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/firmware/sysfb_simplefb.c | 140 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 drivers/firmware/sysfb_simplefb.c (limited to 'drivers/firmware/sysfb_simplefb.c') diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c new file mode 100644 index 000000000..71f542e37 --- /dev/null +++ b/drivers/firmware/sysfb_simplefb.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Generic System Framebuffers + * Copyright (c) 2012-2013 David Herrmann + */ + +/* + * simple-framebuffer probing + * Try to convert "screen_info" into a "simple-framebuffer" compatible mode. + * If the mode is incompatible, we return "false" and let the caller create + * legacy nodes instead. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +static const char simplefb_resname[] = "BOOTFB"; +static const struct simplefb_format formats[] = SIMPLEFB_FORMATS; + +/* try parsing screen_info into a simple-framebuffer mode struct */ +__init bool sysfb_parse_mode(const struct screen_info *si, + struct simplefb_platform_data *mode) +{ + __u8 type; + u32 bits_per_pixel; + unsigned int i; + + type = si->orig_video_isVGA; + if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI) + return false; + + bits_per_pixel = __screen_info_lfb_bits_per_pixel(si); + + for (i = 0; i < ARRAY_SIZE(formats); ++i) { + const struct simplefb_format *f = &formats[i]; + + if (f->transp.length) + continue; /* transparent formats are unsupported by VESA/EFI */ + + if (bits_per_pixel == f->bits_per_pixel && + si->red_size == f->red.length && + si->red_pos == f->red.offset && + si->green_size == f->green.length && + si->green_pos == f->green.offset && + si->blue_size == f->blue.length && + si->blue_pos == f->blue.offset) { + mode->format = f->name; + mode->width = si->lfb_width; + mode->height = si->lfb_height; + mode->stride = si->lfb_linelength; + return true; + } + } + + return false; +} + +__init struct platform_device *sysfb_create_simplefb(const struct screen_info *si, + const struct simplefb_platform_data *mode, + struct device *parent) +{ + struct platform_device *pd; + struct resource res; + u64 base, size; + u32 length; + int ret; + + /* + * If the 64BIT_BASE capability is set, ext_lfb_base will contain the + * upper half of the base address. Assemble the address, then make sure + * it is valid and we can actually access it. + */ + base = si->lfb_base; + if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE) + base |= (u64)si->ext_lfb_base << 32; + if (!base || (u64)(resource_size_t)base != base) { + printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n"); + return ERR_PTR(-EINVAL); + } + + /* + * Don't use lfb_size as IORESOURCE size, since it may contain the + * entire VMEM, and thus require huge mappings. Use just the part we + * need, that is, the part where the framebuffer is located. But verify + * that it does not exceed the advertised VMEM. + * Note that in case of VBE, the lfb_size is shifted by 16 bits for + * historical reasons. + */ + size = si->lfb_size; + if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) + size <<= 16; + length = mode->height * mode->stride; + if (length > size) { + printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n"); + return ERR_PTR(-EINVAL); + } + length = PAGE_ALIGN(length); + + /* setup IORESOURCE_MEM as framebuffer memory */ + memset(&res, 0, sizeof(res)); + res.flags = IORESOURCE_MEM; + res.name = simplefb_resname; + res.start = base; + res.end = res.start + length - 1; + if (res.end <= res.start) + return ERR_PTR(-EINVAL); + + pd = platform_device_alloc("simple-framebuffer", 0); + if (!pd) + return ERR_PTR(-ENOMEM); + + pd->dev.parent = parent; + + sysfb_set_efifb_fwnode(si, pd); + + ret = platform_device_add_resources(pd, &res, 1); + if (ret) + goto err_put_device; + + ret = platform_device_add_data(pd, mode, sizeof(*mode)); + if (ret) + goto err_put_device; + + ret = platform_device_add(pd); + if (ret) + goto err_put_device; + + return pd; + +err_put_device: + platform_device_put(pd); + + return ERR_PTR(ret); +} -- cgit v1.3.1