (((base >> 16) & 0xff)        /* Base 23:16. */
-        | (type << 8)                /* Segment type. */
-        | (class << 12)              /* 0=system, 1=code/data. */
-        | (dpl << 13)                /* Descriptor privilege. */
-        | (1 << 15)                  /* Present. */
-        | (limit & 0xf0000)          /* Limit 16:19. */
-        | (1 << 22)                  /* 32-bit segment. */
-        | (granularity << 23)        /* Byte/page granularity. */
-        | (base & 0xff000000));      /* Base 31:24. */
-
-  return e0 | ((uint64_t) e1 << 32);
-}
-
-/* Returns a descriptor for a readable code segment with base at
-   0, a limit of 4 GB, and the given DPL. */
-static uint64_t
-make_code_desc (int dpl)
-{
-  return make_seg_desc (0, 0xfffff, CLS_CODE_DATA, 10, dpl, GRAN_PAGE);
-}
-
-/* Returns a descriptor for a writable data segment with base at
-   0, a limit of 4 GB, and the given DPL. */
-static uint64_t
-make_data_desc (int dpl)
-{
-  return make_seg_desc (0, 0xfffff, CLS_CODE_DATA, 2, dpl, GRAN_PAGE);
-}
-
-/* Returns a descriptor for an "available" 32-bit Task-State
-   Segment with its base at the given linear address, a limit of
-   0x67 bytes (the size of a 32-bit TSS), and a DPL of 0. */
-static uint64_t
-make_tss_desc (void *laddr)
-{
-  return make_seg_desc ((uint32_t) laddr, 0x67, CLS_SYSTEM, 9, 0, GRAN_BYTE);
-}
-