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2019-09-21powerpc/mm: Fix an Oops in kasan_mmu_init()Christophe Leroy1-1/+14
Uncompressing Kernel Image ... OK Loading Device Tree to 01ff7000, end 01fff74f ... OK [ 0.000000] printk: bootconsole [udbg0] enabled [ 0.000000] BUG: Unable to handle kernel data access at 0xf818c000 [ 0.000000] Faulting instruction address: 0xc0013c7c [ 0.000000] Thread overran stack, or stack corrupted [ 0.000000] Oops: Kernel access of bad area, sig: 11 [#1] [ 0.000000] BE PAGE_SIZE=16K PREEMPT [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.3.0-rc4-s3k-dev-00743-g5abe4a3e8fd3-dirty #2080 [ 0.000000] NIP: c0013c7c LR: c0013310 CTR: 00000000 [ 0.000000] REGS: c0c5ff38 TRAP: 0300 Not tainted (5.3.0-rc4-s3k-dev-00743-g5abe4a3e8fd3-dirty) [ 0.000000] MSR: 00001032 <ME,IR,DR,RI> CR: 99033955 XER: 80002100 [ 0.000000] DAR: f818c000 DSISR: 82000000 [ 0.000000] GPR00: c0013310 c0c5fff0 c0ad6ac0 c0c600c0 f818c031 82000000 00000000 ffffffff [ 0.000000] GPR08: 00000000 f1f1f1f1 c0013c2c c0013304 99033955 00400008 00000000 07ff9598 [ 0.000000] GPR16: 00000000 07ffb94c 00000000 00000000 00000000 00000000 00000000 f818cfb2 [ 0.000000] GPR24: 00000000 00000000 00001000 ffffffff 00000000 c07dbf80 00000000 f818c000 [ 0.000000] NIP [c0013c7c] do_page_fault+0x50/0x904 [ 0.000000] LR [c0013310] handle_page_fault+0xc/0x38 [ 0.000000] Call Trace: [ 0.000000] Instruction dump: [ 0.000000] be010080 91410014 553fe8fe 3d40c001 3d20f1f1 7d800026 394a3c2c 3fffe000 [ 0.000000] 6129f1f1 900100c4 9181007c 91410018 <913f0000> 3d2001f4 6129f4f4 913f0004 Don't map the early shadow page read-only yet when creating the new page tables for the real shadow memory, otherwise the memblock allocations that immediately follows to create the real shadow pages that are about to replace the early shadow page trigger a page fault if they fall into the region being worked on at the moment. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/fe86886fb8db44360417cee0dc515ad47ca6ef72.1566382750.git.christophe.leroy@c-s.fr
2019-09-21powerpc/mm: Add a helper to select PAGE_KERNEL_RO or PAGE_READONLYChristophe Leroy1-8/+13
In a couple of places there is a need to select whether read-only protection of shadow pages is performed with PAGE_KERNEL_RO or with PAGE_READONLY. Add a helper to avoid duplicating the choice. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/9f33f44b9cd741c4a02b3dce7b8ef9438fe2cd2a.1566382750.git.christophe.leroy@c-s.fr
2019-08-20powerpc/kasan: Fix shadow area set up for modules.Christophe Leroy1-1/+1
When loading modules, from time to time an Oops is encountered during the init of shadow area for globals. This is due to the last page not always being mapped depending on the exact distance between the start and the end of the shadow area and the alignment with the page addresses. Fix this by aligning the starting address with the page address. Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") Cc: stable@vger.kernel.org # v5.2+ Reported-by: Erhard F. <erhard_f@mailbox.org> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/4f887e9b77d0d725cbb52035c7ece485c1c5fc14.1565361881.git.christophe.leroy@c-s.fr
2019-08-20powerpc/kasan: Fix parallel loading of modules.Christophe Leroy1-2/+19
Parallel loading of modules may lead to bad setup of shadow page table entries. First, lets align modules so that two modules never share the same shadow page. Second, ensure that two modules cannot allocate two page tables for the same PMD entry at the same time. This is done by using init_mm.page_table_lock in the same way as __pte_alloc_kernel() Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/c97284f912128cbc3f2fe09d68e90e65fb3e6026.1565361876.git.christophe.leroy@c-s.fr
2019-07-31powerpc/kasan: fix early boot failure on PPC32Christophe Leroy1-2/+5
Due to commit 4a6d8cf90017 ("powerpc/mm: don't use pte_alloc_kernel() until slab is available on PPC32"), pte_alloc_kernel() cannot be used during early KASAN init. Fix it by using memblock_alloc() instead. Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") Cc: stable@vger.kernel.org # v5.2+ Reported-by: Erhard F. <erhard_f@mailbox.org> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/da89670093651437f27d2975224712e0a130b055.1564552796.git.christophe.leroy@c-s.fr
2019-05-06powerpc/kasan: add missing/lost MakefileChristophe Leroy1-0/+5
For unknown reason (aka. mpe is a doofus), the new Makefile added via the KASAN support patch didn't land into arch/powerpc/mm/kasan/ This patch restores it. Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03powerpc/32s: map kasan zero shadow with PAGE_READONLY instead of PAGE_KERNEL_ROChristophe Leroy1-2/+8
For hash32, the zero shadow page gets mapped with PAGE_READONLY instead of PAGE_KERNEL_RO, because the PP bits don't provide a RO kernel, so PAGE_KERNEL_RO is equivalent to PAGE_KERNEL. By using PAGE_READONLY, the page is RO for both kernel and user, but this is not a security issue as it contains only zeroes. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03powerpc/32s: set up an early static hash table for KASAN.Christophe Leroy1-1/+22
KASAN requires early activation of hash table, before memblock() functions are available. This patch implements an early hash_table statically defined in __initdata. During early boot, a single page table is used. For hash32, when doing the final init, one page table is allocated for each PGD entry because of the _PAGE_HASHPTE flag which can't be common to several virt pages. This is done after memblock get available but before switching to the final hash table, otherwise there are issues with TLB flushing due to the shared entries. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-03powerpc/32: Add KASAN supportChristophe Leroy1-0/+156
This patch adds KASAN support for PPC32. The following patch will add an early activation of hash table for book3s. Until then, a warning will be raised if trying to use KASAN on an hash 6xx. To support KASAN, this patch initialises that MMU mapings for accessing to the KASAN shadow area defined in a previous patch. An early mapping is set as soon as the kernel code has been relocated at its definitive place. Then the definitive mapping is set once paging is initialised. For modules, the shadow area is allocated at module_alloc(). Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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