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/scsi/a3000.c | 315 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 315 insertions(+) create mode 100644 drivers/scsi/a3000.c (limited to 'drivers/scsi/a3000.c') diff --git a/drivers/scsi/a3000.c b/drivers/scsi/a3000.c new file mode 100644 index 000000000..bf054dd76 --- /dev/null +++ b/drivers/scsi/a3000.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#include +#include +#include +#include +#include +#include "wd33c93.h" +#include "a3000.h" + + +struct a3000_hostdata { + struct WD33C93_hostdata wh; + struct a3000_scsiregs *regs; + struct device *dev; +}; + +#define DMA_DIR(d) ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE) + +static irqreturn_t a3000_intr(int irq, void *data) +{ + struct Scsi_Host *instance = data; + struct a3000_hostdata *hdata = shost_priv(instance); + unsigned int status = hdata->regs->ISTR; + unsigned long flags; + + if (!(status & ISTR_INT_P)) + return IRQ_NONE; + if (status & ISTR_INTS) { + spin_lock_irqsave(instance->host_lock, flags); + wd33c93_intr(instance); + spin_unlock_irqrestore(instance->host_lock, flags); + return IRQ_HANDLED; + } + pr_warn("Non-serviced A3000 SCSI-interrupt? ISTR = %02x\n", status); + return IRQ_NONE; +} + +static int dma_setup(struct scsi_cmnd *cmd, int dir_in) +{ + struct scsi_pointer *scsi_pointer = WD33C93_scsi_pointer(cmd); + unsigned long len = scsi_pointer->this_residual; + struct Scsi_Host *instance = cmd->device->host; + struct a3000_hostdata *hdata = shost_priv(instance); + struct WD33C93_hostdata *wh = &hdata->wh; + struct a3000_scsiregs *regs = hdata->regs; + unsigned short cntr = CNTR_PDMD | CNTR_INTEN; + dma_addr_t addr; + + addr = dma_map_single(hdata->dev, scsi_pointer->ptr, + len, DMA_DIR(dir_in)); + if (dma_mapping_error(hdata->dev, addr)) { + dev_warn(hdata->dev, "cannot map SCSI data block %p\n", + scsi_pointer->ptr); + return 1; + } + scsi_pointer->dma_handle = addr; + + /* + * if the physical address has the wrong alignment, or if + * physical address is bad, or if it is a write and at the + * end of a physical memory chunk, then allocate a bounce + * buffer + * MSch 20220629 - only wrong alignment tested - bounce + * buffer returned by kmalloc is guaranteed to be aligned + */ + if (addr & A3000_XFER_MASK) { + WARN_ONCE(1, "Invalid alignment for DMA!"); + /* drop useless mapping */ + dma_unmap_single(hdata->dev, scsi_pointer->dma_handle, + scsi_pointer->this_residual, + DMA_DIR(dir_in)); + + wh->dma_bounce_len = (scsi_pointer->this_residual + 511) & ~0x1ff; + wh->dma_bounce_buffer = kmalloc(wh->dma_bounce_len, + GFP_KERNEL); + + /* can't allocate memory; use PIO */ + if (!wh->dma_bounce_buffer) { + wh->dma_bounce_len = 0; + scsi_pointer->dma_handle = (dma_addr_t) NULL; + return 1; + } + + if (!dir_in) { + /* copy to bounce buffer for a write */ + memcpy(wh->dma_bounce_buffer, scsi_pointer->ptr, + scsi_pointer->this_residual); + } + + addr = dma_map_single(hdata->dev, scsi_pointer->ptr, + len, DMA_DIR(dir_in)); + if (dma_mapping_error(hdata->dev, addr)) { + dev_warn(hdata->dev, + "cannot map SCSI data block %p\n", + scsi_pointer->ptr); + return 1; + } + scsi_pointer->dma_handle = addr; + } + + /* setup dma direction */ + if (!dir_in) + cntr |= CNTR_DDIR; + + /* remember direction */ + wh->dma_dir = dir_in; + + regs->CNTR = cntr; + + /* setup DMA *physical* address */ + regs->ACR = addr; + + /* no more cache flush here - dma_map_single() takes care */ + + /* start DMA */ + mb(); /* make sure setup is completed */ + regs->ST_DMA = 1; + mb(); /* make sure DMA has started before next IO */ + + /* return success */ + return 0; +} + +static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt, + int status) +{ + struct scsi_pointer *scsi_pointer = WD33C93_scsi_pointer(SCpnt); + struct a3000_hostdata *hdata = shost_priv(instance); + struct WD33C93_hostdata *wh = &hdata->wh; + struct a3000_scsiregs *regs = hdata->regs; + + /* disable SCSI interrupts */ + unsigned short cntr = CNTR_PDMD; + + if (!wh->dma_dir) + cntr |= CNTR_DDIR; + + regs->CNTR = cntr; + mb(); /* make sure CNTR is updated before next IO */ + + /* flush if we were reading */ + if (wh->dma_dir) { + regs->FLUSH = 1; + mb(); /* don't allow prefetch */ + while (!