linux-kernel - [PATCH] powerpc/32s: Fix module loading failure when VMALLOC

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Date:   Fri, 21 Aug 2020 07:15:25 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, schwab@...ux-m68k.org
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] powerpc/32s: Fix module loading failure when VMALLOC_END is
 over 0xf0000000

In is_module_segment(), when VMALLOC_END is over 0xf0000000,
ALIGN(VMALLOC_END, SZ_256M) has value 0.

In that case, addr >= ALIGN(VMALLOC_END, SZ_256M) is always
true then is_module_segment() always returns false.

Use (ALIGN(VMALLOC_END, SZ_256M) - 1) which will have
value 0xffffffff and will be suitable for the comparison.

Reported-by: Andreas Schwab <schwab@...ux-m68k.org>
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
Fixes: c49643319715 ("powerpc/32s: Only leave NX unset on segments used for modules")
---
 arch/powerpc/mm/book3s32/mmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 82ae9e06a773..d426eaf76bb0 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -194,12 +194,12 @@ static bool is_module_segment(unsigned long addr)
 #ifdef MODULES_VADDR
 	if (addr < ALIGN_DOWN(MODULES_VADDR, SZ_256M))
 		return false;
-	if (addr >= ALIGN(MODULES_END, SZ_256M))
+	if (addr > ALIGN(MODULES_END, SZ_256M) - 1)
 		return false;
 #else
 	if (addr < ALIGN_DOWN(VMALLOC_START, SZ_256M))
 		return false;
-	if (addr >= ALIGN(VMALLOC_END, SZ_256M))
+	if (addr > ALIGN(VMALLOC_END, SZ_256M) - 1)
 		return false;
 #endif
 	return true;
-- 
2.25.0