Merge tag 'csky-for-linus-4.20' of https://github.com/c-sky/csky-linux

Pull C-SKY architecture port from Guo Ren:
 "This contains the Linux port for C-SKY(csky) based on linux-4.19
  Release, which has been through 10 rounds of review on mailing list.

  More information:

    http://en.c-sky.com

  The development repo:

    https://github.com/c-sky/csky-linux

  ABI Documentation:

    https://github.com/c-sky/csky-doc

  Here is the pre-built cross compiler for fast test from our CI:

    https://gitlab.com/c-sky/buildroot/-/jobs/101608095/artifacts/file/output/images/csky_toolchain_qemu_csky_ck807f_4.18_glibc_defconfig_482b221e52908be1c9b2ccb444255e1562bb7025.tar.xz

  We use buildroot as our CI-test enviornment. "LTP, Lmbench ..." will
  be tested for every commit. See here for more details:

    https://gitlab.com/c-sky/buildroot/pipelines

  We'll continouslly improve csky subsystem in future"

Arnd acks, and adds the following notes:
 "I did a thorough review of the ABI, which as usual mainly consists of
  spotting any files that don't use the asm-generic ABI itself, and
  having it changed to it matches exactly what we do on other new
  architectures.

  I also looked at every other patch and commented on maybe half of them
  where I saw something that did not quite seem right. Others have
  reviewed specific patches in greater depth. I'm sure that one could
  fine more of the minor details, but as long as they are not ABI
  relevant, they can be fixed later.

  The only patch that is part of the ABI and that nobody reviewed is the
  signal handling. This is one of the areas I never worked on in much
  detail. I did not see anything wrong with it, but I also don't know
  what the problems with the other architectures are here, and we seem
  to be hitting issues occasionally, and we never managed to generalize
  this enough for new architectures to have a trivial implementation.

  I was originally hoping that we could have the 64-bit time_t
  interfaces ready in time to completely drop the 32-bit ones, but that
  did not happen. We might still remove them in the next merge window
  depending on whether the libc upstream people prefer to keep them or
  not.

  One more general comment: I think this may well be the last new CPU
  architecture we ever add to the kernel. Both nds32 and c-sky are made
  by companies that also work on risc-v, and generally speaking risc-v
  seems to be killing off any of the minor licensable instruction set
  projects, just like ARM has mostly killed off the custom
  vendor-specific instruction sets already.

  If we add another architecture in the future, it may instead be
  something like the LLVM bitcode or WebAssembly, who knows?"

To which Geert Uytterhoeven pipes in about another architecture still in
the pipeline: Kalray MPPA.

* tag 'csky-for-linus-4.20' of https://github.com/c-sky/csky-linux: (24 commits)
  dt-bindings: interrupt-controller: C-SKY APB intc
  irqchip: add C-SKY APB bus interrupt controller
  dt-bindings: interrupt-controller: C-SKY SMP intc
  irqchip: add C-SKY SMP interrupt controller
  MAINTAINERS: Add csky
  dt-bindings: Add vendor prefix for csky
  dt-bindings: csky CPU Bindings
  csky: Misc headers
  csky: SMP support
  csky: Debug and Ptrace GDB
  csky: User access
  csky: Library functions
  csky: ELF and module probe
  csky: Atomic operations
  csky: IRQ handling
  csky: VDSO and rt_sigreturn
  csky: Process management and Signal
  csky: MMU and page table management
  csky: Cache and TLB routines
  csky: System Call
  ...

