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/ugecon.c | 142 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) create mode 100644 arch/powerpc/boot/ugecon.c (limited to 'arch/powerpc/boot/ugecon.c') diff --git a/arch/powerpc/boot/ugecon.c b/arch/powerpc/boot/ugecon.c new file mode 100644 index 000000000..938a38bd4 --- /dev/null +++ b/arch/powerpc/boot/ugecon.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * arch/powerpc/boot/ugecon.c + * + * USB Gecko bootwrapper console. + * Copyright (C) 2008-2009 The GameCube Linux Team + * Copyright (C) 2008,2009 Albert Herranz + */ + +#include +#include "stdio.h" +#include "types.h" +#include "io.h" +#include "ops.h" + + +#define EXI_CLK_32MHZ 5 + +#define EXI_CSR 0x00 +#define EXI_CSR_CLKMASK (0x7<<4) +#define EXI_CSR_CLK_32MHZ (EXI_CLK_32MHZ<<4) +#define EXI_CSR_CSMASK (0x7<<7) +#define EXI_CSR_CS_0 (0x1<<7) /* Chip Select 001 */ + +#define EXI_CR 0x0c +#define EXI_CR_TSTART (1<<0) +#define EXI_CR_WRITE (1<<2) +#define EXI_CR_READ_WRITE (2<<2) +#define EXI_CR_TLEN(len) (((len)-1)<<4) + +#define EXI_DATA 0x10 + + +/* virtual address base for input/output, retrieved from device tree */ +static void *ug_io_base; + + +static u32 ug_io_transaction(u32 in) +{ + u32 *csr_reg = ug_io_base + EXI_CSR; + u32 *data_reg = ug_io_base + EXI_DATA; + u32 *cr_reg = ug_io_base + EXI_CR; + u32 csr, data, cr; + + /* select */ + csr = EXI_CSR_CLK_32MHZ | EXI_CSR_CS_0; + out_be32(csr_reg, csr); + + /* read/write */ + data = in; + out_be32(data_reg, data); + cr = EXI_CR_TLEN(2) | EXI_CR_READ_WRITE | EXI_CR_TSTART; + out_be32(cr_reg, cr); + + while (in_be32(cr_reg) & EXI_CR_TSTART) + barrier(); + + /* deselect */ + out_be32(csr_reg, 0); + + data = in_be32(data_reg); + return data; +} + +static int ug_is_txfifo_ready(void) +{ + return ug_io_transaction(0xc0000000) & 0x04000000; +} + +static void ug_raw_putc(char ch) +{ + ug_io_transaction(0xb0000000 | (ch << 20)); +} + +static void ug_putc(char ch) +{ + int count = 16; + + if (!ug_io_base) + return; + + while (!ug_is_txfifo_ready() && count--) + barrier(); + if (count >= 0) + ug_raw_putc(ch); +} + +void ug_console_write(const char *buf, int len) +{ + char *b = (char *)buf; + + while (len--) { + if (*b == '\n') + ug_putc('\r'); + ug_putc(*b++); + } +} + +static int ug_is_adapter_present(void) +{ + if (!ug_io_base) + return 0; + return ug_io_transaction(0x90000000) == 0x04700000; +} + +static void *ug_grab_exi_io_base(void) +{ + u32 v; + void *devp; + + devp = find_node_by_compatible(NULL, "nintendo,flipper-exi"); + if (devp == NULL) + goto err_out; + if (getprop(devp, "virtual-reg", &v, sizeof(v)) != sizeof(v)) + goto err_out; + + return (void *)v; + +err_out: + return NULL; +} + +void *ug_probe(void) +{ + void *exi_io_base; + int i; + + exi_io_base = ug_grab_exi_io_base(); + if (!exi_io_base) + return NULL; + + /* look for a usbgecko on memcard slots A and B */ + for (i = 0; i < 2; i++) { + ug_io_base = exi_io_base + 0x14 * i; + if (ug_is_adapter_present()) + break; + } + if (i == 2) + ug_io_base = NULL; + return ug_io_base; +} + -- cgit v1.3.1