From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/video/fbdev/ocfb.c | 428 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 428 insertions(+) create mode 100644 drivers/video/fbdev/ocfb.c (limited to 'drivers/video/fbdev/ocfb.c') diff --git a/drivers/video/fbdev/ocfb.c b/drivers/video/fbdev/ocfb.c new file mode 100644 index 000000000..893888260 --- /dev/null +++ b/drivers/video/fbdev/ocfb.c @@ -0,0 +1,428 @@ +/* + * OpenCores VGA/LCD 2.0 core frame buffer driver + * + * Copyright (C) 2013 Stefan Kristiansson, stefan.kristiansson@saunalahti.fi + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* OCFB register defines */ +#define OCFB_CTRL 0x000 +#define OCFB_STAT 0x004 +#define OCFB_HTIM 0x008 +#define OCFB_VTIM 0x00c +#define OCFB_HVLEN 0x010 +#define OCFB_VBARA 0x014 +#define OCFB_PALETTE 0x800 + +#define OCFB_CTRL_VEN 0x00000001 /* Video Enable */ +#define OCFB_CTRL_HIE 0x00000002 /* HSync Interrupt Enable */ +#define OCFB_CTRL_PC 0x00000800 /* 8-bit Pseudo Color Enable*/ +#define OCFB_CTRL_CD8 0x00000000 /* Color Depth 8 */ +#define OCFB_CTRL_CD16 0x00000200 /* Color Depth 16 */ +#define OCFB_CTRL_CD24 0x00000400 /* Color Depth 24 */ +#define OCFB_CTRL_CD32 0x00000600 /* Color Depth 32 */ +#define OCFB_CTRL_VBL1 0x00000000 /* Burst Length 1 */ +#define OCFB_CTRL_VBL2 0x00000080 /* Burst Length 2 */ +#define OCFB_CTRL_VBL4 0x00000100 /* Burst Length 4 */ +#define OCFB_CTRL_VBL8 0x00000180 /* Burst Length 8 */ + +#define PALETTE_SIZE 256 + +#define OCFB_NAME "OC VGA/LCD" + +static char *mode_option; + +static const struct fb_videomode default_mode = { + /* 640x480 @ 60 Hz, 31.5 kHz hsync */ + NULL, 60, 640, 480, 39721, 40, 24, 32, 11, 96, 2, + 0, FB_VMODE_NONINTERLACED +}; + +struct ocfb_dev { + struct fb_info info; + void __iomem *regs; + /* flag indicating whether the regs are little endian accessed */ + int little_endian; + /* Physical and virtual addresses of framebuffer */ + dma_addr_t fb_phys; + void __iomem *fb_virt; + u32 pseudo_palette[PALETTE_SIZE]; +}; + +#ifndef MODULE +static int __init ocfb_setup(char *options) +{ + char *curr_opt; + + if (!options || !*options) + return 0; + + while ((curr_opt = strsep(&options, ",")) != NULL) { + if (!*curr_opt) + continue; + mode_option = curr_opt; + } + + return 0; +} +#endif + +static inline u32 ocfb_readreg(struct ocfb_dev *fbdev, loff_t offset) +{ + if (fbdev->little_endian) + return ioread32(fbdev->regs + offset); + else + return ioread32be(fbdev->regs + offset); +} + +static void ocfb_writereg(struct ocfb_dev *fbdev, loff_t offset, u32 data) +{ + if (fbdev->little_endian) + iowrite32(data, fbdev->regs + offset); + else + iowrite32be(data, fbdev->regs + offset); +} + +static int ocfb_setupfb(struct ocfb_dev *fbdev) +{ + unsigned long bpp_config; + struct fb_var_screeninfo *var = &fbdev->info.var; + struct device *dev = fbdev->info.device; + u32 hlen; + u32 vlen; + + /* Disable display */ + ocfb_writereg(fbdev, OCFB_CTRL, 0); + + /* Register framebuffer address */ + fbdev->little_endian = 0; + ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys); + + /* Detect endianess */ + if (ocfb_readreg(fbdev, OCFB_VBARA) != fbdev->fb_phys) { + fbdev->little_endian = 1; + ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys); + } + + /* Horizontal timings */ + ocfb_writereg(fbdev, OCFB_HTIM, (var->hsync_len - 1) << 24 | + (var->left_margin - 1) << 16 | (var->xres - 1)); + + /* Vertical timings */ + ocfb_writereg(fbdev, OCFB_VTIM, (var->vsync_len - 1) << 24 | + (var->upper_margin - 1) << 16 | (var->yres - 1)); + + /* Total length of frame */ + hlen = var->left_margin + var->right_margin + var->hsync_len + + var->xres; + + vlen = var->upper_margin + var->lower_margin + var->vsync_len + + var->yres; + + ocfb_writereg(fbdev, OCFB_HVLEN, (hlen - 1) << 16 | (vlen - 1)); + + bpp_config = OCFB_CTRL_CD8; + switch (var->bits_per_pixel) { + case 8: + if (!var->grayscale) + bpp_config |= OCFB_CTRL_PC; /* enable palette */ + break; + + case 16: + bpp_config |= OCFB_CTRL_CD16; + break; + + case 24: + bpp_config |= OCFB_CTRL_CD24; + break; + + case 32: + bpp_config |= OCFB_CTRL_CD32; + break; + + default: + dev_err(dev, "no bpp specified\n"); + break; + } + + /* maximum (8) VBL (video memory burst length) */ + bpp_config |= OCFB_CTRL_VBL8; + + /* Enable output */ + ocfb_writereg(fbdev, OCFB_CTRL, (OCFB_CTRL_VEN | bpp_config)); + + return 0; +} + +static int ocfb_setcolreg(unsigned regno, unsigned red, unsigned green, + unsigned blue, unsigned transp, + struct fb_info *info) +{ + struct ocfb_dev *fbdev = (struct ocfb_dev *)info->par; + u32 color; + + if (regno >= info->cmap.len) { + dev_err(info->device, "regno >= cmap.len\n"); + return 1; + } + + if (info->var.grayscale) { + /* grayscale = 0.30*R + 0.59*G + 0.11*B */ + red = green = blue = (red * 77 + green * 151 + blue * 28) >> 8; + } + + red >>= (16 - info->var.red.length); + green >>= (16 - info->var.green.length); + blue >>= (16 - info->var.blue.length); + transp >>= (16 - info->var.transp.length); + + if (info->var.bits_per_pixel == 8 && !info->var.grayscale) { + regno <<= 2; + color = (red << 16) | (green << 8) | blue; + ocfb_writereg(fbdev, OCFB_PALETTE + regno, color); + } else { + ((u32 *)(info->pseudo_palette))[regno] = + (red << info->var.red.offset) | + (green << info->var.green.offset) | + (blue << info->var.blue.offset) | + (transp << info->var.transp.offset); + } + + return 0; +} + +static int ocfb_init_fix(struct ocfb_dev *fbdev) +{ + struct fb_var_screeninfo *var = &fbdev->info.var; + struct fb_fix_screeninfo *fix = &fbdev->info.fix; + + strcpy(fix->id, OCFB_NAME); + + fix->line_length = var->xres * var->bits_per_pixel/8; + fix->smem_len = fix->line_length * var->yres; + fix->type = FB_TYPE_PACKED_PIXELS; + + if (var->bits_per_pixel == 8 && !var->grayscale) + fix->visual = FB_VISUAL_PSEUDOCOLOR; + else + fix->visual = FB_VISUAL_TRUECOLOR; + + return 0; +} + +static int ocfb_init_var(struct ocfb_dev *fbdev) +{ + struct fb_var_screeninfo *var = &fbdev->info.var; + + var->accel_flags = FB_ACCEL_NONE; + var->activate = FB_ACTIVATE_NOW; + var->xres_virtual = var->xres; + var->yres_virtual = var->yres; + + switch (var->bits_per_pixel) { + case 8: + var->transp.offset = 0; + var->transp.length = 0; + var->red.offset = 0; + var->red.length = 8; + var->green.offset = 0; + var->green.length = 8; + var->blue.offset = 0; + var->blue.length = 8; + break; + + case 16: + var->transp.offset = 0; + var->transp.length = 0; + var->red.offset = 11; + var->red.length = 5; + var->green.offset = 5; + var->green.length = 6; + var->blue.offset = 0; + var->blue.length = 5; + break; + + case 24: + var->transp.offset = 0; + var->transp.length = 0; + var->red.offset = 16; + var->red.length = 8; + var->green.offset = 8; + var->green.length = 8; + var->blue.offset = 0; + var->blue.length = 8; + break; + + case 32: + var->transp.offset = 24; + var->transp.length = 8; + var->red.offset = 16; + var->red.length = 8; + var->green.offset = 8; + var->green.length = 8; + var->blue.offset = 0; + var->blue.length = 8; + break; + } + + return 0; +} + +static const struct fb_ops ocfb_ops = { + .owner = THIS_MODULE, + FB_DEFAULT_IOMEM_OPS, + .fb_setcolreg = ocfb_setcolreg, +}; + +static int ocfb_probe(struct platform_device *pdev) +{ + int ret = 0; + struct ocfb_dev *fbdev; + int fbsize; + + fbdev = devm_kzalloc(&pdev->dev, sizeof(*fbdev), GFP_KERNEL); + if (!fbdev) + return -ENOMEM; + + platform_set_drvdata(pdev, fbdev); + + fbdev->info.fbops = &ocfb_ops; + fbdev->info.device = &pdev->dev; + fbdev->info.par = fbdev; + + /* Video mode setup */ + if (!fb_find_mode(&fbdev->info.var, &fbdev->info, mode_option, + NULL, 0, &default_mode, 16)) { + dev_err(&pdev->dev, "No valid video modes found\n"); + return -EINVAL; + } + ocfb_init_var(fbdev); + ocfb_init_fix(fbdev); + + fbdev->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(fbdev->regs)) + return PTR_ERR(fbdev->regs); + + /* Allocate framebuffer memory */ + fbsize = fbdev->info.fix.smem_len; + fbdev->fb_virt = dma_alloc_coherent(&pdev->dev, PAGE_ALIGN(fbsize), + &fbdev->fb_phys, GFP_KERNEL); + if (!fbdev->fb_virt) { + dev_err(&pdev->dev, + "Frame buffer memory allocation failed\n"); + return -ENOMEM; + } + fbdev->info.fix.smem_start = fbdev->fb_phys; + fbdev->info.screen_base = fbdev->fb_virt; + fbdev->info.pseudo_palette = fbdev->pseudo_palette; + + /* Clear framebuffer */ + memset_io(fbdev->fb_virt, 0, fbsize); + + /* Setup and enable the framebuffer */ + ocfb_setupfb(fbdev); + + if (fbdev->little_endian) + fbdev->info.flags |= FBINFO_FOREIGN_ENDIAN; + + /* Allocate color map */ + ret = fb_alloc_cmap(&fbdev->info.cmap, PALETTE_SIZE, 0); + if (ret) { + dev_err(&pdev->dev, "Color map allocation failed\n"); + goto err_dma_free; + } + + /* Register framebuffer */ + ret = register_framebuffer(&fbdev->info); + if (ret) { + dev_err(&pdev->dev, "Framebuffer registration failed\n"); + goto err_dealloc_cmap; + } + + return 0; + +err_dealloc_cmap: + fb_dealloc_cmap(&fbdev->info.cmap); + +err_dma_free: + dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbsize), fbdev->fb_virt, + fbdev->fb_phys); + + return ret; +} + +static void ocfb_remove(struct platform_device *pdev) +{ + struct ocfb_dev *fbdev = platform_get_drvdata(pdev); + + unregister_framebuffer(&fbdev->info); + fb_dealloc_cmap(&fbdev->info.cmap); + dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbdev->info.fix.smem_len), + fbdev->fb_virt, fbdev->fb_phys); + + /* Disable display */ + ocfb_writereg(fbdev, OCFB_CTRL, 0); + + platform_set_drvdata(pdev, NULL); +} + +static const struct of_device_id ocfb_match[] = { + { .compatible = "opencores,ocfb", }, + {}, +}; +MODULE_DEVICE_TABLE(of, ocfb_match); + +static struct platform_driver ocfb_driver = { + .probe = ocfb_probe, + .remove = ocfb_remove, + .driver = { + .name = "ocfb_fb", + .of_match_table = ocfb_match, + } +}; + +/* + * Init and exit routines + */ +static int __init ocfb_init(void) +{ +#ifndef MODULE + char *option = NULL; + + if (fb_get_options("ocfb", &option)) + return -ENODEV; + ocfb_setup(option); +#endif + return platform_driver_register(&ocfb_driver); +} + +static void __exit ocfb_exit(void) +{ + platform_driver_unregister(&ocfb_driver); +} + +module_init(ocfb_init); +module_exit(ocfb_exit); + +MODULE_AUTHOR("Stefan Kristiansson "); +MODULE_DESCRIPTION("OpenCores VGA/LCD 2.0 frame buffer driver"); +MODULE_LICENSE("GPL v2"); +module_param(mode_option, charp, 0); +MODULE_PARM_DESC(mode_option, "Video mode ('x[-][@refresh]')"); -- cgit v1.3.1