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Add x86 paging runtime tests

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Sam Tebbs 2019-09-08 22:13:13 +01:00 committed by SamTebbs33
parent 114f5ea234
commit 7fb55437e3
2 changed files with 83 additions and 8 deletions
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89
src/kernel/arch/x86/paging.zig
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@ -7,6 +7,9 @@ const arch = @import("arch.zig");
const isr = @import("isr.zig");
const MemProfile = @import("../../mem.zig").MemProfile;
const tty = @import("../../tty.zig");
const log = @import("../../log.zig");
const options = @import("build_options");
const testing = std.testing;
/// An array of directory entries and page tables. Forms the first level of paging and covers the entire 4GB memory space.
const Directory = packed struct {
@ -271,16 +274,16 @@ fn mapTableEntry(entry: *align(1) TableEntry, phys_addr: usize) PagingError!void
///
/// Arguments:
/// OUT entry: *Directory - The directory to map
/// IN phys_start: usize - The physical address at which to start mapping
/// IN phys_end: usize - The physical address at which to stop mapping
/// IN virt_start: usize - The virtual address at which to start mapping
/// IN virt_end: usize - The virtual address at which to stop mapping
/// IN phys_start: usize - The physical address at which to start mapping
/// IN phys_end: usize - The physical address at which to stop mapping
/// IN allocator: *Allocator - The allocator to use to map any tables needed
///
/// Error: std.mem.allocator.Error || PagingError
/// * - See mapDirEntry.
///
fn mapDir(dir: *Directory, phys_start: usize, phys_end: usize, virt_start: usize, virt_end: usize, allocator: *std.mem.Allocator) (std.mem.Allocator.Error || PagingError)!void {
fn mapDir(dir: *Directory, virt_start: usize, virt_end: usize, phys_start: usize, phys_end: usize, allocator: *std.mem.Allocator) (std.mem.Allocator.Error || PagingError)!void {
var virt_addr = virt_start;
var phys_addr = phys_start;
var page = virt_addr / PAGE_SIZE_4KB;
@ -312,6 +315,7 @@ fn pageFault(state: *arch.InterruptContext) void {
/// IN allocator: *std.mem.Allocator - The allocator to use
///
pub fn init(mem_profile: *const MemProfile, allocator: *std.mem.Allocator) void {
log.logInfo("Init paging\n");
ADDR_OFFSET = @ptrToInt(&KERNEL_ADDR_OFFSET);
// Calculate start and end of mapping
const v_start = std.mem.alignBackward(@ptrToInt(mem_profile.vaddr_start), PAGE_SIZE_4KB);
@ -319,18 +323,24 @@ pub fn init(mem_profile: *const MemProfile, allocator: *std.mem.Allocator) void
const p_start = std.mem.alignBackward(@ptrToInt(mem_profile.physaddr_start), PAGE_SIZE_4KB);
const p_end = std.mem.alignForward(@ptrToInt(mem_profile.physaddr_end) + mem_profile.fixed_alloc_size, PAGE_SIZE_4KB);
var tmp = allocator.alignedAlloc(Directory, @truncate(u29, PAGE_SIZE_4KB), 1) catch panic(@errorReturnTrace(), "Failed to allocate page directory");
var tmp = allocator.alignedAlloc(Directory, @truncate(u29, PAGE_SIZE_4KB), 1) catch |e| {
panic(@errorReturnTrace(), "Failed to allocate page directory: {}\n", e);
};
var kernel_directory = @ptrCast(*Directory, tmp.ptr);
@memset(@ptrCast([*]u8, kernel_directory), 0, @sizeOf(Directory));
// Map in kernel
mapDir(kernel_directory, p_start, p_end, v_start, v_end, allocator) catch panic(@errorReturnTrace(), "Failed to map kernel directory");
mapDir(kernel_directory, v_start, v_end, p_start, p_end, allocator) catch |e| {
panic(@errorReturnTrace(), "Failed to map kernel directory: {}\n", e);
};
const tty_addr = tty.getVideoBufferAddress();
// If the previous mappping space didn't cover the tty buffer, do so now
if (v_start > tty_addr or v_end <= tty_addr) {
const tty_phys = virtToPhys(tty_addr);
const tty_buff_size = 32 * 1024;
mapDir(kernel_directory, tty_phys, tty_phys + tty_buff_size, tty_addr, tty_addr + tty_buff_size, allocator) catch panic(@errorReturnTrace(), "Failed to map vga buffer in kernel directory");
mapDir(kernel_directory, tty_addr, tty_addr + tty_buff_size, tty_phys, tty_phys + tty_buff_size, allocator) catch |e| {
panic(@errorReturnTrace(), "Failed to map vga buffer in kernel directory: {}\n", e);
};
}
