[PATCH v1 6/8] powerpc/32s: Only leave NX unset on segments used for modules

From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v1 6/8] powerpc/32s: Only leave NX unset on segments used for modules
Date: Fri, 19 Jun 2020 15:06:57 +0000 (UTC)	[thread overview]
Message-ID: <c81ed22c5716008463ee14869c25f49c3ae53e25.1592578278.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1592578278.git.christophe.leroy@csgroup.eu>

Instead of leaving NX unset on all segments above the start
of vmalloc space, only leave NX unset on segments used for
modules.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/mm/book3s32/mmu.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 03b6ba54460e..c0162911f6cb 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -187,6 +187,17 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
 	return __mmu_mapin_ram(border, top);
 }
 
+static bool is_module_segment(unsigned long addr)
+{
+	if (!IS_ENABLED(CONFIG_MODULES))
+		return false;
+	if (addr < ALIGN_DOWN(VMALLOC_START, SZ_256M))
+		return false;
+	if (addr >= ALIGN(VMALLOC_END, SZ_256M))
+		return false;
+	return true;
+}
+
 void mmu_mark_initmem_nx(void)
 {
 	int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;
@@ -223,9 +234,9 @@ void mmu_mark_initmem_nx(void)
 
 	for (i = TASK_SIZE >> 28; i < 16; i++) {
 		/* Do not set NX on VM space for modules */
-		if (IS_ENABLED(CONFIG_MODULES) &&
-		    (VMALLOC_START & 0xf0000000) == i << 28)
-			break;
+		if (is_module_segment(i << 28))
+			continue;
+
 		mtsrin(mfsrin(i << 28) | 0x10000000, i << 28);
 	}
 }
-- 
2.25.0

