Make improvements

This change progresses our AARCH64 support:

- The AARCH64 build and tests are now passing
- Add 128-bit floating-point support to printf()
- Fix clone() so it initializes cosmo's x28 TLS register
- Fix TLS memory layout issue with aarch64 _Alignas vars
- Revamp microbenchmarking tools so they work on aarch64
- Make some subtle improvements to aarch64 crash reporting
- Make kisdangerous() memory checks more accurate on aarch64
- Remove sys_open() since it's not available on Linux AARCH64

This change makes general improvements to Cosmo and Redbean:

- Introduce GetHostIsa() function in Redbean
- You can now feature check using pledge(0, 0)
- You can now feature check using unveil("",0)
- Refactor some more x86-specific asm comments
- Refactor and write docs for some libm functions
- Make the mmap() API behave more similar to Linux
- Fix WIFSIGNALED() which wrongly returned true for zero
- Rename some obscure cosmo keywords from noFOO to dontFOO

tool/net/definitions.lua

@@ -1196,6 +1196,10 @@ function GetHost() end
 ---@nodiscard
 function GetHostOs() end
 
+---@return "X86_64"|"AARCH64"|"POWERPC64"|"S390X" isaname string that describes the host instruction set architecture
+---@nodiscard
+function GetHostIsa() end
+
 ---@param str string|integer monospace display width of string.
 --- This is useful for fixed-width formatting. For example, CJK characters
 --- typically take up two cells. This function takes into consideration combining

tool/net/help.txt

@@ -1202,6 +1202,15 @@ FUNCTIONS
           - `"FREEBSD"`
           - `"OPENBSD"`
 
+  GetHostIsa() → str
+          Returns string describing host instruction set architecture.
+
+          This can return:
+
+          - `"X86_64"` for Intel and AMD systems
+          - `"AARCH64"` for ARM64, M1, and Raspberry Pi systems
+          - `"POWERPC64"` for OpenPOWER Raptor Computing Systems
+
   GetMonospaceWidth(str|char) → int
           Returns monospace display width of string. This is useful for
           fixed-width formatting. For example, CJK characters typically take
@@ -4296,6 +4305,16 @@ UNIX MODULE
     OpenBSD should ignore the chown functions without crashing. Linux
     will just EPERM.
 
+    Root access isn't required. Support is limited to OpenBSD and Linux
+    2.6.23+ (i.e. RHEL6 c. 2012) so long as Redbean is running directly
+    on the host system, i.e. not running in a userspace emulator like
+    Blink or Qemu. If your environment isn't supported, then pledge()
+    will return 0 and do nothing, rather than raising ENOSYS, so the
+    apps you share with others will err on the side of not breaking. If
+    a functionality check is needed, please use `unix.pledge(nil, nil)`
+    which is a no-op that will fail appropriately when the necessary
+    system support isn't available to impose security restrictions.
+
     `promises` is a string that may include any of the following groups
     delimited by spaces. This list has been curated to focus on the
     system calls for which this module provides wrappers. See the
@@ -4502,6 +4521,18 @@ UNIX MODULE
     This system call is supported natively on OpenBSD and polyfilled on
     Linux using the Landlock LSM[1].
 
+    This function requires OpenBSD or Linux 5.13+ (2022+). If the kernel
+    support isn't available (or we're in an emulator like Qemu or Blink)
+    then zero is returned and nothing happens (instead of raising
+    ENOSYS) because the files are still unveiled. Use `unix.unveil("",
+    nil)` to feature check the host system, which is defined as a no-op
+    that'll fail if the host system doesn't have the necessary features
+    that allow unix.unveil() impose bona-fide security restrictions.
+    Otherwise, if everything is good, a return value `>=0` is returned,
+    where `0` means OpenBSD, and `>=1` means Linux with Landlock LSM, in
+    which case the return code shall be the maximum supported Landlock
+    ABI version.
+
     `path` is the file or directory to unveil
 
     `permissions` is a string consisting of zero or more of the

tool/net/lfuncs.c

@@ -213,6 +213,23 @@ int LuaGetHostOs(lua_State *L) {
   return 1;
 }
 
+int LuaGetHostIsa(lua_State *L) {
+  const char *s;
+#ifdef __x86_64__
+  s = "X86_64";
+#elif defined(__aarch64__)
+  s = "AARCH64";
+#elif defined(__powerpc64__)
+  s = "POWERPC64";
+#elif defined(__s390x__)
+  s = "S390X";
+#else
+#error "unsupported architecture"
+#endif
+  lua_pushstring(L, s);
+  return 1;
+}
+
 int LuaFormatIp(lua_State *L) {
   char b[16];
   uint32_t ip;

tool/net/lfuncs.h

@@ -41,6 +41,7 @@ int LuaGetCpuCore(lua_State *);
 int LuaGetCpuCount(lua_State *);
 int LuaGetCpuNode(lua_State *);
 int LuaGetCryptoHash(lua_State *);
+int LuaGetHostIsa(lua_State *);
 int LuaGetHostOs(lua_State *);
 int LuaGetHttpReason(lua_State *);
 int LuaGetLogLevel(lua_State *);

tool/net/redbean.c

@@ -1091,7 +1091,6 @@ static void UpdateLuaPath(const char *s) {
 #endif
 }
 
-
 static void ProgramDirectory(const char *path) {
   char *s;
   size_t n;
@@ -5163,6 +5162,7 @@ static const luaL_Reg kLuaFuncs[] = {
     {"GetHeader", LuaGetHeader},                                //
     {"GetHeaders", LuaGetHeaders},                              //
     {"GetHost", LuaGetHost},                                    //
+    {"GetHostIsa", LuaGetHostIsa},                              //
     {"GetHostOs", LuaGetHostOs},                                //
     {"GetHttpReason", LuaGetHttpReason},                        //
     {"GetHttpVersion", LuaGetHttpVersion},                      //
@@ -6905,6 +6905,7 @@ static int HandleConnection(size_t i) {
 }
 
 static void MakeExecutableModifiable(void) {
+#ifdef __x86_64__
   int ft;
   size_t n;
   extern char ape_rom_vaddr[] __attribute__((__weak__));
@@ -6923,6 +6924,9 @@ static void MakeExecutableModifiable(void) {
     ftrace_install();
     ftrace_enabled(ft);
   }
+#else
+  // TODO
+#endif
 }
 
 static int HandleReadline(void) {