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, 184 insertions, 0 deletions

diff --git a/drivers/firmware/trusted_foundations.c b/drivers/firmware/trusted_foundations.c
new file mode 100644
index 000000000..1389fa941
--- /dev/null
+++ b/drivers/firmware/trusted_foundations.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Trusted Foundations support for ARM CPUs
+ *
+ * Copyright (c) 2013, NVIDIA Corporation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of.h>
+
+#include <linux/firmware/trusted_foundations.h>
+
+#include <asm/firmware.h>
+#include <asm/hardware/cache-l2x0.h>
+#include <asm/outercache.h>
+
+#define TF_CACHE_MAINT		0xfffff100
+
+#define TF_CACHE_ENABLE		1
+#define TF_CACHE_DISABLE	2
+#define TF_CACHE_REENABLE	4
+
+#define TF_SET_CPU_BOOT_ADDR_SMC 0xfffff200
+
+#define TF_CPU_PM		0xfffffffc
+#define TF_CPU_PM_S3		0xffffffe3
+#define TF_CPU_PM_S2		0xffffffe6
+#define TF_CPU_PM_S2_NO_MC_CLK	0xffffffe5
+#define TF_CPU_PM_S1		0xffffffe4
+#define TF_CPU_PM_S1_NOFLUSH_L2	0xffffffe7
+
+static unsigned long tf_idle_mode = TF_PM_MODE_NONE;
+static unsigned long cpu_boot_addr;
+
+static void tf_generic_smc(u32 type, u32 arg1, u32 arg2)
+{
+	register u32 r0 asm("r0") = type;
+	register u32 r1 asm("r1") = arg1;
+	register u32 r2 asm("r2") = arg2;
+
+	asm volatile(
+		".arch_extension	sec\n\t"
+		"stmfd	sp!, {r4 - r11}\n\t"
+		__asmeq("%0", "r0")
+		__asmeq("%1", "r1")
+		__asmeq("%2", "r2")
+		"mov	r3, #0\n\t"
+		"mov	r4, #0\n\t"
+		"smc	#0\n\t"
+		"ldmfd	sp!, {r4 - r11}\n\t"
+		:
+		: "r" (r0), "r" (r1), "r" (r2)
+		: "memory", "r3", "r12", "lr");
+}
+
+static int tf_set_cpu_boot_addr(int cpu, unsigned long boot_addr)
+{
+	cpu_boot_addr = boot_addr;
+	tf_generic_smc(TF_SET_CPU_BOOT_ADDR_SMC, cpu_boot_addr, 0);
+
+	return 0;
+}
+
+static int tf_prepare_idle(unsigned long mode)
+{
+	switch (mode) {
+	case TF_PM_MODE_LP0:
+		tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S3, cpu_boot_addr);
+		break;
+
+	case TF_PM_MODE_LP1:
+		tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S2, cpu_boot_addr);
+		break;
+
+	case TF_PM_MODE_LP1_NO_MC_CLK:
+		tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S2_NO_MC_CLK,
+			       cpu_boot_addr);
+		break;
+
+	case TF_PM_MODE_LP2:
+		tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S1, cpu_boot_addr);
+		break;
+
+	case TF_PM_MODE_LP2_NOFLUSH_L2:
+		tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S1_NOFLUSH_L2,
+			       cpu_boot_addr);
+		break;
+
+	case TF_PM_MODE_NONE:
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	tf_idle_mode = mode;
+
+	return 0;
+}
+
+#ifdef CONFIG_CACHE_L2X0
+static void tf_cache_write_sec(unsigned long val, unsigned int reg)
+{
+	u32 enable_op, l2x0_way_mask = 0xff;
+
+	switch (reg) {
+	case L2X0_CTRL:
+		if (l2x0_saved_regs.aux_ctrl & L310_AUX_CTRL_ASSOCIATIVITY_16)
+			l2x0_way_mask = 0xffff;
+
+		switch (tf_idle_mode) {
+		case TF_PM_MODE_LP2:
+			enable_op = TF_CACHE_REENABLE;
+			break;
+
+		default:
+			enable_op = TF_CACHE_ENABLE;
+			break;
+		}
+
+		if (val == L2X0_CTRL_EN)
+			tf_generic_smc(TF_CACHE_MAINT, enable_op,
+				       l2x0_saved_regs.aux_ctrl);
+		else
+			tf_generic_smc(TF_CACHE_MAINT, TF_CACHE_DISABLE,
+				       l2x0_way_mask);
+		break;
+
+	default:
+		break;
+	}
+}
+
+static int tf_init_cache(void)
+{
+	outer_cache.write_sec = tf_cache_write_sec;
+
+	return 0;
+}
+#endif /* CONFIG_CACHE_L2X0 */
+
+static const struct firmware_ops trusted_foundations_ops = {
+	.set_cpu_boot_addr = tf_set_cpu_boot_addr,
+	.prepare_idle = tf_prepare_idle,
+#ifdef CONFIG_CACHE_L2X0
+	.l2x0_init = tf_init_cache,
+#endif
+};
+
+void register_trusted_foundations(struct trusted_foundations_platform_data *pd)
+{
+	/*
+	 * we are not using version information for now since currently
+	 * supported SMCs are compatible with all TF releases
+	 */
+	register_firmware_ops(&trusted_foundations_ops);
+}
+
+void of_register_trusted_foundations(void)
+{
+	struct device_node *node;
+	struct trusted_foundations_platform_data pdata;
+	int err;
+
+	node = of_find_compatible_node(NULL, NULL, "tlm,trusted-foundations");
+	if (!node)
+		return;
+
+	err = of_property_read_u32(node, "tlm,version-major",
+				   &pdata.version_major);
+	if (err != 0)
+		panic("Trusted Foundation: missing version-major property\n");
+	err = of_property_read_u32(node, "tlm,version-minor",
+				   &pdata.version_minor);
+	if (err != 0)
+		panic("Trusted Foundation: missing version-minor property\n");
+	register_trusted_foundations(&pdata);
+}
+
+bool trusted_foundations_registered(void)
+{
+	return firmware_ops == &trusted_foundations_ops;
+}