Merge tag 'xtensa-20210429' of git://github.com/jcmvbkbc/linux-xtensa

Pull Xtensa updates from Max Filippov:

 - switch to generic syscall generation scripts

 - new GDBIO implementation for xtensa semihosting interface

 - various small code fixes and cleanups

 - a few typo fixes in comments and Kconfig help text

* tag 'xtensa-20210429' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: ISS: add GDBIO implementation to semihosting interface
  xtensa: ISS: split simcall implementation from semihosting interface
  xtensa: simcall.h: Change compitible to compatible
  xtensa: Couple of typo fixes
  xtensa: drop extraneous register load from initialize_mmu
  xtensa: fix pgprot_noncached assumptions
  xtensa: simplify coherent_kvaddr logic
  xtensa: syscalls: switch to generic syscallhdr.sh
  xtensa: syscalls: switch to generic syscalltbl.sh
  xtensa: stop filling syscall array with sys_ni_syscall
  xtensa: remove unneeded export in boot-elf/Makefile
  xtensa: move CONFIG_CPU_*_ENDIAN defines to Kconfig
  xtensa: fix warning comparing pointer to 0
  xtensa: fix spelling mistake in Kconfig "wont" -> "won't"

18 files changed, 198 insertions, 220 deletions

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 9ad6b7b82707..6ad4c1161518 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -84,6 +84,12 @@ config KASAN_SHADOW_OFFSET
 	hex
 	default 0x6e400000
 
+config CPU_BIG_ENDIAN
+	def_bool $(success,test "$(shell,echo __XTENSA_EB__ | $(CC) -E -P -)" = 1)
+
+config CPU_LITTLE_ENDIAN
+	def_bool !CPU_BIG_ENDIAN
+
 menu "Processor type and features"
 
 choice
@@ -387,6 +393,28 @@ config PARSE_BOOTPARAM
 
 	  If unsure, say Y.
 
+choice
+	prompt "Semihosting interface"
+	default XTENSA_SIMCALL_ISS
+	depends on XTENSA_PLATFORM_ISS
+	help
+	  Choose semihosting interface that will be used for serial port,
+	  block device and networking.
+
+config XTENSA_SIMCALL_ISS
+	bool "simcall"
+	help
+	  Use simcall instruction. simcall is only available on simulators,
+	  it does nothing on hardware.
+
+config XTENSA_SIMCALL_GDBIO
+	bool "GDBIO"
+	help
+	  Use break instruction. It is available on real hardware when GDB
+	  is attached to it via JTAG.
+
+endchoice
+
 config BLK_DEV_SIMDISK
 	tristate "Host file-based simulated block device support"
 	default n
@@ -466,7 +494,7 @@ config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
 	  then enter your normal kernel breakpoints once the MMU was mapped
 	  to the kernel mappings (0XC0000000).
 
-	  This unfortunately won't work for U-Boot and likely also wont
+	  This unfortunately won't work for U-Boot and likely also won't
 	  work for using KEXEC to have a hot kernel ready for doing a
 	  KDUMP.
 
diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
index cf0940708702..ba9fee75e675 100644
--- a/arch/xtensa/Makefile
+++ b/arch/xtensa/Makefile
@@ -52,14 +52,7 @@ ifneq ($(CONFIG_LD_NO_RELAX),)
 KBUILD_LDFLAGS := --no-relax
 endif
 
-ifeq ($(shell echo __XTENSA_EB__ | $(CC) -E - | grep -v "\#"),1)
-CHECKFLAGS += -D__XTENSA_EB__
-KBUILD_CPPFLAGS += -DCONFIG_CPU_BIG_ENDIAN
-endif
-ifeq ($(shell echo __XTENSA_EL__ | $(CC) -E - | grep -v "\#"),1)
-CHECKFLAGS += -D__XTENSA_EL__
-KBUILD_CPPFLAGS += -DCONFIG_CPU_LITTLE_ENDIAN
-endif
+CHECKFLAGS += -D$(if $(CONFIG_CPU_BIG_ENDIAN),__XTENSA_EB__,__XTENSA_EL__)
 
 vardirs := $(patsubst %,arch/xtensa/variants/%/,$(variant-y))
 plfdirs := $(patsubst %,arch/xtensa/platforms/%/,$(platform-y))
diff --git a/arch/xtensa/boot/Makefile b/arch/xtensa/boot/Makefile
index f6bb352f94b4..a65b7a9ebff2 100644
--- a/arch/xtensa/boot/Makefile
+++ b/arch/xtensa/boot/Makefile
@@ -12,10 +12,6 @@
 KBUILD_CFLAGS	+= -fno-builtin -Iarch/$(ARCH)/boot/include
 HOSTFLAGS	+= -Iarch/$(ARCH)/boot/include
 