(regs->ISTR & ISTR_FE_FLG)) + barrier(); + mb(); /* no IO until FLUSH is done */ + } + + /* clear a possible interrupt */ + /* I think that this CINT is only necessary if you are + * using the terminal count features. HM 7 Mar 1994 + */ + regs->CINT = 1; + + /* stop DMA */ + regs->SP_DMA = 1; + mb(); /* make sure DMA is stopped before next IO */ + + /* restore the CONTROL bits (minus the direction flag) */ + regs->CNTR = CNTR_PDMD | CNTR_INTEN; + mb(); /* make sure CNTR is updated before next IO */ + + dma_unmap_single(hdata->dev, scsi_pointer->dma_handle, + scsi_pointer->this_residual, + DMA_DIR(wh->dma_dir)); + + /* copy from a bounce buffer, if necessary */ + if (status && wh->dma_bounce_buffer) { + if (SCpnt) { + if (wh->dma_dir && SCpnt) + memcpy(scsi_pointer->ptr, wh->dma_bounce_buffer, + scsi_pointer->this_residual); + kfree(wh->dma_bounce_buffer); + wh->dma_bounce_buffer = NULL; + wh->dma_bounce_len = 0; + } else { + kfree(wh->dma_bounce_buffer); + wh->dma_bounce_buffer = NULL; + wh->dma_bounce_len = 0; + } + } +} + +static const struct scsi_host_template amiga_a3000_scsi_template = { + .module = THIS_MODULE, + .name = "Amiga 3000 built-in SCSI", + .show_info = wd33c93_show_info, + .write_info = wd33c93_write_info, + .proc_name = "A3000", + .queuecommand = wd33c93_queuecommand, + .eh_abort_handler = wd33c93_abort, + .eh_host_reset_handler = wd33c93_host_reset, + .can_queue = CAN_QUEUE, + .this_id = 7, + .sg_tablesize = SG_ALL, + .cmd_per_lun = CMD_PER_LUN, + .cmd_size = sizeof(struct scsi_pointer), +}; + +static int __init amiga_a3000_scsi_probe(struct platform_device *pdev) +{ + struct resource *res; + struct Scsi_Host *instance; + int error; + struct a3000_scsiregs *regs; + wd33c93_regs wdregs; + struct a3000_hostdata *hdata; + + if (dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32))) { + dev_warn(&pdev->dev, "cannot use 32 bit DMA\n"); + return -ENODEV; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + if (!request_mem_region(res->start, resource_size(res), "wd33c93")) + return -EBUSY; + + instance = scsi_host_alloc(&amiga_a3000_scsi_template, + sizeof(struct a3000_hostdata)); + if (!instance) { + error = -ENOMEM; + goto fail_alloc; + } + + instance->irq = IRQ_AMIGA_PORTS; + + regs = ZTWO_VADDR(res->start); + regs->DAWR = DAWR_A3000; + + wdregs.SASR = ®s->SASR; + wdregs.SCMD = ®s->SCMD; + + hdata = shost_priv(instance); + hdata->dev = &pdev->dev; + hdata->wh.no_sync = 0xff; + hdata->wh.fast = 0; + hdata->wh.dma_mode = CTRL_DMA; + hdata->regs = regs; + + wd33c93_init(instance, wdregs, dma_setup, dma_stop, WD33C93_FS_12_15); + error = request_irq(IRQ_AMIGA_PORTS, a3000_intr, IRQF_SHARED, + "A3000 SCSI", instance); + if (error) + goto fail_irq; + + regs->CNTR = CNTR_PDMD | CNTR_INTEN; + + error = scsi_add_host(instance, NULL); + if (error) + goto fail_host; + + platform_set_drvdata(pdev, instance); + + scsi_scan_host(instance); + return 0; + +fail_host: + free_irq(IRQ_AMIGA_PORTS, instance); +fail_irq: + scsi_host_put(instance); +fail_alloc: + release_mem_region(res->start, resource_size(res)); + return error; +} + +static void __exit amiga_a3000_scsi_remove(struct platform_device *pdev) +{ + struct Scsi_Host *instance = platform_get_drvdata(pdev); + struct a3000_hostdata *hdata = shost_priv(instance); + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + hdata->regs->CNTR = 0; + scsi_remove_host(instance); + free_irq(IRQ_AMIGA_PORTS, instance); + scsi_host_put(instance); + release_mem_region(res->start, resource_size(res)); +} + +/* + * amiga_a3000_scsi_remove() lives in .exit.text. For drivers registered via + * module_platform_driver_probe() this is ok because they cannot get unbound at + * runtime. So mark the driver struct with __refdata to prevent modpost + * triggering a section mismatch warning. + */ +static struct platform_driver amiga_a3000_scsi_driver __refdata = { + .remove = __exit_p(amiga_a3000_scsi_remove), + .driver = { + .name = "amiga-a3000-scsi", + }, +}; + +module_platform_driver_probe(amiga_a3000_scsi_driver, amiga_a3000_scsi_probe); + +MODULE_DESCRIPTION("Amiga 3000 built-in SCSI"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:amiga-a3000-scsi"); -- cgit v1.3.1