- 07 Mar, 2022 26 commits
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Naveen N. Rao authored
When calling BPF helpers, we load the function address to call into a register. This can result in upto 5 instructions. Optimize this by instead using the kernel toc in r2 and adjusting offset to the BPF helper. This works since all BPF helpers are part of kernel text, and all BPF programs/functions utilize the kernel TOC. Further more: - load the actual function entry address in elf v1, rather than loading it through the function descriptor address. - load the Local Entry Point (LEP) in elf v2 skipping TOC setup. - consolidate code across elf abi v1 and v2 by using r12 on both. Reported-by:
Anton Blanchard <anton@ozlabs.org> Signed-off-by:
Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1233c7544e60dcb021c52b1f840b0f21a87b33ed.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
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Naveen N. Rao authored
BPF helpers always reside in core kernel and all BPF programs use the kernel TOC. As such, there is no need to load the TOC before calling helpers or other BPF functions. Drop code to do the same. Add a check to ensure we don't proceed if this assumption ever changes in future. Signed-off-by:
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Naveen N. Rao authored
In preparation for using kernel TOC, load the same in r2 on entry. With elfv1, the kernel TOC is already setup by our caller. We adjust the number of instructions to skip on a tail call accordingly. We get rid of the #ifdef in bpf_jit_emit_tail_call() since FUNCTION_DESCR_SIZE is itself under a #ifdef. Signed-off-by:
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Naveen N. Rao authored
Set macros to 1 so that they can be used with __is_defined(). Suggested-by:
Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by:
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Naveen N. Rao authored
In preparation for preserving kernel toc in r2, switch BPF_REG_AX from r2 to r12. r12 is not used by bpf JIT except during external helper/bpf calls, or with BPF_NOSPEC. These sequences aren't emitted when BPF_REG_AX is used for constant blinding and other purposes. Signed-off-by:
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Naveen N. Rao authored
Instead of saving and restoring LR before each invocation to bpf_stf_barrier(), set SEEN_FUNC flag so that we save/restore LR in prologue/epilogue. Signed-off-by:
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Naveen N. Rao authored
In some scenarios, it is possible that the program epilogue is outside the branch range for a BPF_EXIT instruction. Instead of rejecting such programs, emit epilogue as an alternate exit point from the program. Track the location of the same so that subsequent exits can take either of the two paths. Reported-by:
Jordan Niethe <jniethe5@gmail.com> Signed-off-by:
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Naveen N. Rao authored
PPC_BCC() emits two instructions to accommodate scenarios where we need to branch outside the range of a conditional branch. PPC_BCC_SHORT() emits a single branch instruction and can be used when the branch is known to be within a conditional branch range. Convert some of the uses of PPC_BCC() in the powerpc BPF JIT over to PPC_BCC_SHORT() where we know the branch range. Signed-off-by:
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Naveen N. Rao authored
During the first pass, addrs[] is still being populated. So, all branches to following instructions will appear to be going to the start of the JIT program. Ignore branch range validation for such instructions and assume those to be in range. Branch range validation will happen during the second pass after addrs[] is setup properly. Signed-off-by:
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Michael Ellerman authored
Paul reported a warning with DEBUG_ATOMIC_SLEEP=y: BUG: sleeping function called from invalid context at include/linux/sched/mm.h:256 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0 preempt_count: 0, expected: 0 ... Call Trace: dump_stack_lvl+0xa0/0xec (unreliable) __might_resched+0x2f4/0x310 kmem_cache_alloc+0x220/0x4b0 __pud_alloc+0x74/0x1d0 hash__map_kernel_page+0x2cc/0x390 do_patch_instruction+0x134/0x4a0 arch_jump_label_transform+0x64/0x78 __jump_label_update+0x148/0x180 static_key_enable_cpuslocked+0xd0/0x120 static_key_enable+0x30/0x50 check_kvm_guest+0x60/0x88 pSeries_smp_probe+0x54/0xb0 smp_prepare_cpus+0x3e0/0x430 kernel_init_freeable+0x20c/0x43c kernel_init+0x30/0x1a0 ret_from_kernel_thread+0x5c/0x64 Peter