[PATCH] powerpc/mm/32s: only use MMU to mark initmem NX if STRICT_KERNEL_RWX

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE2605d

2 messages, 2 authors, 2019-06-15 · open the first message on its own page

[PATCH] powerpc/mm/32s: only use MMU to mark initmem NX if STRICT_KERNEL_RWX

From: Andreas Schwab <hidden>
Date: 2019-06-15 12:47:34

If STRICT_KERNEL_RWX is disabled, never use the MMU to mark initmen
nonexecutable.

Also move a misplaced paren that makes the condition always true.

Fixes: 63b2bc619565 ("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX")
Signed-off-by: Andreas Schwab <redacted>
---
 arch/powerpc/mm/pgtable_32.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index d53188dee18f..3935dc263d65 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c

@@ -360,9 +360,11 @@ void mark_initmem_nx(void)
 	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
 				 PFN_DOWN((unsigned long)_sinittext);
 
-	if (v_block_mapped((unsigned long)_stext) + 1)
+#ifdef CONFIG_STRICT_KERNEL_RWX
+	if (v_block_mapped((unsigned long)_stext + 1))
 		mmu_mark_initmem_nx();
 	else
+#endif
 		change_page_attr(page, numpages, PAGE_KERNEL);
 }

-- 
2.22.0

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Re: [PATCH] powerpc/mm/32s: only use MMU to mark initmem NX if STRICT_KERNEL_RWX

From: Christophe Leroy <hidden>
Date: 2019-06-15 13:26:14

Andreas Schwab [off-list ref] a écrit :

If STRICT_KERNEL_RWX is disabled, never use the MMU to mark initmen
nonexecutable.

I dont understand, can you elaborate ?

This area is mapped with BATs so using change_page_attr() is pointless.

Christophe

quoted hunk

Also move a misplaced paren that makes the condition always true.

Fixes: 63b2bc619565 ("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX")
Signed-off-by: Andreas Schwab <redacted>
---
 arch/powerpc/mm/pgtable_32.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index d53188dee18f..3935dc263d65 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c

@@ -360,9 +360,11 @@ void mark_initmem_nx(void)
 	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
 				 PFN_DOWN((unsigned long)_sinittext);

-	if (v_block_mapped((unsigned long)_stext) + 1)
+#ifdef CONFIG_STRICT_KERNEL_RWX
+	if (v_block_mapped((unsigned long)_stext + 1))
 		mmu_mark_initmem_nx();
 	else
+#endif
 		change_page_attr(page, numpages, PAGE_KERNEL);
 }

--

2.22.0

--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

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