Hi this patch produces a NULL-ptr deref as shown below. The chip is detected as AST 2100. Best regards Thomas ================================================================== [ 23.641896] BUG: KASAN: null-ptr-deref in ast_device_create.cold+0x137/0x210 [ast] [ 23.642257] Read of size 8 at addr 0000000000000610 by task systemd-udevd/321 [ 23.642539] [ 23.642696] CPU: 2 PID: 321 Comm: systemd-udevd Tainted: G E 5.12.0-rc6-1-default+ #876 [ 23.643064] Hardware name: Sun Microsystems SUN FIRE X2270 M2/SUN FIRE X2270 M2, BIOS 2.05 07/01/2010 [ 23.643432] Call Trace: [ 23.643622] ? ast_device_create.cold+0x137/0x210 [ast] [ 23.643898] dump_stack+0xa5/0xdc [ 23.644119] kasan_report.cold+0x50/0x55 [ 23.644363] ? ast_device_create.cold+0x137/0x210 [ast] [ 23.644657] ast_device_create.cold+0x137/0x210 [ast] [ 23.644926] ? devres_get+0xe5/0x160 [ 23.645152] ? ast_detect_chip.isra.0+0x110/0x110 [ast] [ 23.645474] ast_pci_probe+0x4c/0x90 [ast] [ 23.645734] ? ast_kick_out_firmware_fb+0xd0/0xd0 [ast] [ 23.646003] local_pci_probe+0x74/0xc0 [ 23.646249] pci_call_probe+0xb7/0x1d0 [ 23.646473] ? pci_pm_suspend_noirq+0x440/0x440 [ 23.646773] pci_device_probe+0x102/0x140 [ 23.646998] ? driver_sysfs_add+0xe2/0x150 [ 23.647245] really_probe+0x185/0x6c0 [ 23.647506] driver_probe_device+0x13f/0x1d0 [ 23.647762] device_driver_attach+0x114/0x120 [ 23.648010] ? device_driver_attach+0x120/0x120 [ 23.648254] __driver_attach+0xb0/0x1a0 [ 23.648497] ? device_driver_attach+0x120/0x120 [ 23.648739] bus_for_each_dev+0xdd/0x120 [ 23.648971] ? subsys_dev_iter_exit+0x10/0x10 [ 23.649256] bus_add_driver+0x1fb/0x2e0 [ 23.649514] driver_register+0x10f/0x190 [ 23.649752] ? 0xffffffffc05fd000 [ 23.649971] do_one_initcall+0xbb/0x3a0 [ 23.650206] ? trace_event_raw_event_initcall_finish+0x120/0x120 [ 23.650485] ? mark_held_locks+0x23/0x90 [ 23.650718] ? lock_is_held_type+0xe5/0x110 [ 23.650982] ? rcu_read_lock_sched_held+0x3f/0x80 [ 23.651223] ? kasan_unpoison+0x21/0x50 [ 23.651483] do_init_module+0xfd/0x3c0 [ 23.651720] load_module+0xcf2/0xd70 [ 23.651909] ? layout_and_allocate+0x260/0x260 [ 23.652082] ? seccomp_run_filters+0x97/0x1d0 [ 23.652309] ? kernel_read_file_from_fd+0x4b/0x90 [ 23.652584] __do_sys_finit_module+0xff/0x180 [ 23.652824] ? __ia32_sys_init_module+0x40/0x40 [ 23.653198] ? syscall_trace_enter.constprop.0+0x99/0x240 [ 23.653477] do_syscall_64+0x33/0x80 [ 23.653693] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 23.653934] RIP: 0033:0x7f793ecc23dd [ 23.654147] Code: c2 0c 00 0f 05 eb a9 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 63 7a 0c 00 f7 d8 64 89 01 48 [ 23.654749] RSP: 002b:00007ffdc09a08c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 23.655092] RAX: ffffffffffffffda RBX: 000055e8dd73b8d0 RCX: 00007f793ecc23dd [ 23.655375] RDX: 0000000000000000 RSI: 00007f793ede33a3 RDI: 0000000000000010 [ 23.655658] RBP: 0000000000020000 R08: 0000000000000000 R09: 000055e8dd746750 [ 23.655941] R10: 0000000000000010 R11: 0000000000000246 R12: 00007f793ede33a3 [ 23.656224] R13: 000055e8dd743ff0 R14: 0000000000000000 R15: 000055e8dd746a80 [ 23.656603] ================================================================== Am 08.04.21 um 11:30 schrieb KuoHsiang Chou: > [Bug][DP501] > If ASPEED P2A (PCI to AHB) bridge is disabled and disallowed for > CVE_2019_6260 item3, and then the monitor's EDID is unable read through > Parade DP501. > The reason is the DP501's FW is mapped to BMC addressing space rather > than Host addressing space. > The resolution is that using "pci_iomap_range()" maps to DP501's FW that > stored on