kernel.git/arch/powerpc/kernel, branch linux-4.6.y

powerpc/eeh: Fix invalid cached PE primary bus

2016-08-16T07:33:18Z

commit a3aa256b7258b3d19f8b44557cc64525a993b941 upstream. The PE primary bus cannot be got from its child devices when having full hotplug in error recovery. The PE primary bus is cached, which is done in commit <05ba75f84864> ("powerpc/eeh: Fix stale cached primary bus"). In eeh_reset_device(), the flag (EEH_PE_PRI_BUS) is cleared before the PCI hot remove. eeh_pe_bus_get() then returns NULL as the PE primary bus in pnv_eeh_reset() and it crashes the kernel eventually. This fixes the issue by clearing the flag (EEH_PE_PRI_BUS) before the PCI hot add. With it, the PowerNV EEH reset backend (pnv_eeh_reset()) can get valid PE primary bus through eeh_pe_bus_get(). Fixes: 67086e32b564 ("powerpc/eeh: powerpc/eeh: Support error recovery for VF PE") Reported-by: Pridhiviraj Paidipeddi Signed-off-by: Gavin Shan Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/tm: Always reclaim in start_thread() for exec() class syscalls

2016-07-27T15:42:08Z

commit 8e96a87c5431c256feb65bcfc5aec92d9f7839b6 upstream. Userspace can quite legitimately perform an exec() syscall with a suspended transaction. exec() does not return to the old process, rather it load a new one and starts that, the expectation therefore is that the new process starts not in a transaction. Currently exec() is not treated any differently to any other syscall which creates problems. Firstly it could allow a new process to start with a suspended transaction for a binary that no longer exists. This means that the checkpointed state won't be valid and if the suspended transaction were ever to be resumed and subsequently aborted (a possibility which is exceedingly likely as exec()ing will likely doom the transaction) the new process will jump to invalid state. Secondly the incorrect attempt to keep the transactional state while still zeroing state for the new process creates at least two TM Bad Things. The first triggers on the rfid to return to userspace as start_thread() has given the new process a 'clean' MSR but the suspend will still be set in the hardware MSR. The second TM Bad Thing triggers in __switch_to() as the processor is still transactionally suspended but __switch_to() wants to zero the TM sprs for the new process. This is an example of the outcome of calling exec() with a suspended transaction. Note the first 700 is likely the first TM bad thing decsribed earlier only the kernel can't report it as we've loaded userspace registers. c000000000009980 is the rfid in fast_exception_return() Bad kernel stack pointer 3fffcfa1a370 at c000000000009980 Oops: Bad kernel stack pointer, sig: 6 [#1] CPU: 0 PID: 2006 Comm: tm-execed Not tainted NIP: c000000000009980 LR: 0000000000000000 CTR: 0000000000000000 REGS: c00000003ffefd40 TRAP: 0700 Not tainted MSR: 8000000300201031 CR: 00000000 XER: 00000000 CFAR: c0000000000098b4 SOFTE: 0 PACATMSCRATCH: b00000010000d033 GPR00: 0000000000000000 00003fffcfa1a370 0000000000000000 0000000000000000 GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR12: 00003fff966611c0 0000000000000000 0000000000000000 0000000000000000 NIP [c000000000009980] fast_exception_return+0xb0/0xb8 LR [0000000000000000] (null) Call Trace: Instruction dump: f84d0278 e9a100d8 7c7b03a6 e84101a0 7c4ff120 e8410170 7c5a03a6 e8010070 e8410080 e8610088 e8810090 e8210078 <4c000024> 48000000 e8610178 88ed023b Kernel BUG at c000000000043e80 [verbose debug info unavailable] Unexpected TM Bad Thing exception at c000000000043e80 (msr 0x201033) Oops: Unrecoverable exception, sig: 6 [#2] CPU: 0 PID: 2006 Comm: tm-execed Tainted: G D task: c0000000fbea6d80 ti: c00000003ffec000 task.ti: c0000000fb7ec000 NIP: c000000000043e80 LR: c000000000015a24 CTR: 0000000000000000 REGS: c00000003ffef7e0 TRAP: 0700 Tainted: G D MSR: 8000000300201033 CR: 28002828 XER: 00000000 CFAR: c000000000015a20 SOFTE: 0 PACATMSCRATCH: b00000010000d033 GPR00: 0000000000000000 c00000003ffefa60 c000000000db5500 c0000000fbead000 GPR04: 8000000300001033 2222222222222222 2222222222222222 00000000ff160000 GPR08: 0000000000000000 800000010000d033 c0000000fb7e3ea0 c00000000fe00004 GPR12: 0000000000002200 c00000000fe00000 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 c0000000fbea7410 00000000ff160000 GPR24: c0000000ffe1f600 c0000000fbea8700 c0000000fbea8700 c0000000fbead000 GPR28: c000000000e20198 c0000000fbea6d80 c0000000fbeab680 c0000000fbea6d80 NIP [c000000000043e80] tm_restore_sprs+0xc/0x1c LR [c000000000015a24] __switch_to+0x1f4/0x420 Call Trace: Instruction dump: 7c800164 4e800020 7c0022a6 f80304a8 7c0222a6 f80304b0 7c0122a6 f80304b8 4e800020 e80304a8 7c0023a6 e80304b0 <7c0223a6> e80304b8 7c0123a6 4e800020 This fixes CVE-2016-5828. Fixes: bc2a9408fa65 ("powerpc: Hook in new transactional memory code") Signed-off-by: Cyril Bur Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: Fix IBM_ARCH_VEC_NRCORES_OFFSET since POWER8NVL was added

