Runtime page size detection

lib/fuzzer.zig

@@ -480,7 +480,7 @@ pub const MemoryMappedList = struct {
     /// of this ArrayList in accordance with the respective documentation. In
     /// all cases, "invalidated" means that the memory has been passed to this
     /// allocator's resize or free function.
-    items: []align(std.mem.page_size) volatile u8,
+    items: []align(std.heap.min_page_size) volatile u8,
     /// How many bytes this list can hold without allocating additional memory.
     capacity: usize,
 

lib/std/Build/Fuzz/WebServer.zig

@@ -41,7 +41,7 @@ const fuzzer_arch_os_abi = "wasm32-freestanding";
 const fuzzer_cpu_features = "baseline+atomics+bulk_memory+multivalue+mutable_globals+nontrapping_fptoint+reference_types+sign_ext";
 
 const CoverageMap = struct {
-    mapped_memory: []align(std.mem.page_size) const u8,
+    mapped_memory: []align(std.heap.min_page_size) const u8,
     coverage: Coverage,
     source_locations: []Coverage.SourceLocation,
     /// Elements are indexes into `source_locations` pointing to the unit tests that are being fuzz tested.

lib/std/Thread.zig

@@ -767,7 +767,7 @@ const PosixThreadImpl = struct {
         // Use the same set of parameters used by the libc-less impl.
         const stack_size = @max(config.stack_size, 16 * 1024);
         assert(c.pthread_attr_setstacksize(&attr, stack_size) == .SUCCESS);
-        assert(c.pthread_attr_setguardsize(&attr, std.mem.page_size) == .SUCCESS);
+        assert(c.pthread_attr_setguardsize(&attr, std.heap.pageSize()) == .SUCCESS);
 
         var handle: c.pthread_t = undefined;
         switch (c.pthread_create(
@@ -1150,7 +1150,7 @@ const LinuxThreadImpl = struct {
         completion: Completion = Completion.init(.running),
         child_tid: std.atomic.Value(i32) = std.atomic.Value(i32).init(1),
         parent_tid: i32 = undefined,
-        mapped: []align(std.mem.page_size) u8,
+        mapped: []align(std.heap.min_page_size) u8,
 
         /// Calls `munmap(mapped.ptr, mapped.len)` then `exit(1)` without touching the stack (which lives in `mapped.ptr`).
         /// Ported over from musl libc's pthread detached implementation:
@@ -1357,7 +1357,7 @@ const LinuxThreadImpl = struct {
     };
 
     fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
-        const page_size = std.mem.page_size;
+        const page_size = std.heap.pageSize();
         const Args = @TypeOf(args);
         const Instance = struct {
             fn_args: Args,

lib/std/c.zig

@@ -3,7 +3,7 @@ const builtin = @import("builtin");
 const c = @This();
 const maxInt = std.math.maxInt;
 const assert = std.debug.assert;
-const page_size = std.mem.page_size;
+const min_page_size = std.heap.min_page_size;
 const native_abi = builtin.abi;
 const native_arch = builtin.cpu.arch;
 const native_os = builtin.os.tag;
@@ -2210,6 +2210,39 @@ pub const SC = switch (native_os) {
     .linux => linux.SC,
     else => void,
 };
+
+pub const _SC = switch (native_os) {
+    .bridgeos, .driverkit, .ios, .macos, .tvos, .visionos, .watchos => enum(c_int) {
+        PAGESIZE = 29,
+    },
+    .dragonfly => enum(c_int) {
+        PAGESIZE = 47,
+    },
+    .freebsd => enum(c_int) {
+        PAGESIZE = 47,
+    },
+    .fuchsia => enum(c_int) {
+        PAGESIZE = 30,
+    },
+    .haiku => enum(c_int) {
+        PAGESIZE = 27,
+    },
+    .linux => enum(c_int) {
+        PAGESIZE = 30,
+    },
+    .netbsd => enum(c_int) {
+        PAGESIZE = 28,
+    },
+    .openbsd => enum(c_int) {
+        PAGESIZE = 28,
+    },
+    .solaris, .illumos => enum(c_int) {
+        PAGESIZE = 11,
+        NPROCESSORS_ONLN = 15,
+    },
+    else => void,
+};
+
 pub const SEEK = switch (native_os) {
     .linux => linux.SEEK,
     .emscripten => emscripten.SEEK,
@@ -9038,7 +9071,7 @@ pub extern "c" fn getpwnam(name: [*:0]const u8) ?*passwd;
 pub extern "c" fn getpwuid(uid: uid_t) ?*passwd;
 pub extern "c" fn getrlimit64(resource: rlimit_resource, rlim: *rlimit) c_int;
 pub extern "c" fn lseek64(fd: fd_t, offset: i64, whence: c_int) i64;
-pub extern "c" fn mmap64(addr: ?*align(std.mem.page_size) anyopaque, len: usize, prot: c_uint, flags: c_uint, fd: fd_t, offset: i64) *anyopaque;
+pub extern "c" fn mmap64(addr: ?*align(min_page_size) anyopaque, len: usize, prot: c_uint, flags: c_uint, fd: fd_t, offset: i64) *anyopaque;
 pub extern "c" fn open64(path: [*:0]const u8, oflag: O, ...) c_int;
 pub extern "c" fn openat64(fd: c_int, path: [*:0]const u8, oflag: O, ...) c_int;
 pub extern "c" fn pread64(fd: fd_t, buf: [*]u8, nbyte: usize, offset: i64) isize;
@@ -9126,13 +9159,13 @@ pub extern "c" fn signalfd(fd: fd_t, mask: *const sigset_t, flags: u32) c_int;
 
