video:uvesafb: Fix oops that uvesafb try to execute NX-protected page

commit b78f29ca05 upstream.

This patch fix the oops below that catched in my machine

[   81.560602] uvesafb: NVIDIA Corporation, GT216 Board - 0696a290, Chip Rev   , OEM: NVIDIA, VBE v3.0
[   81.609384] uvesafb: protected mode interface info at c000:d350
[   81.609388] uvesafb: pmi: set display start = c00cd3b3, set palette = c00cd40e
[   81.609390] uvesafb: pmi: ports = 3b4 3b5 3ba 3c0 3c1 3c4 3c5 3c6 3c7 3c8 3c9 3cc 3ce 3cf 3d0 3d1 3d2 3d3 3d4 3d5 3da
[   81.614558] uvesafb: VBIOS/hardware doesn't support DDC transfers
[   81.614562] uvesafb: no monitor limits have been set, default refresh rate will be used
[   81.614994] uvesafb: scrolling: ypan using protected mode interface, yres_virtual=4915
[   81.744147] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
[   81.744153] BUG: unable to handle kernel paging request at c00cd3b3
[   81.744159] IP: [<c00cd3b3>] 0xc00cd3b2
[   81.744167] *pdpt = 00000000016d6001 *pde = 0000000001c7b067 *pte = 80000000000cd163
[   81.744171] Oops: 0011 [#1] SMP
[   81.744174] Modules linked in: uvesafb(+) cfbcopyarea cfbimgblt cfbfillrect
[   81.744178]
[   81.744181] Pid: 3497, comm: modprobe Not tainted 3.3.0-rc4NX+ #71 Acer            Aspire 4741                    /Aspire 4741
[   81.744185] EIP: 0060:[<c00cd3b3>] EFLAGS: 00010246 CPU: 0
[   81.744187] EIP is at 0xc00cd3b3
[   81.744189] EAX: 00004f07 EBX: 00000000 ECX: 00000000 EDX: 00000000
[   81.744191] ESI: f763f000 EDI: f763f6e8 EBP: f57f3a0c ESP: f57f3a00
[   81.744192]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[   81.744195] Process modprobe (pid: 3497, ti=f57f2000 task=f748c600 task.ti=f57f2000)
[   81.744196] Stack:
[   81.744197]  f82512c5 f759341c 00000000 f57f3a30 c124a9bc 00000001 00000001 000001e0
[   81.744202]  f8251280 f763f000 f7593400 00000000 f57f3a40 c12598dd f5c0c000 00000000
[   81.744206]  f57f3b10 c1255efe c125a21a 00000006 f763f09c 00000000 c1c6cb60 f7593400
[   81.744210] Call Trace:
[   81.744215]  [<f82512c5>] ? uvesafb_pan_display+0x45/0x60 [uvesafb]
[   81.744222]  [<c124a9bc>] fb_pan_display+0x10c/0x160
[   81.744226]  [<f8251280>] ? uvesafb_vbe_find_mode+0x180/0x180 [uvesafb]
[   81.744230]  [<c12598dd>] bit_update_start+0x1d/0x50
[   81.744232]  [<c1255efe>] fbcon_switch+0x39e/0x550
[   81.744235]  [<c125a21a>] ? bit_cursor+0x4ea/0x560
[   81.744240]  [<c129b6cb>] redraw_screen+0x12b/0x220
[   81.744245]  [<c128843b>] ? tty_do_resize+0x3b/0xc0
[   81.744247]  [<c129ef42>] vc_do_resize+0x3d2/0x3e0
[   81.744250]  [<c129efb4>] vc_resize+0x14/0x20
[   81.744253]  [<c12586bd>] fbcon_init+0x29d/0x500
[   81.744255]  [<c12984c4>] ? set_inverse_trans_unicode+0xe4/0x110
[   81.744258]  [<c129b378>] visual_init+0xb8/0x150
[   81.744261]  [<c129c16c>] bind_con_driver+0x16c/0x360