2016-07-27T15:42:08Z

commit 2c2a63e301fd19ccae673e79de59b30a232ff7f9 upstream. The recent commit 7cc851039d64 ("powerpc/pseries: Add POWER8NVL support to ibm,client-architecture-support call") added a new PVR mask & value to the start of the ibm_architecture_vec[] array. However it missed the fact that further down in the array, we hard code the offset of one of the fields, and then at boot use that value to patch the value in the array. This means every update to the array must also update the #define, ugh. This means that on pseries machines we will misreport to firmware the number of cores we support, by a factor of threads_per_core. Fix it for now by updating the #define. Fixes: 7cc851039d64 ("powerpc/pseries: Add POWER8NVL support to ibm,client-architecture-support call") Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: Add POWER8NVL support to ibm,client-architecture-support call

2016-06-24T17:22:03Z

commit 7cc851039d643a2ee7df4d18177150f2c3a484f5 upstream. If we do not provide the PVR for POWER8NVL, a guest on this system currently ends up in PowerISA 2.06 compatibility mode on KVM, since QEMU does not provide a generic PowerISA 2.07 mode yet. So some new instructions from POWER8 (like "mtvsrd") get disabled for the guest, resulting in crashes when using code compiled explicitly for POWER8 (e.g. with the "-mcpu=power8" option of GCC). Fixes: ddee09c099c3 ("powerpc: Add PVR for POWER8NVL processor") Signed-off-by: Thomas Huth Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/eeh: Restore initial state in eeh_pe_reset_and_recover()

2016-06-08T01:23:39Z

commit 5a0cdbfd17b90a89c64a71d8aec9773ecdb20d0d upstream. The function eeh_pe_reset_and_recover() is used to recover EEH error when the passthrou device are transferred to guest and backwards. The content in the device's config space will be lost on PE reset issued in the middle of the recovery. The function saves/restores it before/after the reset. However, config access to some adapters like Broadcom BCM5719 at this point will causes fenced PHB. The config space is always blocked and we save 0xFF's that are restored at late point. The memory BARs are totally corrupted, causing another EEH error upon access to one of the memory BARs. This restores the config space on those adapters like BCM5719 from the content saved to the EEH device when it's populated, to resolve above issue. Fixes: 5cfb20b9 ("powerpc/eeh: Emulate EEH recovery for VFIO devices") Signed-off-by: Gavin Shan Reviewed-by: Russell Currey Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

Revert "powerpc/eeh: Fix crash in eeh_add_device_early() on Cell"

2016-06-08T01:23:39Z

commit c2078d9ef600bdbe568c89e5ddc2c6f15b7982c8 upstream. This reverts commit 89a51df5ab1d38b257300b8ac940bbac3bb0eb9b. The function eeh_add_device_early() is used to perform EEH initialization in devices added later on the system, like in hotplug/DLPAR scenarios. Since the commit 89a51df5ab1d ("powerpc/eeh: Fix crash in eeh_add_device_early() on Cell") a new check was introduced in this function - Cell has no EEH capabilities which led to kernel oops if hotplug was performed, so checking for eeh_enabled() was introduced to avoid the issue. However, in architectures that EEH is present like pSeries or PowerNV, we might reach a case in which no PCI devices are present on boot time and so EEH is not initialized. Then, if a device is added via DLPAR for example, eeh_add_device_early() fails because eeh_enabled() is false, and EEH end up not being enabled at all. This reverts the aforementioned patch since a new verification was introduced by the commit d91dafc02f42 ("powerpc/eeh: Delay probing EEH device during hotplug") and so the original Cell issue does not happen anymore. Reviewed-by: Gavin Shan Signed-off-by: Guilherme G. Piccoli Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/eeh: Don't report error in eeh_pe_reset_and_recover()

