5 files changed, 509 insertions, 0 deletions
diff --git a/arch/mips/tools/.gitignore b/arch/mips/tools/.gitignore
new file mode 100644
index 000000000..794817dfb
--- /dev/null
+++ b/arch/mips/tools/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+elf-entry
+loongson3-llsc-check
diff --git a/arch/mips/tools/Makefile b/arch/mips/tools/Makefile
new file mode 100644
index 000000000..b851e5dcc
--- /dev/null
+++ b/arch/mips/tools/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+hostprogs := elf-entry
+PHONY += elf-entry
+elf-entry: $(obj)/elf-entry
+	@:
+
+hostprogs += loongson3-llsc-check
+PHONY += loongson3-llsc-check
+loongson3-llsc-check: $(obj)/loongson3-llsc-check
+	@:
diff --git a/arch/mips/tools/elf-entry.c b/arch/mips/tools/elf-entry.c
new file mode 100644
index 000000000..dbd14ff05
--- /dev/null
+++ b/arch/mips/tools/elf-entry.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <byteswap.h>
+#include <elf.h>
+#include <endian.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef be32toh
+/* If libc provides [bl]e{32,64}toh() then we'll use them */
+#elif BYTE_ORDER == LITTLE_ENDIAN
+# define be32toh(x)	bswap_32(x)
+# define le32toh(x)	(x)
+# define be64toh(x)	bswap_64(x)
+# define le64toh(x)	(x)
+#elif BYTE_ORDER == BIG_ENDIAN
+# define be32toh(x)	(x)
+# define le32toh(x)	bswap_32(x)
+# define be64toh(x)	(x)
+# define le64toh(x)	bswap_64(x)
+#endif
+
+__attribute__((noreturn))
+static void die(const char *msg)
+{
+	fputs(msg, stderr);
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, const char *argv[])
+{
+	uint64_t entry;
+	size_t nread;
+	FILE *file;
+	union {
+		Elf32_Ehdr ehdr32;
+		Elf64_Ehdr ehdr64;
+	} hdr;
+
+	if (argc != 2)
+		die("Usage: elf-entry <elf-file>\n");
+
+	file = fopen(argv[1], "r");
+	if (!file) {
+		perror("Unable to open input file");
+		return EXIT_FAILURE;
+	}
+
+	nread = fread(&hdr, 1, sizeof(hdr), file);
+	if (nread != sizeof(hdr)) {
+		perror("Unable to read input file");
+		fclose(file);
+		return EXIT_FAILURE;
+	}
+
+	if (memcmp(hdr.ehdr32.e_ident, ELFMAG, SELFMAG)) {
+		fclose(file);
+		die("Input is not an ELF\n");
+	}
+
+	switch (hdr.ehdr32.e_ident[EI_CLASS]) {
+	case ELFCLASS32:
+		switch (hdr.ehdr32.e_ident[EI_DATA]) {
+		case ELFDATA2LSB:
+			entry = le32toh(hdr.ehdr32.e_entry);
+			break;
+		case ELFDATA2MSB:
+			entry = be32toh(hdr.ehdr32.e_entry);
+			break;
+		default:
+			fclose(file);
+			die("Invalid ELF encoding\n");
+		}
+
+		/* Sign extend to form a canonical address */
+		entry = (int64_t)(int32_t)entry;
+		break;
+
+	case ELFCLASS64:
+		switch (hdr.ehdr32.e_ident[EI_DATA]) {
+		case ELFDATA2LSB:
+			entry = le64toh(hdr.ehdr64.e_entry);
+			break;
+		case ELFDATA2MSB:
+			entry = be64toh(hdr.ehdr64.e_entry);
+			break;
+		default:
+			fclose(file);
+			die("Invalid ELF encoding\n");
+		}
+		break;
+
+	default:
+		fclose(file);
+		die("Invalid ELF class\n");
+	}
+
+	printf("0x%016" PRIx64 "\n", entry);
+	fclose(file);
+	return EXIT_SUCCESS;
+}
diff --git a/arch/mips/tools/generic-board-config.sh b/arch/mips/tools/generic-board-config.sh
new file mode 100755
index 000000000..dfa5f31f5
--- /dev/null
+++ b/arch/mips/tools/generic-board-config.sh
@@ -0,0 +1,84 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright (C) 2017 Imagination Technologies
+# Author: Paul Burton <paul.burton@mips.com>
+#
+# This script merges configuration fragments for boards supported by the
+# generic MIPS kernel. It checks each for requirements specified using
+# formatted comments, and then calls merge_config.sh to merge those
+# fragments which have no unmet requirements.