pointed out that this is because do_patch_instruction() has disabled interrupts, but then map_patch_area() calls map_kernel_page() then hash__map_kernel_page() which does a sleeping memory allocation. We only see the warning in KVM guests with SMT enabled, which is not particularly common, or on other platforms if CONFIG_KPROBES is disabled, also not common. The reason we don't see it in most configurations is that another path that happens to have interrupts enabled has allocated the required page tables for us, eg. there's a path in kprobes init that does that. That's just pure luck though. As Christophe suggested, the simplest solution is to do a dummy map/unmap when we initialise the patching, so that any required page table levels are pre-allocated before the first call to do_patch_instruction(). This works because the unmap doesn't free any page tables that were allocated by the map, it just clears the PTE, leaving the page table levels there for the next map. Reported-by:Paul Menzel <pmenzel@molgen.mpg.de> Debugged-by:
Peter Zijlstra <peterz@infradead.org> Suggested-by:
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Michael Ellerman authored
Since commit 46ddcb39 ("powerpc/mm: Show if a bad page fault on data is read or write.") we use page_fault_is_write(regs->dsisr) in __bad_page_fault() to determine if the fault is for a read or write, and change the message printed accordingly. But SLB faults, aka Data Segment Interrupts, don't set DSISR (Data Storage Interrupt Status Register) to a useful value. All ISA versions from v2.03 through v3.1 specify that the Data Segment Interrupt sets DSISR "to an undefined value". As far as I can see there's no mention of SLB faults setting DSISR in any BookIV content either. This manifests as accesses that should be a read being incorrectly reported as writes, for example, using the xmon "dump" command: 0:mon> d 0x5deadbeef0000000 5deadbeef0000000 [359526.415354][ C6] BUG: Unable to handle kernel data access on write at 0x5deadbeef0000000 [359526.415611][ C6] Faulting instruction address: 0xc00000000010a300 cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf400] pc: c00000000010a300: mread+0x90/0x190 If we disassemble the PC, we see a load instruction: 0:mon> di c00000000010a300 c00000000010a300 89490000 lbz r10,0(r9) We can also see in exceptions-64s.S that the data_access_slb block doesn't set IDSISR=1, which means it doesn't load DSISR into pt_regs. So the value we're using to determine if the fault is a read/write is some stale value in pt_regs from a previous page fault. Rework the printing logic to separate the SLB fault case out, and only print read/write in the cases where we can determine it. The result looks like eg: 0:mon> d 0x5deadbeef0000000 5deadbeef0000000 [ 721.779525][ C6] BUG: Unable to handle kernel data access at 0x5deadbeef0000000 [ 721.779697][ C6] Faulting instruction address: 0xc00000000014cbe0 cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390] 0:mon> d 0 0000000000000000 [ 742.793242][ C6] BUG: Kernel NULL pointer dereference at 0x00000000 [ 742.793316][ C6] Faulting instruction address: 0xc00000000014cbe0 cpu 0x6: Vector: 380 (Data SLB Access) at [c00000000ffbf390] Fixes: 46ddcb39 ("powerpc/mm: Show if a bad page fault on data is read or write.") Reported-by:
Nageswara R Sastry <rnsastry@linux.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Link: https://lore.kernel.org/r/20220222113449.319193-1-mpe@ellerman.id.au
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Jakob Koschel authored
'gtm' will *always* be set by list_for_each_entry(). It is incorrect to assume that the iterator value will be NULL if the list is empty. Instead of checking the pointer it should be checked if the list is empty. Fixes: 83ff9dcf ("powerpc/sysdev: implement FSL GTM support") Signed-off-by:
Jakob Koschel <jakobkoschel@gmail.com> Signed-off-by:
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Haren Myneni authored
Since the VAS windows belong to the VAS hardware resource, the hypervisor expects the partition to close them on source partition and reopen them after the partition migrated on the destination machine. This handler is called before pseries_suspend() to close these windows and again invoked after migration. All active windows for both default and QoS types will be closed and mark them inactive and reopened after migration with this handler. During the migration, the user space receives paste instruction failure if it issues copy/paste on these inactive windows. The current migration implementation does not freeze the user space and applications can continue to open VAS windows while migration is in progress. So when the migration_in_progress flag is set, VAS open window API returns -EBUSY. Signed-off-by:
