LoongArch: Add misc common routines

Add some misc common routines for LoongArch, including: asm-offsets
routines, futex functions, i/o memory access functions, frame-buffer
functions, procfs information display, etc.
Reviewed-by: NWANG Xuerui <git@xen0n.name>
Reviewed-by: NJiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: NHuacai Chen <chenhuacai@loongson.cn>

arch/loongarch/include/asm/asm-offsets.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <generated/asm-offsets.h>

arch/loongarch/include/asm/fb.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_FB_H_
+#define _ASM_FB_H_
+
+#include <linux/fb.h>
+#include <linux/fs.h>
+#include <asm/page.h>
+
+static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma,
+				unsigned long off)
+{
+	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+}
+
+static inline int fb_is_primary_device(struct fb_info *info)
+{
+	return 0;
+}
+
+#endif /* _ASM_FB_H_ */

arch/loongarch/include/asm/futex.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_FUTEX_H
+#define _ASM_FUTEX_H
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/barrier.h>
+#include <asm/compiler.h>
+#include <asm/errno.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)		\
+{									\
+	__asm__ __volatile__(						\
+	"1:	ll.w	%1, %4 # __futex_atomic_op\n"		\
+	"	" insn	"				\n"	\
+	"2:	sc.w	$t0, %2				\n"	\
+	"	beq	$t0, $zero, 1b			\n"	\
+	"3:						\n"	\
+	"	.section .fixup,\"ax\"			\n"	\
+	"4:	li.w	%0, %6				\n"	\
+	"	b	3b				\n"	\
+	"	.previous				\n"	\
+	"	.section __ex_table,\"a\"		\n"	\
+	"	"__UA_ADDR "\t1b, 4b			\n"	\
+	"	"__UA_ADDR "\t2b, 4b			\n"	\
+	"	.previous				\n"	\
+	: "=r" (ret), "=&r" (oldval),				\
+	  "=ZC" (*uaddr)					\
+	: "0" (0), "ZC" (*uaddr), "Jr" (oparg),			\
+	  "i" (-EFAULT)						\
+	: "memory", "t0");					\
+}
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+	int oldval = 0, ret = 0;
+
+	pagefault_disable();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("or	$t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("and	$t0, %1, %z5", ret, oldval, uaddr, ~oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("xor	$t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	pagefault_enable();
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
+{
+	int ret = 0;
+	u32 val = 0;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	__asm__ __volatile__(
+	"# futex_atomic_cmpxchg_inatomic			\n"
+	"1:	ll.w	%1, %3					\n"
+	"	bne	%1, %z4, 3f				\n"
+	"	or	$t0, %z5, $zero				\n"
+	"2:	sc.w	$t0, %2					\n"
+	"	beq	$zero, $t0, 1b				\n"
+	"3:							\n"
+	"	.section .fixup,\"ax\"				\n"
+	"4:	li.d	%0, %6					\n"
+	"	b	3b					\n"
+	"	.previous					\n"
+	"	.section __ex_table,\"a\"			\n"
+	"	"__UA_ADDR "\t1b, 4b				\n"
+	"	"__UA_ADDR "\t2b, 4b				\n"
+	"	.previous					\n"
+	: "+r" (ret), "=&r" (val), "=" GCC_OFF_SMALL_ASM() (*uaddr)
+	: GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
+	  "i" (-EFAULT)
+	: "memory", "t0");
+
+	*uval = val;
+
+	return ret;
+}
+
+#endif /* _ASM_FUTEX_H */

arch/loongarch/include/asm/io.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_IO_H
+#define _ASM_IO_H
+
+#define ARCH_HAS_IOREMAP_WC
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include <asm/addrspace.h>
+#include <asm/bug.h>
+#include <asm/byteorder.h>
+#include <asm/cpu.h>
+#include <asm/page.h>
+#include <asm/pgtable-bits.h>
+#include <asm/string.h>
+
+/*
+ * On LoongArch, I/O ports mappring is following:
+ *
+ *              |         ....          |
+ *              |-----------------------|
+ *              | pci io ports(64K~32M) |
+ *              |-----------------------|
+ *              | isa io ports(0  ~16K) |
+ * PCI_IOBASE ->|-----------------------|
+ *              |         ....          |
+ */
+#define PCI_IOBASE	((void __iomem *)(vm_map_base + (2 * PAGE_SIZE)))
+#define PCI_IOSIZE	SZ_32M
+#define ISA_IOSIZE	SZ_16K
+#define IO_SPACE_LIMIT	(PCI_IOSIZE - 1)
+
+/*
+ * Change "struct page" to physical address.
