From 59aa0dcb991177ccdc0d7887d7af0779fde4ebf3 Mon Sep 17 00:00:00 2001
From: Piotr Kubaj <pkubaj@FreeBSD.org>
Date: Sun, 18 Oct 2026 23:33:41 +0200
Subject: [PATCH] Add FreeBSD/powerpc64 support

FreeBSD runs on 64-bit PowerPC (powerpc64 and powerpc64le), but reptyr
did not build there: ptrace.h includes <asm/ptrace.h> for any PowerPC
compiler, and the FreeBSD ptrace backend has no arch header for it.

Include <asm/ptrace.h> only on Linux, where the PowerPC and RISC-V
register structs come from, and add platform/freebsd/arch/powerpc64.h.
The FreeBSD powerpc64 system call ABI (both ELFv1 and ELFv2, either
endianness) puts the system call number in r0, the arguments in r3-r10
and the result in r3, so all six arguments reptyr passes fit in
registers. SRR0 points past the 4-byte sc instruction when a system call
stops, so arch_fixup_regs() rewinds the PC by 4 like the AArch64 code.

Tested on FreeBSD 15.1 powerpc64le (POWER9).
---
 platform/freebsd/arch/powerpc64.h | 63 +++++++++++++++++++++++++++++++
 platform/freebsd/freebsd_ptrace.c |  2 +
 ptrace.h                          |  5 +--
 3 files changed, 66 insertions(+), 4 deletions(-)
 create mode 100644 platform/freebsd/arch/powerpc64.h

diff --git a/platform/freebsd/arch/powerpc64.h b/platform/freebsd/arch/powerpc64.h
new file mode 100644
index 0000000..a05c2e0
--- /dev/null
+++ b/platform/freebsd/arch/powerpc64.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2026, Piotr Kubaj. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/*
+ * FreeBSD/powerpc64 (ELFv1 and ELFv2, either endianness): the system call
+ * number goes in r0, the arguments in r3-r10 and the result comes back in
+ * r3, so all six arguments reptyr passes fit in registers.
+ */
+static struct ptrace_personality arch_personality[1] = {
+    {
+        offsetof(struct reg, fixreg[3]),
+        offsetof(struct reg, fixreg[3]),
+        offsetof(struct reg, fixreg[4]),
+        offsetof(struct reg, fixreg[5]),
+        offsetof(struct reg, fixreg[6]),
+        offsetof(struct reg, fixreg[7]),
+        offsetof(struct reg, fixreg[8]),
+        offsetof(struct reg, pc),
+        offsetof(struct reg, fixreg[1]),
+    }
+};
+
+#define ptr(regs, off) ((unsigned long*)((void*)(regs)+(off)))
+
+static inline void arch_fixup_regs(struct ptrace_child *child, struct reg *regs) {
+    /* SRR0 already points past the 4-byte sc instruction. */
+    regs->pc -= 4;
+}
+
+static inline void arch_set_register(struct ptrace_child *child, unsigned long oft, unsigned long val)
+{
+    struct reg regs;
+
+    (void)ptrace_command(child, PT_GETREGS, &regs);
+    *ptr(&regs, oft) = val;
+    (void)ptrace_command(child, PT_SETREGS, &regs);
+}
+
+static inline void arch_set_syscall(struct ptrace_child *child,
+                                   unsigned long sysno) {
+    arch_set_register(child, offsetof(struct reg, fixreg[0]), sysno);
+}
+
+#undef ptr
diff --git a/platform/freebsd/freebsd_ptrace.c b/platform/freebsd/freebsd_ptrace.c
index 5c27f7e..e5b9ea6 100644
--- a/platform/freebsd/freebsd_ptrace.c
+++ b/platform/freebsd/freebsd_ptrace.c
@@ -75,6 +75,8 @@ static struct ptrace_personality *personality(struct ptrace_child *child);
 #include "arch/arm.h"
 #elif defined(__aarch64__)
 #include "arch/aarch64.h"
+#elif defined(__powerpc64__)
+#include "arch/powerpc64.h"
 #else
 #error Unsupported architecture.
 #endif
diff --git a/ptrace.h b/ptrace.h
index dbb62bb..a17c20e 100644
--- a/ptrace.h
+++ b/ptrace.h
@@ -22,10 +22,7 @@
 #ifndef PTRACE_H
 #define PTRACE_H
 
-#ifdef __powerpc__
-#include <asm/ptrace.h>
-#endif
-#ifdef __riscv
+#if defined(__linux__) && (defined(__powerpc__) || defined(__riscv))
 #include <asm/ptrace.h>
 #endif
 #include <sys/ptrace.h>