Haren Myneni <haren@linux.ibm.com> Signed-off-by:
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Haren Myneni authored
VAS is a hardware engine stays on the chip. So when the partition migrates, all VAS windows on the source system have to be closed and reopen them on the destination after migration. The kernel has to consider both DLPAR CPU and migration events to take action on VAS windows. So using VAS_WIN_NO_CRED_CLOSE and VAS_WIN_MIGRATE_CLOSE status bits and windows will be reopened after migration only after both status bits are cleared. This patch make changes to the current reconfig_open/close_windows functions to support migration: - Set VAS_WIN_MIGRATE_CLOSE to the window status when closes and reopen windows with the same status during resume. - Continue to close all windows even if deallocate HCALL failed (should not happen) since no way to stop migration with the current LPM implementation. - If the DLPAR CPU event happens while migration is in progress, set VAS_WIN_NO_CRED_CLOSE to the window status. Close window happens with the first event (migration or DLPAR) and Reopen window happens only with the last event (migration or DLPAR). Signed-off-by:
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Haren Myneni authored
The coprocessor capabilities struct is used to get default and QoS capabilities from the hypervisor during init, DLPAR event and migration. So instead of allocating this struct for each event, define global struct and reuse it which allows the migration code to avoid adding an error path. Also disable copy/paste feature flag if any capabilities HCALL is failed. Signed-off-by:
Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by:
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Haren Myneni authored
pseries supports two types of credits - Default (uses normal priority FIFO) and Qality of service (QoS uses high priority FIFO). The user decides the number of QoS credits and sets this value with HMC interface. The total credits for QoS capabilities can be changed dynamically with HMC interface which invokes drmgr to communicate to the kernel. This patch creats 'update_total_credits' entry for QoS capabilities so that drmgr command can write the new target QoS credits in sysfs. Instead of using this value, the kernel gets the new QoS capabilities from the hypervisor whenever update_total_credits is updated to make sure sync with the QoS target credits in the hypervisor. Signed-off-by:
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Haren Myneni authored
The hypervisor provides the available VAS GZIP capabilities such as default or QoS window type and the target available credits in each type. This patch creates sysfs entries and exports the target, used and the available credits for each feature. This interface can be used by the user space to determine the credits usage or to set the target credits in the case of QoS type (for DLPAR). /sys/devices/vas/vas0/gzip/default_capabilities (default GZIP capabilities) nr_total_credits /* Total credits available. Can be /* changed with DLPAR operation */ nr_used_credits /* Used credits */ /sys/devices/vas/vas0/gzip/qos_capabilities (QoS GZIP capabilities) nr_total_credits nr_used_credits Signed-off-by:
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Haren Myneni authored
VAS windows can be closed in the hypervisor due to lost credits when the core is removed and the kernel gets fault for NX requests on these inactive windows. If the NX requests are issued on these inactive windows, OS gets page faults and the paste failure will be returned to the user space. If the lost credits are available later with core add, reopen these windows and set them active. Later when the OS sees page faults on these active windows, it creates mapping on the new paste address. Then the user space can continue to use these windows and send HW compression requests to NX successfully. Signed-off-by:
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Haren Myneni authored
