From: Christophe Leroy <christophe.leroy@c-s.fr>
Date: Mon, 14 Oct 2019 16:51:28 +0000
Subject: powerpc/32s: fix allow/prevent_user_access() when crossing segment
 boundaries.
Git-commit: d10f60ae27d26d811e2a1bb39ded47df96d7499f
Patch-mainline: 5.4-rc6
References: bnc#1151927 5.3.11

Make sure starting addr is aligned to segment boundary so that when
incrementing the segment, the starting address of the new segment is
below the end address. Otherwise the last segment might get  missed.

Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/067a1b09f15f421d40797c2d04c22d4049a1cee8.1571071875.git.christophe.leroy@c-s.fr
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/powerpc/include/asm/book3s/32/kup.h |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -91,6 +91,7 @@
 
 static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
 {
+	addr &= 0xf0000000;	/* align addr to start of segment */
 	barrier();	/* make sure thread.kuap is updated before playing with SRs */
 	while (addr < end) {
 		mtsrin(sr, addr);