-BIG_ENDIAN	:= $(shell echo __XTENSA_EB__ | $(CC) -E - | grep -v "\#")
-
-export BIG_ENDIAN
-
 subdir-y	:= lib
 targets		+= vmlinux.bin vmlinux.bin.gz
 targets		+= uImage xipImage
diff --git a/arch/xtensa/boot/boot-elf/Makefile b/arch/xtensa/boot/boot-elf/Makefile
index f7c775d53012..faec2002923b 100644
--- a/arch/xtensa/boot/boot-elf/Makefile
+++ b/arch/xtensa/boot/boot-elf/Makefile
@@ -4,15 +4,10 @@
 # for more details.
 #
 
-ifeq ($(BIG_ENDIAN),1)
-OBJCOPY_ARGS    := -O elf32-xtensa-be
-else
-OBJCOPY_ARGS    := -O elf32-xtensa-le
-endif
+OBJCOPY_ARGS := -O $(if $(CONFIG_CPU_BIG_ENDIAN),elf32-xtensa-be,elf32-xtensa-le)
 
-export OBJCOPY_ARGS
-export CPPFLAGS_boot.lds += -P -C
-export KBUILD_AFLAGS += -mtext-section-literals
+CPPFLAGS_boot.lds += -P -C
+KBUILD_AFLAGS += -mtext-section-literals
 
 boot-y		:= bootstrap.o
 targets		+= $(boot-y) boot.lds
diff --git a/arch/xtensa/boot/boot-redboot/Makefile b/arch/xtensa/boot/boot-redboot/Makefile
index 07cb24afedc2..1d1d46215b1c 100644
--- a/arch/xtensa/boot/boot-redboot/Makefile
+++ b/arch/xtensa/boot/boot-redboot/Makefile
@@ -4,11 +4,7 @@
 # for more details.
 #
 
-ifeq ($(BIG_ENDIAN),1)
-OBJCOPY_ARGS 	:= -O elf32-xtensa-be
-else
-OBJCOPY_ARGS 	:= -O elf32-xtensa-le
-endif
+OBJCOPY_ARGS := -O $(if $(CONFIG_CPU_BIG_ENDIAN),elf32-xtensa-be,elf32-xtensa-le)
 
 LD_ARGS	= -T $(srctree)/$(obj)/boot.ld
 
diff --git a/arch/xtensa/include/asm/initialize_mmu.h b/arch/xtensa/include/asm/initialize_mmu.h
index 05cb13dfe6f4..9793b49fc641 100644
--- a/arch/xtensa/include/asm/initialize_mmu.h
+++ b/arch/xtensa/include/asm/initialize_mmu.h
@@ -73,7 +73,7 @@
 	_j	2f
 
 	.align	4
-1:	movi	a2, 0x10000000
+1:
 
 #if CONFIG_KERNEL_LOAD_ADDRESS < 0x40000000ul
 #define TEMP_MAPPING_VADDR 0x40000000
diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 4dc04e6c01d7..d7fc45c920c2 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -280,7 +280,9 @@ static inline pte_t pte_mkyoung(pte_t pte)
 static inline pte_t pte_mkwrite(pte_t pte)
 	{ pte_val(pte) |= _PAGE_WRITABLE; return pte; }
 
-#define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CA_MASK))
+#define pgprot_noncached(prot) \
+		((__pgprot((pgprot_val(prot) & ~_PAGE_CA_MASK) | \
+			   _PAGE_CA_BYPASS)))
 
 /*
  * Conversion functions: convert a page and protection to a page entry,
diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S
index e0c1fac0910f..b9b81e76beea 100644
--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S
@@ -212,7 +212,7 @@ ENTRY(_startup)
 	 *
 	 * The linker script used to build the Linux kernel image
 	 * creates a table located at __boot_reloc_table_start
-	 * that contans the information what data needs to be unpacked.
+	 * that contains the information what data needs to be unpacked.
 	 *
 	 * Uses a2-a7.
 	 */
@@ -222,7 +222,7 @@ ENTRY(_startup)
 
