- 25 Jun, 2021 9 commits
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Haren Myneni authored
On PowerVM, the hypervisor defines the maximum buffer length for each NX request and the kernel exported this value via sysfs. This patch reads this value if the sysfs entry is available and is used to limit the request length. Signed-off-by:
Haren Myneni <haren@linux.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/ed908341b1eb7ca0183c028a4ed4a0cf48bfe0f6.camel@linux.ibm.com
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Naveen N. Rao authored
blrl corrupts the link stack. Instead use bctrl when making function calls from BPF programs. Reported-by:
Anton Blanchard <anton@ozlabs.org> Signed-off-by:
Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by:
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Naveen N. Rao authored
It is sometimes desirable to run a command on all cpus in xmon. A typical scenario is to obtain the backtrace from all cpus in xmon if there is a soft lockup. Add rudimentary support for the same. The command to be run on all cpus should be prefixed with 'c#'. As an example, 'c#t' will run 't' command and produce a backtrace on all cpus in xmon. Since many xmon commands are not sensible for running in this manner, we only allow a predefined list of commands -- 'r', 'S' and 't' for now. Signed-off-by:
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Naveen N. Rao authored
Both these config options are generally enabled in distro kernels. Enable the same in a few powerpc64 configs to get better coverage and testing. Signed-off-by:
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Naveen N. Rao authored
When arming and disarming probes, we currently assume that instruction patching can never fail, and don't have a mechanism to surface errors. Add a warning in case instruction patching ever fails. Signed-off-by:
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Naveen N. Rao authored
In kprobes and xmon, we should exclude both 32-bit and 64-bit variants of mtmsr and rfi instructions from being stepped. Have IS_RFID() also detect a rfi instruction similar to IS_MTMSRD(). Signed-off-by:
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Vaibhav Jain authored
Persistent memory devices like NVDIMMs can loose cached writes in case something prevents flush on power-fail. Such situations are termed as dirty shutdown and are exposed to applications as last-shutdown-state (LSS) flag and a dirty-shutdown-counter(DSC) as described at [1]. The latter being useful in conditions where multiple applications want to detect a dirty shutdown event without racing with one another. PAPR-NVDIMMs have so far only exposed LSS style flags to indicate a dirty-shutdown-state. This patch further adds support for DSC via the "ibm,persistence-failed-count" device tree property of an NVDIMM. This property is a monotonic increasing 64-bit counter thats an indication of number of times an NVDIMM has encountered a dirty-shutdown event causing persistence loss. Since this value is not expected to change after system-boot hence papr_scm reads & caches its value during NVDIMM probe and exposes it as a PAPR sysfs attributed named 'dirty_shutdown' to match the name of similarly named NFIT sysfs attribute. Also this value is available to libnvdimm via PAPR_PDSM_HEALTH payload. 'struct nd_papr_pdsm_health' has been extended to add a new member called 'dimm_dsc' presence of which is indicated by the newly introduced PDSM_DIMM_DSC_VALID flag. References: [1] https://pmem.io/documents/Dirty_Shutdown_Handling-V1.0.pdfSigned-off-by:
Vaibhav Jain <vaibhav@linux.ibm.com> Reviewed-by:
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by:
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Vaibhav Jain authored
In case performance stats for an nvdimm are not available, reading the 'perf_stats' sysfs file returns an -ENOENT error. A better approach is to make the 'perf_stats' file entirely invisible to indicate that performance stats for an nvdimm are unavailable. So this patch updates 'papr_nd_attribute_group' to add a 'is_visible' callback implemented as newly introduced 'papr_nd_attribute_visible()' that returns an appropriate mode in case performance stats aren't supported in a given nvdimm. Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is available when 'papr_nd_attribute_visible()' is called during nvdimm initialization. Even though 'perf_stats' attribute is available since v5.9, there are no known user-space tools/scripts that are dependent on presence of its sysfs file. Hence I dont expect any user-space breakage with this patch. Fixes: 2d02bf83 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP") Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Signed-off-by:
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Naveen N. Rao authored
