RFR: 8294211: Zero: Decode arch-specific error context if possible

[Aleksey Shipilev]

After POSIX signal refactorings, Zero error handling had "regressed" a bit: Zero always gets `NULL` as `pc` in error handling code, and thus it fails with SEGV at pc=0x0. We can do better by implementing context decoding where possible.

Unfortunately, this introduces some arch-specific code in Zero code. The arch-specific code is copy-pasted (with inline definitions, if needed) from the relevant `os_linux_*.cpp` files. The unimplemented arches would still report the same confusing `hs_err`-s. We can emulate (and thus test) the generic behavior using new diagnostic VM option.

This reverts parts of [JDK-8259392](https://bugs.openjdk.org/browse/JDK-8259392).

Sample test:


import java.lang.reflect.*;
import sun.misc.Unsafe;

public class Crash {
  public static void main(String... args) throws Exception {
    Field f = Unsafe.class.getDeclaredField("theUnsafe");
    f.setAccessible(true);
    Unsafe u = (Unsafe) f.get(null);
    u.getInt(42); // accesing via broken ptr
  }
}


Linux x86_64 Zero fastdebug crash currently:


# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x0000000000000000, pid=538793, tid=538794
#
...
# (no native frame info)
...
siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x000000000000002a


Linux x86_64 Zero fastdebug crash with this patch:


#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007fbbbf08b584, pid=520119, tid=520120
#
...
# Problematic frame:
# V  [libjvm.so+0xcbe584]  Unsafe_GetInt+0xe4
....
siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x000000000000002a


Linux x86_64 Zero fastdebug crash with this patch and `-XX:-DecodeErrorContext`:


#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x0000000000000000, pid=520268, tid=520269
#
...
# Problematic frame:
# C  0x0000000000000000
...
siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x000000000000002a


Additional testing:
 - [x] Linux x86_64 Zero fastdebug eyeballing crash logs
 - [ ] Linux x86_64 Zero fastdebug, `tier1`
 - [x] Linux {x86_64, x86_32, aarch64, arm, riscv64, s390x, ppc64le, ppc64be} Zero fastdebug builds

-------------

Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/10397/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10397&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294211
  Stats: 150 lines in 4 files changed: 124 ins; 11 del; 15 mod
  Patch: https://git.openjdk.org/jdk/pull/10397.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10397/head:pull/10397

PR: https://git.openjdk.org/jdk/pull/10397