 pub extern "c" fn prlimit(pid: pid_t, resource: rlimit_resource, new_limit: *const rlimit, old_limit: *rlimit) c_int;
 pub extern "c" fn mincore(
-    addr: *align(std.mem.page_size) anyopaque,
+    addr: *align(min_page_size) anyopaque,
     length: usize,
     vec: [*]u8,
 ) c_int;
 
 pub extern "c" fn madvise(
-    addr: *align(std.mem.page_size) anyopaque,
+    addr: *align(min_page_size) anyopaque,
     length: usize,
     advice: u32,
 ) c_int;
@@ -9230,6 +9263,10 @@ pub const posix_memalign = switch (native_os) {
     .dragonfly, .netbsd, .freebsd, .solaris, .openbsd, .linux, .macos, .ios, .tvos, .watchos, .visionos => private.posix_memalign,
     else => {},
 };
+pub const sysconf = switch (native_os) {
+    .solaris => solaris.sysconf,
+    else => private.sysconf,
+};
 
 pub const sf_hdtr = switch (native_os) {
     .freebsd, .macos, .ios, .tvos, .watchos, .visionos => extern struct {
@@ -9271,9 +9308,9 @@ pub extern "c" fn writev(fd: c_int, iov: [*]const iovec_const, iovcnt: c_uint) i
 pub extern "c" fn pwritev(fd: c_int, iov: [*]const iovec_const, iovcnt: c_uint, offset: off_t) isize;
 pub extern "c" fn write(fd: fd_t, buf: [*]const u8, nbyte: usize) isize;
 pub extern "c" fn pwrite(fd: fd_t, buf: [*]const u8, nbyte: usize, offset: off_t) isize;
-pub extern "c" fn mmap(addr: ?*align(page_size) anyopaque, len: usize, prot: c_uint, flags: MAP, fd: fd_t, offset: off_t) *anyopaque;
-pub extern "c" fn munmap(addr: *align(page_size) const anyopaque, len: usize) c_int;
-pub extern "c" fn mprotect(addr: *align(page_size) anyopaque, len: usize, prot: c_uint) c_int;
+pub extern "c" fn mmap(addr: ?*align(min_page_size) anyopaque, len: usize, prot: c_uint, flags: MAP, fd: fd_t, offset: off_t) *anyopaque;
+pub extern "c" fn munmap(addr: *align(min_page_size) const anyopaque, len: usize) c_int;
+pub extern "c" fn mprotect(addr: *align(min_page_size) anyopaque, len: usize, prot: c_uint) c_int;
 pub extern "c" fn link(oldpath: [*:0]const u8, newpath: [*:0]const u8) c_int;
 pub extern "c" fn linkat(oldfd: fd_t, oldpath: [*:0]const u8, newfd: fd_t, newpath: [*:0]const u8, flags: c_int) c_int;
 pub extern "c" fn unlink(path: [*:0]const u8) c_int;
@@ -9625,7 +9662,6 @@ pub const SCM = solaris.SCM;
 pub const SETCONTEXT = solaris.SETCONTEXT;
 pub const SETUSTACK = solaris.GETUSTACK;
 pub const SFD = solaris.SFD;
-pub const _SC = solaris._SC;
 pub const cmsghdr = solaris.cmsghdr;
 pub const ctid_t = solaris.ctid_t;
 pub const file_obj = solaris.file_obj;
@@ -9642,7 +9678,6 @@ pub const priority = solaris.priority;
 pub const procfs = solaris.procfs;
 pub const projid_t = solaris.projid_t;
 pub const signalfd_siginfo = solaris.signalfd_siginfo;
-pub const sysconf = solaris.sysconf;
 pub const taskid_t = solaris.taskid_t;
 pub const zoneid_t = solaris.zoneid_t;
 