The hypervisor assigns vas credits (windows) for each LPAR based on the number of cores configured in that system. The OS is expected to release credits when cores are removed, and may allocate more when cores are added. So there is a possibility of using excessive credits (windows) in the LPAR and the hypervisor expects the system to close the excessive windows so that NX load can be equally distributed across all LPARs in the system. When the OS closes the excessive windows in the hypervisor, it sets the window status inactive and invalidates window virtual address mapping. The user space receives paste instruction failure if any NX requests are issued on the inactive window. Then the user space can use with the available open windows or retry NX requests until this window active again. This patch also adds the notifier for core removal/add to close windows in the hypervisor if the system lost credits (core removal) and reopen windows in the hypervisor when the previously lost credits are available. Signed-off-by:
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Haren Myneni authored
The paste address mapping is done with mmap() after the window is opened with ioctl. The partition has to close VAS windows in the hypervisor if it lost credits due to DLPAR core removal. But the kernel marks these windows inactive until the previously lost credits are available later. If the window is inactive due to DLPAR after this mmap(), the paste instruction returns failure until the the OS reopens this window again. Before the user space issuing mmap(), there is a possibility of happening DLPAR core removal event which causes the corresponding window inactive. So if the window is not active, return mmap() failure with -EACCES and expects the user space reissue mmap() when the window is active or open a new window when the credit is available. Signed-off-by:
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Haren Myneni authored
The VAS window may not be active if the system looses credits and the NX generates page fault when it receives request on unmap paste address. The kernel handles the fault by remap new paste address if the window is active again, Otherwise return the paste instruction failure if the executed instruction that caused the fault was a paste. Signed-off-by:
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Haren Myneni authored
The user space opens VAS windows and issues NX requests by pasting CRB on the corresponding paste address mmap. When the system lost credits due to core removal, the kernel has to close the window in the hypervisor and make the window inactive by unmapping this paste address. Also the OS has to handle NX request page faults if the user space issue NX requests. This handler maps the new paste address with the same VMA when the window is active again (due to core add with DLPAR). Otherwise returns paste failure. Signed-off-by:
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Haren Myneni authored
The kernel sets the VAS window with PID when it is opened in the hypervisor. During DLPAR operation, windows can be closed and reopened in the hypervisor when the credit is available. So saves this PID in pseries_vas_window struct when the window is opened initially and reuse it later during DLPAR operation. Signed-off-by:
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Haren Myneni authored
nr_total/nr_used_credits provides credits usage to user space via sysfs and the same interface can be used on PowerNV in future. Changed with proper naming so that applicable on both pseries and PowerNV. Signed-off-by:
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Michael Ellerman authored
Merge our topic branch containing powerpc KVM related commits. Alexey Kardashevskiy (1): KVM: PPC: Merge powerpc's debugfs entry content into generic entry Fabiano Rosas (9): KVM: PPC: Book3S HV: Stop returning internal values to userspace KVM: PPC: Fix vmx/vsx mixup in mmio emulation KVM: PPC: mmio: Reject instructions that access more than mmio.data size KVM: PPC: mmio: Return to guest after emulation failure KVM: PPC: Book3s: mmio: Deliver DSI after emulation failure KVM: PPC: Book3S HV: Check return value of kvmppc_radix_init KVM: PPC: Book3S HV: Delay setting of kvm ops KVM: PPC: Book3S HV: Free allocated memory if module init fails KVM: PPC: Decrement module refcount if init_vm fails Jason Wang (1): powerpc/kvm: no need to initialise statics to 0 Nour-eddine Taleb (1): KVM: PPC: Book3S HV: remove unnecessary casts -
Michael Ellerman authored
Merge a topic branch we are maintaining with some cross-architecture changes to function descriptor handling and their use in LKDTM. From Christophe's cover letter: Fix LKDTM for PPC64/IA64/PARISC PPC64/IA64/PARISC have function descriptors. LKDTM doesn't work on those three architectures because LKDTM messes up function descriptors with functions. This series does some cleanup in the three architectures and refactors function descriptors so that it can then easily use it in a generic way in LKDTM.