 1:	beq	a2, a3, 3f	# no more entries?
 	l32i	a4, a2, 0	# start destination (in RAM)
-	l32i	a5, a2, 4	# end desination (in RAM)
+	l32i	a5, a2, 4	# end destination (in RAM)
 	l32i	a6, a2, 8	# start source (in ROM)
 	addi	a2, a2, 12	# next entry
 	beq	a4, a5, 1b	# skip, empty entry
diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c
index 3f32e275997a..62c900e400d6 100644
--- a/arch/xtensa/kernel/pci.c
+++ b/arch/xtensa/kernel/pci.c
@@ -76,7 +76,7 @@ int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma)
 	struct pci_controller *pci_ctrl = (struct pci_controller*) pdev->sysdata;
 	resource_size_t ioaddr = pci_resource_start(pdev, bar);
 
-	if (pci_ctrl == 0)
+	if (!pci_ctrl)
 		return -EINVAL;		/* should never happen */
 
 	/* Convert to an offset within this PCI controller */
diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index 2c415fce6801..201356faa7e6 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -17,7 +17,6 @@
  */
 #include <linux/uaccess.h>
 #include <asm/syscall.h>
-#include <asm/unistd.h>
 #include <linux/linkage.h>
 #include <linux/stringify.h>
 #include <linux/errno.h>
@@ -28,12 +27,9 @@
 #include <linux/sched/mm.h>
 #include <linux/shm.h>
 
-syscall_t sys_call_table[__NR_syscalls] /* FIXME __cacheline_aligned */= {
-	[0 ... __NR_syscalls - 1] = (syscall_t)&sys_ni_syscall,
-
-#define __SYSCALL(nr, entry, nargs)[nr] = (syscall_t)entry,
+syscall_t sys_call_table[] /* FIXME __cacheline_aligned */= {
+#define __SYSCALL(nr, entry)	(syscall_t)entry,
 #include <asm/syscall_table.h>
-#undef __SYSCALL
 };
 
 #define COLOUR_ALIGN(addr, pgoff) \
diff --git a/arch/xtensa/kernel/syscalls/Makefile b/arch/xtensa/kernel/syscalls/Makefile
index 285aaba832d9..6713c65a25e1 100644
--- a/arch/xtensa/kernel/syscalls/Makefile
+++ b/arch/xtensa/kernel/syscalls/Makefile
@@ -6,20 +6,14 @@ _dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
 	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
 
 syscall := $(src)/syscall.tbl
-syshdr := $(srctree)/$(src)/syscallhdr.sh
-systbl := $(srctree)/$(src)/syscalltbl.sh
+syshdr := $(srctree)/scripts/syscallhdr.sh
+systbl := $(srctree)/scripts/syscalltbl.sh
 
 quiet_cmd_syshdr = SYSHDR  $@
-      cmd_syshdr = $(CONFIG_SHELL) '$(syshdr)' '$<' '$@'	\
-		   '$(syshdr_abis_$(basetarget))'		\
-		   '$(syshdr_pfx_$(basetarget))'		\
-		   '$(syshdr_offset_$(basetarget))'
+      cmd_syshdr = $(CONFIG_SHELL) $(syshdr) --emit-nr $< $@
 
 quiet_cmd_systbl = SYSTBL  $@
-      cmd_systbl = $(CONFIG_SHELL) '$(systbl)' '$<' '$@'	\
-		   '$(systbl_abis_$(basetarget))'		\
-		   '$(systbl_abi_$(basetarget))'		\
-		   '$(systbl_offset_$(basetarget))'
+      cmd_systbl = $(CONFIG_SHELL) $(systbl) $< $@
 
