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| author |   Christophe Leroy <christophe.leroy@csgroup.eu> | 2022-07-01 08:06:15 +0200 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2022-07-27 21:36:05 +1000 |
| commit | 6042a1652d643d1d34fa89bb314cb102960c0800 (patch) | |
| tree | 8c839cea25acf577091bc5c8adca53255c428ba8 /arch/powerpc/mm | |
| parent | powerpc/32: Set an IBAT covering up to _einittext during init (diff) | |
| download | linux-dev-6042a1652d643d1d34fa89bb314cb102960c0800.tar.xz linux-dev-6042a1652d643d1d34fa89bb314cb102960c0800.zip | |
powerpc/32s: Fix boot failure with KASAN + SMP + JUMP_LABEL_FEATURE_CHECK_DEBUG
Since commit 4291d085b0b0 ("powerpc/32s: Make pte_update() non
atomic on 603 core"), pte_update() has been using
mmu_has_feature(MMU_FTR_HPTE_TABLE) to avoid a useless atomic
operation on 603 cores.
When kasan_early_init() sets up the early zero shadow, it uses
__set_pte_at(). On book3s/32, __set_pte_at() calls pte_update()
when CONFIG_SMP is selected in order to ensure the preservation of
_PAGE_HASHPTE in case of concurrent update of the PTE. But that's
too early for mmu_has_feature(), so when
CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG is selected, mmu_has_feature()
calls printk(). That's too early to call printk() because KASAN
early zero shadow page is not set up yet. It leads to a deadlock.
However, when kasan_early_init() is called, there is only one CPU
running and no risk of concurrent PTE update. So __set_pte_at() can
be called with the 'percpu' flag. With that flag set, the PTE is
written directly instead of being written via pte_update().
Fixes: 4291d085b0b0 ("powerpc/32s: Make pte_update() non atomic on 603 core")
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2ee707512b8b212b079b877f4ceb525a1606a3fb.1656655567.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/kasan/init_32.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_32.c index f3e4d069e0ba..a70828a6d935 100644 --- a/arch/powerpc/mm/kasan/init_32.c +++ b/arch/powerpc/mm/kasan/init_32.c @@ -25,7 +25,7 @@ static void __init kasan_populate_pte(pte_t *ptep, pgprot_t prot) int i; for (i = 0; i < PTRS_PER_PTE; i++, ptep++) - __set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 0); + __set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 1); } int __init kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end) |