10 files changed, 457 insertions, 0 deletions

diff --git a/arch/csky/abiv1/inc/abi/cacheflush.h b/arch/csky/abiv1/inc/abi/cacheflush.h
new file mode 100644
index 000000000000..5f663aef9b1b
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/cacheflush.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ABI_CSKY_CACHEFLUSH_H
+#define __ABI_CSKY_CACHEFLUSH_H
+
+#include <linux/compiler.h>
+#include <asm/string.h>
+#include <asm/cache.h>
+
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
+extern void flush_dcache_page(struct page *);
+
+#define flush_cache_mm(mm)			cache_wbinv_all()
+#define flush_cache_page(vma, page, pfn)	cache_wbinv_all()
+#define flush_cache_dup_mm(mm)			cache_wbinv_all()
+
+/*
+ * if (current_mm != vma->mm) cache_wbinv_range(start, end) will be broken.
+ * Use cache_wbinv_all() here and need to be improved in future.
+ */
+#define flush_cache_range(vma, start, end)	cache_wbinv_all()
+#define flush_cache_vmap(start, end)		cache_wbinv_range(start, end)
+#define flush_cache_vunmap(start, end)		cache_wbinv_range(start, end)
+
+#define flush_icache_page(vma, page)		cache_wbinv_all()
+#define flush_icache_range(start, end)		cache_wbinv_range(start, end)
+
+#define flush_icache_user_range(vma, pg, adr, len) \
+				cache_wbinv_range(adr, adr + len)
+
+#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
+do { \
+	cache_wbinv_all(); \
+	memcpy(dst, src, len); \
+	cache_wbinv_all(); \
+} while (0)
+
+#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
+do { \
+	cache_wbinv_all(); \
+	memcpy(dst, src, len); \
+	cache_wbinv_all(); \
+} while (0)
+
+#define flush_dcache_mmap_lock(mapping)		do {} while (0)
+#define flush_dcache_mmap_unlock(mapping)	do {} while (0)
+
+#endif /* __ABI_CSKY_CACHEFLUSH_H */
diff --git a/arch/csky/abiv1/inc/abi/ckmmu.h b/arch/csky/abiv1/inc/abi/ckmmu.h
new file mode 100644
index 000000000000..3a002017bebe
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/ckmmu.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_CKMMUV1_H
+#define __ASM_CSKY_CKMMUV1_H
+#include <abi/reg_ops.h>
+
+static inline int read_mmu_index(void)
+{
+	return cprcr("cpcr0");
+}
+
+static inline void write_mmu_index(int value)
+{
+	cpwcr("cpcr0", value);
+}
+
+static inline int read_mmu_entrylo0(void)
+{
+	return cprcr("cpcr2") << 6;
+}
+
+static inline int read_mmu_entrylo1(void)
+{
+	return cprcr("cpcr3") << 6;
+}
+
+static inline void write_mmu_pagemask(int value)
+{
+	cpwcr("cpcr6", value);
+}
+
+static inline int read_mmu_entryhi(void)
+{
+	return cprcr("cpcr4");
+}
+
+static inline void write_mmu_entryhi(int value)
+{
+	cpwcr("cpcr4", value);
+}
+
+/*
+ * TLB operations.
+ */
+static inline void tlb_probe(void)
+{
+	cpwcr("cpcr8", 0x80000000);
+}
+
+static inline void tlb_read(void)
+{
+	cpwcr("cpcr8", 0x40000000);