+#
+# An example of requirements in your board config fragment might be:
+#
+# # require CONFIG_CPU_MIPS32_R2=y
+# # require CONFIG_CPU_LITTLE_ENDIAN=y
+#
+# This would mean that your board is only included in kernels which are
+# configured for little endian MIPS32r2 CPUs, and not for example in kernels
+# configured for 64 bit or big endian systems.
+#
+
+srctree="$1"
+objtree="$2"
+ref_cfg="$3"
+cfg="$4"
+boards_origin="$5"
+shift 5
+
+# Only print Skipping... lines if the user explicitly specified BOARDS=. In the
+# general case it only serves to obscure the useful output about what actually
+# was included.
+case ${boards_origin} in
+"command line")
+	print_skipped=1
+	;;
+environment*)
+	print_skipped=1
+	;;
+*)
+	print_skipped=0
+	;;
+esac
+
+for board in $@; do
+	board_cfg="${srctree}/arch/mips/configs/generic/board-${board}.config"
+	if [ ! -f "${board_cfg}" ]; then
+		echo "WARNING: Board config '${board_cfg}' not found"
+		continue
+	fi
+
+	# For each line beginning with # require, cut out the field following
+	# it & search for that in the reference config file. If the requirement
+	# is not found then the subshell will exit with code 1, and we'll
+	# continue on to the next board.
+	grep -E '^# require ' "${board_cfg}" | \
+	    cut -d' ' -f 3- | \
+	    while read req; do
+		case ${req} in
+		*=y)
+			# If we require something =y then we check that a line
+			# containing it is present in the reference config.
+			grep -Eq "^${req}\$" "${ref_cfg}" && continue
+			;;
+		*=n)
+			# If we require something =n then we just invert that
+			# check, considering the requirement met if there isn't
+			# a line containing the value =y in the reference
+			# config.
+			grep -Eq "^${req/%=n/=y}\$" "${ref_cfg}" || continue
+			;;
+		*)
+			echo "WARNING: Unhandled requirement '${req}'"
+			;;
+		esac
+
+		[ ${print_skipped} -eq 1 ] && echo "Skipping ${board_cfg}"
+		exit 1
+	done || continue
+
+	# Merge this board config fragment into our final config file
+	${srctree}/scripts/kconfig/merge_config.sh \
+		-m -O ${objtree} ${cfg} ${board_cfg} \
+		| grep -Ev '^(#|Using)'
+done
diff --git a/arch/mips/tools/loongson3-llsc-check.c b/arch/mips/tools/loongson3-llsc-check.c
new file mode 100644
index 000000000..5f68a4fa8
--- /dev/null
+++ b/arch/mips/tools/loongson3-llsc-check.c
@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <byteswap.h>
+#include <elf.h>
+#include <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#ifdef be32toh
+/* If libc provides le{16,32,64}toh() then we'll use them */
+#elif BYTE_ORDER == LITTLE_ENDIAN
+# define le16toh(x)	(x)
+# define le32toh(x)	(x)
+# define le64toh(x)	(x)
+#elif BYTE_ORDER == BIG_ENDIAN
+# define le16toh(x)	bswap_16(x)
+# define le32toh(x)	bswap_32(x)
+# define le64toh(x)	bswap_64(x)
+#endif
+
+/* MIPS opcodes, in bits 31:26 of an instruction */
