From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap() Date: Mon, 21 Dec 2015 14:12:52 +0000 Message-ID: <1450707172-12561-1-git-send-email-matt@codeblueprint.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Matt Fleming , Josh Triplett , Sai Praneeth Prakhya , Borislav Petkov , =?UTF-8?q?M=C3=B4she=20van=20der=20Sterre?= List-Id: linux-efi@vger.kernel.org M=C3=B4she reported the following warning triggered on his machine sinc= e commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT data"), [ 0.026936] ------------[ cut here ]------------ [ 0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __ear= ly_ioremap+0x102/0x1bb() [ 0.026941] Modules linked in: [ 0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2 [ 0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 = 07/14/2015 [ 0.026946] 0000000000000000 900f03d5a116524d ffffffff81c03e60 ff= ffffff813a3fff [ 0.026948] 0000000000000000 ffffffff81c03e98 ffffffff810a0852 00= 000000d7b76000 [ 0.026949] 0000000000000000 0000000000000001 0000000000000001 00= 0000000000017c [ 0.026951] Call Trace: [ 0.026955] [] dump_stack+0x44/0x55 [ 0.026958] [] warn_slowpath_common+0x82/0xc0 [ 0.026959] [] warn_slowpath_null+0x1a/0x20 [ 0.026961] [] __early_ioremap+0x102/0x1bb [ 0.026962] [] early_memremap+0x13/0x15 [ 0.026964] [] efi_bgrt_init+0x162/0x1ad [ 0.026966] [] efi_late_init+0x9/0xb [ 0.026968] [] start_kernel+0x46f/0x49f [ 0.026970] [] ? early_idt_handler_array+0x120/= 0x120 [ 0.026972] [] x86_64_start_reservations+0x2a/0= x2c [ 0.026974] [] x86_64_start_kernel+0x14a/0x16d [ 0.026977] ---[ end trace f9b3812eb8e24c58 ]--- [ 0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory early_memremap() has an upper limit on the size of mapping it can handle which is ~200KB. Clearly the BGRT image on M=C3=B4she's machine = is much larger than that. There's actually no reason to restrict ourselves to using the early_* version of memremap() - the ACPI BGRT driver is invoked late enough in boot that we can use the standard version, with the benefit that the late version allows mappings of arbitrary size. Reported-by: M=C3=B4she van der Sterre Tested-by: M=C3=B4she van der Sterre Cc: Josh Triplett Cc: Sai Praneeth Prakhya Cc: Borislav Petkov Signed-off-by: Matt Fleming --- arch/x86/platform/efi/efi-bgrt.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/e= fi-bgrt.c index bf51f4c02562..b0970661870a 100644 --- a/arch/x86/platform/efi/efi-bgrt.c +++ b/arch/x86/platform/efi/efi-bgrt.c @@ -72,14 +72,14 @@ void __init efi_bgrt_init(void) return; } =20 - image =3D early_memremap(bgrt_tab->image_address, sizeof(bmp_header))= ; + image =3D memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMRE= MAP_WB); if (!image) { pr_err("Ignoring BGRT: failed to map image header memory\n"); return; } =20 memcpy(&bmp_header, image, sizeof(bmp_header)); - early_memunmap(image, sizeof(bmp_header)); + memunmap(image); bgrt_image_size =3D bmp_header.size; =20 bgrt_image =3D kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN); @@ -89,7 +89,7 @@ void __init efi_bgrt_init(void) return; } =20 - image =3D early_memremap(bgrt_tab->image_address, bmp_header.size); + image =3D memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP= _WB); if (!image) { pr_err("Ignoring BGRT: failed to map image memory\n"); kfree(bgrt_image); @@ -98,5 +98,5 @@ void __init efi_bgrt_init(void) } =20 memcpy(bgrt_image, image, bgrt_image_size); - early_memunmap(image, bmp_header.size); + memunmap(image); } --=20 2.6.2