[PATCH v2 10/11] mips: Implement setjmp/longjmp/initjmp

[Ahmad Fatoum]

From: Sascha Hauer <s.hauer at pengutronix.de>

The header has been taken from glibc, the implementation itself is based
on the newlib implementation.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 arch/mips/Kconfig              |  1 +
 arch/mips/include/asm/setjmp.h | 32 ++++++++++++++++++++++
 arch/mips/lib/Makefile         |  1 +
 arch/mips/lib/setjmp.S         | 50 ++++++++++++++++++++++++++++++++++
 4 files changed, 84 insertions(+)
 create mode 100644 arch/mips/include/asm/setjmp.h
 create mode 100644 arch/mips/lib/setjmp.S

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 48f97c4bbf30..e77c9279ead3 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -12,6 +12,7 @@ config MIPS
 	select HAS_DMA
 	select ARCH_HAS_DATA_ABORT_MASK
 	select ELF
+	select HAS_ARCH_SJLJ
 	default y
 
 config SYS_SUPPORTS_BIG_ENDIAN
diff --git a/arch/mips/include/asm/setjmp.h b/arch/mips/include/asm/setjmp.h
new file mode 100644
index 000000000000..5a9af7773a5f
--- /dev/null
+++ b/arch/mips/include/asm/setjmp.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+/*
+ * Define the machine-dependent type `jmp_buf'.  MIPS version.
+ * Copyright (C) 1992-2021 Free Software Foundation, Inc.
+ * This file is part of the GNU C Library.
+ */
+
+#ifndef _MIPS_BITS_SETJMP_H
+#define _MIPS_BITS_SETJMP_H 1
+
+#include <asm/sgidefs.h>
+
+typedef struct __jmp_buf_internal_tag {
+	/* Program counter.  */
+	void *__pc;
+
+	/* Stack pointer.  */
+	void *__sp;
+
+	/* Callee-saved registers s0 through s7.  */
+	int __regs[8];
+
+	/* The frame pointer.  */
+	void *__fp;
+} jmp_buf[1];
+
+int setjmp(jmp_buf jmp) __attribute__((returns_twice));
+void longjmp(jmp_buf jmp, int ret) __attribute__((noreturn));
+int initjmp(jmp_buf jmp, void __noreturn (*func)(void), void *stack_top);
+
+#endif /* _MIPS_BITS_SETJMP_H */
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index 0761588ae865..f869ac088a7d 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -8,6 +8,7 @@ obj-y += reloc.o
 obj-y += sections.o
 obj-y += shutdown.o
 obj-y += dma-default.o
+obj-y += setjmp.o
 
 obj-$(CONFIG_MIPS_OPTIMIZED_STRING_FUNCTIONS) += memcpy.o
 obj-$(CONFIG_MIPS_OPTIMIZED_STRING_FUNCTIONS) += memset.o
diff --git a/arch/mips/lib/setjmp.S b/arch/mips/lib/setjmp.S
new file mode 100644
index 000000000000..b09a7c55293c
--- /dev/null
+++ b/arch/mips/lib/setjmp.S
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <asm/regdef.h>
+#include <asm/asm.h>
+#include <linux/linkage.h>
+
+/* int setjmp (jmp_buf);  */
+LEAF(setjmp)
+	sw	ra, (0 * 4)(a0)
+	sw	sp, (1 * 4)(a0)
+	sw	s0, (2 * 4)(a0)
+	sw	s1, (3 * 4)(a0)
+	sw	s2, (4 * 4)(a0)
+	sw	s3, (5 * 4)(a0)
+	sw	s4, (6 * 4)(a0)
+	sw	s5, (7 * 4)(a0)
+	sw	s6, (8 * 4)(a0)
+	sw	s7, (9 * 4)(a0)
+	sw	fp, (10 * 4)(a0)
+	move	v0, zero
+	j	ra
+END(setjmp)
+
+/* volatile void longjmp (jmp_buf, int);  */
+LEAF(longjmp)
+	lw	ra, (0 * 4)(a0)
+	lw	sp, (1 * 4)(a0)
+	lw	s0, (2 * 4)(a0)
+	lw	s1, (3 * 4)(a0)
+	lw	s2, (4 * 4)(a0)
+	lw	s3, (5 * 4)(a0)
+	lw	s4, (6 * 4)(a0)
+	lw	s5, (7 * 4)(a0)
+	lw	s6, (8 * 4)(a0)
+	lw	s7, (9 * 4)(a0)
+	lw	fp, (10 * 4)(a0)
+	bne	a1, zero, 1f
+	li	a1, 1
+1:
+	move	v0, a1
+	j	ra
+END(longjmp)
+
+/* int initjmp(jmp_buf jmp, void __noreturn (*func)(void), void *stack_top); */
+LEAF(initjmp)
+	sw	a1, (0 * 4)(a0)
+	sw	a2, (1 * 4)(a0)
+	move	v0, zero
+	j	ra
+END(initjmp)
-- 
2.29.2