kernel/git/stable/linux.git/arch/powerpc, branch linux-5.5.y

powerpc/kasan: Fix kasan_remap_early_shadow_ro()

2020-04-17T14:12:19+00:00

[ Upstream commit af92bad615be75c6c0d1b1c5b48178360250a187 ] At the moment kasan_remap_early_shadow_ro() does nothing, because k_end is 0 and k_cur < 0 is always true. Change the test to k_cur != k_end, as done in kasan_init_shadow_page_tables() Signed-off-by: Christophe Leroy Fixes: cbd18991e24f ("powerpc/mm: Fix an Oops in kasan_mmu_init()") Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/4e7b56865e01569058914c991143f5961b5d4719.1583507333.git.christophe.leroy@c-s.fr Signed-off-by: Sasha Levin

powerpc/64: Prevent stack protection in early boot

2020-04-17T14:12:18+00:00

commit 7053f80d96967d8e72e9f2a724bbfc3906ce2b07 upstream. The previous commit reduced the amount of code that is run before we setup a paca. However there are still a few remaining functions that run with no paca, or worse, with an arbitrary value in r13 that will be used as a paca pointer. In particular the stack protector canary is stored in the paca, so if stack protector is activated for any of these functions we will read the stack canary from wherever r13 points. If r13 happens to point outside of memory we will get a machine check / checkstop. For example if we modify initialise_paca() to trigger stack protection, and then boot in the mambo simulator with r13 poisoned in skiboot before calling the kernel: DEBUG: 19952232: (19952232): INSTRUCTION: PC=0xC0000000191FC1E8: [0x3C4C006D]: addis r2,r12,0x6D [fetch] DEBUG: 19952236: (19952236): INSTRUCTION: PC=0xC00000001807EAD8: [0x7D8802A6]: mflr r12 [fetch] FATAL ERROR: 19952276: (19952276): Check Stop for 0:0: Machine Check with ME bit of MSR off DEBUG: 19952276: (19952276): INSTRUCTION: PC=0xC0000000191FCA7C: [0xE90D0CF8]: ld r8,0xCF8(r13) [Instruction Failed] INFO: 19952276: (19952277): ** Execution stopped: Mambo Error, Machine Check Stop, ** systemsim % bt pc: 0xC0000000191FCA7C initialise_paca+0x54 lr: 0xC0000000191FC22C early_setup+0x44 stack:0x00000000198CBED0 0x0 +0x0 stack:0x00000000198CBF00 0xC0000000191FC22C early_setup+0x44 stack:0x00000000198CBF90 0x1801C968 +0x1801C968 So annotate the relevant functions to ensure stack protection is never enabled for them. Fixes: 06ec27aea9fc ("powerpc/64: add stack protector support") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200320032116.1024773-2-mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman

powerpc/kprobes: Ignore traps that happened in real mode

2020-04-17T14:12:18+00:00

commit 21f8b2fa3ca5b01f7a2b51b89ce97a3705a15aa0 upstream. When a program check exception happens while MMU translation is disabled, following Oops happens in kprobe_handler() in the following code: } else if (*addr != BREAKPOINT_INSTRUCTION) { BUG: Unable to handle kernel data access on read at 0x0000e268 Faulting instruction address: 0xc000ec34 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=16K PREEMPT CMPC885 Modules linked in: CPU: 0 PID: 429 Comm: cat Not tainted 5.6.0-rc1-s3k-dev-00824-g84195dc6c58a #3267 NIP: c000ec34 LR: c000ecd8 CTR: c019cab8 REGS: ca4d3b58 TRAP: 0300 Not tainted (5.6.0-rc1-s3k-dev-00824-g84195dc6c58a) MSR: 00001032 CR: 2a4d3c52 XER: 00000000 DAR: 0000e268 DSISR: c0000000 GPR00: c000b09c ca4d3c10 c66d0620 00000000 ca4d3c60 00000000 00009032 00000000 GPR08: 00020000 00000000 c087de44 c000afe0 c66d0ad0 100d3dd6 fffffff3 00000000 GPR16: 00000000 00000041 00000000 ca4d3d70 00000000 00000000 0000416d 00000000 GPR24: 00000004 c53b6128 00000000 0000e268 00000000 c07c0000 c07bb6fc ca4d3c60 NIP [c000ec34] kprobe_handler+0x128/0x290 LR [c000ecd8] kprobe_handler+0x1cc/0x290 Call Trace: [ca4d3c30] [c000b09c] program_check_exception+0xbc/0x6fc [ca4d3c50] [c000e43c] ret_from_except_full+0x0/0x4 --- interrupt: 700 at 0xe268 Instruction dump: 913e0008 81220000 38600001 3929ffff 91220000 80010024 bb410008 7c0803a6 38210020 4e800020 38600000 4e800020 <813b0000> 6d2a7fe0 2f8a0008 419e0154 ---[ end trace 5b9152d4cdadd06d ]--- kprobe is not prepared to handle events in real mode and functions running in real mode should have been blacklisted, so kprobe_handler() can safely bail out telling 'this trap is not mine' for any trap that happened while in real-mode. If the trap happened with MSR_IR or MSR_DR cleared, return 0 immediately. Reported-by: Larry Finger Fixes: 6cc89bad60a6 ("powerpc/kprobes: Invoke handlers directly") Cc: stable@vger.kernel.org # v4.10+ Signed-off-by: Christophe Leroy Reviewed-by: Masami Hiramatsu Reviewed-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/424331e2006e7291a1bfe40e7f3fa58825f565e1.1582054578.git.christophe.leroy@c-s.fr Signed-off-by: Greg Kroah-Hartman