const dir_physaddr = @ptrToInt(virtToPhys(kernel_directory));
@ -338,7 +348,12 @@ pub fn init(mem_profile: *const MemProfile, allocator: *std.mem.Allocator) void
:
: [addr] "{eax}" (dir_physaddr)
);
isr.registerIsr(14, pageFault) catch panic(@errorReturnTrace(), "Failed to register page fault ISR");
isr.registerIsr(14, if (options.rt_test) rt_pageFault else pageFault) catch |e| {
panic(@errorReturnTrace(), "Failed to register page fault ISR: {}\n", e);
};
log.logInfo("Done\n");
if (options.rt_test) runtimeTests(v_end);
}
fn checkDirEntry(entry: DirectoryEntry, virt_start: usize, virt_end: usize, phys_start: usize, table: *Table) void {
@ -417,6 +432,16 @@ test "mapDirEntry" {
checkDirEntry(entry, virt, virt_end, phys, table);
}
test "mapDirEntry returns errors correctly" {
var allocator = std.heap.direct_allocator;
var dir = Directory{ .entries = [_]DirectoryEntry{0} ** ENTRIES_PER_DIRECTORY, .tables = undefined };
testing.expectError(PagingError.UnalignedVirtAddresses, mapDirEntry(&dir, 1, PAGE_SIZE_4KB + 1, 0, PAGE_SIZE_4KB, allocator));
testing.expectError(PagingError.UnalignedPhysAddresses, mapDirEntry(&dir, 0, PAGE_SIZE_4KB, 1, PAGE_SIZE_4KB + 1, allocator));
testing.expectError(PagingError.PhysicalVirtualMismatch, mapDirEntry(&dir, 0, PAGE_SIZE_4KB, 1, PAGE_SIZE_4KB, allocator));
testing.expectError(PagingError.InvalidVirtAddresses, mapDirEntry(&dir, 1, 0, 0, PAGE_SIZE_4KB, allocator));
testing.expectError(PagingError.InvalidPhysAddresses, mapDirEntry(&dir, 0, PAGE_SIZE_4KB, 1, 0, allocator));
}
test "mapDir" {
var allocator = std.heap.direct_allocator;
var dir = Directory{ .entries = [_]DirectoryEntry{0} ** ENTRIES_PER_DIRECTORY, .tables = [_]?*Table{null} ** ENTRIES_PER_DIRECTORY };
@ -424,7 +449,7 @@ test "mapDir" {
const virt_start: usize = PAGE_SIZE_4MB * 4;
const phys_end: usize = PAGE_SIZE_4MB * 4;
const virt_end: usize = PAGE_SIZE_4MB * 6;
mapDir(&dir, phys_start, phys_end, virt_start, virt_end, allocator) catch unreachable;
mapDir(&dir, virt_start, virt_end, phys_start, phys_end, allocator) catch unreachable;
var virt = virt_start;
var phys = phys_start;
@ -438,3 +463,51 @@ test "mapDir" {
checkDirEntry(entry, virt, virt + PAGE_SIZE_4MB, phys, table);
}
}
// The labels to jump to after attempting to cause a page fault. This is needed as we don't want to cause an
// infinite loop by jummping to the same instruction that caused the fault.
extern var rt_fault_callback: *u32;
extern var rt_fault_callback2: *u32;
var faulted = false;
var use_callback2 = false;
fn rt_pageFault(ctx: *arch.InterruptContext) void {
faulted = true;
// Return to the fault callback
ctx.eip = @ptrToInt(&if (use_callback2) rt_fault_callback2 else rt_fault_callback);
}
fn rt_accessUnmappedMem(v_end: u32) void {
use_callback2 = false;
faulted = false;
// Accessing unmapped mem causes a page fault
var ptr = @intToPtr(*u8, v_end);
var value = ptr.*;
// This is the label that we return to after processing the page fault
asm volatile (
\\.global rt_fault_callback
\\rt_fault_callback:
);
testing.expect(faulted);
log.logInfo("Paging: Tested accessing unmapped memory\n");
}
fn rt_accessMappedMem(v_end: u32) void {
use_callback2 = true;
faulted = false;
// Accessing mapped memory does't cause a page fault
var ptr = @intToPtr(*u8, v_end - PAGE_SIZE_4KB);
var value = ptr.*;
asm volatile (
\\.global rt_fault_callback2
\\rt_fault_callback2:
);
testing.expect(!faulted);
log.logInfo("Paging: Tested accessing mapped memory\n");
}
fn runtimeTests(v_end: u32) void {
rt_accessUnmappedMem(v_end);
rt_accessMappedMem(v_end);
}

2
test/kernel/arch/x86/rt-test.py
View file

@ -7,6 +7,8 @@ def get_test_cases(TestCase):
TestCase("PIC init", [r"Init pic", r"Done"]),
TestCase("PIC tests", [r"PIC: Tested masking"]),
TestCase("PIT init", [r"Init pit", r".+", r"Done"]),
TestCase("Paging init", [r"Init paging", r"Done"]),
TestCase("Paging tests", [r"Paging: Tested accessing unmapped memory", r"Paging: Tested accessing mapped memory"]),
TestCase("Syscalls init", [r"Init syscalls", r"Done"]),
TestCase("Syscall tests", [r"Syscalls: Tested no args", r"Syscalls: Tested 1 arg", r"Syscalls: Tested 2 args", r"Syscalls: Tested 3 args", r"Syscalls: Tested 4 args", r"Syscalls: Tested 5 args"])
]