[PATCH] x86: Use __nostackprotect for sme_encrypt_kernel

From: Laura Abbott <labbott@redhat.com>
To: Ingo Molnar <mingo@kernel.org>, Tom Lendacky <thomas.lendacky@amd.com>
Cc: Laura Abbott <labbott@redhat.com>, Borislav Petkov <bp@suse.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Brijesh Singh <brijesh.singh@amd.com>, X86 ML <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH] x86: Use __nostackprotect for sme_encrypt_kernel
Date: Sat, 20 Jan 2018 17:14:02 -0800	[thread overview]
Message-ID: <20180121011402.9557-1-labbott@redhat.com> (raw)
In-Reply-To: <b7a8e990-9d1d-39b2-671d-a44d5647dbec@amd.com>

Commit bacf6b499e11 ("x86/mm: Use a struct to reduce parameters for
SME PGD mapping") moved some parameters into a structure. The
structure was large enough to trigger the stack protection canary
in sme_encrypt_kernel which doesn't work this early, causing reboots.
Mark sme_encrypt_kernel appropriately to not use the canary.

Fixes: bacf6b499e11 ("x86/mm: Use a struct to reduce parameters for
SME PGD mapping")
Signed-off-by: Laura Abbott <labbott@redhat.com>
---
I hadn't seen this picked up yet so sending explicitly
---
 arch/x86/mm/mem_encrypt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 3ef362f598e3..e1d61e8500f9 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -738,7 +738,7 @@ static unsigned long __init sme_pgtable_calc(unsigned long len)
 	return total;
 }
 
-void __init sme_encrypt_kernel(struct boot_params *bp)
+void __init __nostackprotector sme_encrypt_kernel(struct boot_params *bp)
 {
 	unsigned long workarea_start, workarea_end, workarea_len;
 	unsigned long execute_start, execute_end, execute_len;
-- 
2.15.1