@@ -9796,6 +9831,7 @@ pub const dispatch_semaphore_wait = darwin.dispatch_semaphore_wait;
 pub const dispatch_time = darwin.dispatch_time;
 pub const fcopyfile = darwin.fcopyfile;
 pub const kern_return_t = darwin.kern_return_t;
+pub const vm_size_t = darwin.vm_size_t;
 pub const kevent64 = darwin.kevent64;
 pub const mach_absolute_time = darwin.mach_absolute_time;
 pub const mach_continuous_time = darwin.mach_continuous_time;
@@ -9908,7 +9944,7 @@ const private = struct {
     };
     extern "c" fn getrusage(who: c_int, usage: *rusage) c_int;
     extern "c" fn gettimeofday(noalias tv: ?*timeval, noalias tz: ?*timezone) c_int;
-    extern "c" fn msync(addr: *align(page_size) const anyopaque, len: usize, flags: c_int) c_int;
+    extern "c" fn msync(addr: *align(min_page_size) const anyopaque, len: usize, flags: c_int) c_int;
     extern "c" fn nanosleep(rqtp: *const timespec, rmtp: ?*timespec) c_int;
     extern "c" fn pipe2(fds: *[2]fd_t, flags: O) c_int;
     extern "c" fn readdir(dir: *DIR) ?*dirent;
@@ -9921,6 +9957,7 @@ const private = struct {
     extern "c" fn socket(domain: c_uint, sock_type: c_uint, protocol: c_uint) c_int;
     extern "c" fn stat(noalias path: [*:0]const u8, noalias buf: *Stat) c_int;
     extern "c" fn sigaltstack(ss: ?*stack_t, old_ss: ?*stack_t) c_int;
+    extern "c" fn sysconf(sc: c_int) c_long;
 
     extern "c" fn pthread_setname_np(thread: pthread_t, name: [*:0]const u8) c_int;
     extern "c" fn getcontext(ucp: *ucontext_t) c_int;
@@ -9955,7 +9992,7 @@ const private = struct {
     extern "c" fn __getrusage50(who: c_int, usage: *rusage) c_int;
     extern "c" fn __gettimeofday50(noalias tv: ?*timeval, noalias tz: ?*timezone) c_int;
     extern "c" fn __libc_thr_yield() c_int;
-    extern "c" fn __msync13(addr: *align(std.mem.page_size) const anyopaque, len: usize, flags: c_int) c_int;
+    extern "c" fn __msync13(addr: *align(min_page_size) const anyopaque, len: usize, flags: c_int) c_int;
     extern "c" fn __nanosleep50(rqtp: *const timespec, rmtp: ?*timespec) c_int;
     extern "c" fn __sigaction14(sig: c_int, noalias act: ?*const Sigaction, noalias oact: ?*Sigaction) c_int;
     extern "c" fn __sigfillset14(set: ?*sigset_t) void;

lib/std/c/solaris.zig

@@ -154,10 +154,6 @@ pub const AF_SUN = struct {
     pub const NOPLM = 0x00000004;
 };
 
-pub const _SC = struct {
-    pub const NPROCESSORS_ONLN = 15;
-};
-
 pub const procfs = struct {
     pub const misc_header = extern struct {
         size: u32,

lib/std/crypto/tlcsprng.zig

@@ -6,6 +6,7 @@
 const std = @import("std");
 const builtin = @import("builtin");
 const mem = std.mem;
+const heap = std.heap;
 const native_os = builtin.os.tag;
 const posix = std.posix;
 
@@ -42,7 +43,7 @@ var install_atfork_handler = std.once(struct {
     }
 }.do);
 
