From: Helge Deller <deller@gmx.de>
Date: Tue, 17 May 2022 14:57:06 +0000 (+0200)
Subject: parisc: Prevent ldil() to sign-extend into upper 32 bits
X-Git-Tag: v5.19-rc1~93^2~4
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=44eeb9b56774c6f87155132a92252410e4610384;p=linux-block.git

parisc: Prevent ldil() to sign-extend into upper 32 bits

Add some build time checks to prevent that the various usages of
	"ldil L%(TMPALIAS_MAP_START), %reg"
sign-extends into the upper 32 bits when building a 64-bit kernel.

Signed-off-by: Helge Deller <deller@gmx.de>
---

diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 1dc2e88e7b04..0a81499dd35e 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -555,6 +555,12 @@ void __init mem_init(void)
 	BUILD_BUG_ON(PT_INITIAL > PTRS_PER_PGD);
 #endif
 
+#ifdef CONFIG_64BIT
+	/* avoid ldil_%L() asm statements to sign-extend into upper 32-bits */
+	BUILD_BUG_ON(__PAGE_OFFSET >= 0x80000000);
+	BUILD_BUG_ON(TMPALIAS_MAP_START >= 0x80000000);
+#endif
+
 	high_memory = __va((max_pfn << PAGE_SHIFT));
 	set_max_mapnr(max_low_pfn);
 	memblock_free_all();