Trying to use a kprobe on ppc32 results in the below splat: BUG: Unable to handle kernel data access on read at 0x7c0802a6 Faulting instruction address: 0xc002e9f0 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=4K PowerPC 44x Platform Modules linked in: CPU: 0 PID: 89 Comm: sh Not tainted 5.13.0-rc1-01824-g3a81c0495fdb #7 NIP: c002e9f0 LR: c0011858 CTR: 00008a47 REGS: c292fd50 TRAP: 0300 Not tainted (5.13.0-rc1-01824-g3a81c0495fdb) MSR: 00009000 <EE,ME> CR: 24002002 XER: 20000000 DEAR: 7c0802a6 ESR: 00000000 <snip> NIP [c002e9f0] emulate_step+0x28/0x324 LR [c0011858] optinsn_slot+0x128/0x10000 Call Trace: opt_pre_handler+0x7c/0xb4 (unreliable) optinsn_slot+0x128/0x10000 ret_from_syscall+0x0/0x28 The offending instruction is: 81 24 00 00 lwz r9,0(r4) Here, we are trying to load the second argument to emulate_step(): struct ppc_inst, which is the instruction to be emulated. On ppc64, structures are passed in registers when passed by value. However, per the ppc32 ABI, structures are always passed to functions as pointers. This isn't being adhered to when setting up the call to emulate_step() in the optprobe trampoline. Fix the same. Fixes: eacf4c02 ("powerpc: Enable OPTPROBES on PPC32") Cc: stable@vger.kernel.org Signed-off-by:Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by:
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- 24 Jun, 2021 31 commits
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Nicholas Piggin authored
copy-paste contains implicit "copy buffer" state that can contain arbitrary user data (if the user process executes a copy instruction). This could be snooped by another process if a context switch hits while the state is live. So cp_abort is executed on context switch to clear out possible sensitive data and prevent the leak. cp_abort is done after the low level _switch(), which means it is never reached by newly created tasks, so they could snoop on this buffer between their first and second context switch. Fix this by doing the cp_abort before calling _switch. Add some comments which should make the issue harder to miss. Fixes: 07d2a628 ("powerpc/64s: Avoid cpabort in context switch when possible") Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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Christophe Leroy authored
On booke, SYSCALL_ENTRY macro nests an FTR_SECTION with a #ifdef CONFIG_KVM_BOOKE_HV. Duplicate the single instruction alternative to avoid nesting. Signed-off-by:
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Christophe Leroy authored
booke and non booke do pretty similar things in SYSCALL_ENTRY macro just before calling jumping to transfer_to_syscall(). Do them in transfer_to_syscall() instead. Signed-off-by:
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Christophe Leroy authored
To better match non booke version of SYSCALL_ENTRY macro, interchange r1 and r11 in the booke version. While at it, in both versions use r1 instead of r11 to save _NIP and _CCR. All other uses of r11 will go away in next patch, so don't bother changing them for now. Signed-off-by:
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Christophe Leroy authored
To better match booke version of SYSCALL_ENTRY macro, interchange r10 and r12 in the non booke version. Signed-off-by:
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Christophe Leroy authored
klimit is a global variable initialised at build time with the value of _end. This variable is never modified, so _end symbol can be used directly. Remove klimit. Signed-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by:
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Christophe Leroy authored
Commit aaa22952 ("powerpc/mm: Add physical address to Linux page table dump") changed range coalescing to only combine ranges that are both virtually and physically contiguous, in order to avoid erroneous combination of unrelated mappings in IOREMAP space. But in the VMALLOC space, mappings almost never have contiguous physical pages, so the commit mentionned above leads to dumping one line per page for vmalloc mappings. Taking into account the vmalloc always leave a gap between two areas, we never have two mappings dumped as a single combination even if they have the exact same flags. The only space that may have encountered such an issue was the early IOREMAP which is not using vmalloc engine. But previous commits added gaps between early IO mappings, so it is not an issue anymore. That commit created some difficulties with KASAN mappings, see commit cabe8138 ("powerpc: dump as a single line areas mapping a single physical page.") and with huge page, see commit b00ff6d8 ("powerpc/ptdump: Properly handle non standard page size"). So, almost revert commit aaa22952 to properly coalesce pages mapped with the same flags as before, only keep the display of the first physical address of the range, as it can be usefull especially for IO mappings. It brings back powerpc at the same level as other architectures and simplifies the conversion to GENERIC PTDUMP. With the patch: ---[ kasan shadow mem start ]--- 0xf8000000-0xf8ffffff 0x07000000 16M huge rw present dirty accessed 0xf9000000-0xf91fffff 0x01434000 2M r present accessed 0xf9200000-0xf95affff 0x02104000 3776K rw present dirty accessed 0xfef5c000-0xfeffffff 0x01434000 656K r present accessed ---[ kasan shadow mem end ]--- Before: ---[ kasan shadow mem start ]--- 0xf8000000-0xf8ffffff 0x07000000 16M huge rw present dirty accessed 0xf9000000-0xf91fffff 0x01434000 16K r present accessed 0xf9200000-0xf9203fff 0x02104000 16K rw present dirty accessed 0xf9204000-0xf9207fff 0x0213c000 16K rw present dirty accessed 0xf9208000-0xf920bfff 0x02174000 16K rw present dirty accessed 0xf920c000-0xf920ffff 0x02188000 16K rw present dirty accessed 0xf9210000-0xf9213fff 0x021dc000 16K rw present dirty accessed 0xf9214000-0xf9217fff 0x02220000 16K rw present dirty accessed 0xf9218000-0xf921bfff 0x023c0000 16K rw present dirty accessed 0xf921c000-0xf921ffff 0x023d4000 16K rw present dirty accessed 0xf9220000-0xf9227fff 0x023ec000 32K rw present dirty accessed ... 0xf93b8000-0xf93e3fff 0x02614000 176K rw present dirty accessed 0xf93e4000-0xf94c3fff 0x027c0000 896K rw present dirty accessed 0xf94c4000-0xf94c7fff 0x0236c000 16K rw present dirty accessed 0xf94c8000-0xf94cbfff 0x041f0000 16K rw present dirty accessed 0xf94cc000-0xf94cffff 0x029c0000 16K rw present dirty accessed 0xf94d0000-0xf94d3fff 0x041ec000 16K rw present dirty accessed 0xf94d4000-0xf94d7fff 0x0407c000 16K rw present dirty accessed 0xf94d8000-0xf94f7fff 0x041c0000 128K rw present dirty accessed ... 0xf95ac000-0xf95affff 0x042b0000 16K rw present dirty accessed 0xfef5c000-0xfeffffff 0x01434000 16K r present accessed ---[ kasan shadow mem end ]--- Signed-off-by:
