- 04 Jul, 2017 3 commits
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Balbir Singh authored
All code that patches kernel text has been moved over to using patch_instruction() and patch_instruction() is able to cope with the kernel text being read only. The linker script has been updated to ensure the read only data ends on a large page boundary, so it and the preceding kernel text can be marked R_X. We also have implementations of mark_rodata_ro() for Hash and Radix MMU modes. There are some corner-cases missing when the kernel is built relocatable, so for now make it depend on !RELOCATABLE. There's also a temporary workaround to depend on !HIBERNATION to avoid a build failure, that will be removed once we've merged with the PM tree. Signed-off-by:
Balbir Singh <bsingharora@gmail.com> [mpe: Make it depend on !RELOCATABLE, munge change log] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Balbir Singh authored
The Radix linear mapping code (create_physical_mapping()) tries to use the largest page size it can at each step. Currently the only reason it steps down to a smaller page size is if the start addr is unaligned (never happens in practice), or the end of memory is not aligned to a huge page boundary. To support STRICT_RWX we need to break the mapping at __init_begin, so that the text and rodata prior to that can be marked R_X and the regular pages after can be marked RW. Having done that we can now implement mark_rodata_ro() for Radix, knowing that we won't need to split any mappings. Signed-off-by:
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Balbir Singh authored
With hash we update the bolted pte to mark it read-only. We rely on the MMU_FTR_KERNEL_RO to generate the correct permissions for read-only text. The radix implementation just prints a warning in this implementation Signed-off-by:
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- 03 Jul, 2017 17 commits
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Balbir Singh authored
For CONFIG_STRICT_KERNEL_RWX align __init_begin to 16M. We use 16M since its the larger of 2M on radix and 16M on hash for our linear mapping. The plan is to have .text, .rodata and everything upto __init_begin marked as RX. Note we still have executable read only data. We could further align rodata to another 16M boundary. I've used keeping text plus rodata as read-only-executable as a trade-off to doing read-only-executable for text and read-only for rodata. We don't use multi PT_LOAD in PHDRS because we are not sure if all bootloaders support them. This patch keeps PHDRS in vmlinux.lds.S as the same they are with just one PT_LOAD for all of the kernel marked as RWX (7). mpe: What this means is the added alignment bloats the resulting binary on disk, a powernv kernel goes from 17M to 22M. Signed-off-by:
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Balbir Singh authored
This patch creates the window using text_poke_area, allocated via get_vm_area(). text_poke_area is per CPU to avoid locking. text_poke_area for each cpu is setup using late_initcall, prior to setup of these alternate mapping areas, we continue to use direct write to change/modify kernel text. With the ability to use alternate mappings to write to kernel text, it provides us the freedom to then turn text read-only and implement CONFIG_STRICT_KERNEL_RWX. This code is CPU hotplug aware to ensure that the we have mappings for any new cpus as they come online and tear down mappings for any CPUs that go offline. Signed-off-by:
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Balbir Singh authored
Move from mwrite() to patch_instruction() for xmon for breakpoint addition and removal. Signed-off-by:
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Balbir Singh authored
So that we can implement STRICT_RWX, use patch_instruction() in optprobes. Signed-off-by:
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Balbir Singh authored
arch_arm/disarm_probe() use direct assignment for copying instructions, replace them with patch_instruction(). We don't need to call flush_icache_range() because patch_instruction() does it for us. Signed-off-by:
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Balbir Singh authored
Commit 9abcc981 ("powerpc/mm/radix: Only add X for pages overlapping kernel text") changed the linear mapping on Radix to only mark the kernel text executable. However if the kernel is run relocated, for example as a kdump kernel, then the exception vectors are split from the kernel text, ie. they remain at real address 0. We tend to get away with it, because the kernel itself will usually be below 1G, which means the 1G page at 0-1G is marked executable and everything works OK. However if the kernel is loaded above 1G, or the system has less than 1G in total (meaning we can't use a 1G page), then the exception vectors will not be marked executable and the kernel will fail to boot. Fix it by also checking if the address range overlaps the exception vectors when deciding if we should add PAGE_KERNEL_X. Fixes: 9abcc981 ("powerpc/mm/radix: Only add X for pages overlapping kernel text") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by:
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Balbir Singh authored