+}
+
+static inline void tlb_invalid_all(void)
+{
+	cpwcr("cpcr8", 0x04000000);
+}
+
+static inline void tlb_invalid_indexed(void)
+{
+	cpwcr("cpcr8", 0x02000000);
+}
+
+static inline void setup_pgd(unsigned long pgd, bool kernel)
+{
+	cpwcr("cpcr29", pgd);
+}
+
+static inline unsigned long get_pgd(void)
+{
+	return cprcr("cpcr29");
+}
+#endif /* __ASM_CSKY_CKMMUV1_H */
diff --git a/arch/csky/abiv1/inc/abi/elf.h b/arch/csky/abiv1/inc/abi/elf.h
new file mode 100644
index 000000000000..3058cc06b104
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/elf.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ABI_CSKY_ELF_H
+#define __ABI_CSKY_ELF_H
+
+#define ELF_CORE_COPY_REGS(pr_reg, regs) do {	\
+	pr_reg[0] = regs->pc;			\
+	pr_reg[1] = regs->regs[9];		\
+	pr_reg[2] = regs->usp;			\
+	pr_reg[3] = regs->sr;			\
+	pr_reg[4] = regs->a0;			\
+	pr_reg[5] = regs->a1;			\
+	pr_reg[6] = regs->a2;			\
+	pr_reg[7] = regs->a3;			\
+	pr_reg[8] = regs->regs[0];		\
+	pr_reg[9] = regs->regs[1];		\
+	pr_reg[10] = regs->regs[2];		\
+	pr_reg[11] = regs->regs[3];		\
+	pr_reg[12] = regs->regs[4];		\
+	pr_reg[13] = regs->regs[5];		\
+	pr_reg[14] = regs->regs[6];		\
+	pr_reg[15] = regs->regs[7];		\
+	pr_reg[16] = regs->regs[8];		\
+	pr_reg[17] = regs->lr;			\
+} while (0);
+#endif /* __ABI_CSKY_ELF_H */
diff --git a/arch/csky/abiv1/inc/abi/entry.h b/arch/csky/abiv1/inc/abi/entry.h
new file mode 100644
index 000000000000..3f3faab3d747
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/entry.h
@@ -0,0 +1,160 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_ENTRY_H
+#define __ASM_CSKY_ENTRY_H
+
+#include <asm/setup.h>
+#include <abi/regdef.h>
+
+#define LSAVE_PC	8
+#define LSAVE_PSR	12
+#define LSAVE_A0	24
+#define LSAVE_A1	28
+#define LSAVE_A2	32
+#define LSAVE_A3	36
+#define LSAVE_A4	40
+#define LSAVE_A5	44
+
+#define EPC_INCREASE	2
+#define EPC_KEEP	0
+
+.macro USPTOKSP
+	mtcr	sp, ss1
+	mfcr	sp, ss0
+.endm
+
+.macro KSPTOUSP
+	mtcr	sp, ss0
+	mfcr	sp, ss1
+.endm
+
+.macro INCTRAP	rx
+	addi	\rx, EPC_INCREASE
+.endm
+
+.macro	SAVE_ALL epc_inc
+	mtcr    r13, ss2
+	mfcr    r13, epsr
+	btsti   r13, 31
+	bt      1f
+	USPTOKSP
+1:
+	subi    sp, 32
+	subi    sp, 32
+	subi    sp, 16
+	stw     r13, (sp, 12)
+
+	stw     lr, (sp, 4)
+
+	mfcr	lr, epc
+	movi	r13, \epc_inc
+	add	lr, r13
+	stw     lr, (sp, 8)
+
+	mfcr	lr, ss1
+	stw     lr, (sp, 16)
+
+	stw     a0, (sp, 20)
+	stw     a0, (sp, 24)
+	stw     a1, (sp, 28)
+	stw     a2, (sp, 32)
+	stw     a3, (sp, 36)
+
+	addi	sp, 32
+	addi	sp, 8
+	mfcr    r13, ss2
+	stw	r6, (sp)
+	stw	r7, (sp, 4)
+	stw	r8, (sp, 8)
+	stw	r9, (sp, 12)
+	stw	r10, (sp, 16)
+	stw	r11, (sp, 20)
+	stw	r12, (sp, 24)
+	stw	r13, (sp, 28)
+	stw	r14, (sp, 32)
+	stw	r1, (sp, 36)
+	subi	sp, 32
+	subi	sp, 8
+.endm
+
+.macro	RESTORE_ALL
+	psrclr  ie
