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 --- drivers/nvmem/lan9662-otpc.c | 228 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 228 insertions(+) create mode 100644 drivers/nvmem/lan9662-otpc.c (limited to 'drivers/nvmem/lan9662-otpc.c') diff --git a/drivers/nvmem/lan9662-otpc.c b/drivers/nvmem/lan9662-otpc.c new file mode 100644 index 000000000..62d1d6381 --- /dev/null +++ b/drivers/nvmem/lan9662-otpc.c @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include + +#define OTP_OTP_PWR_DN(t) (t + 0x00) +#define OTP_OTP_PWR_DN_OTP_PWRDN_N BIT(0) +#define OTP_OTP_ADDR_HI(t) (t + 0x04) +#define OTP_OTP_ADDR_LO(t) (t + 0x08) +#define OTP_OTP_PRGM_DATA(t) (t + 0x10) +#define OTP_OTP_PRGM_MODE(t) (t + 0x14) +#define OTP_OTP_PRGM_MODE_OTP_PGM_MODE_BYTE BIT(0) +#define OTP_OTP_RD_DATA(t) (t + 0x18) +#define OTP_OTP_FUNC_CMD(t) (t + 0x20) +#define OTP_OTP_FUNC_CMD_OTP_PROGRAM BIT(1) +#define OTP_OTP_FUNC_CMD_OTP_READ BIT(0) +#define OTP_OTP_CMD_GO(t) (t + 0x28) +#define OTP_OTP_CMD_GO_OTP_GO BIT(0) +#define OTP_OTP_PASS_FAIL(t) (t + 0x2c) +#define OTP_OTP_PASS_FAIL_OTP_READ_PROHIBITED BIT(3) +#define OTP_OTP_PASS_FAIL_OTP_WRITE_PROHIBITED BIT(2) +#define OTP_OTP_PASS_FAIL_OTP_FAIL BIT(0) +#define OTP_OTP_STATUS(t) (t + 0x30) +#define OTP_OTP_STATUS_OTP_CPUMPEN BIT(1) +#define OTP_OTP_STATUS_OTP_BUSY BIT(0) + +#define OTP_SLEEP_US 10 +#define OTP_TIMEOUT_US 500000 + +struct lan9662_otp { + struct device *dev; + void __iomem *base; +}; + +static int lan9662_otp_wait_flag_clear(void __iomem *reg, u32 flag) +{ + u32 val; + + return readl_poll_timeout(reg, val, !(val & flag), + OTP_SLEEP_US, OTP_TIMEOUT_US); +} + +static int lan9662_otp_power(struct lan9662_otp *otp, bool up) +{ + void __iomem *pwrdn = OTP_OTP_PWR_DN(otp->base); + + if (up) { + writel(readl(pwrdn) & ~OTP_OTP_PWR_DN_OTP_PWRDN_N, pwrdn); + if (lan9662_otp_wait_flag_clear(OTP_OTP_STATUS(otp->base), + OTP_OTP_STATUS_OTP_CPUMPEN)) + return -ETIMEDOUT; + } else { + writel(readl(pwrdn) | OTP_OTP_PWR_DN_OTP_PWRDN_N, pwrdn); + } + + return 0; +} + +static int lan9662_otp_execute(struct lan9662_otp *otp) +{ + if (lan9662_otp_wait_flag_clear(OTP_OTP_CMD_GO(otp->base), + OTP_OTP_CMD_GO_OTP_GO)) + return -ETIMEDOUT; + + if (lan9662_otp_wait_flag_clear(OTP_OTP_STATUS(otp->base), + OTP_OTP_STATUS_OTP_BUSY)) + return -ETIMEDOUT; + + return 0; +} + +static void lan9662_otp_set_address(struct lan9662_otp *otp, u32 offset) +{ + writel(0xff & (offset >> 8), OTP_OTP_ADDR_HI(otp->base)); + writel(0xff & offset, OTP_OTP_ADDR_LO(otp->base)); +} + +static int lan9662_otp_read_byte(struct lan9662_otp *otp, u32 offset, u8 *dst) +{ + u32 pass; + int rc; + + lan9662_otp_set_address(otp, offset); + writel(OTP_OTP_FUNC_CMD_OTP_READ, OTP_OTP_FUNC_CMD(otp->base)); + writel(OTP_OTP_CMD_GO_OTP_GO, OTP_OTP_CMD_GO(otp->base)); + rc = lan9662_otp_execute(otp); + if (!rc) { + pass = readl(OTP_OTP_PASS_FAIL(otp->base)); + if (pass & OTP_OTP_PASS_FAIL_OTP_READ_PROHIBITED) + return -EACCES; + *dst = (u8) readl(OTP_OTP_RD_DATA(otp->base)); + } + return rc; +} + +static int lan9662_otp_write_byte(struct lan9662_otp *otp, u32 offset, u8 data) +{ + u32 pass; + int rc; + + lan9662_otp_set_address(otp, offset); + writel(OTP_OTP_PRGM_MODE_OTP_PGM_MODE_BYTE, OTP_OTP_PRGM_MODE(otp->base)); + writel(data, OTP_OTP_PRGM_DATA(otp->base)); + writel(OTP_OTP_FUNC_CMD_OTP_PROGRAM, OTP_OTP_FUNC_CMD(otp->base)); + writel(OTP_OTP_CMD_GO_OTP_GO, OTP_OTP_CMD_GO(otp->base)); + + rc = lan9662_otp_execute(otp); + if (!rc) { + pass = readl(OTP_OTP_PASS_FAIL(otp->base)); + if (pass & OTP_OTP_PASS_FAIL_OTP_WRITE_PROHIBITED) + return -EACCES; + if (pass & OTP_OTP_PASS_FAIL_OTP_FAIL) + return -EIO; + } + return rc; +} + +static int lan9662_otp_read(void *context, unsigned int offset, + void *_val, size_t bytes) +{ + struct lan9662_otp *otp = context; + u8 *val = _val; + uint8_t data; + int i, rc = 0; + + lan9662_otp_power(otp, true); + for (i = 0; i < bytes; i++) { + rc = lan9662_otp_read_byte(otp, offset + i, &data); + if (rc < 0) + break; + *val++ = data; + } + lan9662_otp_power(otp, false); + + return rc; +} + +static int lan9662_otp_write(void *context, unsigned int offset, + void *_val, size_t bytes) +{ + struct lan9662_otp *otp = context; + u8 *val = _val; + u8 data, newdata; + int i, rc = 0; + + lan9662_otp_power(otp, true); + for (i = 0; i < bytes; i++) { + /* Skip zero bytes */ + if (val[i]) { + rc = lan9662_otp_read_byte(otp, offset + i, &data); + if (rc < 0) + break; + + newdata = data | val[i]; + if (newdata == data) + continue; + + rc = lan9662_otp_write_byte(otp, offset + i, + newdata); + if (rc < 0) + break; + } + } + lan9662_otp_power(otp, false); + + return rc; +} + +static struct nvmem_config otp_config = { + .name = "lan9662-otp", + .stride = 1, + .word_size = 1, + .reg_read = lan9662_otp_read, + .reg_write = lan9662_otp_write, +}; + +static int lan9662_otp_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct nvmem_device *nvmem; + struct lan9662_otp *otp; + + otp = devm_kzalloc(&pdev->dev, sizeof(*otp), GFP_KERNEL); + if (!otp) + return -ENOMEM; + + otp->dev = dev; + otp->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(otp->base)) + return PTR_ERR(otp->base); + + otp_config.priv = otp; + otp_config.dev = dev; + otp_config.size = (uintptr_t) device_get_match_data(dev); + + nvmem = devm_nvmem_register(dev, &otp_config); + + return PTR_ERR_OR_ZERO(nvmem); +} + +static const struct of_device_id lan9662_otp_match[] = { + { + .compatible = "microchip,lan9662-otpc", + .data = (const void *) SZ_8K, + }, + { + .compatible = "microchip,lan9691-otpc", + .data = (const void *) SZ_16K, + }, + { }, +}; +MODULE_DEVICE_TABLE(of, lan9662_otp_match); + +static struct platform_driver lan9662_otp_driver = { + .probe = lan9662_otp_probe, + .driver = { + .name = "lan9662-otp", + .of_match_table = lan9662_otp_match, + }, +}; +module_platform_driver(lan9662_otp_driver); + +MODULE_AUTHOR("Horatiu Vultur "); +MODULE_DESCRIPTION("lan9662 OTP driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1