+ */
+#define page_to_phys(page)	((phys_addr_t)page_to_pfn(page) << PAGE_SHIFT)
+
+extern void __init __iomem *early_ioremap(u64 phys_addr, unsigned long size);
+extern void __init early_iounmap(void __iomem *addr, unsigned long size);
+
+#define early_memremap early_ioremap
+#define early_memunmap early_iounmap
+
+static inline void __iomem *ioremap_prot(phys_addr_t offset, unsigned long size,
+					 unsigned long prot_val)
+{
+	if (prot_val == _CACHE_CC)
+		return (void __iomem *)(unsigned long)(CACHE_BASE + offset);
+	else
+		return (void __iomem *)(unsigned long)(UNCACHE_BASE + offset);
+}
+
+/*
+ * ioremap -   map bus memory into CPU space
+ * @offset:    bus address of the memory
+ * @size:      size of the resource to map
+ *
+ * ioremap performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ */
+#define ioremap(offset, size)					\
+	ioremap_prot((offset), (size), _CACHE_SUC)
+
+/*
+ * ioremap_wc - map bus memory into CPU space
+ * @offset:     bus address of the memory
+ * @size:       size of the resource to map
+ *
+ * ioremap_wc performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ *
+ * This version of ioremap ensures that the memory is marked uncachable
+ * but accelerated by means of write-combining feature. It is specifically
+ * useful for PCIe prefetchable windows, which may vastly improve a
+ * communications performance. If it was determined on boot stage, what
+ * CPU CCA doesn't support WUC, the method shall fall-back to the
+ * _CACHE_SUC option (see cpu_probe() method).
+ */
+#define ioremap_wc(offset, size)				\
+	ioremap_prot((offset), (size), _CACHE_WUC)
+
+/*
+ * ioremap_cache -  map bus memory into CPU space
+ * @offset:	    bus address of the memory
+ * @size:	    size of the resource to map
+ *
+ * ioremap_cache performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ *
+ * This version of ioremap ensures that the memory is marked cachable by
+ * the CPU.  Also enables full write-combining.	 Useful for some
+ * memory-like regions on I/O busses.
+ */
+#define ioremap_cache(offset, size)				\
+	ioremap_prot((offset), (size), _CACHE_CC)
+
+static inline void iounmap(const volatile void __iomem *addr)
+{
+}
+
+#define mmiowb() asm volatile ("dbar 0" ::: "memory")
+
+/*
+ * String version of I/O memory access operations.
+ */
+extern void __memset_io(volatile void __iomem *dst, int c, size_t count);
+extern void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count);
+extern void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count);
+#define memset_io(c, v, l)     __memset_io((c), (v), (l))
+#define memcpy_fromio(a, c, l) __memcpy_fromio((a), (c), (l))
+#define memcpy_toio(c, a, l)   __memcpy_toio((c), (a), (l))
+
+#include <asm-generic/io.h>
+
+#endif /* _ASM_IO_H */

arch/loongarch/kernel/asm-offsets.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * asm-offsets.c: Calculate pt_regs and task_struct offsets.
