From d12381cb95f0a4a7bc07c1cef4141ad413260741 Mon Sep 17 00:00:00 2001
From: "R. Matthew Emerson" <rme@acm.org>
Date: Fri, 23 Nov 2018 15:39:00 -0800
Subject: [PATCH] Bring back the DarwinSigReturn hack for pre-Mojave systems

---
 lisp-kernel/platform-darwinx8632.h | 13 ++++++++++++-
 lisp-kernel/platform-darwinx8664.h | 14 +++++++++++---
 lisp-kernel/pmcl-kernel.c          |  2 +-
 lisp-kernel/x86-asmutils32.s       |  8 ++++++++
 lisp-kernel/x86-asmutils64.s       | 11 ++++++++++-
 5 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/lisp-kernel/platform-darwinx8632.h b/lisp-kernel/platform-darwinx8632.h
index 9282f3207..abd03f85b 100644
--- a/lisp-kernel/platform-darwinx8632.h
+++ b/lisp-kernel/platform-darwinx8632.h
@@ -49,6 +49,17 @@ typedef ucontext_t ExceptionInformation;
 /* xp accessors, sigreturn stuff */
 #define DARWIN_USE_PSEUDO_SIGRETURN 1
 
+extern void darwin_sigreturn(ExceptionInformation *, unsigned);
+extern natural os_major_version;
+
+#define DarwinSigReturn(context) do {		     \
+    if (os_major_version < 18) { /* Mojave */	     \
+      darwin_sigreturn(context, 0x1e);		     \
+      Bug(context,"sigreturn returned");	     \
+    }						     \
+} while (0)
+
+
 #define xpGPRvector(x) ((natural *)(&(UC_MCONTEXT(x)->__ss)))
 #define xpGPR(x,gprno) (xpGPRvector(x)[gprno])
 #define set_xpGPR(x,gpr,new) xpGPR((x),(gpr)) = (natural)(new)
@@ -62,7 +73,7 @@ typedef ucontext_t ExceptionInformation;
 #define SIGNUM_FOR_INTN_TRAP SIGSEGV /* Not really, but our Mach handler fakes that */
 #define IS_MAYBE_INT_TRAP(info,xp) ((UC_MCONTEXT(xp)->__es.__trapno == 0xd) && (((UC_MCONTEXT(xp)->__es.__err)&7)==2))
 #define IS_PAGE_FAULT(info,xp) (UC_MCONTEXT(xp)->__es.__trapno == 0xe)
-#define SIGRETURN(context)
+#define SIGRETURN(context) DarwinSigReturn(context)
 
 #include <mach/mach.h>
 #include <mach/mach_error.h>
diff --git a/lisp-kernel/platform-darwinx8664.h b/lisp-kernel/platform-darwinx8664.h
index eb877d1fb..825ce739c 100644
--- a/lisp-kernel/platform-darwinx8664.h
+++ b/lisp-kernel/platform-darwinx8664.h
@@ -53,11 +53,19 @@ typedef ucontext_t ExceptionInformation;
 #define REG_RIP 16
 #define REG_RFL 17
 
-extern void darwin_sigreturn(ExceptionInformation *,unsigned);
-
 /* xp accessors, sigreturn stuff */
 #define DARWIN_USE_PSEUDO_SIGRETURN 1
 
+extern void darwin_sigreturn(ExceptionInformation *, unsigned);
+extern natural os_major_version;
+
+#define DarwinSigReturn(context) do {		     \
+    if (os_major_version < 18) { /* Mojave */	     \
+      darwin_sigreturn(context, 0x1e);		     \
+      Bug(context,"sigreturn returned");	     \
+    }						     \
+} while (0)
+
 #define xpGPRvector(x) ((natural *)(&(UC_MCONTEXT(x)->__ss)))
 #define xpGPR(x,gprno) (xpGPRvector(x)[gprno])
 #define set_xpGPR(x,gpr,new) xpGPR((x),(gpr)) = (natural)(new)
@@ -71,7 +79,7 @@ extern void darwin_sigreturn(ExceptionInformation *,unsigned);
 #define SIGNUM_FOR_INTN_TRAP SIGSEGV /* Not really, but our Mach handler fakes that */
 #define IS_MAYBE_INT_TRAP(info,xp) ((UC_MCONTEXT(xp)->__es.__trapno == 0xd) && (((UC_MCONTEXT(xp)->__es.__err)&7)==2))
 #define IS_PAGE_FAULT(info,xp) (UC_MCONTEXT(xp)->__es.__trapno == 0xe)
-#define SIGRETURN(context)
+#define SIGRETURN(context) DarwinSigReturn(context)
 
 #include <mach/mach.h>
 #include <mach/mach_error.h>
diff --git a/lisp-kernel/pmcl-kernel.c b/lisp-kernel/pmcl-kernel.c
index 45a009153..ee54203a7 100644
--- a/lisp-kernel/pmcl-kernel.c
+++ b/lisp-kernel/pmcl-kernel.c
@@ -1455,7 +1455,7 @@ terminate_lisp()
 #endif
 
 #ifdef DARWIN
-#define min_os_version "8.0"    /* aka Tiger */
+#define min_os_version "13.0"    /* Mavericks */
 #endif
 #ifdef LINUX
 #ifdef PPC
diff --git a/lisp-kernel/x86-asmutils32.s b/lisp-kernel/x86-asmutils32.s
index 04f5c6961..9f6abb7e2 100644
--- a/lisp-kernel/x86-asmutils32.s
+++ b/lisp-kernel/x86-asmutils32.s
@@ -179,6 +179,14 @@ _exportfn(C(freebsd_sigreturn))
 _endfn
         __endif
 
+	__ifdef(`DARWIN')
+ _exportfn(C(darwin_sigreturn))
+	__(movl $0xb8,%eax)	/* SYS_sigreturn */
+	__(int $0x80)
+	__(ret)			/* shouldn't return */
+ _endfn
+         __endif
+
 _exportfn(C(get_vector_registers))
 	__(ret)
 _endfn
diff --git a/lisp-kernel/x86-asmutils64.s b/lisp-kernel/x86-asmutils64.s
index 6ba713482..1d4653c65 100644
--- a/lisp-kernel/x86-asmutils64.s
+++ b/lisp-kernel/x86-asmutils64.s
@@ -183,7 +183,16 @@ _endfn
 
 _exportfn(C(put_vector_registers))
 _endfn				
-        
+
+        __ifdef(`DARWIN')
+_exportfn(C(darwin_sigreturn))
+        .globl C(sigreturn)
+        __(movl $0x20000b8,%eax)
+        __(syscall)
+        __(ret)
+_endfn
+        __endif
+
         __ifdef(`WIN_64')
 /* %rcx = CONTEXT, %rdx = tcr, %r8 = old_valence.  This pretty
    much has to be uninterruptible */