ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 178 insertions, 0 deletions

diff --git a/arch/mips/bcm63xx/setup.c b/arch/mips/bcm63xx/setup.c
new file mode 100644
index 000000000..81529084b
--- /dev/null
+++ b/arch/mips/bcm63xx/setup.c
@@ -0,0 +1,178 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/memblock.h>
+#include <linux/ioport.h>
+#include <linux/pm.h>
+#include <asm/bmips.h>
+#include <asm/bootinfo.h>
+#include <asm/time.h>
+#include <asm/reboot.h>
+#include <asm/cacheflush.h>
+#include <bcm63xx_board.h>
+#include <bcm63xx_cpu.h>
+#include <bcm63xx_regs.h>
+#include <bcm63xx_io.h>
+#include <bcm63xx_gpio.h>
+
+/*
+ * CBR addr doesn't change and we can cache it.
+ * For broken SoC/Bootloader CBR addr might also be provided via DT
+ * with "brcm,bmips-cbr-reg" in the "cpus" node.
+ */
+void __iomem *bmips_cbr_addr __read_mostly;
+
+void bcm63xx_machine_halt(void)
+{
+	pr_info("System halted\n");
+	while (1)
+		;
+}
+
+static void bcm6348_a1_reboot(void)
+{
+	u32 reg;
+
+	/* soft reset all blocks */
+	pr_info("soft-resetting all blocks ...\n");
+	reg = bcm_perf_readl(PERF_SOFTRESET_REG);
+	reg &= ~SOFTRESET_6348_ALL;
+	bcm_perf_writel(reg, PERF_SOFTRESET_REG);
+	mdelay(10);
+
+	reg = bcm_perf_readl(PERF_SOFTRESET_REG);
+	reg |= SOFTRESET_6348_ALL;
+	bcm_perf_writel(reg, PERF_SOFTRESET_REG);
+	mdelay(10);
+
+	/* Jump to the power on address. */
+	pr_info("jumping to reset vector.\n");
+	/* set high vectors (base at 0xbfc00000 */
+	set_c0_status(ST0_BEV | ST0_ERL);
+	/* run uncached in kseg0 */
+	change_c0_config(CONF_CM_CMASK, CONF_CM_UNCACHED);
+	__flush_cache_all();
+	/* remove all wired TLB entries */
+	write_c0_wired(0);
+	__asm__ __volatile__(
+		"jr\t%0"
+		:
+		: "r" (0xbfc00000));
+	while (1)
+		;
+}
+
+void bcm63xx_machine_reboot(void)
+{
+	u32 reg, perf_regs[2] = { 0, 0 };
+	unsigned int i;
+
+	/* mask and clear all external irq */
+	switch (bcm63xx_get_cpu_id()) {
+	case BCM3368_CPU_ID:
+		perf_regs[0] = PERF_EXTIRQ_CFG_REG_3368;
+		break;
+	case BCM6328_CPU_ID:
+		perf_regs[0] = PERF_EXTIRQ_CFG_REG_6328;
+		break;
+	case BCM6338_CPU_ID:
+		perf_regs[0] = PERF_EXTIRQ_CFG_REG_6338;
+		break;
+	case BCM6345_CPU_ID:
+		perf_regs[0] = PERF_EXTIRQ_CFG_REG_6345;
+		break;
+	case BCM6348_CPU_ID:
+		perf_regs[0] = PERF_EXTIRQ_CFG_REG_6348;
+		break;
+	case BCM6358_CPU_ID:
+		perf_regs[0] = PERF_EXTIRQ_CFG_REG_6358;
+		break;
+	case BCM6362_CPU_ID:
+		perf_regs[0] = PERF_EXTIRQ_CFG_REG_6362;
+		break;
+	}
+
+	for (i = 0; i < 2; i++) {
+		if (!perf_regs[i])
+			break;
+
+		reg = bcm_perf_readl(perf_regs[i]);
+		if (BCMCPU_IS_6348()) {
+			reg &= ~EXTIRQ_CFG_MASK_ALL_6348;
+			reg |= EXTIRQ_CFG_CLEAR_ALL_6348;
+		} else {
+			reg &= ~EXTIRQ_CFG_MASK_ALL;
+			reg |= EXTIRQ_CFG_CLEAR_ALL;
+		}
+		bcm_perf_writel(reg, perf_regs[i]);
+	}
+
+	if (BCMCPU_IS_6348() && (bcm63xx_get_cpu_rev() == 0xa1))
+		bcm6348_a1_reboot();
+
+	pr_info("triggering watchdog soft-reset...\n");
+	if (BCMCPU_IS_6328()) {
+		bcm_wdt_writel(1, WDT_SOFTRESET_REG);
+	} else {
+		reg = bcm_perf_readl(PERF_SYS_PLL_CTL_REG);
+		reg |= SYS_PLL_SOFT_RESET;
+		bcm_perf_writel(reg, PERF_SYS_PLL_CTL_REG);
+	}
+	while (1)
+		;
+}
+
+static void __bcm63xx_machine_reboot(char *p)
+{
+	bcm63xx_machine_reboot();
+}
+
+/*
+ * return system type in /proc/cpuinfo
+ */
+const char *get_system_type(void)
+{
+	static char buf[128];
+	snprintf(buf, sizeof(buf), "bcm63xx/%s (0x%04x/0x%02X)",
+		 board_get_name(),
+		 bcm63xx_get_cpu_id(), bcm63xx_get_cpu_rev());
+	return buf;
+}
+
+void __init plat_time_init(void)
+{
+	mips_hpt_frequency = bcm63xx_get_cpu_freq() / 2;
+}
+
+void __init plat_mem_setup(void)
+{
+	memblock_add(0, bcm63xx_get_memory_size());
+
+	_machine_halt = bcm63xx_machine_halt;
+	_machine_restart = __bcm63xx_machine_reboot;
+	pm_power_off = bcm63xx_machine_halt;
+
+	set_io_port_base(0);
+	ioport_resource.start = 0;
+	ioport_resource.end = ~0;
+
+	board_setup();
+}
+
+static int __init bcm63xx_register_devices(void)
+{
+	/* register gpiochip */
+	bcm63xx_gpio_init();
+
+	return board_register_devices();
+}
+
+arch_initcall(bcm63xx_register_devices);