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arm64: mm: Use __pa_symbol() for set_swapper_pgd()

PATCH New James Morse 3 participants 3 messages Oct 10, 2018 arm64

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James Morse

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#0 lore raw

PATCH 1/1 arm64: mm: Use __pa_symbol() for set_swapper_pgd()

commit 2330b7ca78350efcb ("arm64/mm: use fixmap to modify swapper_pg_dir") modifies the swapper_pg_dir via the fixmap as the kernel page tables have been moved to a read-only part of the kernel mapping.

Using __pa() to setup the fixmap causes CONFIG_DEBUG_VIRTUAL to fire, as this function is used on the kernel-image swapper address. The in_swapper_pgdir() test before each call of this function means set_swapper_pgd() will only ever be called when pgdp points somewhere in the kernel-image mapping of swapper_pd_dir. Use __pa_symbol().

Reported-by Geert Uytterhoeven <[email protected]>
Signed-off-by James Morse <[email protected]>
CC Jun Yao <[email protected]>
Tested-by Geert Uytterhoeven <[email protected]>
---
 arch/arm64/mm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/arm64/mm/mmu.c +1 -1
index 6f0e2edcc114..6deb836a102a 100644
@@ -74,7 +74,7 @@ void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
 	pgd_t *fixmap_pgdp;
 
 	spin_lock(&swapper_pgdir_lock);
-	fixmap_pgdp = pgd_set_fixmap(__pa(pgdp));
+	fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
 	WRITE_ONCE(*fixmap_pgdp, pgd);
 	/*
 	 * We need dsb(ishst) here to ensure the page-table-walker sees
Signature · 1 line
2.19.0
#1 lore raw

PATCH 1/1 arm64: mm: Use __pa_symbol() for set_swapper_pgd()

Quoted 12 lines · James Morse

commit 2330b7ca78350efcb ("arm64/mm: use fixmap to modify swapper_pg_dir") modifies the swapper_pg_dir via the fixmap as the kernel page tables have been moved to a read-only part of the kernel mapping.

Using __pa() to setup the fixmap causes CONFIG_DEBUG_VIRTUAL to fire, as this function is used on the kernel-image swapper address. The in_swapper_pgdir() test before each call of this function means set_swapper_pgd() will only ever be called when pgdp points somewhere in the kernel-image mapping of swapper_pd_dir. Use __pa_symbol().

Quoted 7 lines
Reported-by Geert Uytterhoeven <[email protected]>
Signed-off-by James Morse <[email protected]>
CC Jun Yao <[email protected]>
Tested-by Geert Uytterhoeven <[email protected]>
---
 arch/arm64/mm/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Since this only affects for-next/core, Catalin should pick this up for 4.20.

Acked-by Will Deacon <[email protected]>

Will

maintainer Applied
#2 lore raw

PATCH 1/1 arm64: mm: Use __pa_symbol() for set_swapper_pgd()

In reply to James Morse
Quoted 12 lines · James Morse

commit 2330b7ca78350efcb ("arm64/mm: use fixmap to modify swapper_pg_dir") modifies the swapper_pg_dir via the fixmap as the kernel page tables have been moved to a read-only part of the kernel mapping.

Using __pa() to setup the fixmap causes CONFIG_DEBUG_VIRTUAL to fire, as this function is used on the kernel-image swapper address. The in_swapper_pgdir() test before each call of this function means set_swapper_pgd() will only ever be called when pgdp points somewhere in the kernel-image mapping of swapper_pd_dir. Use __pa_symbol().

Quoted 4 lines
Reported-by Geert Uytterhoeven <[email protected]>
Signed-off-by James Morse <[email protected]>
CC Jun Yao <[email protected]>
Tested-by Geert Uytterhoeven <[email protected]>

Applied. Thanks.

Signature · 1 line
Catalin