Once upon a time there were only two PP (page protection) bits. In ISA 2.03 an additional PP bit was added, but because of the layout of the HPTE it could not be made contiguous with the existing PP bits. The result is that we now have three PP bits, named pp0, pp1, pp2, where pp0 occupies bit 63 of dword 1 of the HPTE and pp1 and pp2 occupy bits 1 and 0 respectively. Until recently Linux hasn't used pp0, however with the addition of _PAGE_KERNEL_RO we started using it. The problem arises in the LPAR code, where we need to translate the PP bits into the argument for the H_PROTECT hypercall. Currently the code only passes bits 0-2 of newpp, which covers pp1, pp2 and N (no execute), meaning pp0 is not passed to the hypervisor at all. We can't simply pass it through in bit 63, as that would collide with a different field in the flags argument, as defined in PAPR. Instead we have to shift it down to bit 8 (IBM bit 55). Fixes: e58e87ad ("powerpc/mm: Update _PAGE_KERNEL_RO") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by:
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Naveen N. Rao authored
We can't take traps with relocation off, so blacklist enter_rtas() and rtas_return_loc(). However, instead of blacklisting all of enter_rtas(), introduce a new symbol __enter_rtas from where on we can't take a trap and blacklist that. Signed-off-by:
Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by:
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Naveen N. Rao authored
Blacklist all functions involved while handling a trap. We: - convert some of the symbols into private symbols, and - blacklist most functions involved while handling a trap. Reviewed-by:
Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by:
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Naveen N. Rao authored
It is actually safe to probe system_call() in entry_64.S, but only till we unset MSR_RI. To allow this, add a new symbol system_call_exit() after the mtmsrd and blacklist that. Suggested-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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Naveen N. Rao authored
It is common to get a PMU interrupt right after the mtmsr instruction that enables interrupts. Due to this, the stack trace profile gets needlessly split across system_call_common() and system_call(). Previously, system_call() symbol was at the current place to hide a few earlier symbols which have since been made private or removed entirely. So, let's move system_call() slightly higher up, right after the mtmsr instruction that enables interrupts. Convert existing references to system_call to a local syscall symbol. Suggested-by:
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Naveen N. Rao authored
Convert some of the symbols into private symbols and blacklist system_call_common() and system_call() from kprobes. We can't take a trap at parts of these functions as either MSR_RI is unset or the kernel stack pointer is not yet setup. Reviewed-by:
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Naveen N. Rao authored
Commit b48bbb82 ("powerpc/64s: Don't unbalance the return branch predictor in __replay_interrupt()") introduced __replay_interrupt_return symbol with '.L' prefix in hopes of keeping it private. However, due to the use of LOAD_REG_ADDR(), the assembler kept this symbol visible. Fix the same by instead using the local label '1'. Fixes: Commit b48bbb82 ("powerpc/64s: Don't unbalance the return branch predictor in __replay_interrupt()") Suggested-by:
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Naveen N. Rao authored
Currently, we assume that the function pointer we receive in ppc_function_entry() points to a function descriptor. However, this is not always the case. In particular, assembly symbols without the right annotation do not have an associated function descriptor. Some of these symbols are added to the kprobe blacklist using _ASM_NOKPROBE_SYMBOL(). When such addresses are subsequently processed through arch_deref_entry_point() in populate_kprobe_blacklist(), we see the below errors during bootup: [ 0.663963] Failed to find blacklist at 7d9b02a648029b6c [ 0.663970] Failed to find blacklist at a14d03d0394a0001 [ 0.663972] Failed to find blacklist at 7d5302a6f94d0388 [ 0.663973] Failed to find blacklist at 48027d11e8610178 [ 0.663974] Failed to find blacklist at f8010070f8410080 [ 0.663976] Failed to find blacklist at 386100704801f89d [ 0.663977] Failed to find blacklist at 7d5302a6f94d00b0 Fix this by checking if the function pointer we receive in ppc_function_entry() already points to kernel text. If so, we just return it as is. If not, we assume that this is a function descriptor and proceed to dereference it. Suggested-by: -
Christophe Lombard authored
This patch exports a in-kernel 'library' API which can be called by other drivers to help interacting with an IBM XSL on a POWER9 system. The XSL (Translation Service Layer) is a stripped down version of the PSL (Power Service Layer) used in some cards such as the Mellanox CX5. Like the PSL, it implements the CAIA architecture, but has a number of differences, mostly in it's implementation dependent registers. The XSL also uses a special DMA cxl mode, which uses a slightly different init sequence for the CAPP and PHB. Signed-off-by:
Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by:
Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by:
Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by:
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Michael Ellerman authored
Merge our fixes branch, a few of them are tripping people up while working on top of next, and we also have a dependency between the CXL fixes and new CXL code we want to merge into next.
