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initial arm64 support #1429

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merged 9 commits into from
Oct 6, 2018
Merged

initial arm64 support #1429

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d956d30
this is not arch-specific
shawnl Aug 26, 2018
4a8c992
os: use less syscalls
shawnl Aug 30, 2018
342cff2
initial arm64 support
shawnl Aug 30, 2018
f8808ed
simplify f64_min to equivilent value
shawnl Aug 30, 2018
cba0d76
clone() on arm64
shawnl Aug 30, 2018
fdeb876
use vfork in stage1 compiler to avoid OOM
shawnl Sep 1, 2018
7d6d1d1
NaNs do not have signedness.
shawnl Sep 1, 2018
17cb69c
fix elf auxv handling
shawnl Sep 8, 2018
2d27341
arm64: respond to code review
shawnl Oct 5, 2018
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5 changes: 5 additions & 0 deletions std/elf.zig
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Expand Up @@ -859,6 +859,11 @@ pub const Elf_MIPS_ABIFlags_v0 = extern struct {
flags2: Elf32_Word,
};

pub const Auxv = switch (@sizeOf(usize)) {
4 => Elf32_auxv_t,
8 => Elf64_auxv_t,
else => @compileError("expected pointer size of 32 or 64"),
};
pub const Ehdr = switch (@sizeOf(usize)) {
4 => Elf32_Ehdr,
8 => Elf64_Ehdr,
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11 changes: 8 additions & 3 deletions std/os/index.zig
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Expand Up @@ -633,16 +633,21 @@ fn posixExecveErrnoToErr(err: usize) PosixExecveError {
};
}

pub var linux_aux_raw = []usize{0} ** 38;
pub var linux_elf_aux_maybe: ?[*]std.elf.Auxv = undefined;
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it looks like you want this to be initialized to null, not undefined.

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but it is always set at program initialization, initializing it to null requires more code in every executable. I make it a maybe because one might want to unmap the entire elf auxiliary vector to save space.

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@andrewrk andrewrk Oct 5, 2018 •
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It is not set at program initialization when zig code is used as a library, with main in a C object, for example. It's also not set at program initialization when the user puts export fn main(argc: c_int, argv: [*][*]u8) c_int {...} and links with libc. Why would initializing it to null require more code? It's static data, so if it's null it would go in the .bss section.

pub var posix_environ_raw: [][*]u8 = undefined;

/// See std.elf for the constants.
pub fn linuxGetAuxVal(index: usize) usize {
if (builtin.link_libc) {
return usize(std.c.getauxval(index));
} else {
return linux_aux_raw[index];
} else if (linux_elf_aux_maybe) |auxv| {
var i: usize = 0;
while (auxv[i].a_type != std.elf.AT_NULL) : (i += 1) {
if (auxv[i].a_type == index)
return auxv[i].a_un.a_val;
}
}
return 0;
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should this return null, and make the return ?usize

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The libc version doesn't distinguish, so the zig-native version matches the API.

}

pub fn getBaseAddress() usize {
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6 changes: 2 additions & 4 deletions std/os/linux/arm64.zig
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Expand Up @@ -282,10 +282,8 @@ pub const SYS_io_pgetevents = 292;
pub const SYS_syscalls = 293;

pub const VDSO_USEFUL = true;
pub const VDSO_CGT_SYM = "__vdso_clock_gettime";
pub const VDSO_CGT_VER = "LINUX_2.6";
pub const VDSO_GETCPU_SYM = "__vdso_getcpu";
pub const VDSO_GETCPU_VER = "LINUX_2.6";
pub const VDSO_CGT_SYM = "__kernel_clock_gettime";
pub const VDSO_CGT_VER = "LINUX_2.6.39";

pub fn syscall0(number: usize) usize {
return asm volatile ("svc #0"
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2 changes: 1 addition & 1 deletion std/os/linux/vdso.zig
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Expand Up @@ -5,7 +5,7 @@ const cstr = std.cstr;
const mem = std.mem;

pub fn lookup(vername: []const u8, name: []const u8) usize {
const vdso_addr = std.os.linux_aux_raw[std.elf.AT_SYSINFO_EHDR];
const vdso_addr = std.os.linuxGetAuxVal(std.elf.AT_SYSINFO_EHDR);
if (vdso_addr == 0) return 0;

const eh = @intToPtr(*elf.Ehdr, vdso_addr);
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7 changes: 2 additions & 5 deletions std/special/bootstrap.zig
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Expand Up @@ -59,11 +59,8 @@ fn posixCallMainAndExit() noreturn {
const envp = @ptrCast([*][*]u8, envp_optional)[0..envp_count];
if (builtin.os == builtin.Os.linux) {
const auxv = @ptrCast([*]usize, envp.ptr + envp_count + 1);
var i: usize = 0;
while (auxv[i] != 0) : (i += 2) {
if (auxv[i] < std.os.linux_aux_raw.len) std.os.linux_aux_raw[auxv[i]] = auxv[i + 1];
}
std.debug.assert(std.os.linux_aux_raw[std.elf.AT_PAGESZ] == std.os.page_size);
std.os.linux_elf_aux_maybe = @ptrCast([*]std.elf.Auxv, auxv);
std.debug.assert(std.os.linuxGetAuxVal(std.elf.AT_PAGESZ) == std.os.page_size);
}

std.os.posix.exit(callMainWithArgs(argc, argv, envp));
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