+	ldw	lr, (sp, 4)
+	ldw     a0, (sp, 8)
+	mtcr    a0, epc
+	ldw     a0, (sp, 12)
+	mtcr    a0, epsr
+	btsti   a0, 31
+	ldw     a0, (sp, 16)
+	mtcr	a0, ss1
+
+	ldw     a0, (sp, 24)
+	ldw     a1, (sp, 28)
+	ldw     a2, (sp, 32)
+	ldw     a3, (sp, 36)
+
+	addi	sp, 32
+	addi	sp, 8
+	ldw	r6, (sp)
+	ldw	r7, (sp, 4)
+	ldw	r8, (sp, 8)
+	ldw	r9, (sp, 12)
+	ldw	r10, (sp, 16)
+	ldw	r11, (sp, 20)
+	ldw	r12, (sp, 24)
+	ldw	r13, (sp, 28)
+	ldw	r14, (sp, 32)
+	ldw	r1, (sp, 36)
+	addi	sp, 32
+	addi	sp, 8
+
+	bt      1f
+	KSPTOUSP
+1:
+	rte
+.endm
+
+.macro SAVE_SWITCH_STACK
+	subi    sp, 32
+	stm     r8-r15, (sp)
+.endm
+
+.macro RESTORE_SWITCH_STACK
+	ldm     r8-r15, (sp)
+	addi    sp, 32
+.endm
+
+/* MMU registers operators. */
+.macro RD_MIR	rx
+	cprcr   \rx, cpcr0
+.endm
+
+.macro RD_MEH	rx
+	cprcr   \rx, cpcr4
+.endm
+
+.macro RD_MCIR	rx
+	cprcr   \rx, cpcr8
+.endm
+
+.macro RD_PGDR  rx
+	cprcr   \rx, cpcr29
+.endm
+
+.macro WR_MEH	rx
+	cpwcr   \rx, cpcr4
+.endm
+
+.macro WR_MCIR	rx
+	cpwcr   \rx, cpcr8
+.endm
+
+.macro SETUP_MMU rx
+	lrw	\rx, PHYS_OFFSET | 0xe
+	cpwcr	\rx, cpcr30
+	lrw	\rx, (PHYS_OFFSET + 0x20000000) | 0xe
+	cpwcr	\rx, cpcr31
+.endm
+
+#endif /* __ASM_CSKY_ENTRY_H */
diff --git a/arch/csky/abiv1/inc/abi/page.h b/arch/csky/abiv1/inc/abi/page.h
new file mode 100644
index 000000000000..6336e92a103a
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/page.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+extern unsigned long shm_align_mask;
+extern void flush_dcache_page(struct page *page);
+
+static inline unsigned long pages_do_alias(unsigned long addr1,
+					   unsigned long addr2)
+{
+	return (addr1 ^ addr2) & shm_align_mask;
+}
+
+static inline void clear_user_page(void *addr, unsigned long vaddr,
+				   struct page *page)
+{
+	clear_page(addr);
+	if (pages_do_alias((unsigned long) addr, vaddr & PAGE_MASK))
+		flush_dcache_page(page);
+}
+
+static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
+				  struct page *page)
+{
+	copy_page(to, from);
+	if (pages_do_alias((unsigned long) to, vaddr & PAGE_MASK))
+		flush_dcache_page(page);
+}
diff --git a/arch/csky/abiv1/inc/abi/pgtable-bits.h b/arch/csky/abiv1/inc/abi/pgtable-bits.h
new file mode 100644
index 000000000000..455075b5db0d
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/pgtable-bits.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_PGTABLE_BITS_H
+#define __ASM_CSKY_PGTABLE_BITS_H
+
+/* implemented in software */
+#define _PAGE_ACCESSED		(1<<3)
+#define PAGE_ACCESSED_BIT	(3)
+
+#define _PAGE_READ		(1<<1)
+#define _PAGE_WRITE		(1<<2)
+#define _PAGE_PRESENT		(1<<0)
+
+#define _PAGE_MODIFIED		(1<<4)
+#define PAGE_MODIFIED_BIT	(4)
+
+/* implemented in hardware */
+#define _PAGE_GLOBAL		(1<<6)
+
+#define _PAGE_VALID		(1<<7)
+#define PAGE_VALID_BIT		(7)
+