-threadlocal var wipe_mem: []align(mem.page_size) u8 = &[_]u8{};
+threadlocal var wipe_mem: []align(heap.min_page_size) u8 = &[_]u8{};
 
 fn tlsCsprngFill(_: *anyopaque, buffer: []u8) void {
     if (os_has_arc4random) {
@@ -77,7 +78,7 @@ fn tlsCsprngFill(_: *anyopaque, buffer: []u8) void {
         } else {
             // Use a static thread-local buffer.
             const S = struct {
-                threadlocal var buf: Context align(mem.page_size) = .{
+                threadlocal var buf: Context align(heap.min_page_size) = .{
                     .init_state = .uninitialized,
                     .rng = undefined,
                 };

lib/std/debug.zig

@@ -2,6 +2,7 @@ const builtin = @import("builtin");
 const std = @import("std.zig");
 const math = std.math;
 const mem = std.mem;
+const heap = std.heap;
 const io = std.io;
 const posix = std.posix;
 const fs = std.fs;
@@ -1021,7 +1022,7 @@ fn printLineFromFileAnyOs(out_stream: anytype, source_location: SourceLocation)
     defer f.close();
     // TODO fstat and make sure that the file has the correct size
 
-    var buf: [mem.page_size]u8 = undefined;
+    var buf: [4096]u8 = undefined;
     var amt_read = try f.read(buf[0..]);
     const line_start = seek: {
         var current_line_start: usize = 0;
@@ -1124,7 +1125,7 @@ test printLineFromFileAnyOs {
 
         const overlap = 10;
         var writer = file.writer();
-        try writer.writeByteNTimes('a', mem.page_size - overlap);
+        try writer.writeByteNTimes('a', heap.min_page_size - overlap);
         try writer.writeByte('\n');
         try writer.writeByteNTimes('a', overlap);
 
@@ -1139,10 +1140,10 @@ test printLineFromFileAnyOs {
         defer allocator.free(path);
 
         var writer = file.writer();
-        try writer.writeByteNTimes('a', mem.page_size);
+        try writer.writeByteNTimes('a', heap.max_page_size);
 
         try printLineFromFileAnyOs(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
-        try expectEqualStrings(("a" ** mem.page_size) ++ "\n", output.items);
+        try expectEqualStrings(("a" ** heap.max_page_size) ++ "\n", output.items);
         output.clearRetainingCapacity();
     }
     {
@@ -1152,18 +1153,18 @@ test printLineFromFileAnyOs {
         defer allocator.free(path);
 
         var writer = file.writer();
-        try writer.writeByteNTimes('a', 3 * mem.page_size);
+        try writer.writeByteNTimes('a', 3 * heap.max_page_size);
 
         try expectError(error.EndOfFile, printLineFromFileAnyOs(output_stream, .{ .file_name = path, .line = 2, .column = 0 }));
 
         try printLineFromFileAnyOs(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
-        try expectEqualStrings(("a" ** (3 * mem.page_size)) ++ "\n", output.items);
+        try expectEqualStrings(("a" ** (3 * heap.max_page_size)) ++ "\n", output.items);
         output.clearRetainingCapacity();
 
         try writer.writeAll("a\na");
 
         try printLineFromFileAnyOs(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
-        try expectEqualStrings(("a" ** (3 * mem.page_size)) ++ "a\n", output.items);
+        try expectEqualStrings(("a" ** (3 * heap.max_page_size)) ++ "a\n", output.items);
         output.clearRetainingCapacity();
 
         try printLineFromFileAnyOs(output_stream, .{ .file_name = path, .line = 2, .column = 0 });
@@ -1177,7 +1178,7 @@ test printLineFromFileAnyOs {
         defer allocator.free(path);
 
         var writer = file.writer();
-        const real_file_start = 3 * mem.page_size;
+        const real_file_start = 3 * heap.min_page_size;
         try writer.writeByteNTimes('\n', real_file_start);
         try writer.writeAll("abc\ndef");
 

lib/std/debug/Dwarf.zig

@@ -2110,8 +2110,8 @@ fn pcRelBase(field_ptr: usize, pc_rel_offset: i64) !usize {
 pub const ElfModule = struct {
     base_address: usize,
     dwarf: Dwarf,
-    mapped_memory: []align(std.mem.page_size) const u8,
-    external_mapped_memory: ?[]align(std.mem.page_size) const u8,
+    mapped_memory: []align(std.heap.min_page_size) const u8,
+    external_mapped_memory: ?[]align(std.heap.min_page_size) const u8,
 