+#define OP_SPECIAL	0x00
+#define OP_REGIMM	0x01
+#define OP_BEQ		0x04
+#define OP_BNE		0x05
+#define OP_BLEZ		0x06
+#define OP_BGTZ		0x07
+#define OP_BEQL		0x14
+#define OP_BNEL		0x15
+#define OP_BLEZL	0x16
+#define OP_BGTZL	0x17
+#define OP_LL		0x30
+#define OP_LLD		0x34
+#define OP_SC		0x38
+#define OP_SCD		0x3c
+
+/* Bits 20:16 of OP_REGIMM instructions */
+#define REGIMM_BLTZ	0x00
+#define REGIMM_BGEZ	0x01
+#define REGIMM_BLTZL	0x02
+#define REGIMM_BGEZL	0x03
+#define REGIMM_BLTZAL	0x10
+#define REGIMM_BGEZAL	0x11
+#define REGIMM_BLTZALL	0x12
+#define REGIMM_BGEZALL	0x13
+
+/* Bits 5:0 of OP_SPECIAL instructions */
+#define SPECIAL_SYNC	0x0f
+
+static void usage(FILE *f)
+{
+	fprintf(f, "Usage: loongson3-llsc-check /path/to/vmlinux\n");
+}
+
+static int se16(uint16_t x)
+{
+	return (int16_t)x;
+}
+
+static bool is_ll(uint32_t insn)
+{
+	switch (insn >> 26) {
+	case OP_LL:
+	case OP_LLD:
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+static bool is_sc(uint32_t insn)
+{
+	switch (insn >> 26) {
+	case OP_SC:
+	case OP_SCD:
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+static bool is_sync(uint32_t insn)
+{
+	/* Bits 31:11 should all be zeroes */
+	if (insn >> 11)
+		return false;
+
+	/* Bits 5:0 specify the SYNC special encoding */
+	if ((insn & 0x3f) != SPECIAL_SYNC)
+		return false;
+
+	return true;
+}
+
+static bool is_branch(uint32_t insn, int *off)
+{
+	switch (insn >> 26) {
+	case OP_BEQ:
+	case OP_BEQL:
+	case OP_BNE:
+	case OP_BNEL:
+	case OP_BGTZ:
+	case OP_BGTZL:
+	case OP_BLEZ:
+	case OP_BLEZL:
+		*off = se16(insn) + 1;
+		return true;
+
+	case OP_REGIMM:
+		switch ((insn >> 16) & 0x1f) {
+		case REGIMM_BGEZ:
+		case REGIMM_BGEZL:
+		case REGIMM_BGEZAL:
+		case REGIMM_BGEZALL:
+		case REGIMM_BLTZ:
+		case REGIMM_BLTZL:
+		case REGIMM_BLTZAL:
+		case REGIMM_BLTZALL:
+			*off = se16(insn) + 1;
+			return true;
+
+		default:
+			return false;
+		}
+
+	default:
+		return false;
+	}
+}
+
+static int check_ll(uint64_t pc, uint32_t *code, size_t sz)
+{
+	ssize_t i, max, sc_pos;
+	int off;
+
+	/*
+	 * Every LL must be preceded by a sync instruction in order to ensure
+	 * that instruction reordering doesn't allow a prior memory access to
+	 * execute after the LL & cause erroneous results.
+	 */
+	if (!is_sync(le32toh(code[-1]))) {
+		fprintf(stderr, "%" PRIx64 ": LL not preceded by sync\n", pc);
+		return -EINVAL;
+	}
+
+	/* Find the matching SC instruction */
+	max = sz / 4;
+	for (sc_pos = 0; sc_pos < max; sc_pos++) {
+		if (is_sc(le32toh(code[sc_pos])))
+			break;
+	}
+	if (sc_pos >= max) {
+		fprintf(stderr, "%" PRIx64 ": LL has no matching SC\n", pc);
+		return -EINVAL;
+	}
+
+	/*
+	 * Check branches within the LL/SC loop target sync instructions,
+	 * ensuring that speculative execution can't generate memory accesses
+	 * due to instructions outside of the loop.
