csky: Process management and Signal

This patch adds files related to task_switch, sigcontext, signal,
fpu context switch.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>

2 files changed, 341 insertions, 0 deletions

diff --git a/arch/csky/abiv2/fpu.c b/arch/csky/abiv2/fpu.c
new file mode 100644
index 000000000000..e7e11344005a
--- /dev/null
+++ b/arch/csky/abiv2/fpu.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/ptrace.h>
+#include <linux/uaccess.h>
+#include <abi/reg_ops.h>
+
+#define MTCR_MASK	0xFC00FFE0
+#define MFCR_MASK	0xFC00FFE0
+#define MTCR_DIST	0xC0006420
+#define MFCR_DIST	0xC0006020
+
+void __init init_fpu(void)
+{
+	mtcr("cr<1, 2>", 0);
+}
+
+/*
+ * fpu_libc_helper() is to help libc to excute:
+ *  - mfcr %a, cr<1, 2>
+ *  - mfcr %a, cr<2, 2>
+ *  - mtcr %a, cr<1, 2>
+ *  - mtcr %a, cr<2, 2>
+ */
+int fpu_libc_helper(struct pt_regs *regs)
+{
+	int fault;
+	unsigned long instrptr, regx = 0;
+	unsigned long index = 0, tmp = 0;
+	unsigned long tinstr = 0;
+	u16 instr_hi, instr_low;
+
+	instrptr = instruction_pointer(regs);
+	if (instrptr & 1)
+		return 0;
+
+	fault = __get_user(instr_low, (u16 *)instrptr);
+	if (fault)
+		return 0;
+
+	fault = __get_user(instr_hi, (u16 *)(instrptr + 2));
+	if (fault)
+		return 0;
+
+	tinstr = instr_hi | ((unsigned long)instr_low << 16);
+
+	if (((tinstr >> 21) & 0x1F) != 2)
+		return 0;
+
+	if ((tinstr & MTCR_MASK) == MTCR_DIST) {
+		index = (tinstr >> 16) & 0x1F;
+		if (index > 13)
+			return 0;
+
+		tmp = tinstr & 0x1F;
+		if (tmp > 2)
+			return 0;
+
+		regx =  *(&regs->a0 + index);
+
+		if (tmp == 1)
+			mtcr("cr<1, 2>", regx);
+		else if (tmp == 2)
+			mtcr("cr<2, 2>", regx);
+		else
+			return 0;
+
+		regs->pc += 4;
+		return 1;
+	}
+
+	if ((tinstr & MFCR_MASK) == MFCR_DIST) {
+		index = tinstr & 0x1F;
+		if (index > 13)
+			return 0;
+
+		tmp = ((tinstr >> 16) & 0x1F);
+		if (tmp > 2)
+			return 0;
+
+		if (tmp == 1)
+			regx = mfcr("cr<1, 2>");
+		else if (tmp == 2)
+			regx = mfcr("cr<2, 2>");
+		else
+			return 0;
+
+		*(&regs->a0 + index) = regx;
+
+		regs->pc += 4;
+		return 1;
+	}
+
+	return 0;
+}
+
+void fpu_fpe(struct pt_regs *regs)
+{
+	int sig, code;
+	unsigned int fesr;
+
+	fesr = mfcr("cr<2, 2>");
+
+	sig = SIGFPE;
+	code = FPE_FLTUNK;
+
+	if (fesr & FPE_ILLE) {
+		sig = SIGILL;
+		code = ILL_ILLOPC;
+	} else if (fesr & FPE_IDC) {
+		sig = SIGILL;
+		code = ILL_ILLOPN;
+	} else if (fesr & FPE_FEC) {
+		sig = SIGFPE;
+		if (fesr & FPE_IOC)
+			code = FPE_FLTINV;
+		else if (fesr & FPE_DZC)
+			code = FPE_FLTDIV;
+		else if (fesr & FPE_UFC)
+			code = FPE_FLTUND;
+		else if (fesr & FPE_OFC)