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Masahiro Yamada authored
Most of DT files in PowerPC use #include "..." to make pre-processor include DT in the same directory, but we have 3 exceptional files that use #include <...> for that. Fix them to remove -I$(srctree)/arch/$(SRCARCH)/boot/dts path from dtc_cpp_flags. Signed-off-by:
Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by:
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- 02 Jul, 2017 19 commits
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Thiago Jung Bauermann authored
On POWER9 SMT8 the 24x7 API returns two result elements for physical core and virtual CPU events and we need to add their counts to get the final result. Reviewed-by:
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by:
Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Signed-off-by:
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Thiago Jung Bauermann authored
POWER9 introduces a new version of the hypervisor API to access the 24x7 perf counters. The new version changed some of the structures used for requests and results. Signed-off-by:
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Thiago Jung Bauermann authored
There's an H24x7_DATA_BUFFER_SIZE constant, so use it in init_24x7_request. There's also an HV_PERF_DOMAIN_MAX constant, so use it in h_24x7_event_init. This makes the comment above the check redundant, so remove it. In add_event_to_24x7_request, a statement is terminated with a comma instead of a semicolon. Fix it. In hv-24x7.h, improve comments in struct hv_24x7_result. Signed-off-by:
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Thiago Jung Bauermann authored
The H_GET_24X7_CATALOG_PAGE hcall can return a signed error code, so fix this in the code. The H_GET_24X7_DATA hcall can return a signed error code, so fix this in the code. Also, don't truncate it to 32 bit to use as return value for make_24x7_request. In case of error h_24x7_event_commit_txn passes that return value to generic code, so it should be a proper errno. The other caller of make_24x7_request is single_24x7_request, whose callers don't actually care which error code is returned so they are not affected by this change. Finally, h_24x7_get_value doesn't use the error code from single_24x7_request, so there's no need to store it. Reviewed-by:
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Thiago Jung Bauermann authored
make_24x7_request already calls log_24x7_hcall if it fails, so callers don't have to do it again. In fact, since the latter is now only called from the former, there's no need for a separate log_24x7_hcall anymore so remove it. Reviewed-by:
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Thiago Jung Bauermann authored
hv-24x7.h has a comment mentioning that result_buffer->results can't be indexed as a normal array because it may contain results of variable sizes, so fix the loop in h_24x7_event_commit_txn to take the variation into account when iterating through results. Another problem in that loop is that it sets h24x7hw->events[i] to NULL. This assumes that only the i'th result maps to the i'th request, but that is not guaranteed to be true. We need to leave the event in the array so that we don't dereference a NULL pointer in case more than one result maps to one request. We still assume that each result has only one result element, so warn if that assumption is violated. Reviewed-by:
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Thiago Jung Bauermann authored
request_buffer can hold 254 requests, so if it already has that number of entries we can't add a new one. Also, define constant to show where the number comes from. Fixes: e3ee15dc ("powerpc/perf/hv-24x7: Define add_event_to_24x7_request()") Reviewed-by:
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Thiago Jung Bauermann authored
H_GET_24X7_CATALOG_PAGE needs to be passed the version number obtained from the first catalog page obtained previously. This is a 64 bit number, but create_events_from_catalog truncates it to 32-bit. This worked on POWER8, but POWER9 actually uses the upper bits so the call fails with H_P3 because the hypervisor doesn't recognize the version. This patch also adds the hcall return code to the error message, which is helpful when debugging the problem. Fixes: 5c5cd7b5 ("powerpc/perf/hv-24x7: parse catalog and populate sysfs with events") Reviewed-by:
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Oliver O'Halloran authored
Flip the switch. Running around and screaming "IT'S ALIVE" is optional, but recommended. Signed-off-by:
Oliver O'Halloran <oohall@gmail.com> Signed-off-by:
