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%3Ba=commit%3Bh=3e7b... A segmental fault will happen if the Binutils misses this patch.

Vincent Chen (3): riscv: add required functions to enable HAVE_REGS_AND_STACK_ACCESS_API riscv: Add support for restartable sequence rseq/selftests: Add support for riscv

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 | 3 + 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, 783 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/rseq/rseq-riscv.h