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Christophe Leroy authored
Vmalloc system leaves a gap between allocated areas. It helps catching overflows. Do the same for IO areas which are allocated with early_ioremap_range() until slab_is_available(). Signed-off-by:
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Andy Shevchenko authored
Parse to and export from UUID own type, before dereferencing. This also fixes wrong comment (Little Endian UUID is something else) and should eliminate the direct strict types assignments. Fixes: 43001c52 ("powerpc/papr_scm: Use ibm,unit-guid as the iset cookie") Fixes: 259a948c ("powerpc/pseries/scm: Use a specific endian format for storing uuid from the device tree") Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by:
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Daniel Henrique Barboza authored
The validation done at the start of dlpar_memory_add_by_ic() is an all of nothing scenario - if any LMBs in the range is marked as RESERVED we can fail right away. We then can remove the 'lmbs_available' var and its check with 'lmbs_to_add' since the whole LMB range was already validated in the previous step. Signed-off-by:
Daniel Henrique Barboza <danielhb413@gmail.com> Signed-off-by:
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Daniel Henrique Barboza authored
After a successful dlpar_add_lmb() call the LMB is marked as reserved. Later on, depending whether we added enough LMBs or not, we rely on the marked LMBs to see which ones might need to be removed, and we remove the reservation of all of them. These are done in for_each_drmem_lmb() loops without any break condition. This means that we're going to check all LMBs of the partition even after going through all the reserved ones. This patch adds break conditions in both loops to avoid this. The 'lmbs_added' variable was renamed to 'lmbs_reserved', and it's now being decremented each time a lmb reservation is removed, indicating if there are still marked LMBs to be processed. Signed-off-by:
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Daniel Henrique Barboza authored
The function is counting reserved LMBs as available to be added, but they aren't. This will cause the function to miscalculate the available LMBs and can trigger errors later on when executing dlpar_add_lmb(). Signed-off-by:
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Nicholas Piggin authored
printk_safe_flush_on_panic() has special lock breaking code for the case where we panic()ed with the console lock held. It relies on panic IPI causing other CPUs to mark themselves offline. Do as most other architectures do. This effectively reverts commit de6e5d38 ("powerpc: smp_send_stop do not offline stopped CPUs"), unfortunately it may result in some false positive warnings, but the alternative is more situations where we can crash without getting messages out. Fixes: de6e5d38 ("powerpc: smp_send_stop do not offline stopped CPUs") Signed-off-by:
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Nicholas Piggin authored
32-bit platforms don't have irq soft masking. Signed-off-by:
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Nicholas Piggin authored
The caller has been moved to C after irq soft-mask state has been reconciled, and Linux IRQs have been marked as disabled, so this no longer needs to play games with IRQ internals. Fixes: 68b34588 ("powerpc/64/sycall: Implement syscall entry/exit logic in C") Signed-off-by:
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Nicholas Piggin authored
PowerVM will not arbitrarily oversubscribe or stop guests, page out the guest kernel text to a NFS volume connected by carrier pigeon to abacus based storage, etc., as a KVM host might. So PowerVM guests are not likely to be killed by the hard lockup watchdog in normal operation, even with shared processor LPARs which still get a minimum allotment of CPU time. Enable the hard lockup detector by default on !KVM guests, which we will assume is PowerVM. It has been useful in finding problems on bare metal kernels. Signed-off-by:
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Nicholas Piggin authored
The PPC_RFI_SRR_DEBUG check added by patch "powerpc/64s: avoid reloading (H)SRR registers if they are still valid" has a few deficiencies. It does not fix the actual problem, it's not enabled by default, and it causes a program check interrupt which can cause more difficulties. However there are a lot of paths which may clobber SRRs or change return regs, and difficult to have a high confidence that all paths are covered without wider testing. Add a relatively low overhead always-enabled check that catches most such cases, reports once, and fixes it so the kernel can continue. Signed-off-by:
