Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

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;
+}