 $(uapi)/unistd_32.h: $(syscall) $(syshdr) FORCE
 	$(call if_changed,syshdr)
diff --git a/arch/xtensa/kernel/syscalls/syscallhdr.sh b/arch/xtensa/kernel/syscalls/syscallhdr.sh
deleted file mode 100644
index eebfb8a8ace6..000000000000
--- a/arch/xtensa/kernel/syscalls/syscallhdr.sh
+++ /dev/null
@@ -1,36 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-
-in="$1"
-out="$2"
-my_abis=`echo "($3)" | tr ',' '|'`
-prefix="$4"
-offset="$5"
-
-fileguard=_UAPI_ASM_XTENSA_`basename "$out" | sed \
-	-e 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' \
-	-e 's/[^A-Z0-9_]/_/g' -e 's/__/_/g'`
-grep -E "^[0-9A-Fa-fXx]+[[:space:]]+${my_abis}" "$in" | sort -n | (
-	printf "#ifndef %s\n" "${fileguard}"
-	printf "#define %s\n" "${fileguard}"
-	printf "\n"
-
-	nxt=0
-	while read nr abi name entry ; do
-		if [ -z "$offset" ]; then
-			printf "#define __NR_%s%s\t%s\n" \
-				"${prefix}" "${name}" "${nr}"
-		else
-			printf "#define __NR_%s%s\t(%s + %s)\n" \
-				"${prefix}" "${name}" "${offset}" "${nr}"
-		fi
-		nxt=$((nr+1))
-	done
-
-	printf "\n"
-	printf "#ifdef __KERNEL__\n"
-	printf "#define __NR_syscalls\t%s\n" "${nxt}"
-	printf "#endif\n"
-	printf "\n"
-	printf "#endif /* %s */\n" "${fileguard}"
-) > "$out"
diff --git a/arch/xtensa/kernel/syscalls/syscalltbl.sh b/arch/xtensa/kernel/syscalls/syscalltbl.sh
deleted file mode 100644
index 85d78d9309ad..000000000000
--- a/arch/xtensa/kernel/syscalls/syscalltbl.sh
+++ /dev/null
@@ -1,32 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-
-in="$1"
-out="$2"
-my_abis=`echo "($3)" | tr ',' '|'`
-my_abi="$4"
-offset="$5"
-
-emit() {
-	t_nxt="$1"
-	t_nr="$2"
-	t_entry="$3"
-
-	while [ $t_nxt -lt $t_nr ]; do
-		printf "__SYSCALL(%s, sys_ni_syscall, )\n" "${t_nxt}"
-		t_nxt=$((t_nxt+1))
-	done
-	printf "__SYSCALL(%s, %s, )\n" "${t_nxt}" "${t_entry}"
-}
-
-grep -E "^[0-9A-Fa-fXx]+[[:space:]]+${my_abis}" "$in" | sort -n | (
-	nxt=0
-	if [ -z "$offset" ]; then
-		offset=0
-	fi
-
-	while read nr abi name entry ; do
-		emit $((nxt+offset)) $((nr+offset)) $entry
-		nxt=$((nr+1))
-	done
-) > "$out"
diff --git a/arch/xtensa/mm/cache.c b/arch/xtensa/mm/cache.c
index 085b8c77b9d9..19e5a478a7e8 100644
--- a/arch/xtensa/mm/cache.c
+++ b/arch/xtensa/mm/cache.c
@@ -81,13 +81,8 @@ static inline void kmap_invalidate_coherent(struct page *page,
 static inline void *coherent_kvaddr(struct page *page, unsigned long base,
 				    unsigned long vaddr, unsigned long *paddr)
 {
-	if (PageHighMem(page) || !DCACHE_ALIAS_EQ(page_to_phys(page), vaddr)) {
-		*paddr = page_to_phys(page);
-		return (void *)(base + (vaddr & DCACHE_ALIAS_MASK));
-	} else {
-		*paddr = 0;
-		return page_to_virt(page);
-	}
+	*paddr = page_to_phys(page);
+	return (void *)(base + (vaddr & DCACHE_ALIAS_MASK));
 }
 
 void clear_user_highpage(struct page *page, unsigned long vaddr)
diff --git a/arch/xtensa/mm/misc.S b/arch/xtensa/mm/misc.S
index 25cd67debee6..0527bf6e3211 100644
--- a/arch/xtensa/mm/misc.S
+++ b/arch/xtensa/mm/misc.S
@@ -118,20 +118,13 @@ ENTRY(clear_page_alias)
 
 	abi_entry_default
 
-	/* Skip setting up a temporary DTLB if not aliased low page. */
-
 	movi	a5, PAGE_OFFSET
-	movi	a6, 0
-	beqz	a3, 1f
-
-	/* Setup a temporary DTLB for the addr. */
-
 	addi	a6, a3, (PAGE_KERNEL | _PAGE_HW_WRITE)
 	mov	a4, a2
 	wdtlb	a6, a2
 	dsync
 