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- 04 Mar, 2022 1 commit
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Nour-eddine Taleb authored
Remove unnecessary casts, from "void *" to "struct kvmppc_xics *" Signed-off-by:
Nour-eddine Taleb <kernel.noureddine@gmail.com> Signed-off-by:
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- 01 Mar, 2022 13 commits
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Anders Roxell authored
Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian 2.37.90.20220207) the following build error shows up: {standard input}: Assembler messages: {standard input}:10576: Error: unrecognized opcode: `stbcx.' {standard input}:10680: Error: unrecognized opcode: `lharx' {standard input}:10694: Error: unrecognized opcode: `lbarx' Rework to add assembler directives [1] around the instruction. The problem with this might be that we can trick a power6 into single-stepping through an stbcx. for instance, and it will execute that in kernel mode. [1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002dPseudo Fixes: 350779a2 ("powerpc: Handle most loads and stores in instruction emulation code") Cc: stable@vger.kernel.org # v4.14+ Co-developed-by:Arnd Bergmann <arnd@arndb.de> Signed-off-by:
Anders Roxell <anders.roxell@linaro.org> Reviewed-by:
Segher Boessenkool <segher@kernel.crashing.org> Signed-off-by:
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Anders Roxell authored
Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian 2.37.90.20220207) the following build error shows up: {standard input}: Assembler messages: {standard input}:1190: Error: unrecognized opcode: `stbcix' {standard input}:1433: Error: unrecognized opcode: `lwzcix' {standard input}:1453: Error: unrecognized opcode: `stbcix' {standard input}:1460: Error: unrecognized opcode: `stwcix' {standard input}:1596: Error: unrecognized opcode: `stbcix' ... Rework to add assembler directives [1] around the instruction. Going through them one by one shows that the changes should be safe. Like __get_user_atomic_128_aligned() is only called in p9_hmi_special_emu(), which according to the name is specific to power9. And __raw_rm_read*() are only called in things that are powernv or book3s_hv specific. [1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002dPseudo Cc: stable@vger.kernel.org Co-developed-by: -
Anders Roxell authored
Looks like there been a copy paste mistake when added the instruction 'stbcx' twice and one was probably meant to be 'sthcx'. Changing to 'sthcx' from 'stbcx'. Fixes: 350779a2 ("powerpc: Handle most loads and stores in instruction emulation code") Cc: stable@vger.kernel.org # v4.14+ Reported-by:
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Michael Ellerman authored
When CONFIG_GENERIC_CPU=y (true for all our defconfigs) we pass -mcpu=powerpc64 to the compiler, even when we're building a 32-bit kernel. This happens because we have an ifdef CONFIG_PPC_BOOK3S_64/else block in the Makefile that was written before 32-bit supported GENERIC_CPU. Prior to that the else block only applied to 64-bit Book3E. The GCC man page says -mcpu=powerpc64 "[specifies] a pure ... 64-bit big endian PowerPC ... architecture machine [type], with an appropriate, generic processor model assumed for scheduling purposes." It's unclear how that interacts with -m32, which we are also passing, although obviously -m32 is taking precedence in some sense, as the 32-bit kernel only contains 32-bit instructions. This was noticed by inspection, not via any bug reports, but it does affect code generation. Comparing before/after code generation, there are some changes to instruction scheduling, and the after case (with -mcpu=powerpc64 removed) the compiler seems more keen to use r8. Fix it by making the else case only apply to Book3E 64, which excludes 32-bit. Fixes: 0e00a8c9 ("powerpc: Allow CPU selection also on PPC32") Signed-off-by:
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Daniel Henrique Barboza authored
