[PATCH V2 0/3] riscv: add support for restartable sequence

[Vincent Chen <vincent.chen@sifive.com>]

Add RSEQ, restartable sequence, support and related selftest to RISCV.
The Kconfig option HAVE_REGS_AND_STACK_ACCESS_API is also required by
RSEQ because RSEQ will modify the content of pt_regs.sepc through
instruction_pointer_set() during the fixup procedure. In order to select
the config HAVE_REGS_AND_STACK_ACCESS_API, the missing APIs for accessing
pt_regs are also added in this patch set.
  
The relevant RSEQ tests in kselftest require the Binutils patch "RISC-V:
Fix linker problems with TLS copy relocs" to avoid placing
PREINIT_ARRAY and TLS variable of librseq.so at the same address.
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=3e7bd7f24146f162565edf878840449f36a8d974
A segmental fault will happen if binutils misses this patch.

Patrick Stählin (1):
  riscv: add required functions to enable HAVE_REGS_AND_STACK_ACCESS_API

Vincent Chen (2):
  riscv: Add support for restartable sequence
  rseq/selftests: Add support for riscv

Changes since v1:
1. Use the correct register name to access pt_regs


 arch/riscv/Kconfig                        |   2 +
 arch/riscv/include/asm/ptrace.h           |  29 +-
 arch/riscv/kernel/entry.S                 |   4 +
 arch/riscv/kernel/ptrace.c                |  99 +++++
 arch/riscv/kernel/signal.c                |   2 +
 tools/testing/selftests/rseq/param_test.c |  23 ++
 tools/testing/selftests/rseq/rseq-riscv.h | 622 ++++++++++++++++++++++++++++++
 tools/testing/selftests/rseq/rseq.h       |   2 +
 8 files changed, 782 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/rseq/rseq-riscv.h

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2.7.4