+ *
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/kbuild.h>
+#include <linux/suspend.h>
+#include <asm/cpu-info.h>
+#include <asm/ptrace.h>
+#include <asm/processor.h>
+
+void output_ptreg_defines(void)
+{
+	COMMENT("LoongArch pt_regs offsets.");
+	OFFSET(PT_R0, pt_regs, regs[0]);
+	OFFSET(PT_R1, pt_regs, regs[1]);
+	OFFSET(PT_R2, pt_regs, regs[2]);
+	OFFSET(PT_R3, pt_regs, regs[3]);
+	OFFSET(PT_R4, pt_regs, regs[4]);
+	OFFSET(PT_R5, pt_regs, regs[5]);
+	OFFSET(PT_R6, pt_regs, regs[6]);
+	OFFSET(PT_R7, pt_regs, regs[7]);
+	OFFSET(PT_R8, pt_regs, regs[8]);
+	OFFSET(PT_R9, pt_regs, regs[9]);
+	OFFSET(PT_R10, pt_regs, regs[10]);
+	OFFSET(PT_R11, pt_regs, regs[11]);
+	OFFSET(PT_R12, pt_regs, regs[12]);
+	OFFSET(PT_R13, pt_regs, regs[13]);
+	OFFSET(PT_R14, pt_regs, regs[14]);
+	OFFSET(PT_R15, pt_regs, regs[15]);
+	OFFSET(PT_R16, pt_regs, regs[16]);
+	OFFSET(PT_R17, pt_regs, regs[17]);
+	OFFSET(PT_R18, pt_regs, regs[18]);
+	OFFSET(PT_R19, pt_regs, regs[19]);
+	OFFSET(PT_R20, pt_regs, regs[20]);
+	OFFSET(PT_R21, pt_regs, regs[21]);
+	OFFSET(PT_R22, pt_regs, regs[22]);
+	OFFSET(PT_R23, pt_regs, regs[23]);
+	OFFSET(PT_R24, pt_regs, regs[24]);
+	OFFSET(PT_R25, pt_regs, regs[25]);
+	OFFSET(PT_R26, pt_regs, regs[26]);
+	OFFSET(PT_R27, pt_regs, regs[27]);
+	OFFSET(PT_R28, pt_regs, regs[28]);
+	OFFSET(PT_R29, pt_regs, regs[29]);
+	OFFSET(PT_R30, pt_regs, regs[30]);
+	OFFSET(PT_R31, pt_regs, regs[31]);
+	OFFSET(PT_CRMD, pt_regs, csr_crmd);
+	OFFSET(PT_PRMD, pt_regs, csr_prmd);
+	OFFSET(PT_EUEN, pt_regs, csr_euen);
+	OFFSET(PT_ECFG, pt_regs, csr_ecfg);
+	OFFSET(PT_ESTAT, pt_regs, csr_estat);
+	OFFSET(PT_ERA, pt_regs, csr_era);
+	OFFSET(PT_BVADDR, pt_regs, csr_badvaddr);
+	OFFSET(PT_ORIG_A0, pt_regs, orig_a0);
+	DEFINE(PT_SIZE, sizeof(struct pt_regs));
+	BLANK();
+}
+
+void output_task_defines(void)
+{
+	COMMENT("LoongArch task_struct offsets.");
+	OFFSET(TASK_STATE, task_struct, __state);
+	OFFSET(TASK_THREAD_INFO, task_struct, stack);
+	OFFSET(TASK_FLAGS, task_struct, flags);
+	OFFSET(TASK_MM, task_struct, mm);
+	OFFSET(TASK_PID, task_struct, pid);
+	DEFINE(TASK_STRUCT_SIZE, sizeof(struct task_struct));
+	BLANK();
+}
+
+void output_thread_info_defines(void)
+{
+	COMMENT("LoongArch thread_info offsets.");
+	OFFSET(TI_TASK, thread_info, task);
+	OFFSET(TI_FLAGS, thread_info, flags);
+	OFFSET(TI_TP_VALUE, thread_info, tp_value);
+	OFFSET(TI_CPU, thread_info, cpu);
+	OFFSET(TI_PRE_COUNT, thread_info, preempt_count);
