From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Triplett Subject: Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap() Date: Mon, 21 Dec 2015 12:07:52 -0800 Message-ID: <20151221200752.GA23410@x> References: <1450707172-12561-1-git-send-email-matt@codeblueprint.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <1450707172-12561-1-git-send-email-matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matt Fleming Cc: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" , linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Sai Praneeth Prakhya , Borislav Petkov , =?iso-8859-1?Q?M=F4she?= van der Sterre List-Id: linux-efi@vger.kernel.org On Mon, Dec 21, 2015 at 02:12:52PM +0000, Matt Fleming wrote: > M=F4she reported the following warning triggered on his machine since > commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGR= T > data"), >=20 > [ 0.026936] ------------[ cut here ]------------ > [ 0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __e= arly_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 A0= 5 07/14/2015 > [ 0.026946] 0000000000000000 900f03d5a116524d ffffffff81c03e60 = ffffffff813a3fff > [ 0.026948] 0000000000000000 ffffffff81c03e98 ffffffff810a0852 = 00000000d7b76000 > [ 0.026949] 0000000000000000 0000000000000001 0000000000000001 = 000000000000017c > [ 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+0x12= 0/0x120 > [ 0.026972] [] x86_64_start_reservations+0x2a= /0x2c > [ 0.026974] [] x86_64_start_kernel+0x14a/0x16= d > [ 0.026977] ---[ end trace f9b3812eb8e24c58 ]--- > [ 0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory >=20 > early_memremap() has an upper limit on the size of mapping it can > handle which is ~200KB. Clearly the BGRT image on M=F4she's machine i= s > much larger than that. >=20 > There's actually no reason to restrict ourselves to using the early_* > version of memremap() - the ACPI BGRT driver is invoked late enough i= n > boot that we can use the standard version, with the benefit that the > late version allows mappings of arbitrary size. >=20 > Reported-by: M=F4she van der Sterre > Tested-by: M=F4she van der Sterre > Cc: Josh Triplett > Cc: Sai Praneeth Prakhya > Cc: Borislav Petkov > Signed-off-by: Matt Fleming Reviewed-by: Josh Triplett > arch/x86/platform/efi/efi-bgrt.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) >=20 > diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi= /efi-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), MEM= REMAP_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, MEMREM= AP_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 >=20