From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock 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 Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- arch/powerpc/boot/mpc8xx.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 arch/powerpc/boot/mpc8xx.c (limited to 'arch/powerpc/boot/mpc8xx.c') diff --git a/arch/powerpc/boot/mpc8xx.c b/arch/powerpc/boot/mpc8xx.c new file mode 100644 index 000000000..e19ef64df --- /dev/null +++ b/arch/powerpc/boot/mpc8xx.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * MPC8xx support functions + * + * Author: Scott Wood + * + * Copyright (c) 2007 Freescale Semiconductor, Inc. + */ + +#include "ops.h" +#include "types.h" +#include "fsl-soc.h" +#include "mpc8xx.h" +#include "stdio.h" +#include "io.h" + +#define MPC8XX_PLPRCR (0x284/4) /* PLL and Reset Control Register */ + +/* Return system clock from crystal frequency */ +u32 mpc885_get_clock(u32 crystal) +{ + u32 *immr; + u32 plprcr; + int mfi, mfn, mfd, pdf; + u32 ret; + + immr = fsl_get_immr(); + if (!immr) { + printf("mpc885_get_clock: Couldn't get IMMR base.\r\n"); + return 0; + } + + plprcr = in_be32(&immr[MPC8XX_PLPRCR]); + + mfi = (plprcr >> 16) & 15; + if (mfi < 5) { + printf("Warning: PLPRCR[MFI] value of %d out-of-bounds\r\n", + mfi); + mfi = 5; + } + + pdf = (plprcr >> 1) & 0xf; + mfd = (plprcr >> 22) & 0x1f; + mfn = (plprcr >> 27) & 0x1f; + + ret = crystal * mfi; + + if (mfn != 0) + ret += crystal * mfn / (mfd + 1); + + return ret / (pdf + 1); +} + +/* Set common device tree fields based on the given clock frequencies. */ +void mpc8xx_set_clocks(u32 sysclk) +{ + void *node; + + dt_fixup_cpu_clocks(sysclk, sysclk / 16, sysclk); + + node = finddevice("/soc/cpm"); + if (node) + setprop(node, "clock-frequency", &sysclk, 4); + + node = finddevice("/soc/cpm/brg"); + if (node) + setprop(node, "clock-frequency", &sysclk, 4); +} + +int mpc885_fixup_clocks(u32 crystal) +{ + u32 sysclk = mpc885_get_clock(crystal); + if (!sysclk) + return 0; + + mpc8xx_set_clocks(sysclk); + return 1; +} -- cgit v1.3.1