+	OFFSET(TI_REGS, thread_info, regs);
+	DEFINE(_THREAD_SIZE, THREAD_SIZE);
+	DEFINE(_THREAD_MASK, THREAD_MASK);
+	DEFINE(_IRQ_STACK_SIZE, IRQ_STACK_SIZE);
+	DEFINE(_IRQ_STACK_START, IRQ_STACK_START);
+	BLANK();
+}
+
+void output_thread_defines(void)
+{
+	COMMENT("LoongArch specific thread_struct offsets.");
+	OFFSET(THREAD_REG01, task_struct, thread.reg01);
+	OFFSET(THREAD_REG03, task_struct, thread.reg03);
+	OFFSET(THREAD_REG22, task_struct, thread.reg22);
+	OFFSET(THREAD_REG23, task_struct, thread.reg23);
+	OFFSET(THREAD_REG24, task_struct, thread.reg24);
+	OFFSET(THREAD_REG25, task_struct, thread.reg25);
+	OFFSET(THREAD_REG26, task_struct, thread.reg26);
+	OFFSET(THREAD_REG27, task_struct, thread.reg27);
+	OFFSET(THREAD_REG28, task_struct, thread.reg28);
+	OFFSET(THREAD_REG29, task_struct, thread.reg29);
+	OFFSET(THREAD_REG30, task_struct, thread.reg30);
+	OFFSET(THREAD_REG31, task_struct, thread.reg31);
+	OFFSET(THREAD_CSRCRMD, task_struct,
+	       thread.csr_crmd);
+	OFFSET(THREAD_CSRPRMD, task_struct,
+	       thread.csr_prmd);
+	OFFSET(THREAD_CSREUEN, task_struct,
+	       thread.csr_euen);
+	OFFSET(THREAD_CSRECFG, task_struct,
+	       thread.csr_ecfg);
+
+	OFFSET(THREAD_SCR0, task_struct, thread.scr0);
+	OFFSET(THREAD_SCR1, task_struct, thread.scr1);
+	OFFSET(THREAD_SCR2, task_struct, thread.scr2);
+	OFFSET(THREAD_SCR3, task_struct, thread.scr3);
+
+	OFFSET(THREAD_EFLAGS, task_struct, thread.eflags);
+
+	OFFSET(THREAD_FPU, task_struct, thread.fpu);
+
+	OFFSET(THREAD_BVADDR, task_struct, \
+	       thread.csr_badvaddr);
+	OFFSET(THREAD_ECODE, task_struct, \
+	       thread.error_code);
+	OFFSET(THREAD_TRAPNO, task_struct, thread.trap_nr);
+	BLANK();
+}
+
+void output_thread_fpu_defines(void)
+{
+	OFFSET(THREAD_FPR0, loongarch_fpu, fpr[0]);
+	OFFSET(THREAD_FPR1, loongarch_fpu, fpr[1]);
+	OFFSET(THREAD_FPR2, loongarch_fpu, fpr[2]);
+	OFFSET(THREAD_FPR3, loongarch_fpu, fpr[3]);
+	OFFSET(THREAD_FPR4, loongarch_fpu, fpr[4]);
+	OFFSET(THREAD_FPR5, loongarch_fpu, fpr[5]);
+	OFFSET(THREAD_FPR6, loongarch_fpu, fpr[6]);
+	OFFSET(THREAD_FPR7, loongarch_fpu, fpr[7]);
+	OFFSET(THREAD_FPR8, loongarch_fpu, fpr[8]);
+	OFFSET(THREAD_FPR9, loongarch_fpu, fpr[9]);
+	OFFSET(THREAD_FPR10, loongarch_fpu, fpr[10]);
+	OFFSET(THREAD_FPR11, loongarch_fpu, fpr[11]);
+	OFFSET(THREAD_FPR12, loongarch_fpu, fpr[12]);
+	OFFSET(THREAD_FPR13, loongarch_fpu, fpr[13]);
+	OFFSET(THREAD_FPR14, loongarch_fpu, fpr[14]);