the end of FB (Frame Buffer). > In this case, FrameBuffer reserves the last 2MB used for the image of > DP501. > > Signed-off-by: KuoHsiang Chou > Reported-by: kernel test robot > --- > drivers/gpu/drm/ast/ast_dp501.c | 139 +++++++++++++++++++++++--------- > drivers/gpu/drm/ast/ast_drv.h | 12 +++ > drivers/gpu/drm/ast/ast_main.c | 8 ++ > 3 files changed, 123 insertions(+), 36 deletions(-) > > diff --git a/drivers/gpu/drm/ast/ast_dp501.c b/drivers/gpu/drm/ast/ast_dp501.c > index 88121c0e0..cd93c44f2 100644 > --- a/drivers/gpu/drm/ast/ast_dp501.c > +++ b/drivers/gpu/drm/ast/ast_dp501.c > @@ -189,6 +189,9 @@ bool ast_backup_fw(struct drm_device *dev, u8 *addr, u32 size) > u32 i, data; > u32 boot_address; > > + if (ast->config_mode != ast_use_p2a) > + return false; > + > data = ast_mindwm(ast, 0x1e6e2100) & 0x01; > if (data) { > boot_address = get_fw_base(ast); > @@ -207,6 +210,9 @@ static bool ast_launch_m68k(struct drm_device *dev) > u8 *fw_addr = NULL; > u8 jreg; > > + if (ast->config_mode != ast_use_p2a) > + return false; > + > data = ast_mindwm(ast, 0x1e6e2100) & 0x01; > if (!data) { > > @@ -271,25 +277,55 @@ u8 ast_get_dp501_max_clk(struct drm_device *dev) > struct ast_private *ast = to_ast_private(dev); > u32 boot_address, offset, data; > u8 linkcap[4], linkrate, linklanes, maxclk = 0xff; > + u32 *plinkcap; > > - boot_address = get_fw_base(ast); > - > - /* validate FW version */ > - offset = 0xf000; > - data = ast_mindwm(ast, boot_address + offset); > - if ((data & 0xf0) != 0x10) /* version: 1x */ > - return maxclk; > - > - /* Read Link Capability */ > - offset = 0xf014; > - *(u32 *)linkcap = ast_mindwm(ast, boot_address + offset); > - if (linkcap[2] == 0) { > - linkrate = linkcap[0]; > - linklanes = linkcap[1]; > - data = (linkrate == 0x0a) ? (90 * linklanes) : (54 * linklanes); > - if (data > 0xff) > - data = 0xff; > - maxclk = (u8)data; > + if (ast->config_mode == ast_use_p2a) { > + boot_address = get_fw_base(ast); > + > + /* validate FW version */ > + offset = AST_DP501_GBL_VERSION; > + data = ast_mindwm(ast, boot_address + offset); > + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1) /* version: 1x */ > + return maxclk; > + > + /* Read Link Capability */ > + offset = AST_DP501_LINKRATE; > + plinkcap = (u32 *)linkcap; > + *plinkcap = ast_mindwm(ast, boot_address + offset); > + if (linkcap[2] == 0) { > + linkrate = linkcap[0]; > + linklanes = linkcap[1]; > + data = (linkrate == 0x0a) ? (90 * linklanes) : (54 * linklanes); > + if (data > 0xff) > + data = 0xff; > + maxclk = (u8)data; > + } > + } else { > + if (!ast->dp501_fw_buf) > + return AST_DP501_DEFAULT_DCLK; /* 1024x768 as default */ > + > + /* dummy read */ > + offset = 0x0000; > + data = readl(ast->dp501_fw_buf + offset); > + > + /* validate FW version */ > + offset = AST_DP501_GBL_VERSION; > + data = readl(ast->dp501_fw_buf + offset); > + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1) /* version: 1x */ > + return maxclk; > + > + /* Read Link Capability */ > + offset = AST_DP501_LINKRATE; > + plinkcap = (u32 *)linkcap; > + *plinkcap = readl(ast->dp501_fw_buf + offset); > + if (linkcap[2] == 0) { > + linkrate = linkcap[0]; > + linklanes = linkcap[1]; > + data = (linkrate == 0x0a) ? (90 * linklanes) : (54 * linklanes); > + if (data > 0xff) > + data = 0xff; > + maxclk = (u8)data; > + } > } > return maxclk; > } > @@ -298,26 +334,57 @@ bool ast_dp501_read_edid(struct drm_device *dev, u8 *ediddata) > { > struct ast_private *ast = to_ast_private(dev); > u32 i, boot_address, offset, data; > + u32 *pEDIDidx; > > - boot_address = get_fw_base(ast); > - > - /* validate FW version */ > - offset = 0xf000; > - data = ast_mindwm(ast, boot_address + offset); > - if ((data & 0xf0) != 0x10) > - return false; > - > - /* validate PnP Monitor */ > - offset = 0xf010; > - data = ast_mindwm(ast, boot_address + offset); > - if (!