-1:	movi	a3, 0
+	movi	a3, 0
 	__loopi	a2, a7, PAGE_SIZE, 32
 	s32i	a3, a2, 0
 	s32i	a3, a2, 4
@@ -143,12 +136,9 @@ ENTRY(clear_page_alias)
 	s32i	a3, a2, 28
 	__endla	a2, a7, 32
 
-	bnez	a6, 1f
-	abi_ret_default
-
-	/* We need to invalidate the temporary idtlb entry, if any. */
+	/* We need to invalidate the temporary dtlb entry. */
 
-1:	idtlb	a4
+	idtlb	a4
 	dsync
 
 	abi_ret_default
@@ -166,22 +156,12 @@ ENTRY(copy_page_alias)
 
 	abi_entry_default
 
-	/* Skip setting up a temporary DTLB for destination if not aliased. */
-
-	movi	a6, 0
-	movi	a7, 0
-	beqz	a4, 1f
-
 	/* Setup a temporary DTLB for destination. */
 
 	addi	a6, a4, (PAGE_KERNEL | _PAGE_HW_WRITE)
 	wdtlb	a6, a2
 	dsync
 
-	/* Skip setting up a temporary DTLB for source if not aliased. */
-
-1:	beqz	a5, 1f
-
 	/* Setup a temporary DTLB for source. */
 
 	addi	a7, a5, PAGE_KERNEL
@@ -219,17 +199,11 @@ ENTRY(copy_page_alias)
 
 	/* We need to invalidate any temporary mapping! */
 
-	bnez	a6, 1f
-	bnez	a7, 2f
-	abi_ret_default
-
-1:	addi	a2, a2, -PAGE_SIZE
+	addi	a2, a2, -PAGE_SIZE
 	idtlb	a2
 	dsync
-	bnez	a7, 2f
-	abi_ret_default
 