+	 */
+	for (i = 0; i < sc_pos; i++) {
+		if (!is_branch(le32toh(code[i]), &off))
+			continue;
+
+		/*
+		 * If the branch target is within the LL/SC loop then we don't
+		 * need to worry about it.
+		 */
+		if ((off >= -i) && (off <= sc_pos))
+			continue;
+
+		/* If the branch targets a sync instruction we're all good... */
+		if (is_sync(le32toh(code[i + off])))
+			continue;
+
+		/* ...but if not, we have a problem */
+		fprintf(stderr, "%" PRIx64 ": Branch target not a sync\n",
+			pc + (i * 4));
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int check_code(uint64_t pc, uint32_t *code, size_t sz)
+{
+	int err = 0;
+
+	if (sz % 4) {
+		fprintf(stderr, "%" PRIx64 ": Section size not a multiple of 4\n",
+			pc);
+		err = -EINVAL;
+		sz -= (sz % 4);
+	}
+
+	if (is_ll(le32toh(code[0]))) {
+		fprintf(stderr, "%" PRIx64 ": First instruction in section is an LL\n",
+			pc);
+		err = -EINVAL;
+	}
+
+#define advance() (	\
+	code++,		\
+	pc += 4,	\
+	sz -= 4		\
+)
+
+	/*
+	 * Skip the first instruction, allowing check_ll to look backwards
+	 * unconditionally.
+	 */
+	advance();
+
+	/* Now scan through the code looking for LL instructions */
+	for (; sz; advance()) {
+		if (is_ll(le32toh(code[0])))
+			err |= check_ll(pc, code, sz);
+	}
+
+	return err;
+}
+
+int main(int argc, char *argv[])
+{
+	int vmlinux_fd, status, err, i;
+	const char *vmlinux_path;
+	struct stat st;
+	Elf64_Ehdr *eh;
+	Elf64_Shdr *sh;
+	void *vmlinux;
+
+	status = EXIT_FAILURE;
+
+	if (argc < 2) {
+		usage(stderr);
+		goto out_ret;
+	}
+
+	vmlinux_path = argv[1];
+	vmlinux_fd = open(vmlinux_path, O_RDONLY);
+	if (vmlinux_fd == -1) {
+		perror("Unable to open vmlinux");
+		goto out_ret;
+	}
+
+	err = fstat(vmlinux_fd, &st);
+	if (err) {
+		perror("Unable to stat vmlinux");
+		goto out_close;
+	}
+
+	vmlinux = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, vmlinux_fd, 0);
+	if (vmlinux == MAP_FAILED) {
+		perror("Unable to mmap vmlinux");
+		goto out_close;
+	}
+
+	eh = vmlinux;
+	if (memcmp(eh->e_ident, ELFMAG, SELFMAG)) {
+		fprintf(stderr, "vmlinux is not an ELF?\n");
+		goto out_munmap;
+	}
+
+	if (eh->e_ident[EI_CLASS] != ELFCLASS64) {
+		fprintf(stderr, "vmlinux is not 64b?\n");
+		goto out_munmap;
+	}
+
+	if (eh->e_ident[EI_DATA] != ELFDATA2LSB) {
+		fprintf(stderr, "vmlinux is not little endian?\n");
+		goto out_munmap;
+	}
+
+	for (i = 0; i < le16toh(eh->e_shnum); i++) {
+		sh = vmlinux + le64toh(eh->e_shoff) + (i * le16toh(eh->e_shentsize));
+
+		if (sh->sh_type != SHT_PROGBITS)
+			continue;
+		if (!(sh->sh_flags & SHF_EXECINSTR))
+			continue;
+
+		err = check_code(le64toh(sh->sh_addr),
+				 vmlinux + le64toh(sh->sh_offset),
+				 le64toh(sh->sh_size));
+		if (err)
+			goto out_munmap;
+	}
+
+	status = EXIT_SUCCESS;
+out_munmap:
+	munmap(vmlinux, st.st_size);
+out_close:
+	close(vmlinux_fd);
+out_ret:
+	fprintf(stdout, "loongson3-llsc-check returns %s\n",
+		status ? "failure" : "success");
+	return status;
+}