From: Greg Hackmann <ghackmann@google.com>
Date: Mon, 9 Apr 2018 20:48:49 +0000 (-0700)
Subject: ANDROID: arm64: mark kpti_install_ng_mappings as __nocfi
X-Git-Tag: khadas-vims-v0.9.6-release~1584^2~123
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=eba1ffe631bc5e379ebce8342c287c47f4549c16;p=platform%2Fkernel%2Flinux-amlogic.git

ANDROID: arm64: mark kpti_install_ng_mappings as __nocfi

4.9.93 panics on boot when CFI_CLANG and UNMAP_KERNEL_AT_EL0 are both
enabled.  From Sami Tolvanen:

"kpti_install_ng_mappings makes an indirect call to a physical address,
which trips CFI. Adding the __nocfi attribute to this function should
fix the problem."

Bug: 77811249
Change-Id: I87d1ceb29f1ba2caee8954547596f4236bdfc31f
Reported-by: Jean-Baptiste Theou <jb@essential.com>
Signed-off-by: Greg Hackmann <ghackmann@google.com>
---

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 785a54e..08344c9 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -791,7 +791,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
 						     ID_AA64PFR0_CSV3_SHIFT);
 }
 
-static int kpti_install_ng_mappings(void *__unused)
+static int __nocfi kpti_install_ng_mappings(void *__unused)
 {
 	typedef void (kpti_remap_fn)(int, int, phys_addr_t);
 	extern kpti_remap_fn idmap_kpti_install_ng_mappings;