+			code = FPE_FLTOVF;
+		else if (fesr & FPE_IXC)
+			code = FPE_FLTRES;
+	}
+
+	force_sig_fault(sig, code, (void __user *)regs->pc, current);
+}
+
+#define FMFVR_FPU_REGS(vrx, vry)	\
+	"fmfvrl %0, "#vrx"\n"		\
+	"fmfvrh %1, "#vrx"\n"		\
+	"fmfvrl %2, "#vry"\n"		\
+	"fmfvrh %3, "#vry"\n"
+
+#define FMTVR_FPU_REGS(vrx, vry)	\
+	"fmtvrl "#vrx", %0\n"		\
+	"fmtvrh "#vrx", %1\n"		\
+	"fmtvrl "#vry", %2\n"		\
+	"fmtvrh "#vry", %3\n"
+
+#define STW_FPU_REGS(a, b, c, d)	\
+	"stw    %0, (%4, "#a")\n"	\
+	"stw    %1, (%4, "#b")\n"	\
+	"stw    %2, (%4, "#c")\n"	\
+	"stw    %3, (%4, "#d")\n"
+
+#define LDW_FPU_REGS(a, b, c, d)	\
+	"ldw    %0, (%4, "#a")\n"	\
+	"ldw    %1, (%4, "#b")\n"	\
+	"ldw    %2, (%4, "#c")\n"	\
+	"ldw    %3, (%4, "#d")\n"
+
+void save_to_user_fp(struct user_fp *user_fp)
+{
+	unsigned long flg;
+	unsigned long tmp1, tmp2;
+	unsigned long *fpregs;
+
+	local_irq_save(flg);
+
+	tmp1 = mfcr("cr<1, 2>");
+	tmp2 = mfcr("cr<2, 2>");
+
+	user_fp->fcr = tmp1;
+	user_fp->fesr = tmp2;
+
+	fpregs = &user_fp->vr[0];
+#ifdef CONFIG_CPU_HAS_FPUV2
+#ifdef CONFIG_CPU_HAS_VDSP
+	asm volatile(
+		"vstmu.32    vr0-vr3,   (%0)\n"
+		"vstmu.32    vr4-vr7,   (%0)\n"
+		"vstmu.32    vr8-vr11,  (%0)\n"
+		"vstmu.32    vr12-vr15, (%0)\n"
+		"fstmu.64    vr16-vr31, (%0)\n"
+		: "+a"(fpregs)
+		::"memory");
+#else
+	asm volatile(
+		"fstmu.64    vr0-vr31,  (%0)\n"
+		: "+a"(fpregs)
+		::"memory");
+#endif
+#else
+	{
+	unsigned long tmp3, tmp4;
+
+	asm volatile(
+		FMFVR_FPU_REGS(vr0, vr1)
+		STW_FPU_REGS(0, 4, 16, 20)
+		FMFVR_FPU_REGS(vr2, vr3)
+		STW_FPU_REGS(32, 36, 48, 52)
+		FMFVR_FPU_REGS(vr4, vr5)
+		STW_FPU_REGS(64, 68, 80, 84)
+		FMFVR_FPU_REGS(vr6, vr7)
+		STW_FPU_REGS(96, 100, 112, 116)
+		"addi	%4, 128\n"
+		FMFVR_FPU_REGS(vr8, vr9)
+		STW_FPU_REGS(0, 4, 16, 20)
+		FMFVR_FPU_REGS(vr10, vr11)
+		STW_FPU_REGS(32, 36, 48, 52)
+		FMFVR_FPU_REGS(vr12, vr13)
+		STW_FPU_REGS(64, 68, 80, 84)
+		FMFVR_FPU_REGS(vr14, vr15)
+		STW_FPU_REGS(96, 100, 112, 116)
+		: "=a"(tmp1), "=a"(tmp2), "=a"(tmp3),
+		  "=a"(tmp4), "+a"(fpregs)
+		::"memory");
+	}
+#endif
+
+	local_irq_restore(flg);
+}
+
+void restore_from_user_fp(struct user_fp *user_fp)
+{
+	unsigned long flg;
+	unsigned long tmp1, tmp2;
+	unsigned long *fpregs;
+
+	local_irq_save(flg);
+
+	tmp1 = user_fp->fcr;
+	tmp2 = user_fp->fesr;
+
+	mtcr("cr<1, 2>", tmp1);
+	mtcr("cr<2, 2>", tmp2);
+
+	fpregs = &user_fp->vr[0];
+#ifdef CONFIG_CPU_HAS_FPUV2
+#ifdef CONFIG_CPU_HAS_VDSP
+	asm volatile(
+		"vldmu.32    vr0-vr3,   (%0)\n"
+		"vldmu.32    vr4-vr7,   (%0)\n"
+		"vldmu.32    vr8-vr11,  (%0)\n"
+		"vldmu.32    vr12-vr15, (%0)\n"
+		"fldmu.64    vr16-vr31, (%0)\n"
