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/ebony.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 arch/powerpc/boot/ebony.c (limited to 'arch/powerpc/boot/ebony.c') diff --git a/arch/powerpc/boot/ebony.c b/arch/powerpc/boot/ebony.c new file mode 100644 index 000000000..add2316d3 --- /dev/null +++ b/arch/powerpc/boot/ebony.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2007 David Gibson, IBM Corporation. + * + * Based on earlier code: + * Copyright (C) Paul Mackerras 1997. + * + * Matt Porter + * Copyright 2002-2005 MontaVista Software Inc. + * + * Eugene Surovegin or + * Copyright (c) 2003, 2004 Zultys Technologies + */ +#include +#include +#include "types.h" +#include "elf.h" +#include "string.h" +#include "stdio.h" +#include "page.h" +#include "ops.h" +#include "reg.h" +#include "io.h" +#include "dcr.h" +#include "4xx.h" +#include "44x.h" + +static u8 *ebony_mac0, *ebony_mac1; + +#define EBONY_FPGA_PATH "/plb/opb/ebc/fpga" +#define EBONY_FPGA_FLASH_SEL 0x01 +#define EBONY_SMALL_FLASH_PATH "/plb/opb/ebc/small-flash" + +static void ebony_flashsel_fixup(void) +{ + void *devp; + u32 reg[3] = {0x0, 0x0, 0x80000}; + u8 *fpga; + u8 fpga_reg0 = 0x0; + + devp = finddevice(EBONY_FPGA_PATH); + if (!devp) + fatal("Couldn't locate FPGA node %s\n\r", EBONY_FPGA_PATH); + + if (getprop(devp, "virtual-reg", &fpga, sizeof(fpga)) != sizeof(fpga)) + fatal("%s has missing or invalid virtual-reg property\n\r", + EBONY_FPGA_PATH); + + fpga_reg0 = in_8(fpga); + + devp = finddevice(EBONY_SMALL_FLASH_PATH); + if (!devp) + fatal("Couldn't locate small flash node %s\n\r", + EBONY_SMALL_FLASH_PATH); + + if (getprop(devp, "reg", reg, sizeof(reg)) != sizeof(reg)) + fatal("%s has reg property of unexpected size\n\r", + EBONY_SMALL_FLASH_PATH); + + /* Invert address bit 14 (IBM-endian) if FLASH_SEL fpga bit is set */ + if (fpga_reg0 & EBONY_FPGA_FLASH_SEL) + reg[1] ^= 0x80000; + + setprop(devp, "reg", reg, sizeof(reg)); +} + +static void ebony_fixups(void) +{ + // FIXME: sysclk should be derived by reading the FPGA registers + unsigned long sysclk = 33000000; + + ibm440gp_fixup_clocks(sysclk, 6 * 1843200); + ibm4xx_sdram_fixup_memsize(); + dt_fixup_mac_address_by_alias("ethernet0", ebony_mac0); + dt_fixup_mac_address_by_alias("ethernet1", ebony_mac1); + ibm4xx_fixup_ebc_ranges("/plb/opb/ebc"); + ebony_flashsel_fixup(); +} + +void ebony_init(void *mac0, void *mac1) +{ + platform_ops.fixups = ebony_fixups; + platform_ops.exit = ibm44x_dbcr_reset; + ebony_mac0 = mac0; + ebony_mac1 = mac1; + fdt_init(_dtb_start); + serial_console_init(); +} -- cgit v1.3.1