[src/trunk]: src/sys/arch/mips/include Add PTRACE_ILLEGAL_ASM using the MIPS3...

[simonb <simonb%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/55ee04d0917f
branches:  trunk
changeset: 960419:55ee04d0917f
user:      simonb <simonb%NetBSD.org@localhost>
date:      Thu Mar 18 23:18:36 2021 +0000

description:
Add PTRACE_ILLEGAL_ASM using the MIPS32r6/MIPS64r6 backwards and
forwards compatible "sigrie" instruction to generate a Reserved
Instruction trap.

diffstat:

 sys/arch/mips/include/ptrace.h |  17 ++++++++++++++++-
 1 files changed, 16 insertions(+), 1 deletions(-)

diffs (31 lines):

diff -r 71fed5d2b6fa -r 55ee04d0917f sys/arch/mips/include/ptrace.h
--- a/sys/arch/mips/include/ptrace.h    Thu Mar 18 22:51:32 2021 +0000
+++ b/sys/arch/mips/include/ptrace.h    Thu Mar 18 23:18:36 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ptrace.h,v 1.18 2020/07/26 08:08:41 simonb Exp $       */
+/*     $NetBSD: ptrace.h,v 1.19 2021/03/18 23:18:36 simonb Exp $       */
 
 /*
  * Copyright (c) 1992, 1993
@@ -67,6 +67,21 @@
 #define        PTRACE_REG_SP(r)        (r)->r_regs[29]
 #define        PTRACE_REG_INTRV(r)     (r)->r_regs[2]
 
+/*
+ * The sigrie is defined in the MIPS32r6 and MIPS64r6 specs to
+ * generate a Reserved Instruction trap but uses a previously
+ * reserved instruction encoding and is thus both backwards and
+ * forwards compatible.
+ */
+#define        PTRACE_ILLEGAL_ASM      do {                                    \
+               asm volatile(                                           \
+                       ".set   push;           "                       \
+                       ".set   mips32r6;       "                       \
+                       "sigrie 0;              "                       \
+                       ".set   pop;            "                       \
+               );                                                      \
+       } while (0);
+
 #define        PTRACE_BREAKPOINT       ((const uint8_t[]) { 0x00, 0x00, 0x00, 0x0d })
 #define        PTRACE_BREAKPOINT_ASM   __asm __volatile("break")
 #define        PTRACE_BREAKPOINT_SIZE  4