Revision 38860b2c8bb1b92f61396eb06a63adff916fc31d authored by John David Anglin on 08 November 2021, 21:48:16 UTC, committed by Helge Deller on 13 November 2021, 21:10:56 UTC
For years, there have been random segmentation faults in userspace on SMP PA-RISC machines. It occurred to me that this might be a problem in set_pte_at(). MIPS and some other architectures do cache flushes when installing PTEs with the present bit set. Here I have adapted the code in update_mmu_cache() to flush the kernel mapping when the kernel flush is deferred, or when the kernel mapping may alias with the user mapping. This simplifies calls to update_mmu_cache(). I also changed the barrier in set_pte() from a compiler barrier to a full memory barrier. I know this change is not sufficient to fix the problem. It might not be needed. I have had a few days of operation with 5.14.16 to 5.15.1 and haven't seen any random segmentation faults on rp3440 or c8000 so far. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de> Cc: stable@kernel.org # 5.12+
1 parent f0d1cfa
irq_sim.c
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017-2018 Bartosz Golaszewski <brgl@bgdev.pl>
* Copyright (C) 2020 Bartosz Golaszewski <bgolaszewski@baylibre.com>
*/
#include <linux/irq.h>
#include <linux/irq_sim.h>
#include <linux/irq_work.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
struct irq_sim_work_ctx {
struct irq_work work;
int irq_base;
unsigned int irq_count;
unsigned long *pending;
struct irq_domain *domain;
};
struct irq_sim_irq_ctx {
int irqnum;
bool enabled;
struct irq_sim_work_ctx *work_ctx;
};
static void irq_sim_irqmask(struct irq_data *data)
{
struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
irq_ctx->enabled = false;
}
static void irq_sim_irqunmask(struct irq_data *data)
{
struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
irq_ctx->enabled = true;
}
static int irq_sim_set_type(struct irq_data *data, unsigned int type)
{
/* We only support rising and falling edge trigger types. */
if (type & ~IRQ_TYPE_EDGE_BOTH)
return -EINVAL;
irqd_set_trigger_type(data, type);
return 0;
}
static int irq_sim_get_irqchip_state(struct irq_data *data,
enum irqchip_irq_state which, bool *state)
{
struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
irq_hw_number_t hwirq = irqd_to_hwirq(data);
switch (which) {
case IRQCHIP_STATE_PENDING:
if (irq_ctx->enabled)
*state = test_bit(hwirq, irq_ctx->work_ctx->pending);
break;
default:
return -EINVAL;
}
return 0;
}
static int irq_sim_set_irqchip_state(struct irq_data *data,
enum irqchip_irq_state which, bool state)
{
struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
irq_hw_number_t hwirq = irqd_to_hwirq(data);
switch (which) {
case IRQCHIP_STATE_PENDING:
if (irq_ctx->enabled) {
assign_bit(hwirq, irq_ctx->work_ctx->pending, state);
if (state)
irq_work_queue(&irq_ctx->work_ctx->work);
}
break;
default:
return -EINVAL;
}
return 0;
}
static struct irq_chip irq_sim_irqchip = {
.name = "irq_sim",
.irq_mask = irq_sim_irqmask,
.irq_unmask = irq_sim_irqunmask,
.irq_set_type = irq_sim_set_type,
.irq_get_irqchip_state = irq_sim_get_irqchip_state,
.irq_set_irqchip_state = irq_sim_set_irqchip_state,
};
static void irq_sim_handle_irq(struct irq_work *work)
{
struct irq_sim_work_ctx *work_ctx;
unsigned int offset = 0;
int irqnum;
work_ctx = container_of(work, struct irq_sim_work_ctx, work);
while (!bitmap_empty(work_ctx->pending, work_ctx->irq_count)) {
offset = find_next_bit(work_ctx->pending,
work_ctx->irq_count, offset);
clear_bit(offset, work_ctx->pending);