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Anton Blanchard authored
Adds support for removing bolted (i.e kernel linear mapping) mappings on powernv. This is needed to support memory hot unplug operations which are required for the teardown of DAX/PMEM devices. Reviewed-by:
Rashmica Gupta <rashmica.g@gmail.com> Signed-off-by:
Anton Blanchard <anton@samba.org> Signed-off-by:
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Oliver O'Halloran authored
Add support for the devmap bit on PTEs and PMDs for PPC64 Book3S. This is used to differentiate device backed memory from transparent huge pages since they are handled in more or less the same manner by the core mm code. Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by:
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Oliver O'Halloran authored
Adds support to powerpc for the altmap feature of ZONE_DEVICE memory. An altmap is a driver provided region that is used to provide the backing storage for the struct pages of ZONE_DEVICE memory. In situations where large amount of ZONE_DEVICE memory is being added to the system the altmap reduces pressure on main system memory by allowing the mm/ metadata to be stored on the device itself rather in main memory. Reviewed-by:
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Oliver O'Halloran authored
Removes an indentation level and shuffles some code around to make the following patch cleaner. No functional changes. Reviewed-by:
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Oliver O'Halloran authored
Currently ZONE_DEVICE depends on X86_64 and this will get unwieldly as new architectures (and platforms) get ZONE_DEVICE support. Move to an arch selected Kconfig option to save us the trouble. Cc: linux-mm@kvack.org Acked-by:
Ingo Molnar <mingo@kernel.org> Acked-by:
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Oliver O'Halloran authored
Export it so it can be referenced inside a module. Signed-off-by:
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Andrew Donnellan authored
As Ian's stepping down from his maintainer role now that he's leaving IBM, Frederic has asked me to add myself to the cxl maintainer list. Updating accordingly. Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Cc: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by:
Ian Munsie <imunsie@au1.ibm.com> Signed-off-by:
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Ian Munsie authored
I am no longer employed by IBM and will no longer have access to cxl hardware, so remove myself as a cxl maintainer. If anyone needs to contact me in the future, please use my personal email address darkstarsword@gmail.com Signed-off-by:
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Nicholas Piggin authored
Use the different spin loop primitives in some simple powerpc spin loops, including those which will spin as a common case. This will help to test the spin loop primitives before more conversions are done. Signed-off-by:
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Nicholas Piggin authored
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- 28 Jun, 2017 1 commit
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Nicholas Piggin authored
Current busy-wait loops are implemented by repeatedly calling cpu_relax() to give an arch option for a low-latency option to improve power and/or SMT resource contention. This poses some difficulties for powerpc, which has SMT priority setting instructions (priorities determine how ifetch cycles are apportioned). powerpc's cpu_relax() is implemented by setting a low priority then setting normal priority. This has several problems: - Changing thread priority can have some execution cost and potential impact to other threads in the core. It's inefficient to execute them every time around a busy-wait loop. - Depending on implementation details, a `low ; medium` sequence may not have much if any affect. Some software with similar pattern actually inserts a lot of nops between, in order to cause a few fetch cycles with the low priority. - The busy-wait loop runs with regular priority. This might only be a few fetch cycles, but if there are several threads running such loops, they could cause a noticable impact on a non-idle thread. Implement spin_begin, spin_end primitives that can be used around busy wait loops, which default to no-ops. And spin_cpu_relax which defaults to cpu_relax. This will allow architectures to hook the entry and exit of busy-wait loops, and will allow powerpc to set low SMT priority at entry, and normal priority at exit. Suggested-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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