selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 139 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
new file mode 100644
index 000000000..83fae5172
--- /dev/null
+++ b/arch/arm/mach-omap2/clock.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/arch/arm/mach-omap2/clock.c
+ *
+ *  Copyright (C) 2005-2008 Texas Instruments, Inc.
+ *  Copyright (C) 2004-2010 Nokia Corporation
+ *
+ *  Contacts:
+ *  Richard Woodruff <r-woodruff2@ti.com>
+ *  Paul Walmsley
+ */
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/of_address.h>
+#include <asm/cpu.h>
+
+#include <trace/events/power.h>
+
+#include "soc.h"
+#include "clockdomain.h"
+#include "clock.h"
+#include "cm.h"
+#include "cm2xxx.h"
+#include "cm3xxx.h"
+#include "cm-regbits-24xx.h"
+#include "cm-regbits-34xx.h"
+#include "common.h"
+
+/* DPLL valid Fint frequency band limits - from 34xx TRM Section 4.7.6.2 */
+#define OMAP3430_DPLL_FINT_BAND1_MIN	750000
+#define OMAP3430_DPLL_FINT_BAND1_MAX	2100000
+#define OMAP3430_DPLL_FINT_BAND2_MIN	7500000
+#define OMAP3430_DPLL_FINT_BAND2_MAX	21000000
+
+/*
+ * DPLL valid Fint frequency range for OMAP36xx and OMAP4xxx.
+ * From device data manual section 4.3 "DPLL and DLL Specifications".
+ */
+#define OMAP3PLUS_DPLL_FINT_MIN		32000
+#define OMAP3PLUS_DPLL_FINT_MAX		52000000
+
+struct ti_clk_ll_ops omap_clk_ll_ops = {
+	.clkdm_clk_enable = clkdm_clk_enable,
+	.clkdm_clk_disable = clkdm_clk_disable,
+	.clkdm_lookup = clkdm_lookup,
+	.cm_wait_module_ready = omap_cm_wait_module_ready,
+	.cm_split_idlest_reg = cm_split_idlest_reg,
+};
+
+/**
+ * omap2_clk_setup_ll_ops - setup clock driver low-level ops
+ *
+ * Sets up clock driver low-level platform ops. These are needed
+ * for register accesses and various other misc platform operations.
+ * Returns 0 on success, -EBUSY if low level ops have been registered
+ * already.
+ */
+int __init omap2_clk_setup_ll_ops(void)
+{
+	return ti_clk_setup_ll_ops(&omap_clk_ll_ops);
+}
+
+/*
+ * OMAP2+ specific clock functions
+ */
+
+/**
+ * ti_clk_init_features - init clock features struct for the SoC
+ *
+ * Initializes the clock features struct based on the SoC type.
+ */
+void __init ti_clk_init_features(void)
+{
+	struct ti_clk_features features = { 0 };
+	/* Fint setup for DPLLs */
+	if (cpu_is_omap3430()) {
+		features.fint_min = OMAP3430_DPLL_FINT_BAND1_MIN;
+		features.fint_max = OMAP3430_DPLL_FINT_BAND2_MAX;
+		features.fint_band1_max = OMAP3430_DPLL_FINT_BAND1_MAX;
+		features.fint_band2_min = OMAP3430_DPLL_FINT_BAND2_MIN;
+	} else {
+		features.fint_min = OMAP3PLUS_DPLL_FINT_MIN;
+		features.fint_max = OMAP3PLUS_DPLL_FINT_MAX;
+	}
+
+	/* Bypass value setup for DPLLs */
+	if (cpu_is_omap24xx()) {
+		features.dpll_bypass_vals |=
+			(1 << OMAP2XXX_EN_DPLL_LPBYPASS) |
+			(1 << OMAP2XXX_EN_DPLL_FRBYPASS);
+	} else if (cpu_is_omap34xx()) {
+		features.dpll_bypass_vals |=
+			(1 << OMAP3XXX_EN_DPLL_LPBYPASS) |
+			(1 << OMAP3XXX_EN_DPLL_FRBYPASS);
+	} else if (soc_is_am33xx() || cpu_is_omap44xx() || soc_is_am43xx() ||
+		   soc_is_omap54xx() || soc_is_dra7xx()) {
+		features.dpll_bypass_vals |=
+			(1 << OMAP4XXX_EN_DPLL_LPBYPASS) |
+			(1 << OMAP4XXX_EN_DPLL_FRBYPASS) |
+			(1 << OMAP4XXX_EN_DPLL_MNBYPASS);
+	}
+
+	/* Jitter correction only available on OMAP343X */
+	if (cpu_is_omap343x())
+		features.flags |= TI_CLK_DPLL_HAS_FREQSEL;
+
+	if (omap_type() == OMAP2_DEVICE_TYPE_GP)
+		features.flags |= TI_CLK_DEVICE_TYPE_GP;
+
+	/* Idlest value for interface clocks.
+	 * 24xx uses 0 to indicate not ready, and 1 to indicate ready.
+	 * 34xx reverses this, just to keep us on our toes
+	 * AM35xx uses both, depending on the module.
+	 */
+	if (cpu_is_omap24xx())
+		features.cm_idlest_val = OMAP24XX_CM_IDLEST_VAL;
+	else if (cpu_is_omap34xx())
+		features.cm_idlest_val = OMAP34XX_CM_IDLEST_VAL;
+
+	/* On OMAP3430 ES1.0, DPLL4 can't be re-programmed */
+	if (omap_rev() == OMAP3430_REV_ES1_0)
+		features.flags |= TI_CLK_DPLL4_DENY_REPROGRAM;
+
+	/* Errata I810 for omap5 / dra7 */
+	if (soc_is_omap54xx() || soc_is_dra7xx())
+		features.flags |= TI_CLK_ERRATA_I810;
+
+	ti_clk_setup_features(&features);
+}