mirror of
https://github.com/ziglang/zig.git
synced 2025-12-06 06:13:07 +00:00
427f0025db
Fixes #25209. On PowerPC, some registers are both inputs to syscalls and clobbered by them. An example is r0, which initially contains the syscall number, but may be overwritten during execution of the syscall. musl and glibc use a `+` (read-write) constraint to indicate this, which isn't supported in Zig. The current implementation of PowerPC syscalls in the Zig standard library instead lists these registers as both inputs and clobbers, but this results in the C backend generating code that is invalid for at least some C compilers, like GCC, which doesn't support the specifying the same register as both an input and a clobber. This PR changes the PowerPC syscall functions to list such registers as inputs and outputs rather than inputs and clobbers. Thanks to jacobly0 who pointed out that it's possible to have multiple outputs; I had gotten the wrong idea from the documentation.
379 lines
11 KiB
Zig
379 lines
11 KiB
Zig
const builtin = @import("builtin");
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const std = @import("../../std.zig");
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const maxInt = std.math.maxInt;
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const linux = std.os.linux;
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const SYS = linux.SYS;
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const socklen_t = linux.socklen_t;
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const iovec = std.posix.iovec;
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const iovec_const = std.posix.iovec_const;
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const uid_t = linux.uid_t;
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const gid_t = linux.gid_t;
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const pid_t = linux.pid_t;
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const stack_t = linux.stack_t;
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const sigset_t = linux.sigset_t;
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const sockaddr = linux.sockaddr;
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const timespec = linux.timespec;
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pub fn syscall0(number: SYS) usize {
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// r0 is both an input register and a clobber. musl and glibc achieve this with
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// a "+" constraint, which isn't supported in Zig, so instead we separately list
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// r0 as both an input and an output. (Listing it as an input and a clobber would
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// cause the C backend to emit invalid code; see #25209.)
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var r0_out: usize = undefined;
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return asm volatile (
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\\ sc
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\\ bns+ 1f
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\\ neg 3, 3
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\\ 1:
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: [ret] "={r3}" (-> usize),
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[r0_out] "={r0}" (r0_out),
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: [number] "{r0}" (@intFromEnum(number)),
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: .{ .memory = true, .cr0 = true, .r4 = true, .r5 = true, .r6 = true, .r7 = true, .r8 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true, .ctr = true, .xer = true });
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}
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pub fn syscall1(number: SYS, arg1: usize) usize {
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// r0 is both an input and a clobber.
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var r0_out: usize = undefined;
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return asm volatile (
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\\ sc
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\\ bns+ 1f
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\\ neg 3, 3
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\\ 1:
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: [ret] "={r3}" (-> usize),
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[r0_out] "={r0}" (r0_out),
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: [number] "{r0}" (@intFromEnum(number)),
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[arg1] "{r3}" (arg1),
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: .{ .memory = true, .cr0 = true, .r4 = true, .r5 = true, .r6 = true, .r7 = true, .r8 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true, .ctr = true, .xer = true });
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}
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pub fn syscall2(number: SYS, arg1: usize, arg2: usize) usize {
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// These registers are both inputs and clobbers.
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var r0_out: usize = undefined;
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var r4_out: usize = undefined;
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return asm volatile (
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\\ sc
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\\ bns+ 1f
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\\ neg 3, 3
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\\ 1:
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: [ret] "={r3}" (-> usize),
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[r0_out] "={r0}" (r0_out),
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[r4_out] "={r4}" (r4_out),
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: [number] "{r0}" (@intFromEnum(number)),
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[arg1] "{r3}" (arg1),
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[arg2] "{r4}" (arg2),
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: .{ .memory = true, .cr0 = true, .r5 = true, .r6 = true, .r7 = true, .r8 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true, .ctr = true, .xer = true });
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}
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pub fn syscall3(number: SYS, arg1: usize, arg2: usize, arg3: usize) usize {
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// These registers are both inputs and clobbers.
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var r0_out: usize = undefined;
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var r4_out: usize = undefined;
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var r5_out: usize = undefined;
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return asm volatile (
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\\ sc
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\\ bns+ 1f
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\\ neg 3, 3
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\\ 1:
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: [ret] "={r3}" (-> usize),
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[r0_out] "={r0}" (r0_out),
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[r4_out] "={r4}" (r4_out),
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[r5_out] "={r5}" (r5_out),
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: [number] "{r0}" (@intFromEnum(number)),
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[arg1] "{r3}" (arg1),
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[arg2] "{r4}" (arg2),
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[arg3] "{r5}" (arg3),
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: .{ .memory = true, .cr0 = true, .r6 = true, .r7 = true, .r8 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true, .ctr = true, .xer = true });
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}
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pub fn syscall4(number: SYS, arg1: usize, arg2: usize, arg3: usize, arg4: usize) usize {
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// These registers are both inputs and clobbers.
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var r0_out: usize = undefined;
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var r4_out: usize = undefined;
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var r5_out: usize = undefined;
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var r6_out: usize = undefined;
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return asm volatile (
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\\ sc
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\\ bns+ 1f
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\\ neg 3, 3
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\\ 1:
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: [ret] "={r3}" (-> usize),
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[r0_out] "={r0}" (r0_out),
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[r4_out] "={r4}" (r4_out),
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[r5_out] "={r5}" (r5_out),
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[r6_out] "={r6}" (r6_out),
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: [number] "{r0}" (@intFromEnum(number)),
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[arg1] "{r3}" (arg1),
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[arg2] "{r4}" (arg2),
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[arg3] "{r5}" (arg3),
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[arg4] "{r6}" (arg4),
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: .{ .memory = true, .cr0 = true, .r7 = true, .r8 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true, .ctr = true, .xer = true });
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}
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pub fn syscall5(number: SYS, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) usize {
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// These registers are both inputs and clobbers.
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var r0_out: usize = undefined;
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var r4_out: usize = undefined;
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var r5_out: usize = undefined;
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var r6_out: usize = undefined;
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var r7_out: usize = undefined;
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return asm volatile (
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\\ sc
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\\ bns+ 1f
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\\ neg 3, 3
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\\ 1:
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: [ret] "={r3}" (-> usize),
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[r0_out] "={r0}" (r0_out),
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[r4_out] "={r4}" (r4_out),
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[r5_out] "={r5}" (r5_out),
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[r6_out] "={r6}" (r6_out),
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[r7_out] "={r7}" (r7_out),
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: [number] "{r0}" (@intFromEnum(number)),
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[arg1] "{r3}" (arg1),
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[arg2] "{r4}" (arg2),
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[arg3] "{r5}" (arg3),
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[arg4] "{r6}" (arg4),
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[arg5] "{r7}" (arg5),
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: .{ .memory = true, .cr0 = true, .r8 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true, .ctr = true, .xer = true });
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}
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pub fn syscall6(
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number: SYS,
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arg1: usize,
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arg2: usize,
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arg3: usize,
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arg4: usize,
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arg5: usize,
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arg6: usize,
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) usize {
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// These registers are both inputs and clobbers.
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var r0_out: usize = undefined;
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var r4_out: usize = undefined;
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var r5_out: usize = undefined;
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var r6_out: usize = undefined;
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var r7_out: usize = undefined;
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var r8_out: usize = undefined;
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return asm volatile (
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\\ sc
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\\ bns+ 1f
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\\ neg 3, 3
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\\ 1:
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: [ret] "={r3}" (-> usize),
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[r0_out] "={r0}" (r0_out),
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[r4_out] "={r4}" (r4_out),
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[r5_out] "={r5}" (r5_out),
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[r6_out] "={r6}" (r6_out),
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[r7_out] "={r7}" (r7_out),
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[r8_out] "={r8}" (r8_out),
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: [number] "{r0}" (@intFromEnum(number)),
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[arg1] "{r3}" (arg1),
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[arg2] "{r4}" (arg2),
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[arg3] "{r5}" (arg3),
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[arg4] "{r6}" (arg4),
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[arg5] "{r7}" (arg5),
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[arg6] "{r8}" (arg6),
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: .{ .memory = true, .cr0 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true, .ctr = true, .xer = true });
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}
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pub fn clone() callconv(.naked) usize {
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// __clone(func, stack, flags, arg, ptid, tls, ctid)
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// 3, 4, 5, 6, 7, 8, 9
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//
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// syscall(SYS_clone, flags, stack, ptid, tls, ctid)
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// 0 3, 4, 5, 6, 7
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asm volatile (
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\\ # store non-volatile regs r29, r30 on stack in order to put our
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\\ # start func and its arg there
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\\ stwu 29, -16(1)
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\\ stw 30, 4(1)
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\\
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\\ # save r3 (func) into r29, and r6(arg) into r30
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\\ mr 29, 3
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\\ mr 30, 6
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\\
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\\ # create initial stack frame for new thread
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\\ clrrwi 4, 4, 4
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\\ li 0, 0
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\\ stwu 0, -16(4)
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\\
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\\ #move c into first arg
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\\ mr 3, 5
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\\ #mr 4, 4
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\\ mr 5, 7
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\\ mr 6, 8
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\\ mr 7, 9
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\\
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\\ # move syscall number into r0
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\\ li 0, 120 # SYS_clone
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\\
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\\ sc
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\\
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\\ # check for syscall error
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\\ bns+ 1f # jump to label 1 if no summary overflow.
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\\ #else
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\\ neg 3, 3 #negate the result (errno)
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\\ 1:
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\\ # compare sc result with 0
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\\ cmpwi cr7, 3, 0
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\\
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\\ # if not 0, restore stack and return
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\\ beq cr7, 2f
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\\ lwz 29, 0(1)
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\\ lwz 30, 4(1)
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\\ addi 1, 1, 16
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\\ blr
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\\
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\\ #else: we're the child
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\\ 2:
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);
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if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
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\\ .cfi_undefined lr
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);
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asm volatile (
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\\ li 31, 0
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\\ mtlr 0
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\\
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\\ #call funcptr: move arg (d) into r3
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\\ mr 3, 30
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\\ #move r29 (funcptr) into CTR reg
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\\ mtctr 29
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\\ # call CTR reg
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\\ bctrl
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\\ # mov SYS_exit into r0 (the exit param is already in r3)
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\\ li 0, 1
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\\ sc
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);
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}
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pub const restore = restore_rt;
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pub fn restore_rt() callconv(.naked) noreturn {
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asm volatile (
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\\ sc
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:
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: [number] "{r0}" (@intFromEnum(SYS.rt_sigreturn)),
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: .{ .memory = true, .cr0 = true, .r4 = true, .r5 = true, .r6 = true, .r7 = true, .r8 = true, .r9 = true, .r10 = true, .r11 = true, .r12 = true });
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}
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pub const F = struct {
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pub const DUPFD = 0;
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pub const GETFD = 1;
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pub const SETFD = 2;
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pub const GETFL = 3;
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pub const SETFL = 4;
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pub const SETOWN = 8;
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pub const GETOWN = 9;
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pub const SETSIG = 10;
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pub const GETSIG = 11;
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pub const GETLK = 12;
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pub const SETLK = 13;
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pub const SETLKW = 14;
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pub const SETOWN_EX = 15;
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pub const GETOWN_EX = 16;
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pub const GETOWNER_UIDS = 17;
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pub const RDLCK = 0;
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pub const WRLCK = 1;
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pub const UNLCK = 2;
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};
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pub const VDSO = struct {
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pub const CGT_SYM = "__kernel_clock_gettime";
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pub const CGT_VER = "LINUX_2.6.15";
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};
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pub const Flock = extern struct {
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type: i16,
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whence: i16,
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start: off_t,
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len: off_t,
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pid: pid_t,
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};
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pub const blksize_t = i32;
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pub const nlink_t = u32;
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pub const time_t = isize;
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pub const mode_t = u32;
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pub const off_t = i64;
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pub const ino_t = u64;
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pub const dev_t = u64;
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pub const blkcnt_t = i64;
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// The `stat` definition used by the Linux kernel.
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pub const Stat = extern struct {
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dev: dev_t,
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ino: ino_t,
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mode: mode_t,
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nlink: nlink_t,
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uid: uid_t,
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gid: gid_t,
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rdev: dev_t,
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__rdev_padding: i16,
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size: off_t,
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blksize: blksize_t,
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blocks: blkcnt_t,
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atim: timespec,
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mtim: timespec,
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ctim: timespec,
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__unused: [2]u32,
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pub fn atime(self: @This()) timespec {
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return self.atim;
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}
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pub fn mtime(self: @This()) timespec {
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return self.mtim;
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}
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pub fn ctime(self: @This()) timespec {
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return self.ctim;
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}
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};
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pub const timeval = extern struct {
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sec: time_t,
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usec: isize,
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};
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pub const timezone = extern struct {
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minuteswest: i32,
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dsttime: i32,
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};
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pub const greg_t = u32;
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pub const gregset_t = [48]greg_t;
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pub const fpregset_t = [33]f64;
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pub const vrregset = extern struct {
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vrregs: [32][4]u32,
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vrsave: u32,
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_pad: [2]u32,
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vscr: u32,
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};
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pub const vrregset_t = vrregset;
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pub const mcontext_t = extern struct {
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gp_regs: gregset_t,
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fp_regs: fpregset_t,
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v_regs: vrregset_t align(16),
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};
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pub const ucontext_t = extern struct {
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flags: u32,
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link: ?*ucontext_t,
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stack: stack_t,
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pad: [7]i32,
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regs: *mcontext_t,
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sigmask: [1024 / @bitSizeOf(c_ulong)]c_ulong, // Currently a libc-compatible (1024-bit) sigmask
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pad2: [3]i32,
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mcontext: mcontext_t,
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};
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pub const Elf_Symndx = u32;
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/// TODO
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pub const getcontext = {};
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