2016-06-08T01:23:39Z

commit affeb0f2d3a9af419ad7ef4ac782e1540b2f7b28 upstream. The function eeh_pe_reset_and_recover() is used to recover EEH error when the passthrough device are transferred to guest and backwards, meaning the device's driver is vfio-pci or none. When the driver is vfio-pci that provides error_detected() error handler only, the handler simply stops the guest and it's not expected behaviour. On the other hand, no error handlers will be called if we don't have a bound driver. This ignores the error handler in eeh_pe_reset_and_recover() that reports the error to device driver to avoid the exceptional behaviour. Fixes: 5cfb20b9 ("powerpc/eeh: Emulate EEH recovery for VFIO devices") Signed-off-by: Gavin Shan Reviewed-by: Russell Currey Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/book3s64: Fix branching to OOL handlers in relocatable kernel

2016-06-08T01:23:39Z

commit 8ed8ab40047a570fdd8043a40c104a57248dd3fd upstream. Some of the interrupt vectors on 64-bit POWER server processors are only 32 bytes long (8 instructions), which is not enough for the full first-level interrupt handler. For these we need to branch to an out-of-line (OOL) handler. But when we are running a relocatable kernel, interrupt vectors till __end_interrupts marker are copied down to real address 0x100. So, branching to labels (ie. OOL handlers) outside this section must be handled differently (see LOAD_HANDLER()), considering relocatable kernel, which would need at least 4 instructions. However, branching from interrupt vector means that we corrupt the CFAR (come-from address register) on POWER7 and later processors as mentioned in commit 1707dd16. So, EXCEPTION_PROLOG_0 (6 instructions) that contains the part up to the point where the CFAR is saved in the PACA should be part of the short interrupt vectors before we branch out to OOL handlers. But as mentioned already, there are interrupt vectors on 64-bit POWER server processors that are only 32 bytes long (like vectors 0x4f00, 0x4f20, etc.), which cannot accomodate the above two cases at the same time owing to space constraint. Currently, in these interrupt vectors, we simply branch out to OOL handlers, without using LOAD_HANDLER(), which leaves us vulnerable when running a relocatable kernel (eg. kdump case). While this has been the case for sometime now and kdump is used widely, we were fortunate not to see any problems so far, for three reasons: 1. In almost all cases, production kernel (relocatable) is used for kdump as well, which would mean that crashed kernel's OOL handler would be at the same place where we end up branching to, from short interrupt vector of kdump kernel. 2. Also, OOL handler was unlikely the reason for crash in almost all the kdump scenarios, which meant we had a sane OOL handler from crashed kernel that we branched to. 3. On most 64-bit POWER server processors, page size is large enough that marking interrupt vector code as executable (see commit 429d2e83) leads to marking OOL handler code from crashed kernel, that sits right below interrupt vector code from kdump kernel, as executable as well. Let us fix this by moving the __end_interrupts marker down past OOL handlers to make sure that we also copy OOL handlers to real address 0x100 when running a relocatable kernel. This fix has been tested successfully in kdump scenario, on an LPAR with 4K page size by using different default/production kernel and kdump kernel. Also tested by manually corrupting the OOL handlers in the first kernel and then kdump'ing, and then causing the OOL handlers to fire - mpe. Fixes: c1fb6816fb1b ("powerpc: Add relocation on exception vector handlers") Signed-off-by: Hari Bathini Signed-off-by: Mahesh Salgaonkar Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc: Update TM user feature bits in scan_features()

2016-04-18T10:10:45Z

We need to update the user TM feature bits (PPC_FEATURE2_HTM and PPC_FEATURE2_HTM) to mirror what we do with the kernel TM feature bit. At the moment, if firmware reports TM is not available we turn off the kernel TM feature bit but leave the userspace ones on. Userspace thinks it can execute TM instructions and it dies trying. This (together with a QEMU patch) fixes PR KVM, which doesn't currently support TM. Signed-off-by: Anton Blanchard Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman

powerpc: Update cpu_user_features2 in scan_features()

2016-04-18T10:10:45Z

scan_features() updates cpu_user_features but not cpu_user_features2. Amongst other things, cpu_user_features2 contains the user TM feature bits which we must keep in sync with the kernel TM feature bit. Signed-off-by: Anton Blanchard Cc: stable@vger.kernel.org Signed-off-by: Michael Ellerman