Executing node_set_online() when nid = NUMA_NO_NODE results in an undefined behavior. node_set_online() will call node_set_state(), into __node_set(), into set_bit(), and since NUMA_NO_NODE is -1 we'll end up doing a negative shift operation inside arch/powerpc/include/asm/bitops.h. This potential UB was detected running a kernel with CONFIG_UBSAN. The behavior was introduced by commit 10f78fd0 ("powerpc/numa: Fix a regression on memoryless node 0"), where the check for nid > 0 was removed to fix a problem that was happening with nid = 0, but the result is that now we're trying to online NUMA_NO_NODE nids as well. Checking for nid >= 0 will allow node 0 to be onlined while avoiding this UB with NUMA_NO_NODE. Fixes: 10f78fd0 ("powerpc/numa: Fix a regression on memoryless node 0") Reported-by:
Ping Fang <pifang@redhat.com> Signed-off-by:
Daniel Henrique Barboza <danielhb413@gmail.com> Signed-off-by:
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Christophe Leroy authored
Since commit ceff77ef ("powerpc/64e/interrupt: Use new interrupt context tracking scheme") struct interrupt_state has been empty and unused. Remove it. Signed-off-by:
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Hari Bathini authored
Crash recovery (fadump) is setup in the userspace by some service. This service rebuilds initrd with dump capture capability, if it is not already dump capture capable before proceeding to register for firmware assisted dump (echo 1 > /sys/kernel/fadump/registered). But arming the kernel with crash recovery support does not have to wait for userspace configuration. So, register for fadump while setting it up itself. This can at worst lead to a scenario, where /proc/vmcore is ready afer crash but the initrd does not know how/where to offload it, which is always better than not having a /proc/vmcore at all due to incomplete configuration in the userspace at the time of crash. Commit 0823c68b ("powerpc/fadump: re-register firmware-assisted dump if already registered") ensures this change does not break userspace. Signed-off-by:
Hari Bathini <hbathini@linux.ibm.com> [mpe: Reword comment] Signed-off-by:
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Kajol Jain authored
The testcase uses event code 0x35340401e0 to verify the settings for different fields in Monitor Mode Control Register A (MMCRA). The fields include thresh_start, thresh_stop thresh_select, sdar mode, sample and marked bit. Checks if these fields are translated correctly via perf interface to MMCRA. Signed-off-by:
Kajol Jain <kjain@linux.ibm.com> [mpe: Add error checking, drop GET_MMCR_FIELD, add to .gitignore] Signed-off-by:
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Kajol Jain authored
The testcase uses event code 0x1340000001c040 to verify the settings for different src fields in Monitor Mode Control Register 3 (MMCR3). Checks if these fields are translated correctly via perf interface to MMCR3 on ISA v3.1 platform. Signed-off-by:
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Madhavan Srinivasan authored
The testcases uses cycles event to verify the freeze counter settings in Monitor Mode Control Register 2 (MMCR2). Event modifier (exclude_kernel) setting is used for the event attribute to check the FCxS and FCxH ( Freeze counter in privileged and hypervisor state ) settings via perf interface. Signed-off-by:
Madhavan Srinivasan <maddy@linux.ibm.com> [mpe: Add error checking, check MSR for MSR_HV, drop GET_MMCR_FIELD, add to .gitignore] Signed-off-by:
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Madhavan Srinivasan authored
The testcases uses event code 0x010000046080 to verify the l2l3 bit setting for Monitor Mode Control Register 2 (MMCR2). check if this bit is set correctly via perf interface in ISA v3.1 platform. Signed-off-by:
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Athira Rajeev authored
The testcase uses event code "0x26880" to verify the settings for different fields in Monitor Mode Control Register 1 (MMCR1). The field include PMCxCOMB. Checks if this field are translated correctly via perf interface to MMCR1 Add selftest for mmcr1 comb field. Signed-off-by:
Athira Rajeev <atrajeev@linux.vnet.ibm.com> [mpe: Add error checking, drop GET_MMCR_FIELD, add to .gitignore] Signed-off-by:
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Athira Rajeev authored
The testcase uses event code 0x500fa to verify the FC5-6 bit setting in Monitor Mode Control Register 0 (MMCR0). Check if FC5-6 bit is not set in MMCR0 when using Performance Monitor Counter 5 and 6 (PMC5 and PMC6). Signed-off-by:
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