+		: "+a"(fpregs)
+		::"memory");
+#else
+	asm volatile(
+		"fldmu.64    vr0-vr31,  (%0)\n"
+		: "+a"(fpregs)
+		::"memory");
+#endif
+#else
+	{
+	unsigned long tmp3, tmp4;
+
+	asm volatile(
+		LDW_FPU_REGS(0, 4, 16, 20)
+		FMTVR_FPU_REGS(vr0, vr1)
+		LDW_FPU_REGS(32, 36, 48, 52)
+		FMTVR_FPU_REGS(vr2, vr3)
+		LDW_FPU_REGS(64, 68, 80, 84)
+		FMTVR_FPU_REGS(vr4, vr5)
+		LDW_FPU_REGS(96, 100, 112, 116)
+		FMTVR_FPU_REGS(vr6, vr7)
+		"addi	%4, 128\n"
+		LDW_FPU_REGS(0, 4, 16, 20)
+		FMTVR_FPU_REGS(vr8, vr9)
+		LDW_FPU_REGS(32, 36, 48, 52)
+		FMTVR_FPU_REGS(vr10, vr11)
+		LDW_FPU_REGS(64, 68, 80, 84)
+		FMTVR_FPU_REGS(vr12, vr13)
+		LDW_FPU_REGS(96, 100, 112, 116)
+		FMTVR_FPU_REGS(vr14, vr15)
+		: "=a"(tmp1), "=a"(tmp2), "=a"(tmp3),
+		  "=a"(tmp4), "+a"(fpregs)
+		::"memory");
+	}
+#endif
+	local_irq_restore(flg);
+}
diff --git a/arch/csky/abiv2/inc/abi/fpu.h b/arch/csky/abiv2/inc/abi/fpu.h
new file mode 100644
index 000000000000..22ca3cf2794a
--- /dev/null
+++ b/arch/csky/abiv2/inc/abi/fpu.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_FPU_H
+#define __ASM_CSKY_FPU_H
+
+#include <asm/sigcontext.h>
+#include <asm/ptrace.h>
+
+int fpu_libc_helper(struct pt_regs *regs);
+void fpu_fpe(struct pt_regs *regs);
+void __init init_fpu(void);
+
+void save_to_user_fp(struct user_fp *user_fp);
+void restore_from_user_fp(struct user_fp *user_fp);
+
+/*
+ * Define the fesr bit for fpe handle.
+ */
+#define  FPE_ILLE  (1 << 16)    /* Illegal instruction  */
+#define  FPE_FEC   (1 << 7)     /* Input float-point arithmetic exception */
+#define  FPE_IDC   (1 << 5)     /* Input denormalized exception */
+#define  FPE_IXC   (1 << 4)     /* Inexact exception */
+#define  FPE_UFC   (1 << 3)     /* Underflow exception */
+#define  FPE_OFC   (1 << 2)     /* Overflow exception */
+#define  FPE_DZC   (1 << 1)     /* Divide by zero exception */
+#define  FPE_IOC   (1 << 0)     /* Invalid operation exception */
+#define  FPE_REGULAR_EXCEPTION (FPE_IXC | FPE_UFC | FPE_OFC | FPE_DZC | FPE_IOC)
+
+#ifdef CONFIG_OPEN_FPU_IDE
+#define IDE_STAT   (1 << 5)
+#else
+#define IDE_STAT   0
+#endif
+
+#ifdef CONFIG_OPEN_FPU_IXE
+#define IXE_STAT   (1 << 4)
+#else
+#define IXE_STAT   0
+#endif
+
+#ifdef CONFIG_OPEN_FPU_UFE
+#define UFE_STAT   (1 << 3)
+#else
+#define UFE_STAT   0
+#endif
+
+#ifdef CONFIG_OPEN_FPU_OFE
+#define OFE_STAT   (1 << 2)
+#else
+#define OFE_STAT   0
+#endif
+
+#ifdef CONFIG_OPEN_FPU_DZE
+#define DZE_STAT   (1 << 1)
+#else
+#define DZE_STAT   0
+#endif
+
+#ifdef CONFIG_OPEN_FPU_IOE
+#define IOE_STAT   (1 << 0)
+#else
+#define IOE_STAT   0
+#endif
+
+#endif /* __ASM_CSKY_FPU_H */