+	OFFSET(THREAD_FPR15, loongarch_fpu, fpr[15]);
+	OFFSET(THREAD_FPR16, loongarch_fpu, fpr[16]);
+	OFFSET(THREAD_FPR17, loongarch_fpu, fpr[17]);
+	OFFSET(THREAD_FPR18, loongarch_fpu, fpr[18]);
+	OFFSET(THREAD_FPR19, loongarch_fpu, fpr[19]);
+	OFFSET(THREAD_FPR20, loongarch_fpu, fpr[20]);
+	OFFSET(THREAD_FPR21, loongarch_fpu, fpr[21]);
+	OFFSET(THREAD_FPR22, loongarch_fpu, fpr[22]);
+	OFFSET(THREAD_FPR23, loongarch_fpu, fpr[23]);
+	OFFSET(THREAD_FPR24, loongarch_fpu, fpr[24]);
+	OFFSET(THREAD_FPR25, loongarch_fpu, fpr[25]);
+	OFFSET(THREAD_FPR26, loongarch_fpu, fpr[26]);
+	OFFSET(THREAD_FPR27, loongarch_fpu, fpr[27]);
+	OFFSET(THREAD_FPR28, loongarch_fpu, fpr[28]);
+	OFFSET(THREAD_FPR29, loongarch_fpu, fpr[29]);
+	OFFSET(THREAD_FPR30, loongarch_fpu, fpr[30]);
+	OFFSET(THREAD_FPR31, loongarch_fpu, fpr[31]);
+
+	OFFSET(THREAD_FCSR, loongarch_fpu, fcsr);
+	OFFSET(THREAD_FCC,  loongarch_fpu, fcc);
+	OFFSET(THREAD_VCSR, loongarch_fpu, vcsr);
+	BLANK();
+}
+
+void output_mm_defines(void)
+{
+	COMMENT("Size of struct page");
+	DEFINE(STRUCT_PAGE_SIZE, sizeof(struct page));
+	BLANK();
+	COMMENT("Linux mm_struct offsets.");
+	OFFSET(MM_USERS, mm_struct, mm_users);
+	OFFSET(MM_PGD, mm_struct, pgd);
+	OFFSET(MM_CONTEXT, mm_struct, context);
+	BLANK();
+	DEFINE(_PGD_T_SIZE, sizeof(pgd_t));
+	DEFINE(_PMD_T_SIZE, sizeof(pmd_t));
+	DEFINE(_PTE_T_SIZE, sizeof(pte_t));
+	BLANK();
+	DEFINE(_PGD_T_LOG2, PGD_T_LOG2);
+#ifndef __PAGETABLE_PMD_FOLDED
+	DEFINE(_PMD_T_LOG2, PMD_T_LOG2);
+#endif
+	DEFINE(_PTE_T_LOG2, PTE_T_LOG2);
+	BLANK();
+	DEFINE(_PGD_ORDER, PGD_ORDER);
+#ifndef __PAGETABLE_PMD_FOLDED
+	DEFINE(_PMD_ORDER, PMD_ORDER);
+#endif
+	DEFINE(_PTE_ORDER, PTE_ORDER);
+	BLANK();
+	DEFINE(_PMD_SHIFT, PMD_SHIFT);
+	DEFINE(_PGDIR_SHIFT, PGDIR_SHIFT);
+	BLANK();
+	DEFINE(_PTRS_PER_PGD, PTRS_PER_PGD);
+	DEFINE(_PTRS_PER_PMD, PTRS_PER_PMD);
+	DEFINE(_PTRS_PER_PTE, PTRS_PER_PTE);
+	BLANK();
+	DEFINE(_PAGE_SHIFT, PAGE_SHIFT);
+	DEFINE(_PAGE_SIZE, PAGE_SIZE);
+	BLANK();
+}
+
+void output_sc_defines(void)
+{
+	COMMENT("Linux sigcontext offsets.");
+	OFFSET(SC_REGS, sigcontext, sc_regs);
+	OFFSET(SC_PC, sigcontext, sc_pc);
+	BLANK();
+}
+
+void output_signal_defines(void)
+{
+	COMMENT("Linux signal numbers.");
+	DEFINE(_SIGHUP, SIGHUP);
+	DEFINE(_SIGINT, SIGINT);
+	DEFINE(_SIGQUIT, SIGQUIT);
+	DEFINE(_SIGILL, SIGILL);
+	DEFINE(_SIGTRAP, SIGTRAP);
+	DEFINE(_SIGIOT, SIGIOT);
+	DEFINE(_SIGABRT, SIGABRT);
+	DEFINE(_SIGFPE, SIGFPE);