+#define _PAGE_DIRTY		(1<<8)
+#define PAGE_DIRTY_BIT		(8)
+
+#define _PAGE_CACHE		(3<<9)
+#define _PAGE_UNCACHE		(2<<9)
+
+#define _CACHE_MASK		(7<<9)
+
+#define _CACHE_CACHED		(_PAGE_VALID | _PAGE_CACHE)
+#define _CACHE_UNCACHED		(_PAGE_VALID | _PAGE_UNCACHE)
+
+#define HAVE_ARCH_UNMAPPED_AREA
+
+#endif /* __ASM_CSKY_PGTABLE_BITS_H */
diff --git a/arch/csky/abiv1/inc/abi/reg_ops.h b/arch/csky/abiv1/inc/abi/reg_ops.h
new file mode 100644
index 000000000000..a153bd3918f7
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/reg_ops.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ABI_REG_OPS_H
+#define __ABI_REG_OPS_H
+#include <asm/reg_ops.h>
+
+#define cprcr(reg)					\
+({							\
+	unsigned int tmp;				\
+	asm volatile("cprcr %0, "reg"\n":"=b"(tmp));	\
+	tmp;						\
+})
+
+#define cpwcr(reg, val)					\
+({							\
+	asm volatile("cpwcr %0, "reg"\n"::"b"(val));	\
+})
+
+static inline unsigned int mfcr_hint(void)
+{
+	return mfcr("cr30");
+}
+
+static inline unsigned int mfcr_ccr2(void) { return 0; }
+
+#endif /* __ABI_REG_OPS_H */
diff --git a/arch/csky/abiv1/inc/abi/regdef.h b/arch/csky/abiv1/inc/abi/regdef.h
new file mode 100644
index 000000000000..876689291b71
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/regdef.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ASM_CSKY_REGDEF_H
+#define __ASM_CSKY_REGDEF_H
+
+#define syscallid	r1
+#define r11_sig		r11
+
+#define regs_syscallid(regs) regs->regs[9]
+
+/*
+ * PSR format:
+ * | 31 | 30-24 | 23-16 | 15 14 | 13-0 |
+ *   S     CPID     VEC     TM
+ *
+ *    S: Super Mode
+ * CPID: Coprocessor id, only 15 for MMU
+ *  VEC: Exception Number
+ *   TM: Trace Mode
+ */
+#define DEFAULT_PSR_VALUE	0x8f000000
+
+#define SYSTRACE_SAVENUM	2
+
+#endif /* __ASM_CSKY_REGDEF_H */
diff --git a/arch/csky/abiv1/inc/abi/string.h b/arch/csky/abiv1/inc/abi/string.h
new file mode 100644
index 000000000000..5abe80be044d
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/string.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#ifndef __ABI_CSKY_STRING_H
+#define __ABI_CSKY_STRING_H
+
+#define __HAVE_ARCH_MEMCPY
+extern void *memcpy(void *, const void *, __kernel_size_t);
+
+#define __HAVE_ARCH_MEMSET
+extern void *memset(void *, int, __kernel_size_t);
+
+#endif /* __ABI_CSKY_STRING_H */
diff --git a/arch/csky/abiv1/inc/abi/vdso.h b/arch/csky/abiv1/inc/abi/vdso.h
new file mode 100644
index 000000000000..14352f524f1d
--- /dev/null
+++ b/arch/csky/abiv1/inc/abi/vdso.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/uaccess.h>
+
+static inline int setup_vdso_page(unsigned short *ptr)
+{
+	int err = 0;
+
+	/* movi r1, 127 */
+	err |= __put_user(0x67f1, ptr + 0);
+	/* addi r1, (139 - 127) */
+	err |= __put_user(0x20b1, ptr + 1);
+	/* trap 0 */
+	err |= __put_user(0x0008, ptr + 2);
+
+	return err;
+}