powerpc/xive: Fix xmon support on the PowerNV platform

2020-04-17T14:12:18+00:00

commit 97ef275077932c65b1b8ec5022abd737a9fbf3e0 upstream. The PowerNV platform has multiple IRQ chips and the xmon command dumping the state of the XIVE interrupt should only operate on the XIVE IRQ chip. Fixes: 5896163f7f91 ("powerpc/xmon: Improve output of XIVE interrupts") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Cédric Le Goater Reviewed-by: Greg Kurz Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200306150143.5551-3-clg@kaod.org Signed-off-by: Greg Kroah-Hartman

powerpc/64: Setup a paca before parsing device tree etc.

2020-04-17T14:12:18+00:00

commit d4a8e98621543d5798421eed177978bf2b3cdd11 upstream. Currently we set up the paca after parsing the device tree for CPU features. Prior to that, r13 contains random data, which means there is random data in r13 while we're running the generic dt parsing code. This random data varies depending on whether we boot through a vmlinux or a zImage: for the vmlinux case it's usually around zero, but for zImages we see random values like 912a72603d420015. This is poor practice, and can also lead to difficult-to-debug crashes. For example, when kcov is enabled, the kcov instrumentation attempts to read preempt_count out of the current task, which goes via the paca. This then crashes in the zImage case. Similarly stack protector can cause crashes if r13 is bogus, by reading from the stack canary in the paca. To resolve this: - move the paca setup to before the CPU feature parsing. - because we no longer have access to CPU feature flags in paca setup, change the HV feature test in the paca setup path to consider the actual value of the MSR rather than the CPU feature. Translations get switched on once we leave early_setup, so I think we'd already catch any other cases where the paca or task aren't set up. Boot tested on a P9 guest and host. Fixes: fb0b0a73b223 ("powerpc: Enable kcov") Fixes: 06ec27aea9fc ("powerpc/64: add stack protector support") Cc: stable@vger.kernel.org # v4.20+ Reviewed-by: Andrew Donnellan Suggested-by: Michael Ellerman Signed-off-by: Daniel Axtens [mpe: Reword comments & change log a bit to mention stack protector] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200320032116.1024773-1-mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman

powerpc/xive: Use XIVE_BAD_IRQ instead of zero to catch non configured IPIs

2020-04-17T14:12:17+00:00

commit b1a504a6500df50e83b701b7946b34fce27ad8a3 upstream. When a CPU is brought up, an IPI number is allocated and recorded under the XIVE CPU structure. Invalid IPI numbers are tracked with interrupt number 0x0. On the PowerNV platform, the interrupt number space starts at 0x10 and this works fine. However, on the sPAPR platform, it is possible to allocate the interrupt number 0x0 and this raises an issue when CPU 0 is unplugged. The XIVE spapr driver tracks allocated interrupt numbers in a bitmask and it is not correctly updated when interrupt number 0x0 is freed. It stays allocated and it is then impossible to reallocate. Fix by using the XIVE_BAD_IRQ value instead of zero on both platforms. Reported-by: David Gibson Fixes: eac1e731b59e ("powerpc/xive: guest exploitation of the XIVE interrupt controller") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Cédric Le Goater Reviewed-by: David Gibson Tested-by: David Gibson Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200306150143.5551-2-clg@kaod.org Signed-off-by: Greg Kroah-Hartman

powerpc/hash64/devmap: Use H_PAGE_THP_HUGE when setting up huge devmap PTE entries

2020-04-17T14:12:17+00:00

commit 36b78402d97a3b9aeab136feb9b00d8647ec2c20 upstream. H_PAGE_THP_HUGE is used to differentiate between a THP hugepage and hugetlb hugepage entries. The difference is WRT how we handle hash fault on these address. THP address enables MPSS in segments. We want to manage devmap hugepage entries similar to THP pt entries. Hence use H_PAGE_THP_HUGE for devmap huge PTE entries. With current code while handling hash PTE fault, we do set is_thp = true when finding devmap PTE huge PTE entries. Current code also does the below sequence we setting up huge devmap entries. entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); if (pfn_t_devmap(pfn)) entry = pmd_mkdevmap(entry); In that case we would find both H_PAGE_THP_HUGE and PAGE_DEVMAP set for huge devmap PTE entries. This results in false positive error like below. kernel BUG at /home/kvaneesh/src/linux/mm/memory.c:4321! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 56 PID: 67996 Comm: t_mmap_dio Not tainted 5.6.0-rc4-59640-g371c804dedbc #128 .... NIP [c00000000044c9e4] __follow_pte_pmd+0x264/0x900 LR [c0000000005d45f8] dax_writeback_one+0x1a8/0x740 Call Trace: str_spec.74809+0x22ffb4/0x2d116c (unreliable) dax_writeback_one+0x1a8/0x740 dax_writeback_mapping_range+0x26c/0x700 ext4_dax_writepages+0x150/0x5a0 do_writepages+0x68/0x180 __filemap_fdatawrite_range+0x138/0x180 file_write_and_wait_range+0xa4/0x110 ext4_sync_file+0x370/0x6e0 vfs_fsync_range+0x70/0xf0 sys_msync+0x220/0x2e0 system_call+0x5c/0x68 This is because our pmd_trans_huge check doesn't exclude _PAGE_DEVMAP. To make this all consistent, update pmd_mkdevmap to set H_PAGE_THP_HUGE and pmd_trans_huge check now excludes _PAGE_DEVMAP correctly. Fixes: ebd31197931d ("powerpc/mm: Add devmap support for ppc64") Cc: stable@vger.kernel.org # v4.13+ Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200313094842.351830-1-aneesh.kumar@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

powerpc/fsl_booke: Avoid creating duplicate tlb1 entry

2020-04-17T14:12:17+00:00

commit aa4113340ae6c2811e046f08c2bc21011d20a072 upstream. In the current implementation, the call to loadcam_multi() is wrapped between switch_to_as1() and restore_to_as0() calls so, when it tries to create its own temporary AS=1 TLB1 entry, it ends up duplicating the existing one created by switch_to_as1(). Add a check to skip creating the temporary entry if already running in AS=1. Fixes: d9e1831a4202 ("powerpc/85xx: Load all early TLB entries at once") Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Laurentiu Tudor Acked-by: Scott Wood Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200123111914.2565-1-laurentiu.tudor@nxp.com Signed-off-by: Greg Kroah-Hartman

powerpc/64/tm: Don't let userspace set regs->trap via sigreturn

2020-04-17T14:12:17+00:00

commit c7def7fbdeaa25feaa19caf4a27c5d10bd8789e4 upstream. In restore_tm_sigcontexts() we take the trap value directly from the user sigcontext with no checking: err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]); This means we can be in the kernel with an arbitrary regs->trap value. Although that's not immediately problematic, there is a risk we could trigger one of the uses of CHECK_FULL_REGS(): #define CHECK_FULL_REGS(regs) BUG_ON(regs->trap & 1) It can also cause us to unnecessarily save non-volatile GPRs again in save_nvgprs(), which shouldn't be problematic but is still wrong. It's also possible it could trick the syscall restart machinery, which relies on regs->trap not being == 0xc00 (see 9a81c16b5275 ("powerpc: fix double syscall restarts")), though I haven't been able to make that happen. Finally it doesn't match the behaviour of the non-TM case, in restore_sigcontext() which zeroes regs->trap. So change restore_tm_sigcontexts() to zero regs->trap. This was discovered while testing Nick's upcoming rewrite of the syscall entry path. In that series the call to save_nvgprs() prior to signal handling (do_notify_resume()) is removed, which leaves the low-bit of regs->trap uncleared which can then trigger the FULL_REGS() WARNs in setup_tm_sigcontexts(). Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context") Cc: stable@vger.kernel.org # v3.9+ Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200401023836.3286664-1-mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman

powerpc: Make setjmp/longjmp signature standard

2020-04-17T14:12:17+00:00

commit c17eb4dca5a353a9dbbb8ad6934fe57af7165e91 upstream. Declaring setjmp()/longjmp() as taking longs makes the signature non-standard, and makes clang complain. In the past, this has been worked around by adding -ffreestanding to the compile flags. The implementation looks like it only ever propagates the value (in longjmp) or sets it to 1 (in setjmp), and we only call longjmp with integer parameters. This allows removing -ffreestanding from the compilation flags. Fixes: c9029ef9c957 ("powerpc: Avoid clang warnings around setjmp and longjmp") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Clement Courbet Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200330080400.124803-1-courbet@google.com Signed-off-by: Greg Kroah-Hartman