From 248fbcd5aee00f6519a12c5ed3bc3dc0f5e84de5 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 7 Aug 2015 09:36:55 +0100 Subject: x86/efi-bgrt: Switch pr_err() to pr_debug() for invalid BGRT It's totally legitimate, per the ACPI spec, for the firmware to set the BGRT 'status' field to zero to indicate that the BGRT image isn't being displayed, and we shouldn't be printing an error message in that case because it's just noise for users. So swap pr_err() for pr_debug(). However, Josh points that out it still makes sense to test the validity of the upper 7 bits of the 'status' field, since they're marked as "reserved" in the spec and must be zero. If firmware violates this it really *is* an error. Reported-by: Tom Yan Tested-by: Tom Yan Signed-off-by: Matt Fleming Reviewed-by: Josh Triplett Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Matthew Garrett Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1438936621-5215-2-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar --- arch/x86/platform/efi/efi-bgrt.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c index d7f997f7c26d..ea48449b2e63 100644 --- a/arch/x86/platform/efi/efi-bgrt.c +++ b/arch/x86/platform/efi/efi-bgrt.c @@ -50,11 +50,16 @@ void __init efi_bgrt_init(void) bgrt_tab->version); return; } - if (bgrt_tab->status != 1) { - pr_err("Ignoring BGRT: invalid status %u (expected 1)\n", + if (bgrt_tab->status & 0xfe) { + pr_err("Ignoring BGRT: reserved status bits are non-zero %u\n", bgrt_tab->status); return; } + if (bgrt_tab->status != 1) { + pr_debug("Ignoring BGRT: invalid status %u (expected 1)\n", + bgrt_tab->status); + return; + } if (bgrt_tab->image_type != 0) { pr_err("Ignoring BGRT: invalid image type %u (expected 0)\n", bgrt_tab->image_type); -- cgit v1.2.3