[   81.744264]  [<c129b47e>] ? register_con_driver+0x6e/0x190
[   81.744267]  [<c129c3a1>] take_over_console+0x41/0x50
[   81.744269]  [<c1257b7a>] fbcon_takeover+0x6a/0xd0
[   81.744272]  [<c12594b8>] fbcon_event_notify+0x758/0x790
[   81.744277]  [<c10929e2>] notifier_call_chain+0x42/0xb0
[   81.744280]  [<c1092d30>] __blocking_notifier_call_chain+0x60/0x90
[   81.744283]  [<c1092d7a>] blocking_notifier_call_chain+0x1a/0x20
[   81.744285]  [<c124a5a1>] fb_notifier_call_chain+0x11/0x20
[   81.744288]  [<c124b759>] register_framebuffer+0x1d9/0x2b0
[   81.744293]  [<c1061c73>] ? ioremap_wc+0x33/0x40
[   81.744298]  [<f82537c6>] uvesafb_probe+0xaba/0xc40 [uvesafb]
[   81.744302]  [<c12bb81f>] platform_drv_probe+0xf/0x20
[   81.744306]  [<c12ba558>] driver_probe_device+0x68/0x170
[   81.744309]  [<c12ba731>] __device_attach+0x41/0x50
[   81.744313]  [<c12b9088>] bus_for_each_drv+0x48/0x70
[   81.744316]  [<c12ba7f3>] device_attach+0x83/0xa0
[   81.744319]  [<c12ba6f0>] ? __driver_attach+0x90/0x90
[   81.744321]  [<c12b991f>] bus_probe_device+0x6f/0x90
[   81.744324]  [<c12b8a45>] device_add+0x5e5/0x680
[   81.744329]  [<c122a1a3>] ? kvasprintf+0x43/0x60
[   81.744332]  [<c121e6e4>] ? kobject_set_name_vargs+0x64/0x70
[   81.744335]  [<c121e6e4>] ? kobject_set_name_vargs+0x64/0x70
[   81.744339]  [<c12bbe9f>] platform_device_add+0xff/0x1b0
[   81.744343]  [<f8252906>] uvesafb_init+0x50/0x9b [uvesafb]
[   81.744346]  [<c100111f>] do_one_initcall+0x2f/0x170
[   81.744350]  [<f82528b6>] ? uvesafb_is_valid_mode+0x66/0x66 [uvesafb]
[   81.744355]  [<c10c6994>] sys_init_module+0xf4/0x1410
[   81.744359]  [<c1157fc0>] ? vfsmount_lock_local_unlock_cpu+0x30/0x30
[   81.744363]  [<c144cb10>] sysenter_do_call+0x12/0x36
[   81.744365] Code: f5 00 00 00 32 f6 66 8b da 66 d1 e3 66 ba d4 03 8a e3 b0 1c 66 ef b0 1e 66 ef 8a e7 b0 1d 66 ef b0 1f 66 ef e8 fa 00 00 00 61 c3 <60> e8 c8 00 00 00 66 8b f3 66 8b da 66 ba d4 03 b0 0c 8a e5 66
[   81.744388] EIP: [<c00cd3b3>] 0xc00cd3b3 SS:ESP 0068:f57f3a00
[   81.744391] CR2: 00000000c00cd3b3
[   81.744393] ---[ end trace 18b2c87c925b54d6 ]---

Signed-off-by: Wang YanQing <udknight@gmail.com>
Cc: Michal Januszewski <spock@gentoo.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/video/uvesafb.c

@@ -815,8 +815,15 @@ static int __devinit uvesafb_vbe_init(struct fb_info *info)
 	par->pmi_setpal = pmi_setpal;
 	par->ypan = ypan;
 
-	if (par->pmi_setpal || par->ypan)
-		uvesafb_vbe_getpmi(task, par);
+	if (par->pmi_setpal || par->ypan) {
+		if (__supported_pte_mask & _PAGE_NX) {
+			par->pmi_setpal = par->ypan = 0;
+			printk(KERN_WARNING "uvesafb: NX protection is actively."
+				"We have better not to use the PMI.\n");
+		} else {
+			uvesafb_vbe_getpmi(task, par);
+		}
+	}
 #else
 	/* The protected mode interface is not available on non-x86. */
 	par->pmi_setpal = par->ypan = 0;