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core: expand clock_gettime fast clocks, unify timespec writes, fix NULL EINVAL (#62)

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Refactored parts of the time subsystem to improve POSIX/Orbis compliance and secure guest memory boundaries.

**1. POSIX `clock_gettime` updates:**
- Added `CLOCK_REALTIME_FAST` (10) and `CLOCK_MONOTONIC_FAST` (12) support for games using FreeBSD fast clock extensions.
- Fixed `NULL` pointer handling for `timespecAddress == 0`. It now returns `-1` with `EINVAL` (22) instead of `EFAULT` to match Orbis runtime behavior.
- Invalid `clock_id` values now properly fallback to `default` -> `-1` + `EINVAL`.

**2. Memory safety & monotonic tracking:**
- Replaced dual 8-byte scalar writes in both POSIX `clock_gettime` and Orbis `sceKernelClockGettime` with a single 16-byte write via `stackalloc byte[16]` and `BinaryPrimitives`. This prevents partial memory corruption at page boundaries.
- Bad non-NULL guest addresses now fail cleanly as `EFAULT` (POSIX) or `MEMORY_FAULT` (Orbis).
- Extracted core monotonic math into `GetProcessMonotonicTime()` in `KernelRuntimeCompatExports.cs` so both clock paths share the exact same `_processStartCounter` base.

**3. Host RDTSC optimization:**
- Fixed `CreateRdtscReader()` to copy stack-allocated opcode bytes into host `VirtualAlloc` memory via `unsafe { Buffer.MemoryCopy(...) }`. This completely gets rid of the redundant `.ToArray()` allocation on the hot path.

**Out of scope:** `sceKernelGettimeofday` / POSIX `gettimeofday` partial-write hardening; stricter clock validation in `sceKernelClockGettime`.
This commit is contained in:
Mike Saito
2026-07-11 17:32:48 +03:00
committed by GitHub
parent 9ddc09ea91
commit 65a40773fa
2 changed files with 69 additions and 15 deletions
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src/SharpEmu.Libs/Kernel/KernelRuntimeCompatExports.cs
+22 -7
View File
@@ -194,13 +194,14 @@ public static class KernelRuntimeCompatExports
}
else
{
var elapsedTicks = Stopwatch.GetTimestamp() - _processStartCounter;
seconds = elapsedTicks / Stopwatch.Frequency;
nanoseconds = (elapsedTicks % Stopwatch.Frequency) * 1_000_000_000L / Stopwatch.Frequency;
GetProcessMonotonicTime(out seconds, out nanoseconds);
}
if (!ctx.TryWriteUInt64(timeAddress, unchecked((ulong)seconds)) ||
!ctx.TryWriteUInt64(timeAddress + sizeof(long), unchecked((ulong)nanoseconds)))
Span<byte> timespecBuffer = stackalloc byte[16];
BinaryPrimitives.WriteInt64LittleEndian(timespecBuffer, seconds);
BinaryPrimitives.WriteInt64LittleEndian(timespecBuffer[sizeof(long)..], nanoseconds);
if (!ctx.Memory.TryWrite(timeAddress, timespecBuffer))
{
return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_MEMORY_FAULT;
}
@@ -617,6 +618,13 @@ public static class KernelRuntimeCompatExports
return address != 0 && ctx.TryWriteInt32(address, value);
}
internal static void GetProcessMonotonicTime(out long seconds, out long nanoseconds)
{
var elapsedTicks = Stopwatch.GetTimestamp() - _processStartCounter;
seconds = elapsedTicks / Stopwatch.Frequency;
nanoseconds = (elapsedTicks % Stopwatch.Frequency) * 1_000_000_000L / Stopwatch.Frequency;
}
[SysAbiExport(
Nid = "bnZxYgAFeA0",
ExportName = "sceKernelGetSanitizerNewReplaceExternal",
@@ -1713,7 +1721,7 @@ public static class KernelRuntimeCompatExports
return null;
}
Span<byte> stub = stackalloc byte[]
ReadOnlySpan<byte> stub = stackalloc byte[]
{
0x0F, 0x31,
0x48, 0xC1, 0xE2, 0x20,
@@ -1721,7 +1729,14 @@ public static class KernelRuntimeCompatExports
0xC3,
};
Marshal.Copy(stub.ToArray(), 0, stubAddress, stub.Length);
unsafe
{
fixed (byte* src = stub)
{
Buffer.MemoryCopy(src, (void*)stubAddress, stub.Length, stub.Length);
}
}
return Marshal.GetDelegateForFunctionPointer<RdtscDelegate>(stubAddress);
}
catch