-2:	addi	a3, a3, -PAGE_SIZE+1
+	addi	a3, a3, -PAGE_SIZE+1
 	idtlb	a3
 	dsync
 
diff --git a/arch/xtensa/platforms/iss/include/platform/simcall-gdbio.h b/arch/xtensa/platforms/iss/include/platform/simcall-gdbio.h
new file mode 100644
index 000000000000..e642860e25a8
--- /dev/null
+++ b/arch/xtensa/platforms/iss/include/platform/simcall-gdbio.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2021 Cadence Design Systems Inc. */
+
+#ifndef _XTENSA_PLATFORM_ISS_SIMCALL_GDBIO_H
+#define _XTENSA_PLATFORM_ISS_SIMCALL_GDBIO_H
+
+/*
+ *  System call like services offered by the GDBIO host.
+ */
+
+#define SYS_open	-2
+#define SYS_close	-3
+#define SYS_read	-4
+#define SYS_write	-5
+#define SYS_lseek	-6
+
+static int errno;
+
+static inline int __simc(int a, int b, int c, int d)
+{
+	register int a1 asm("a2") = a;
+	register int b1 asm("a6") = b;
+	register int c1 asm("a3") = c;
+	register int d1 asm("a4") = d;
+	__asm__ __volatile__ (
+			"break 1, 14\n"
+			: "+r"(a1), "+r"(c1)
+			: "r"(b1), "r"(d1)
+			: "memory");
+	errno = c1;
+	return a1;
+}
+
+#endif /* _XTENSA_PLATFORM_ISS_SIMCALL_GDBIO_H */
diff --git a/arch/xtensa/platforms/iss/include/platform/simcall-iss.h b/arch/xtensa/platforms/iss/include/platform/simcall-iss.h
new file mode 100644
index 000000000000..5a1e7a1f182e
--- /dev/null
+++ b/arch/xtensa/platforms/iss/include/platform/simcall-iss.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2021 Cadence Design Systems Inc. */
+
+#ifndef _XTENSA_PLATFORM_ISS_SIMCALL_ISS_H
+#define _XTENSA_PLATFORM_ISS_SIMCALL_ISS_H
+
+/*
+ *  System call like services offered by the simulator host.
+ */
+
+#define SYS_nop		0	/* unused */
+#define SYS_exit	1	/*x*/
+#define SYS_fork	2
+#define SYS_read	3	/*x*/
+#define SYS_write	4	/*x*/
+#define SYS_open	5	/*x*/
+#define SYS_close	6	/*x*/
+#define SYS_rename	7	/*x 38 - waitpid */
+#define SYS_creat	8	/*x*/
+#define SYS_link	9	/*x (not implemented on WIN32) */
+#define SYS_unlink	10	/*x*/
+#define SYS_execv	11	/* n/a - execve */
+#define SYS_execve	12	/* 11 - chdir */
+#define SYS_pipe	13	/* 42 - time */
+#define SYS_stat	14	/* 106 - mknod */
+#define SYS_chmod	15
+#define SYS_chown	16	/* 202 - lchown */
+#define SYS_utime	17	/* 30 - break */
+#define SYS_wait	18	/* n/a - oldstat */
+#define SYS_lseek	19	/*x*/
+#define SYS_getpid	20
+#define SYS_isatty	21	/* n/a - mount */
+#define SYS_fstat	22	/* 108 - oldumount */
+#define SYS_time	23	/* 13 - setuid */
+#define SYS_gettimeofday 24	/*x 78 - getuid (not implemented on WIN32) */
+#define SYS_times	25	/*X 43 - stime (Xtensa-specific implementation) */
+#define SYS_socket      26
+#define SYS_sendto      27
+#define SYS_recvfrom    28
+#define SYS_select_one  29      /* not compatible select, one file descriptor at the time */
+#define SYS_bind        30
+#define SYS_ioctl	31
+
+#define SYS_iss_argc	1000	/* returns value of argc */
+#define SYS_iss_argv_size 1001	/* bytes needed for argv & arg strings */
+#define SYS_iss_set_argv 1002	/* saves argv & arg strings at given addr */
+
+/*
+ * SYS_select_one specifiers
+ */
+
+#define  XTISS_SELECT_ONE_READ    1
+#define  XTISS_SELECT_ONE_WRITE   2
+#define  XTISS_SELECT_ONE_EXCEPT  3
+
+static int errno;
+
+static inline int __simc(int a, int b, int c, int d)
+{
+	register int a1 asm("a2") = a;
+	register int b1 asm("a3") = b;
+	register int c1 asm("a4") = c;
+	register int d1 asm("a5") = d;
+	__asm__ __volatile__ (
+			"simcall\n"
+			: "+r"(a1), "+r"(b1)
+			: "r"(c1), "r"(d1)
+			: "memory");
+	errno = b1;
+	return a1;
+}
+
+#endif /* _XTENSA_PLATFORM_ISS_SIMCALL_ISS_H */
diff --git a/arch/xtensa/platforms/iss/include/platform/simcall.h b/arch/xtensa/platforms/iss/include/platform/simcall.h
index f42870ab551b..e1ec50ce39ee 100644
--- a/arch/xtensa/platforms/iss/include/platform/simcall.h
+++ b/arch/xtensa/platforms/iss/include/platform/simcall.h
@@ -6,82 +6,29 @@
  * for more details.
  *
  * Copyright (C) 2001 Tensilica Inc.
- * Copyright (C) 2017 Cadence Design Systems Inc.
+ * Copyright (C) 2017 - 2021 Cadence Design Systems Inc.
  */
 
