RISC-V: Libitm add RISC-V support.

Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>

libitm/ChangeLog:

	* configure.tgt: Add riscv support.
	* config/riscv/asm.h: New file.
	* config/riscv/sjlj.S: New file.
	* config/riscv/target.h: New file.

4 files changed, 273 insertions, 0 deletions

diff --git a/libitm/config/riscv/asm.h b/libitm/config/riscv/asm.h
new file mode 100644
index 0000000..f0e3bd0
--- /dev/null
+++ b/libitm/config/riscv/asm.h
@@ -0,0 +1,63 @@
+/* Copyright (C) 2022 Free Software Foundation, Inc.
+   Contributed by Xiongchuan Tan <xc-tan@outlook.com>.
+
+   This file is part of the GNU Transactional Memory Library (libitm).
+
+   Libitm is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+   more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _RV_ASM_H
+#define _RV_ASM_H
+
+#ifdef __riscv_e
+#  error "rv32e and rv64e unsupported"
+#endif
+
+#if __riscv_xlen == 64
+#  define GPR_L ld
+#  define GPR_S sd
+#  define SZ_GPR 8
+#  define LEN_GPR 14
+#elif __riscv_xlen == 32
+#  define GPR_L lw
+#  define GPR_S sw
+#  define SZ_GPR 4
+#  define LEN_GPR 16 /* Extra padding to align the stack to 16 bytes */
+#else
+#  error Unsupported XLEN (must be 64-bit or 32-bit).
+#endif
+
+#if defined(__riscv_flen) && __riscv_flen == 64
+#  define FPR_L fld
+#  define FPR_S fsd
+#  define SZ_FPR 8
+#elif defined(__riscv_flen) && __riscv_flen == 32
+#  define FPR_L flw
+#  define FPR_S fsw
+#  define SZ_FPR 4
+#elif defined(__riscv_flen)
+#  error Q-extension unsupported
+#else
+#  define SZ_FPR 0
+#endif
+
+/* The size of gtm_jmpbuf */
+#define ADJ_STACK_SIZE (LEN_GPR*SZ_GPR+12*SZ_FPR)
+
+#endif  /* _RV_ASM_H */
diff --git a/libitm/config/riscv/sjlj.S b/libitm/config/riscv/sjlj.S
new file mode 100644
index 0000000..18521ae
--- /dev/null
+++ b/libitm/config/riscv/sjlj.S
@@ -0,0 +1,144 @@
+/* Copyright (C) 2022 Free Software Foundation, Inc.
+   Contributed by Xiongchuan Tan <xc-tan@outlook.com>.
+
+   This file is part of the GNU Transactional Memory Library (libitm).
+
+   Libitm is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+   more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "asmcfi.h"
+#include "asm.h"
+
+	.text
+	.align	2
+	.global	_ITM_beginTransaction
+	.type	_ITM_beginTransaction, @function
+
+_ITM_beginTransaction:
+	cfi_startproc
+	mv a1, sp
+	addi sp, sp, -ADJ_STACK_SIZE
+	cfi_adjust_cfa_offset(ADJ_STACK_SIZE)
+
+	/* Return Address */
+	GPR_S ra, 0*SZ_GPR(sp)
+	cfi_rel_offset(ra, 0*SZ_GPR)
+
+	/* Caller's sp */
+	GPR_S a1, 1*SZ_GPR(sp)
+
+	/* Caller's s0/fp */
+	GPR_S fp, 2*SZ_GPR(sp)
+	cfi_rel_offset(fp, 2*SZ_GPR)
+
+	/* Callee-saved registers */
+	GPR_S s1, 3*SZ_GPR(sp)
+	GPR_S s2, 4*SZ_GPR(sp)
+	GPR_S s3, 5*SZ_GPR(sp)
+	GPR_S s4, 6*SZ_GPR(sp)
+	GPR_S s5, 7*SZ_GPR(sp)
+	GPR_S s6, 8*SZ_GPR(sp)
+	GPR_S s7, 9*SZ_GPR(sp)
+	GPR_S s8, 10*SZ_GPR(sp)
+	GPR_S s9, 11*SZ_GPR(sp)
+	GPR_S s10, 12*SZ_GPR(sp)
+	GPR_S s11, 13*SZ_GPR(sp)
+
+#if defined(__riscv_flen)
+	/* Callee-saved floating-point registers */
+	FPR_S fs0, 0*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs1, 1*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs2, 2*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs3, 3*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs4, 4*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs5, 5*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs6, 6*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs7, 7*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs8, 8*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs9, 9*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs10, 10*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+	FPR_S fs11, 11*SZ_FPR+LEN_GPR*SZ_GPR(sp)