+	DEFINE(_SIGKILL, SIGKILL);
+	DEFINE(_SIGBUS, SIGBUS);
+	DEFINE(_SIGSEGV, SIGSEGV);
+	DEFINE(_SIGSYS, SIGSYS);
+	DEFINE(_SIGPIPE, SIGPIPE);
+	DEFINE(_SIGALRM, SIGALRM);
+	DEFINE(_SIGTERM, SIGTERM);
+	DEFINE(_SIGUSR1, SIGUSR1);
+	DEFINE(_SIGUSR2, SIGUSR2);
+	DEFINE(_SIGCHLD, SIGCHLD);
+	DEFINE(_SIGPWR, SIGPWR);
+	DEFINE(_SIGWINCH, SIGWINCH);
+	DEFINE(_SIGURG, SIGURG);
+	DEFINE(_SIGIO, SIGIO);
+	DEFINE(_SIGSTOP, SIGSTOP);
+	DEFINE(_SIGTSTP, SIGTSTP);
+	DEFINE(_SIGCONT, SIGCONT);
+	DEFINE(_SIGTTIN, SIGTTIN);
+	DEFINE(_SIGTTOU, SIGTTOU);
+	DEFINE(_SIGVTALRM, SIGVTALRM);
+	DEFINE(_SIGPROF, SIGPROF);
+	DEFINE(_SIGXCPU, SIGXCPU);
+	DEFINE(_SIGXFSZ, SIGXFSZ);
+	BLANK();
+}

arch/loongarch/kernel/io.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/io.h>
+
+/*
+ * Copy data from IO memory space to "real" memory space.
+ */
+void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
+{
+	while (count && !IS_ALIGNED((unsigned long)from, 8)) {
+		*(u8 *)to = __raw_readb(from);
+		from++;
+		to++;
+		count--;
+	}
+
+	while (count >= 8) {
+		*(u64 *)to = __raw_readq(from);
+		from += 8;
+		to += 8;
+		count -= 8;
+	}
+
+	while (count) {
+		*(u8 *)to = __raw_readb(from);
+		from++;
+		to++;
+		count--;
+	}
+}
+EXPORT_SYMBOL(__memcpy_fromio);
+
+/*
+ * Copy data from "real" memory space to IO memory space.
+ */
+void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
+{
+	while (count && !IS_ALIGNED((unsigned long)to, 8)) {
+		__raw_writeb(*(u8 *)from, to);
+		from++;
+		to++;
+		count--;
+	}
+
+	while (count >= 8) {
+		__raw_writeq(*(u64 *)from, to);
+		from += 8;
+		to += 8;
+		count -= 8;
+	}
+
+	while (count) {
+		__raw_writeb(*(u8 *)from, to);
+		from++;
+		to++;
+		count--;
+	}
+}
+EXPORT_SYMBOL(__memcpy_toio);
+
+/*
+ * "memset" on IO memory space.
+ */
+void __memset_io(volatile void __iomem *dst, int c, size_t count)
+{
+	u64 qc = (u8)c;
+
+	qc |= qc << 8;
+	qc |= qc << 16;
+	qc |= qc << 32;
+
+	while (count && !IS_ALIGNED((unsigned long)dst, 8)) {
+		__raw_writeb(c, dst);
+		dst++;
+		count--;
+	}
+
+	while (count >= 8) {
+		__raw_writeq(qc, dst);
+		dst += 8;
+		count -= 8;
+	}
+
+	while (count) {
+		__raw_writeb(c, dst);
+		dst++;
+		count--;
+	}
+}
+EXPORT_SYMBOL(__memset_io);

arch/loongarch/kernel/proc.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/cpu-features.h>
+#include <asm/idle.h>
+#include <asm/processor.h>
+#include <asm/time.h>
+
+/*
+ * No lock; only written during early bootup by CPU 0.