 #ifndef _XTENSA_PLATFORM_ISS_SIMCALL_H
 #define _XTENSA_PLATFORM_ISS_SIMCALL_H
 
+#include <linux/bug.h>
 
-/*
- *  System call like services offered by the simulator host.
- */
-
-#define SYS_nop		0	/* unused */
-#define SYS_exit	1	/*x*/
-#define SYS_fork	2
-#define SYS_read	3	/*x*/
-#define SYS_write	4	/*x*/
-#define SYS_open	5	/*x*/
-#define SYS_close	6	/*x*/
-#define SYS_rename	7	/*x 38 - waitpid */
-#define SYS_creat	8	/*x*/
-#define SYS_link	9	/*x (not implemented on WIN32) */
-#define SYS_unlink	10	/*x*/
-#define SYS_execv	11	/* n/a - execve */
-#define SYS_execve	12	/* 11 - chdir */
-#define SYS_pipe	13	/* 42 - time */
-#define SYS_stat	14	/* 106 - mknod */
-#define SYS_chmod	15
-#define SYS_chown	16	/* 202 - lchown */
-#define SYS_utime	17	/* 30 - break */
-#define SYS_wait	18	/* n/a - oldstat */
-#define SYS_lseek	19	/*x*/
-#define SYS_getpid	20
-#define SYS_isatty	21	/* n/a - mount */
-#define SYS_fstat	22	/* 108 - oldumount */
-#define SYS_time	23	/* 13 - setuid */
-#define SYS_gettimeofday 24	/*x 78 - getuid (not implemented on WIN32) */
-#define SYS_times	25	/*X 43 - stime (Xtensa-specific implementation) */
-#define SYS_socket      26
-#define SYS_sendto      27
-#define SYS_recvfrom    28
-#define SYS_select_one  29      /* not compitible select, one file descriptor at the time */
-#define SYS_bind        30
-#define SYS_ioctl	31
-
-#define SYS_iss_argc	1000	/* returns value of argc */
-#define SYS_iss_argv_size 1001	/* bytes needed for argv & arg strings */
-#define SYS_iss_set_argv 1002	/* saves argv & arg strings at given addr */
-
-/*
- * SYS_select_one specifiers
- */
-
-#define  XTISS_SELECT_ONE_READ    1
-#define  XTISS_SELECT_ONE_WRITE   2
-#define  XTISS_SELECT_ONE_EXCEPT  3
-
-static int errno;
-
-static inline int __simc(int a, int b, int c, int d)
-{
-	register int a1 asm("a2") = a;
-	register int b1 asm("a3") = b;
-	register int c1 asm("a4") = c;
-	register int d1 asm("a5") = d;
-	__asm__ __volatile__ (
-			"simcall\n"
-			: "+r"(a1), "+r"(b1)
-			: "r"(c1), "r"(d1)
-			: "memory");
-	errno = b1;
-	return a1;
-}
+#ifdef CONFIG_XTENSA_SIMCALL_ISS
+#include <platform/simcall-iss.h>
+#endif
+#ifdef CONFIG_XTENSA_SIMCALL_GDBIO
+#include <platform/simcall-gdbio.h>
+#endif
 
 static inline int simc_exit(int exit_code)
 {
+#ifdef SYS_exit
 	return __simc(SYS_exit, exit_code, 0, 0);
+#else
+	WARN_ONCE(1, "%s: not implemented\n", __func__);
+	return -1;
+#endif
 }
 
 static inline int simc_open(const char *file, int flags, int mode)
@@ -96,7 +43,12 @@ static inline int simc_close(int fd)
 
 static inline int simc_ioctl(int fd, int request, void *arg)
 {
+#ifdef SYS_ioctl
 	return __simc(SYS_ioctl, fd, request, (int) arg);
+#else
+	WARN_ONCE(1, "%s: not implemented\n", __func__);
+	return -1;
+#endif
 }
 
 static inline int simc_read(int fd, void *buf, size_t count)
@@ -111,9 +63,14 @@ static inline int simc_write(int fd, const void *buf, size_t count)
 
 static inline int simc_poll(int fd)
 {
+#ifdef SYS_select_one
 	long timeval[2] = { 0, 0 };
 
 	return __simc(SYS_select_one, fd, XTISS_SELECT_ONE_READ, (int)&timeval);
+#else
+	WARN_ONCE(1, "%s: not implemented\n", __func__);
+	return -1;
+#endif
 }
 
 static inline int simc_lseek(int fd, uint32_t off, int whence)
@@ -123,18 +80,31 @@ static inline int simc_lseek(int fd, uint32_t off, int whence)
 
 static inline int simc_argc(void)
 {
+#ifdef SYS_iss_argc
 	return __simc(SYS_iss_argc, 0, 0, 0);
+#else
+	WARN_ONCE(1, "%s: not implemented\n", __func__);
+	return 0;
+#endif
 }
 
 static inline int simc_argv_size(void)
 {
+#ifdef SYS_iss_argv_size
 	return __simc(SYS_iss_argv_size, 0, 0, 0);
+#else
+	WARN_ONCE(1, "%s: not implemented\n", __func__);
+	return 0;
+#endif
 }
 
 static inline void simc_argv(void *buf)
 {
+#ifdef SYS_iss_set_argv
 	__simc(SYS_iss_set_argv, (int)buf, 0, 0);
+#else
+	WARN_ONCE(1, "%s: not implemented\n", __func__);
+#endif
 }
 
 #endif /* _XTENSA_PLATFORM_ISS_SIMCALL_H */
-