irqnum = irq_find_mapping(work_ctx->domain, offset);
handle_simple_irq(irq_to_desc(irqnum));
}
}
static int irq_sim_domain_map(struct irq_domain *domain,
unsigned int virq, irq_hw_number_t hw)
{
struct irq_sim_work_ctx *work_ctx = domain->host_data;
struct irq_sim_irq_ctx *irq_ctx;
irq_ctx = kzalloc(sizeof(*irq_ctx), GFP_KERNEL);
if (!irq_ctx)
return -ENOMEM;
irq_set_chip(virq, &irq_sim_irqchip);
irq_set_chip_data(virq, irq_ctx);
irq_set_handler(virq, handle_simple_irq);
irq_modify_status(virq, IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
irq_ctx->work_ctx = work_ctx;
return 0;
}
static void irq_sim_domain_unmap(struct irq_domain *domain, unsigned int virq)
{
struct irq_sim_irq_ctx *irq_ctx;
struct irq_data *irqd;
irqd = irq_domain_get_irq_data(domain, virq);
irq_ctx = irq_data_get_irq_chip_data(irqd);
irq_set_handler(virq, NULL);
irq_domain_reset_irq_data(irqd);
kfree(irq_ctx);
}
static const struct irq_domain_ops irq_sim_domain_ops = {
.map = irq_sim_domain_map,
.unmap = irq_sim_domain_unmap,
};
/**
* irq_domain_create_sim - Create a new interrupt simulator irq_domain and
* allocate a range of dummy interrupts.
*
* @fwnode: struct fwnode_handle to be associated with this domain.
* @num_irqs: Number of interrupts to allocate.
*
* On success: return a new irq_domain object.
* On failure: a negative errno wrapped with ERR_PTR().
*/
struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
unsigned int num_irqs)
{
struct irq_sim_work_ctx *work_ctx;
work_ctx = kmalloc(sizeof(*work_ctx), GFP_KERNEL);
if (!work_ctx)
goto err_out;
work_ctx->pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
if (!work_ctx->pending)
goto err_free_work_ctx;
work_ctx->domain = irq_domain_create_linear(fwnode, num_irqs,
&irq_sim_domain_ops,
work_ctx);
if (!work_ctx->domain)
goto err_free_bitmap;
work_ctx->irq_count = num_irqs;
init_irq_work(&work_ctx->work, irq_sim_handle_irq);
return work_ctx->domain;
err_free_bitmap:
bitmap_free(work_ctx->pending);
err_free_work_ctx:
kfree(work_ctx);
err_out:
return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL_GPL(irq_domain_create_sim);
/**
* irq_domain_remove_sim - Deinitialize the interrupt simulator domain: free
* the interrupt descriptors and allocated memory.
*
* @domain: The interrupt simulator domain to tear down.
*/
void irq_domain_remove_sim(struct irq_domain *domain)
{
struct irq_sim_work_ctx *work_ctx = domain->host_data;
irq_work_sync(&work_ctx->work);
bitmap_free(work_ctx->pending);
kfree(work_ctx);
irq_domain_remove(domain);
}
EXPORT_SYMBOL_GPL(irq_domain_remove_sim);
static void devm_irq_domain_remove_sim(void *data)
{
struct irq_domain *domain = data;
irq_domain_remove_sim(domain);
}
/**
* devm_irq_domain_create_sim - Create a new interrupt simulator for
* a managed device.
*
* @dev: Device to initialize the simulator object for.
* @fwnode: struct fwnode_handle to be associated with this domain.
* @num_irqs: Number of interrupts to allocate
*
* On success: return a new irq_domain object.
* On failure: a negative errno wrapped with ERR_PTR().
*/
struct irq_domain *devm_irq_domain_create_sim(struct device *dev,
struct fwnode_handle *fwnode,
unsigned int num_irqs)
{
struct irq_domain *domain;
int ret;
domain = irq_domain_create_sim(fwnode, num_irqs);
if (IS_ERR(domain))
return domain;
ret = devm_add_action_or_reset(dev, devm_irq_domain_remove_sim, domain);
if (ret)
return ERR_PTR(ret);
return domain;
}
EXPORT_SYMBOL_GPL(devm_irq_domain_create_sim);
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...