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Christophe Leroy authored
prep_irq_for_user_exit() has only one caller, squash it inside that caller. Signed-off-by:
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Christophe Leroy authored
prep_irq_for_user_exit() is a superset of prep_irq_for_kernel_enabled_exit(). Rename prep_irq_for_kernel_enabled_exit() as prep_irq_for_enabled_exit() and have prep_irq_for_user_exit() use it. Signed-off-by:
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Christophe Leroy authored
prep_irq_for_user_exit() is a superset of prep_irq_for_kernel_enabled_exit(). In order to allow refactoring in following patch, interchange the two. This will allow prep_irq_for_user_exit() to call a renamed version of prep_irq_for_kernel_enabled_exit(). Signed-off-by:
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Christophe Leroy authored
interrupt_exit_user_prepare() is a superset of interrupt_exit_user_prepare_main(). Refactor to avoid code duplication. Signed-off-by:
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Christophe Leroy authored
Rename syscall_exit_prepare_main() into interrupt_exit_prepare_main() Pass it the 'ret' so that it can 'or' it directly instead of oring twice, once inside the function and once outside. And remove 'r3' parameter which is not used. Signed-off-by:
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Nicholas Piggin authored
Use the restart table facility to return from interrupt or system calls without disabling MSR[EE] or MSR[RI]. Interrupt return asm is put into the low soft-masked region, to prevent interrupts being processed here, although they are still taken as masked interrupts which causes SRRs to be clobbered, and a pending soft-masked interrupt to require replaying. The return code uses restart table regions to redirct to a fixup handler rather than continue with the exit, if such an interrupt happens. In this case the interrupt return is redirected to a fixup handler which reloads r1 for the interrupt stack and reloads registers and sets state up to replay the soft-masked interrupt and try the exit again. Some types of security exit fallback flushes and barriers are currently unable to cope with reentrant interrupts, e.g., because they store some state in the scratch SPR which would be clobbered even by masked interrupts. For now the interrupts-enabled exits are disabled when these flushes are used. Signed-off-by:
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Nicholas Piggin authored
Treat code below __end_soft_masked as soft-masked for the purpose of alternate return. 64s already mostly does this for scv entry. This will be used to exit from interrupts without disabling MSR[EE]. Signed-off-by:
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Nicholas Piggin authored
Prevent interrupt restore from allowing racing hard interrupts going ahead of previous soft-pending ones, by using the soft-masked restart handler to allow a store to clear the soft-mask while knowing nothing is soft-pending. This probably doesn't matter much in practice, but it's a simple demonstrator / test case to exercise the restart table logic. Signed-off-by:
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Nicholas Piggin authored
The exception table fixup adjusts a failed page fault's interrupt return location if it was taken at an address specified in the exception table, to a corresponding fixup handler address. Introduce a variation of that idea which adds a fixup table for NMIs and soft-masked asynchronous interrupts. This will be used to protect certain critical sections that are sensitive to being clobbered by interrupts coming in (due to using the same SPRs and/or irq soft-mask state). Signed-off-by:
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Nicholas Piggin authored
This frees up one more register (and takes advantage of that to clean things up a little bit). This register will be used in the following patch. Signed-off-by:
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Nicholas Piggin authored
This extends the MSR[RI]=0 window a little further into the system call in order to pair RI and EE enabling with a single mtmsrd. Signed-off-by:
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Nicholas Piggin authored
The next patch would like to move interrupt return assembly code to a low location before general text, so move it into its own file and include via head_64.S Signed-off-by:
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Nicholas Piggin authored
When an interrupt is taken, the SRR registers are set to return to where it left off. Unless they are modified in the meantime, or the return address or MSR are modified, there is no need to reload these registers when returning from interrupt. Introduce per-CPU flags that track the validity of SRR and HSRR registers. These are cleared when returning from interrupt, when using the registers for something else (e.g., OPAL calls), when adjusting the return address or MSR of a context, and when context switching (which changes the return address and MSR). This improves the performance of interrupt returns. Signed-off-by:
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Nicholas Piggin authored
This makes no real difference yet except that HSRR type interrupts will use hrfid to return. This is important for the next patch. Signed-off-by:
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