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2021-06-10KVM: PPC: Book3S 64: Move hcall early register setup to KVMNicholas Piggin1-0/+13
System calls / hcalls have a different calling convention than other interrupts, so there is code in the KVMTEST to massage these into the same form as other interrupt handlers. Move this work into the KVM hcall handler. This means teaching KVM a little more about the low level interrupt handler setup, PACA save areas, etc., although that's not obviously worse than the current approach of coming up with an entirely different interrupt register / save convention. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210528090752.3542186-5-npiggin@gmail.com
2021-01-20powerpc/64s: fix scv entry fallback flush vs interruptNicholas Piggin1-0/+13
The L1D flush fallback functions are not recoverable vs interrupts, yet the scv entry flush runs with MSR[EE]=1. This can result in a timer (soft-NMI) or MCE or SRESET interrupt hitting here and overwriting the EXRFI save area, which ends up corrupting userspace registers for scv return. Fix this by disabling RI and EE for the scv entry fallback flush. Fixes: f79643787e0a0 ("powerpc/64s: flush L1D on kernel entry") Cc: stable@vger.kernel.org # 5.9+ which also have flush L1D patch backport Reported-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210111062408.287092-1-npiggin@gmail.com
2020-11-19powerpc/64s: flush L1D after user accessesNicholas Piggin1-0/+3
IBM Power9 processors can speculatively operate on data in the L1 cache before it has been completely validated, via a way-prediction mechanism. It is not possible for an attacker to determine the contents of impermissible memory using this method, since these systems implement a combination of hardware and software security measures to prevent scenarios where protected data could be leaked. However these measures don't address the scenario where an attacker induces the operating system to speculatively execute instructions using data that the attacker controls. This can be used for example to speculatively bypass "kernel user access prevention" techniques, as discovered by Anthony Steinhauser of Google's Safeside Project. This is not an attack by itself, but there is a possibility it could be used in conjunction with side-channels or other weaknesses in the privileged code to construct an attack. This issue can be mitigated by flushing the L1 cache between privilege boundaries of concern. This patch flushes the L1 cache after user accesses. This is part of the fix for CVE-2020-4788. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2020-11-19powerpc/64s: flush L1D on kernel entryNicholas Piggin1-1/+8
IBM Power9 processors can speculatively operate on data in the L1 cache before it has been completely validated, via a way-prediction mechanism. It is not possible for an attacker to determine the contents of impermissible memory using this method, since these systems implement a combination of hardware and software security measures to prevent scenarios where protected data could be leaked. However these measures don't address the scenario where an attacker induces the operating system to speculatively execute instructions using data that the attacker controls. This can be used for example to speculatively bypass "kernel user access prevention" techniques, as discovered by Anthony Steinhauser of Google's Safeside Project. This is not an attack by itself, but there is a possibility it could be used in conjunction with side-channels or other weaknesses in the privileged code to construct an attack. This issue can be mitigated by flushing the L1 cache between privilege boundaries of concern. This patch flushes the L1 cache on kernel entry. This is part of the fix for CVE-2020-4788. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2020-07-23Merge branch 'scv' support into nextMichael Ellerman1-0/+6