+ */
+static RAW_NOTIFIER_HEAD(proc_cpuinfo_chain);
+
+int __ref register_proc_cpuinfo_notifier(struct notifier_block *nb)
+{
+	return raw_notifier_chain_register(&proc_cpuinfo_chain, nb);
+}
+
+int proc_cpuinfo_notifier_call_chain(unsigned long val, void *v)
+{
+	return raw_notifier_call_chain(&proc_cpuinfo_chain, val, v);
+}
+
+static int show_cpuinfo(struct seq_file *m, void *v)
+{
+	unsigned long n = (unsigned long) v - 1;
+	unsigned int version = cpu_data[n].processor_id & 0xff;
+	unsigned int fp_version = cpu_data[n].fpu_vers;
+	struct proc_cpuinfo_notifier_args proc_cpuinfo_notifier_args;
+
+	/*
+	 * For the first processor also print the system type
+	 */
+	if (n == 0)
+		seq_printf(m, "system type\t\t: %s\n\n", get_system_type());
+
+	seq_printf(m, "processor\t\t: %ld\n", n);
+	seq_printf(m, "package\t\t\t: %d\n", cpu_data[n].package);
+	seq_printf(m, "core\t\t\t: %d\n", cpu_data[n].core);
+	seq_printf(m, "CPU Family\t\t: %s\n", __cpu_family[n]);
+	seq_printf(m, "Model Name\t\t: %s\n", __cpu_full_name[n]);
+	seq_printf(m, "CPU Revision\t\t: 0x%02x\n", version);
+	seq_printf(m, "FPU Revision\t\t: 0x%02x\n", fp_version);
+	seq_printf(m, "CPU MHz\t\t\t: %llu.%02llu\n",
+		      cpu_clock_freq / 1000000, (cpu_clock_freq / 10000) % 100);
+	seq_printf(m, "BogoMIPS\t\t: %llu.%02llu\n",
+		      (lpj_fine * cpu_clock_freq / const_clock_freq) / (500000/HZ),
+		      ((lpj_fine * cpu_clock_freq / const_clock_freq) / (5000/HZ)) % 100);
+	seq_printf(m, "TLB Entries\t\t: %d\n", cpu_data[n].tlbsize);
+	seq_printf(m, "Address Sizes\t\t: %d bits physical, %d bits virtual\n",
+		      cpu_pabits + 1, cpu_vabits + 1);
+
+	seq_printf(m, "ISA\t\t\t:");
+	if (cpu_has_loongarch32)
+		seq_printf(m, " loongarch32");
+	if (cpu_has_loongarch64)
+		seq_printf(m, " loongarch64");
+	seq_printf(m, "\n");
+
+	seq_printf(m, "Features\t\t:");
+	if (cpu_has_cpucfg)	seq_printf(m, " cpucfg");
+	if (cpu_has_lam)	seq_printf(m, " lam");
+	if (cpu_has_ual)	seq_printf(m, " ual");
+	if (cpu_has_fpu)	seq_printf(m, " fpu");
+	if (cpu_has_lsx)	seq_printf(m, " lsx");
+	if (cpu_has_lasx)	seq_printf(m, " lasx");
+	if (cpu_has_complex)	seq_printf(m, " complex");
+	if (cpu_has_crypto)	seq_printf(m, " crypto");
+	if (cpu_has_lvz)	seq_printf(m, " lvz");
+	if (cpu_has_lbt_x86)	seq_printf(m, " lbt_x86");
+	if (cpu_has_lbt_arm)	seq_printf(m, " lbt_arm");
+	if (cpu_has_lbt_mips)	seq_printf(m, " lbt_mips");
+	seq_printf(m, "\n");
+
+	seq_printf(m, "Hardware Watchpoint\t: %s",
+		      cpu_has_watch ? "yes, " : "no\n");
+	if (cpu_has_watch) {
+		seq_printf(m, "iwatch count: %d, dwatch count: %d\n",
+		      cpu_data[n].watch_ireg_count, cpu_data[n].watch_dreg_count);
+	}
+
+	proc_cpuinfo_notifier_args.m = m;
+	proc_cpuinfo_notifier_args.n = n;
+
+	raw_notifier_call_chain(&proc_cpuinfo_chain, 0,
+				&proc_cpuinfo_notifier_args);
+
+	seq_printf(m, "\n");
+
+	return 0;
+}
+
+static void *c_start(struct seq_file *m, loff_t *pos)
+{
+	unsigned long i = *pos;
+
+	return i < NR_CPUS ? (void *)(i + 1) : NULL;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	++*pos;
+	return c_start(m, pos);
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+}
+
+const struct seq_operations cpuinfo_op = {
+	.start	= c_start,
+	.next	= c_next,
+	.stop	= c_stop,
+	.show	= show_cpuinfo,
+};