From: Matt Fleming Date: Mon, 21 Dec 2015 14:12:52 +0000 Subject: x86/efi-bgrt: Replace early_memremap() with memremap() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Origin: https://git.kernel.org/cgit/linux/kernel/git/mfleming/efi.git/commit?id=e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f Bug-Debian: https://bugs.debian.org/815125 Môshe reported the following warning triggered on his machine since 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 __early_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 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+0x120/0x120 [ 0.026972] [] x86_64_start_reservations+0x2a/0x2c [ 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 Môshe'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: Môshe van der Sterre Tested-by: Môshe van der Sterre Signed-off-by: Matt Fleming Cc: Josh Triplett Cc: Sai Praneeth Prakhya Cc: Borislav Petkov Link: http://lkml.kernel.org/r/1450707172-12561-1-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Thomas Gleixner --- arch/x86/platform/efi/efi-bgrt.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/arch/x86/platform/efi/efi-bgrt.c +++ b/arch/x86/platform/efi/efi-bgrt.c @@ -69,14 +69,14 @@ void __init efi_bgrt_init(void) return; } - image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header)); + image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB); if (!image) { pr_err("Ignoring BGRT: failed to map image header memory\n"); return; } memcpy(&bmp_header, image, sizeof(bmp_header)); - early_memunmap(image, sizeof(bmp_header)); + memunmap(image); bgrt_image_size = bmp_header.size; bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN); @@ -86,7 +86,7 @@ void __init efi_bgrt_init(void) return; } - image = early_memremap(bgrt_tab->image_address, bmp_header.size); + image = 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); @@ -95,5 +95,5 @@ void __init efi_bgrt_init(void) } memcpy(bgrt_image, image, bgrt_image_size); - early_memunmap(image, bmp_header.size); + memunmap(image); }