From Nick's cover letter: Linux powerpc new system call instruction and ABI System Call Vectored (scv) ABI ============================== The scv instruction is introduced with POWER9 / ISA3, it comes with an rfscv counter-part. The benefit of these instructions is performance (trading slower SRR0/1 with faster LR/CTR registers, and entering the kernel with MSR[EE] and MSR[RI] left enabled, which can reduce MSR updates. The scv instruction has 128 levels (not enough to cover the Linux system call space). Assignment and advertisement ---------------------------- The proposal is to assign scv levels conservatively, and advertise them with HWCAP feature bits as we add support for more. Linux has not enabled FSCR[SCV] yet, so executing the scv instruction will cause the kernel to log a "SCV facility unavilable" message, and deliver a SIGILL with ILL_ILLOPC to the process. Linux has defined a HWCAP2 bit PPC_FEATURE2_SCV for SCV support, but does not set it. This change allocates the zero level ('scv 0'), advertised with PPC_FEATURE2_SCV, which will be used to provide normal Linux system calls (equivalent to 'sc'). Attempting to execute scv with other levels will cause a SIGILL to be delivered the same as before, but will not log a "SCV facility unavailable" message (because the processor facility is enabled). Calling convention ------------------ The proposal is for scv 0 to provide the standard Linux system call ABI with the following differences from sc convention[1]: - LR is to be volatile across scv calls. This is necessary because the scv instruction clobbers LR. From previous discussion, this should be possible to deal with in GCC clobbers and CFI. - cr1 and cr5-cr7 are volatile. This matches the C ABI and would allow the kernel system call exit to avoid restoring the volatile cr registers (although we probably still would anyway to avoid information leaks). - Error handling: The consensus among kernel, glibc, and musl is to move to using negative return values in r3 rather than CR0[SO]=1 to indicate error, which matches most other architectures, and is closer to a function call. Notes ----- - r0,r4-r8 are documented as volatile in the ABI, but the kernel patch as submitted currently preserves them. This is to leave room for deciding which way to go with these. Some small benefit was found by preserving them[1] but I'm not convinced it's worth deviating from the C function call ABI just for this. Release code should follow the ABI. Previous discussions: https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-April/208691.html https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-April/209268.html [1] https://github.com/torvalds/linux/blob/master/Documentation/powerpc/syscall64-abi.rst [2] https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-April/209263.html
2020-07-23powerpc: Select ARCH_HAS_MEMBARRIER_SYNC_CORENicholas Piggin1-0/+8
powerpc return from interrupt and return from system call sequences are context synchronising. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200716013522.338318-1-npiggin@gmail.com
2020-07-22powerpc/64s: system call support for scv/rfscv instructionsNicholas Piggin1-0/+6
Add support for the scv instruction on POWER9 and later CPUs. For now this implements the zeroth scv vector 'scv 0', as identical to 'sc' system calls, with the exception that LR is not preserved, nor are volatile CR registers, and error is not indicated with CR0[SO], but by returning a negative errno. rfscv is implemented to return from scv type system calls. It can not be used to return from sc system calls because those are defined to preserve LR. getpid syscall throughput on POWER9 is improved by 26% (428 to 318 cycles), largely due to reducing mtmsr and mtspr. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Fix ppc64e build] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200611081203.995112-3-npiggin@gmail.com
2020-04-01powerpc/64s/exception: Move real to virt switch into the common handlerNicholas Piggin1-4/+0
The real mode interrupt entry points currently use rfid to branch to the common handler in virtual mode. This is a significant amount of code, and forces other code (notably the KVM test) to live in the real mode handler. In the interest of minimising the amount of code that runs unrelocated move the switch to virt mode into the common code, and do it with mtmsrd, which avoids clobbering SRRs (although the post-KVMTEST performance of real-mode interrupt handlers is not a big concern these days). This requires CTR to always be saved (real-mode needs to reach 0xc...) but that's not a huge impact these days. It could be optimized away in future. mpe: Incorporate fix from Nick: It's possible for interrupts to be replayed when TM is enabled and suspended, for example rt_sigreturn, where the mtmsrd MSR_KERNEL in the real-mode entry point to the common handler causes a TM Bad Thing exception (due to attempting to clear suspended). The fix for this is to have replay interrupts go to the _virt entry point and skip the mtmsrd, which matches what happens before this patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200225173541.1549955-11-npiggin@gmail.com
2019-07-14Merge tag 'powerpc-5.3-1' of ↵Linus Torvalds1-604/+5
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: "Notable changes: - Removal of the NPU DMA code, used by the out-of-tree Nvidia driver, as well as some other functions only used by drivers that haven't (yet?) made it upstream. - A fix for a bug in our handling of hardware watchpoints (eg. perf record -e mem: ...) which could lead to register corruption and kernel crashes. - Enable HAVE_ARCH_HUGE_VMAP, which allows us to use large pages for vmalloc when using the Radix MMU. - A large but incremental rewrite of our exception handling code to use gas macros rather than multiple levels of nested CPP macros. And the usual small fixes, cleanups and improvements. Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Cédric Le Goater, Christian Lamparter, Christophe Leroy, Christophe Lombard, Christoph Hellwig, Daniel Axtens, Denis Efremov, Enrico Weigelt, Frederic Barrat, Gautham R. Shenoy, Geert Uytterhoeven, Geliang Tang, Gen Zhang, Greg Kroah-Hartman, Greg Kurz, Gustavo Romero, Krzysztof Kozlowski, Madhavan Srinivasan, Masahiro Yamada, Mathieu Malaterre, Michael Neuling, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nishad Kamdar, Oliver O'Halloran, Qian Cai, Ravi Bangoria, Sachin Sant, Sam Bobroff, Satheesh Rajendran, Segher Boessenkool, Shaokun Zhang, Shawn Anastasio, Stewart Smith, Suraj Jitindar Singh, Thiago Jung Bauermann, YueHaibing" * tag 'powerpc-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (163 commits) powerpc/powernv/idle: Fix restore of SPRN_LDBAR for POWER9 stop state. powerpc/eeh: Handle hugepages in ioremap space ocxl: Update for AFU descriptor template version 1.1 powerpc/boot: pass CONFIG options in a simpler and more robust way powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h powerpc/irq: Don't WARN continuously in arch_local_irq_restore() powerpc/module64: Use symbolic instructions names. powerpc/module32: Use symbolic instructions names. powerpc: Move PPC_HA() PPC_HI() and PPC_LO() to ppc-opcode.h powerpc/module64: Fix comment in R_PPC64_ENTRY handling powerpc/boot: Add lzo support for uImage powerpc/boot: Add lzma support for uImage powerpc/boot: don't force gzipped uImage powerpc/8xx: Add microcode patch to move SMC parameter RAM. powerpc/8xx: Use IO accessors in microcode programming. powerpc/8xx: replace #ifdefs by IS_ENABLED() in microcode.c powerpc/8xx: refactor programming of microcode CPM params. powerpc/8xx: refactor printing of microcode patch name. powerpc/8xx: Refactor microcode write powerpc/8xx: refactor writing of CPM microcode arrays ...
2019-07-02powerpc/64s/exception: remove bad stack branchNicholas Piggin1-7/+0
The bad stack test in interrupt handlers has a few problems. For performance it is taken in the common case, which is a fetch bubble and a waste of i-cache. For code development and maintainence, it requires yet another stack frame setup routine, and that constrains all exception handlers to follow the same register save pattern which inhibits future optimisation. Remove the test/branch and replace it with a trap. Teach the program check handler to use the emergency stack for this case. This does not result in quite so nice a message, however the SRR0 and SRR1 of the crashed interrupt can be seen in r11 and r12, as is the original r1 (adjusted by INT_FRAME_SIZE). These are the most important parts to debugging the issue. The original r9-12 and cr0 is lost, which is the main downside. kernel BUG at linux/arch/powerpc/kernel/exceptions-64s.S:847! Oops: Exception in kernel mode, sig: 5 [#1] BE SMP NR_CPUS=2048 NUMA PowerNV Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted NIP: c000000000009108 LR: c000000000cadbcc CTR: c0000000000090f0 REGS: c0000000fffcbd70 TRAP: 0700 Not tainted MSR: 9000000000021032 <SF,HV,ME,IR,DR,RI> CR: 28222448 XER: 20040000 CFAR: c000000000009100 IRQMASK: 0 GPR00: 000000000000003d fffffffffffffd00 c0000000018cfb00 c0000000f02b3166 GPR04: fffffffffffffffd 0000000000000007 fffffffffffffffb 0000000000000030 GPR08: 0000000000000037 0000000028222448 0000000000000000 c000000000ca8de0 GPR12: 9000000002009032 c000000001ae0000 c000000000010a00 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: c0000000f00322c0 c000000000f85200 0000000000000004 ffffffffffffffff GPR24: fffffffffffffffe 0000000000000000 0000000000000000 000000000000000a GPR28: 0000000000000000 0000000000000000 c0000000f02b391c c0000000f02b3167 NIP [c000000000009108] decrementer_common+0x18/0x160 LR [c000000000cadbcc] .vsnprintf+0x3ec/0x4f0 Call Trace: Instruction dump: 996d098a 994d098b 38610070 480246ed 48005518 60000000 38200000 718a4000 7c2a0b78 3821fd00 41c20008 e82d0970 <0981fd00> f92101a0 f9610170 f9810178 Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: move paca save area offsets into exception-64s.SNicholas Piggin1-14/+3