     pub fn deinit(self: *@This(), allocator: Allocator) void {
         self.dwarf.deinit(allocator);
@@ -2157,11 +2157,11 @@ pub const ElfModule = struct {
     /// sections from an external file.
     pub fn load(
         gpa: Allocator,
-        mapped_mem: []align(std.mem.page_size) const u8,
+        mapped_mem: []align(std.heap.min_page_size) const u8,
         build_id: ?[]const u8,
         expected_crc: ?u32,
         parent_sections: *Dwarf.SectionArray,
-        parent_mapped_mem: ?[]align(std.mem.page_size) const u8,
+        parent_mapped_mem: ?[]align(std.heap.min_page_size) const u8,
         elf_filename: ?[]const u8,
     ) LoadError!Dwarf.ElfModule {
         if (expected_crc) |crc| if (crc != std.hash.crc.Crc32.hash(mapped_mem)) return error.InvalidDebugInfo;
@@ -2413,7 +2413,7 @@ pub const ElfModule = struct {
         build_id: ?[]const u8,
         expected_crc: ?u32,
         parent_sections: *Dwarf.SectionArray,
-        parent_mapped_mem: ?[]align(std.mem.page_size) const u8,
+        parent_mapped_mem: ?[]align(std.heap.min_page_size) const u8,
     ) LoadError!Dwarf.ElfModule {
         const elf_file = elf_file_path.root_dir.handle.openFile(elf_file_path.sub_path, .{}) catch |err| switch (err) {
             error.FileNotFound => return missing(),

lib/std/debug/Info.zig

@@ -10,7 +10,6 @@ const std = @import("../std.zig");
 const Allocator = std.mem.Allocator;
 const Path = std.Build.Cache.Path;
 const Dwarf = std.debug.Dwarf;
-const page_size = std.mem.page_size;
 const assert = std.debug.assert;
 const Coverage = std.debug.Coverage;
 const SourceLocation = std.debug.Coverage.SourceLocation;

lib/std/debug/MemoryAccessor.zig

@@ -7,7 +7,7 @@ const native_os = builtin.os.tag;
 const std = @import("../std.zig");
 const posix = std.posix;
 const File = std.fs.File;
-const page_size = std.mem.page_size;
+const min_page_size = std.heap.min_page_size;
 
 const MemoryAccessor = @This();
 
@@ -81,9 +81,10 @@ pub fn isValidMemory(address: usize) bool {
     // We are unable to determine validity of memory for freestanding targets
     if (native_os == .freestanding or native_os == .uefi) return true;
 
-    const aligned_address = address & ~@as(usize, @intCast((page_size - 1)));
+    const page_size = std.heap.pageSize();
+    const aligned_address = address & ~(page_size - 1);
     if (aligned_address == 0) return false;
-    const aligned_memory = @as([*]align(page_size) u8, @ptrFromInt(aligned_address))[0..page_size];
+    const aligned_memory = @as([*]align(min_page_size) u8, @ptrFromInt(aligned_address))[0..page_size];
 
     if (native_os == .windows) {
         const windows = std.os.windows;
@@ -92,7 +93,7 @@ pub fn isValidMemory(address: usize) bool {
 
         // The only error this function can throw is ERROR_INVALID_PARAMETER.
         // supply an address that invalid i'll be thrown.
-        const rc = windows.VirtualQuery(aligned_memory, &memory_info, aligned_memory.len) catch {
+        const rc = windows.VirtualQuery(@ptrCast(aligned_memory), &memory_info, aligned_memory.len) catch {
             return false;
         };
 

lib/std/debug/SelfInfo.zig

@@ -504,7 +504,7 @@ pub const Module = switch (native_os) {
     .macos, .ios, .watchos, .tvos, .visionos => struct {
         base_address: usize,
         vmaddr_slide: usize,
-        mapped_memory: []align(mem.page_size) const u8,
+        mapped_memory: []align(std.heap.min_page_size) const u8,
         symbols: []const MachoSymbol,
         strings: [:0]const u8,
         ofiles: OFileTable,
@@ -1046,7 +1046,7 @@ pub fn readElfDebugInfo(
     build_id: ?[]const u8,
     expected_crc: ?u32,
     parent_sections: *Dwarf.SectionArray,
-    parent_mapped_mem: ?[]align(mem.page_size) const u8,
+    parent_mapped_mem: ?[]align(std.heap.min_page_size) const u8,
 ) !Dwarf.ElfModule {
     nosuspend {
         const elf_file = (if (elf_filename) |filename| blk: {
@@ -1088,7 +1088,7 @@ const MachoSymbol = struct {
 
 /// Takes ownership of file, even on error.
 /// TODO it's weird to take ownership even on error, rework this code.
-fn mapWholeFile(file: File) ![]align(mem.page_size) const u8 {
+fn mapWholeFile(file: File) ![]align(std.heap.min_page_size) const u8 {
     nosuspend {
         defer file.close();