From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- 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