No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: move head-64.h code to exception-64s.S where it is usedNicholas Piggin1-1/+0
No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: move exception-64s.h code to exception-64s.S where it ↵Nicholas Piggin1-431/+0
is used No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: move KVM related code togetherNicholas Piggin1-19/+21
No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: remove STD_EXCEPTION_COMMON variantsNicholas Piggin1-22/+0
These are only called in one place each. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: move EXCEPTION_PROLOG_2* to a more logical placeNicholas Piggin1-56/+57
No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: unwind exception-64s.h macrosNicholas Piggin1-101/+0
Many of these macros just specify 1-4 lines which are only called a few times each at most, and often just once. Remove this indirection. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: Move EXCEPTION_COMMON additions into callersNicholas Piggin1-29/+13
More cases of code insertion via macros that does not add a great deal. All the additions have to be specified in the macro arguments, so they can just as well go after the macro. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: Move EXCEPTION_COMMON handler and return branches ↵Nicholas Piggin1-13/+13
into callers The aim is to reduce the amount of indirection it takes to get through the exception handler macros, particularly where it provides little code sharing. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: Make EXCEPTION_PROLOG_0 a gas macro for consistency ↵Nicholas Piggin1-12/+13
with others No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: KVM handler can set the HSRR trap bitNicholas Piggin1-0/+5
Move the KVM trap HSRR bit into the KVM handler, which can be conditionally applied when hsrr parameter is set. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: merge KVM handler and skip variantsNicholas Piggin1-18/+10
Conditionally expand the skip case if it is specified. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: consolidate maskable and non-maskable prologsNicholas Piggin1-67/+45
Conditionally expand the soft-masking test if a mask is passed in. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: remove the "extra" macro parameterNicholas Piggin1-88/+70
Rather than pass in the soft-masking and KVM tests via macro that is passed to another macro to expand it, switch to usig gas macros and conditionally expand the soft-masking and KVM tests. The system reset with its idle test is open coded as it is a one-off. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: move and tidy EXCEPTION_PROLOG_2 variantsNicholas Piggin1-45/+42
- Re-name the macros to _REAL and _VIRT suffixes rather than no and _RELON suffix. - Move the macro definitions together in the file. - Move RELOCATABLE ifdef inside the _VIRT macro. Further consolidation between variants does not buy much here. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: consolidate EXCEPTION_PROLOG_2 with _NORI variantNicholas Piggin1-32/+11
Switch to a gas macro that conditionally expands the RI clearing instruction. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: remove H concatenation for EXC_HV variantsNicholas Piggin1-139/+193
Replace all instances of this with gas macros that test the hsrr parameter and use the appropriate register names / labels. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Remove extraneous 2nd check for 0xea0 in SOFTEN_TEST] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-02powerpc/64s/exception: Remove unused SOFTEN_VALUE_0x980Michael Ellerman1-1/+0
Remove SOFTEN_VALUE_0x980, it's been unused since commit dabe859ec636 ("powerpc: Give hypervisor decrementer interrupts their own handler") (Sep 2012). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-07-01powerpc/64s/exception: fix line wrap and semicolon inconsistencies in macrosNicholas Piggin1-18/+18