(data & 0x01)) > - return false; > + if (ast->config_mode == ast_use_p2a) { > + boot_address = get_fw_base(ast); > > - /* Read EDID */ > - offset = 0xf020; > - for (i = 0; i < 128; i += 4) { > - data = ast_mindwm(ast, boot_address + offset + i); > - *(u32 *)(ediddata + i) = data; > + /* validate FW version */ > + offset = AST_DP501_GBL_VERSION; > + data = ast_mindwm(ast, boot_address + offset); > + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1) > + return false; > + > + /* validate PnP Monitor */ > + offset = AST_DP501_PNPMONITOR; > + data = ast_mindwm(ast, boot_address + offset); > + if (!(data & AST_DP501_PNP_CONNECTED)) > + return false; > + > + /* Read EDID */ > + offset = AST_DP501_EDID_DATA; > + for (i = 0; i < 128; i += 4) { > + data = ast_mindwm(ast, boot_address + offset + i); > + pEDIDidx = (u32 *)(ediddata + i); > + *pEDIDidx = data; > + } > + } else { > + if (!ast->dp501_fw_buf) > + return false; > + > + /* dummy read */ > + offset = 0x0000; > + data = readl(ast->dp501_fw_buf + offset); > + > + /* validate FW version */ > + offset = AST_DP501_GBL_VERSION; > + data = readl(ast->dp501_fw_buf + offset); > + if ((data & AST_DP501_FW_VERSION_MASK) != AST_DP501_FW_VERSION_1) > + return false; > + > + /* validate PnP Monitor */ > + offset = AST_DP501_PNPMONITOR; > + data = readl(ast->dp501_fw_buf + offset); > + if (!(data & AST_DP501_PNP_CONNECTED)) > + return false; > + > + /* Read EDID */ > + offset = AST_DP501_EDID_DATA; > + for (i = 0; i < 128; i += 4) { > + data = readl(ast->dp501_fw_buf + offset + i); > + pEDIDidx = (u32 *)(ediddata + i); > + *pEDIDidx = data; > + } > } > > return true; > diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h > index e82ab8628..911f9f414 100644 > --- a/drivers/gpu/drm/ast/ast_drv.h > +++ b/drivers/gpu/drm/ast/ast_drv.h > @@ -150,6 +150,7 @@ struct ast_private { > > void __iomem *regs; > void __iomem *ioregs; > + void __iomem *dp501_fw_buf; > > enum ast_chip chip; > bool vga2_clone; > @@ -325,6 +326,17 @@ int ast_mode_config_init(struct ast_private *ast); > #define AST_MM_ALIGN_SHIFT 4 > #define AST_MM_ALIGN_MASK ((1 << AST_MM_ALIGN_SHIFT) - 1) > > +#define AST_DP501_FW_VERSION_MASK GENMASK(7, 4) > +#define AST_DP501_FW_VERSION_1 BIT(4) > +#define AST_DP501_PNP_CONNECTED BIT(1) > + > +#define AST_DP501_DEFAULT_DCLK 65 > + > +#define AST_DP501_GBL_VERSION 0xf000 > +#define AST_DP501_PNPMONITOR 0xf010 > +#define AST_DP501_LINKRATE 0xf014 > +#define AST_DP501_EDID_DATA 0xf020 > + > int ast_mm_init(struct ast_private *ast); > > /* ast post */ > diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c > index 0ac3c2039..dbf5224ab 100644 > --- a/drivers/gpu/drm/ast/ast_main.c > +++ b/drivers/gpu/drm/ast/ast_main.c > @@ -450,6 +450,14 @@ struct ast_private *ast_device_create(const struct drm_driver *drv, > if (ret) > return ERR_PTR(ret); > > + /* map reserved buffer */ > + ast->dp501_fw_buf = NULL; > + if (dev->vram_mm->vram_size < pci_resource_len(dev->pdev, 0)) { > + ast->dp501_fw_buf = pci_iomap_range(dev->pdev, 0, dev->vram_mm->vram_size, 0); > + if (!ast->dp501_fw_buf) > + drm_info(dev, "failed to map reserved buffer!\n"); > + } > + > ret = ast_mode_config_init(ast); > if (ret) > return ERR_PTR(ret); > -- > 2.18.4 > -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer