summaryrefslogtreecommitdiffstats
path: root/include/drm/drm_panic.h
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /include/drm/drm_panic.h
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'include/drm/drm_panic.h')
-rw-r--r--include/drm/drm_panic.h189
1 files changed, 189 insertions, 0 deletions
diff --git a/include/drm/drm_panic.h b/include/drm/drm_panic.h
new file mode 100644
index 000000000..ac0e46b73
--- /dev/null
+++ b/include/drm/drm_panic.h
@@ -0,0 +1,189 @@
+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+
+/*
+ * Copyright (c) 2024 Intel
+ * Copyright (c) 2024 Red Hat
+ */
+
+#ifndef __DRM_PANIC_H__
+#define __DRM_PANIC_H__
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/iosys-map.h>
+
+#include <drm/drm_device.h>
+#include <drm/drm_fourcc.h>
+
+/**
+ * struct drm_scanout_buffer - DRM scanout buffer
+ *
+ * This structure holds the information necessary for drm_panic to draw the
+ * panic screen, and display it.
+ */
+struct drm_scanout_buffer {
+ /**
+ * @format:
+ *
+ * drm format of the scanout buffer.
+ */
+ const struct drm_format_info *format;
+
+ /**
+ * @map:
+ *
+ * Virtual address of the scanout buffer, either in memory or iomem.
+ * The scanout buffer should be in linear format, and can be directly
+ * sent to the display hardware. Tearing is not an issue for the panic
+ * screen.
+ */
+ struct iosys_map map[DRM_FORMAT_MAX_PLANES];
+
+ /**
+ * @pages: Optional, if the scanout buffer is not mapped, set this field
+ * to the array of pages of the scanout buffer. The panic code will use
+ * kmap_local_page_try_from_panic() to map one page at a time to write
+ * all the pixels. This array shouldn't be allocated from the
+ * get_scanoutbuffer() callback.
+ * The scanout buffer should be in linear format.
+ */
+ struct page **pages;
+
+ /**
+ * @width: Width of the scanout buffer, in pixels.
+ */
+ unsigned int width;
+
+ /**
+ * @height: Height of the scanout buffer, in pixels.
+ */
+ unsigned int height;
+
+ /**
+ * @pitch: Length in bytes between the start of two consecutive lines.
+ */
+ unsigned int pitch[DRM_FORMAT_MAX_PLANES];
+
+ /**
+ * @set_pixel: Optional function, to set a pixel color on the
+ * framebuffer. It allows to handle special tiling format inside the
+ * driver. It takes precedence over the @map and @pages fields.
+ */
+ void (*set_pixel)(struct drm_scanout_buffer *sb, unsigned int x,
+ unsigned int y, u32 color);
+
+ /**
+ * @private: private pointer that you can use in the callbacks
+ * set_pixel()
+ */
+ void *private;
+
+};
+
+#ifdef CONFIG_DRM_PANIC
+
+/**
+ * drm_panic_trylock - try to enter the panic printing critical section
+ * @dev: struct drm_device
+ * @flags: unsigned long irq flags you need to pass to the unlock() counterpart
+ *
+ * This function must be called by any panic printing code. The panic printing
+ * attempt must be aborted if the trylock fails.
+ *
+ * Panic printing code can make the following assumptions while holding the
+ * panic lock:
+ *
+ * - Anything protected by drm_panic_lock() and drm_panic_unlock() pairs is safe
+ * to access.
+ *
+ * - Furthermore the panic printing code only registers in drm_dev_unregister()
+ * and gets removed in drm_dev_unregister(). This allows the panic code to
+ * safely access any state which is invariant in between these two function
+ * calls, like the list of planes &drm_mode_config.plane_list or most of the
+ * struct drm_plane structure.
+ *
+ * Specifically thanks to the protection around plane updates in
+ * drm_atomic_helper_swap_state() the following additional guarantees hold:
+ *
+ * - It is safe to deference the drm_plane.state pointer.
+ *
+ * - Anything in struct drm_plane_state or the driver's subclass thereof which
+ * stays invariant after the atomic check code has finished is safe to access.
+ * Specifically this includes the reference counted pointers to framebuffer
+ * and buffer objects.
+ *
+ * - Anything set up by &drm_plane_helper_funcs.fb_prepare and cleaned up
+ * &drm_plane_helper_funcs.fb_cleanup is safe to access, as long as it stays
+ * invariant between these two calls. This also means that for drivers using
+ * dynamic buffer management the framebuffer is pinned, and therefer all
+ * relevant datastructures can be accessed without taking any further locks
+ * (which would be impossible in panic context anyway).
+ *
+ * - Importantly, software and hardware state set up by
+ * &drm_plane_helper_funcs.begin_fb_access and
+ * &drm_plane_helper_funcs.end_fb_access is not safe to access.
+ *
+ * Drivers must not make any assumptions about the actual state of the hardware,
+ * unless they explicitly protected these hardware access with drm_panic_lock()
+ * and drm_panic_unlock().
+ *
+ * Return:
+ * %0 when failing to acquire the raw spinlock, nonzero on success.
+ */
+#define drm_panic_trylock(dev, flags) \
+ raw_spin_trylock_irqsave(&(dev)->mode_config.panic_lock, flags)
+
+/**
+ * drm_panic_lock - protect panic printing relevant state
+ * @dev: struct drm_device
+ * @flags: unsigned long irq flags you need to pass to the unlock() counterpart
+ *
+ * This function must be called to protect software and hardware state that the
+ * panic printing code must be able to rely on. The protected sections must be
+ * as small as possible. It uses the irqsave/irqrestore variant, and can be
+ * called from irq handler. Examples include:
+ *
+ * - Access to peek/poke or other similar registers, if that is the way the
+ * driver prints the pixels into the scanout buffer at panic time.
+ *
+ * - Updates to pointers like &drm_plane.state, allowing the panic handler to
+ * safely deference these. This is done in drm_atomic_helper_swap_state().
+ *
+ * - An state that isn't invariant and that the driver must be able to access
+ * during panic printing.
+ */
+
+#define drm_panic_lock(dev, flags) \
+ raw_spin_lock_irqsave(&(dev)->mode_config.panic_lock, flags)
+
+/**
+ * drm_panic_unlock - end of the panic printing critical section
+ * @dev: struct drm_device
+ * @flags: irq flags that were returned when acquiring the lock
+ *
+ * Unlocks the raw spinlock acquired by either drm_panic_lock() or
+ * drm_panic_trylock().
+ */
+#define drm_panic_unlock(dev, flags) \
+ raw_spin_unlock_irqrestore(&(dev)->mode_config.panic_lock, flags)
+
+#else
+
+static inline bool drm_panic_trylock(struct drm_device *dev, unsigned long flags)
+{
+ return true;
+}
+
+static inline void drm_panic_lock(struct drm_device *dev, unsigned long flags) {}
+static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) {}
+
+#endif
+
+#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
+size_t drm_panic_qr_max_data_size(u8 version, size_t url_len);
+
+u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size,
+ u8 *tmp, size_t tmp_size);
+#endif
+
+#endif /* __DRM_PANIC_H__ */