By convention, all lines should be separated by a semicolons. Last line should have neither semicolon or line wrap. No generated code change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner1-5/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-21powerpc/64s: Implement KUAP for Radix MMUMichael Ellerman1-0/+2
Kernel Userspace Access Prevention utilises a feature of the Radix MMU which disallows read and write access to userspace addresses. By utilising this, the kernel is prevented from accessing user data from outside of trusted paths that perform proper safety checks, such as copy_{to/from}_user() and friends. Userspace access is disabled from early boot and is only enabled when performing an operation like copy_{to/from}_user(). The register that controls this (AMR) does not prevent userspace from accessing itself, so there is no need to save and restore when entering and exiting userspace. When entering the kernel from the kernel we save AMR and if it is not blocking user access (because eg. we faulted doing a user access) we reblock user access for the duration of the exception (ie. the page fault) and then restore the AMR when returning back to the kernel. This feature can be tested by using the lkdtm driver (CONFIG_LKDTM=y) and performing the following: # (echo ACCESS_USERSPACE) > [debugfs]/provoke-crash/DIRECT If enabled, this should send SIGSEGV to the thread. We also add paranoid checking of AMR in switch and syscall return under CONFIG_PPC_KUAP_DEBUG. Co-authored-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-02-23powerpc/64: Replace CURRENT_THREAD_INFO with PACA_THREAD_INFOChristophe Leroy1-2/+2
Now that current_thread_info is located at the beginning of 'current' task struct, CURRENT_THREAD_INFO macro is not really needed any more. This patch replaces it by loads of the value at PACA_THREAD_INFO(r13). Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> [mpe: Add PACA_THREAD_INFO rather than using PACACURRENT] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-14powerpc/64s/hash: Convert SLB miss handlers to CNicholas Piggin1-8/+0
This patch moves SLB miss handlers completely to C, using the standard exception handler macros to set up the stack and branch to C. This can be done because the segment containing the kernel stack is always bolted, so accessing it with relocation on will not cause an SLB exception. Arbitrary kernel memory must not be accessed when handling kernel space SLB misses, so care should be taken there. However user SLB misses can access any kernel memory, which can be used to move some fields out of the paca (in later patches). User SLB misses could quite easily reconcile IRQs and set up a first class kernel environment and exit via ret_from_except, however that doesn't seem to be necessary at the moment, so we only do that if a bad fault is encountered. [ Credit to Aneesh for bug fixes, error checks, and improvements to bad address handling, etc ] Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Disallow tracing for all of slb.c for now.] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-14powerpc/64: Interrupts save PPR on stack rather than thread_structNicholas Piggin1-5/+4
PPR is the odd register out when it comes to interrupt handling, it is saved in current->thread.ppr while all others are saved on the stack. The difficulty with this is that accessing thread.ppr can cause a SLB fault, but the SLB fault handler implementation in C change had assumed the normal exception entry handlers would not cause an SLB fault. Fix this by allocating room in the interrupt stack to save PPR. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-03Revert "convert SLB miss handlers to C" and subsequent commitsMichael Ellerman1-0/+8
This reverts commits: 5e46e29e6a97 ("powerpc/64s/hash: convert SLB miss handlers to C") 8fed04d0f6ae ("powerpc/64s/hash: remove user SLB data from the paca") 655deecf67b2 ("powerpc/64s/hash: SLB allocation status bitmaps") 2e1626744e8d ("powerpc/64s/hash: provide arch_setup_exec hooks for hash slice setup") 89ca4e126a3f ("powerpc/64s/hash: Add a SLB preload cache") This series had a few bugs, and the fixes are not all trivial. So revert most of it for now. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-09-19powerpc/64s/hash: convert SLB miss handlers to CNicholas Piggin1-8/+0