+#endif
+	mv fp, sp
+
+	/* Invoke GTM_begin_transaction with the struct we've just built.  */
+	mv a1, sp
+	jal ra, GTM_begin_transaction
+
+	/* Return; we don't need to restore any of the call-saved regs.  */
+	GPR_L ra, 0*SZ_GPR(sp)
+	cfi_restore(ra)
+	GPR_L fp, 2*SZ_GPR(sp)
+	cfi_restore(fp)
+
+	addi sp, sp, ADJ_STACK_SIZE
+	cfi_adjust_cfa_offset(-ADJ_STACK_SIZE)
+
+	ret
+	cfi_endproc
+	.size	_ITM_beginTransaction, . - _ITM_beginTransaction
+
+	.align	2
+	.global	GTM_longjmp
+	.hidden	GTM_longjmp
+	.type	GTM_longjmp, @function
+
+GTM_longjmp:
+	/* The first parameter becomes the return value (a0).
+	   The third parameter is ignored for now.  */
+    cfi_startproc
+	GPR_L s1, 3*SZ_GPR(a1)
+	GPR_L s2, 4*SZ_GPR(a1)
+	GPR_L s3, 5*SZ_GPR(a1)
+	GPR_L s4, 6*SZ_GPR(a1)
+	GPR_L s5, 7*SZ_GPR(a1)
+	GPR_L s6, 8*SZ_GPR(a1)
+	GPR_L s7, 9*SZ_GPR(a1)
+	GPR_L s8, 10*SZ_GPR(a1)
+	GPR_L s9, 11*SZ_GPR(a1)
+	GPR_L s10, 12*SZ_GPR(a1)
+	GPR_L s11, 13*SZ_GPR(a1)
+
+#if defined(__riscv_flen)
+	FPR_L fs0, 0*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs1, 1*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs2, 2*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs3, 3*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs4, 4*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs5, 5*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs6, 6*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs7, 7*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs8, 8*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs9, 9*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs10, 10*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+	FPR_L fs11, 11*SZ_FPR+LEN_GPR*SZ_GPR(a1)
+#endif
+
+	GPR_L ra, 0*SZ_GPR(a1)
+	GPR_L fp, 2*SZ_GPR(a1)
+	GPR_L a3, 1*SZ_GPR(a1)
+	cfi_def_cfa(a1, 0)
+	mv sp, a3
+	jr ra
+	cfi_endproc
+	.size	GTM_longjmp, . - GTM_longjmp
+
+#ifdef __linux__
+.section .note.GNU-stack, "", @progbits
+#endif
diff --git a/libitm/config/riscv/target.h b/libitm/config/riscv/target.h
new file mode 100644
index 0000000..7dcaa6a
--- /dev/null
+++ b/libitm/config/riscv/target.h
@@ -0,0 +1,64 @@
+/* Copyright (C) 2022 Free Software Foundation, Inc.
+   Contributed by Xiongchuan Tan <xc-tan@outlook.com>.
+
+   This file is part of the GNU Transactional Memory Library (libitm).
+
+   Libitm is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+   more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+namespace GTM HIDDEN {
+
+typedef struct gtm_jmpbuf
+  {
+    long int pc;
+    void *cfa;
+    long int s[12]; /* Saved registers, s0 is fp */
+
+#if __riscv_xlen == 32
+    /* Ensure that the stack is 16-byte aligned */
+    long int padding[2];
+#endif
+
+    /* FP saved registers */
+#if defined(__riscv_flen) && __riscv_flen == 64
+    double fs[12];
+#elif defined(__riscv_flen) && __riscv_flen == 32
+    float fs[12];
+#elif defined(__riscv_flen)
+#  error Q-extension unsupported
+#endif
+  } gtm_jmpbuf;
+
+/* The size of one line in hardware caches (in bytes). */
+/* 64 bytes is a suggested value in the RVA profiles (see
+   https://github.com/riscv/riscv-profiles/blob/main/profiles.adoc). */
+#define HW_CACHELINE_SIZE 64
+
+static inline void
+cpu_relax (void)
+{
+  #ifdef __riscv_zihintpause
+      __asm volatile ("pause");
+  #else
+      /* Encoding of the pause instruction */
+      __asm volatile (".4byte 0x100000F");
+  #endif
+}
+
+} // namespace GTM
diff --git a/libitm/configure.tgt b/libitm/configure.tgt
index 4c0e78c..635c1d4 100644
--- a/libitm/configure.tgt
+++ b/libitm/configure.tgt
@@ -82,6 +82,8 @@ EOF
 
   loongarch*)   ARCH=loongarch ;;
 
+  riscv*)		ARCH=riscv ;;
+
   sh*)		ARCH=sh ;;
 
   sparc)