This patch moves SLB miss handlers completely to C, using the standard exception handler macros to set up the stack and branch to C. This can be done because the segment containing the kernel stack is always bolted, so accessing it with relocation on will not cause an SLB exception. Arbitrary kernel memory may not be accessed when handling kernel space SLB misses, so care should be taken there. However user SLB misses can access any kernel memory, which can be used to move some fields out of the paca (in later patches). User SLB misses could quite easily reconcile IRQs and set up a first class kernel environment and exit via ret_from_except, however that doesn't seem to be necessary at the moment, so we only do that if a bad fault is encountered. [ Credit to Aneesh for bug fixes, error checks, and improvements to bad address handling, etc ] Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Since RFC: - Added MSR[RI] handling - Fixed up a register loss bug exposed by irq tracing (Aneesh) - Reject misses outside the defined kernel regions (Aneesh) - Added several more sanity checks and error handling (Aneesh), we may look at consolidating these tests and tightenig up the code but for a first pass we decided it's better to check carefully. Since v1: - Fixed SLB cache corruption (Aneesh) - Fixed untidy SLBE allocation "leak" in get_vsid error case - Now survives some stress testing on real hardware Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Drop unused loc parameter to MASKABLE_EXCEPTION macrosMichael Ellerman1-4/+4
We pass the "loc" (location) parameter to MASKABLE_EXCEPTION and friends, but it's not used, so drop it. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Remove PSERIES naming from the MASKABLE macrosMichael Ellerman1-14/+10
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Drop _MASKABLE_RELON_EXCEPTION_PSERIES()Michael Ellerman1-7/+4
_MASKABLE_RELON_EXCEPTION_PSERIES() does nothing useful, update all callers to use __MASKABLE_RELON_EXCEPTION_PSERIES() directly. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Drop _MASKABLE_EXCEPTION_PSERIES()Michael Ellerman1-7/+4
_MASKABLE_EXCEPTION_PSERIES() does nothing useful, update all callers to use __MASKABLE_EXCEPTION_PSERIES() directly. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename EXCEPTION_PROLOG_PSERIES to EXCEPTION_PROLOGMichael Ellerman1-8/+6
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename EXCEPTION_RELON_PROLOG_PSERIESMichael Ellerman1-4/+3
To just EXCEPTION_RELON_PROLOG(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename EXCEPTION_RELON_PROLOG_PSERIES_1Michael Ellerman1-10/+10
The EXCEPTION_RELON_PROLOG_PSERIES_1() macro does the same job as EXCEPTION_PROLOG_2 (which we just recently created), except for "RELON" (relocation on) exceptions. So rename it as such. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Remove PSERIES from the NORI macrosMichael Ellerman1-5/+5
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename EXCEPTION_PROLOG_PSERIES_1 to EXCEPTION_PROLOG_2Michael Ellerman1-10/+10
As with the other patches in this series, we are removing the "PSERIES" from the name as it's no longer meaningful. In this case it's not simply a case of removing the "PSERIES" as that would result in a clash with the existing EXCEPTION_PROLOG_1. Instead we name this one EXCEPTION_PROLOG_2, as it's usually used in sequence after 0 and 1. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename STD_RELON_EXCEPTION_PSERIES_OOL to STD_RELON_EXCEPTION_OOLMichael Ellerman1-1/+1
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename STD_RELON_EXCEPTION_PSERIES to STD_RELON_EXCEPTIONMichael Ellerman1-1/+1
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename STD_EXCEPTION_PSERIES_OOL to STD_EXCEPTION_OOLMichael Ellerman1-1/+1
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Rename STD_EXCEPTION_PSERIES to STD_EXCEPTIONMichael Ellerman1-1/+1
The "PSERIES" in STD_EXCEPTION_PSERIES is to differentiate the macros from the legacy iSeries versions, which are called STD_EXCEPTION_ISERIES. It is not anything to do with pseries vs powernv or powermac etc. We removed the legacy iSeries code in 2012, in commit 8ee3e0d69623x ("powerpc: Remove the main legacy iSerie platform code"). So remove "PSERIES" from the macros. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-07powerpc/64s: Move SET_SCRATCH0() into EXCEPTION_RELON_PROLOG_PSERIES()Michael Ellerman1-2/+1
EXCEPTION_RELON_PROLOG_PSERIES() only has two users, STD_RELON_EXCEPTION_PSERIES() and STD_RELON_EXCEPTION_HV() both of which "call" SET_SCRATCH0(), so just move SET_SCRATCH0() into EXCEPTION_RELON_PROLOG_PSERIES(). Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>