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2021-03-03MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() sectionAlexander Lobakin1-0/+1
commit 8ac7c87acdcac156670f9920c8acbd84308ff4b1 upstream. MIPS uses its own declaration of rwdata, and thus it should be kept in sync with the asm-generic one. Currently PAGE_ALIGNED_DATA() is missing from the linker script, which emits the following ld warnings: mips-alpine-linux-musl-ld: warning: orphan section `.data..page_aligned' from `arch/mips/kernel/vdso.o' being placed in section `.data..page_aligned' mips-alpine-linux-musl-ld: warning: orphan section `.data..page_aligned' from `arch/mips/vdso/vdso-image.o' being placed in section `.data..page_aligned' Add the necessary declaration, so the mentioned structures will be placed in vmlinux as intended: ffffffff80630580 D __end_once ffffffff80630580 D __start___dyndbg ffffffff80630580 D __start_once ffffffff80630580 D __stop___dyndbg ffffffff80634000 d mips_vdso_data ffffffff80638000 d vdso_data ffffffff80638580 D _gp ffffffff8063c000 T __init_begin ffffffff8063c000 D _edata ffffffff8063c000 T _sinittext -> ffffffff805a4000 D __end_init_task ffffffff805a4000 D __nosave_begin ffffffff805a4000 D __nosave_end ffffffff805a4000 d mips_vdso_data ffffffff805a8000 d vdso_data ffffffff805ac000 D mmlist_lock ffffffff805ac080 D tasklist_lock Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-24MIPS: Fix BUILD_ROLLBACK_PROLOGUE for microMIPSPaul Burton1-2/+1
[ Upstream commit 1eefcbc89cf3a8e252e5aeb25825594699b47360 ] When the kernel is built for microMIPS, branches targets need to be known to be microMIPS code in order to result in bit 0 of the PC being set. The branch target in the BUILD_ROLLBACK_PROLOGUE macro was simply the end of the macro, which may be pointing at padding rather than at code. This results in recent enough GNU linkers complaining like so: mips-img-linux-gnu-ld: arch/mips/built-in.o: .text+0x3e3c: Unsupported branch between ISA modes. mips-img-linux-gnu-ld: final link failed: Bad value Makefile:936: recipe for target 'vmlinux' failed make: *** [vmlinux] Error 1 Fix this by changing the branch target to be the start of the appropriate handler, skipping over any padding. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14019/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-21MIPS: CPU#0 is not hotpluggableHuacai Chen1-1/+1
commit 9cce844abf07b683cff5f0273977d5f8d0af94c7 upstream. Now CPU#0 is not hotpluggable on MIPS, so prevent to create /sys/devices /system/cpu/cpu0/online which confuses some user-space tools. Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen <chenhc@lemote.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-22MIPS: Fix build for LTS kernel caused by backporting lpj adjustmentHuacai Chen1-9/+4
Commit ed26aacfb5f71eecb20a ("mips: Add udelay lpj numbers adjustment") has backported to 4.4~5.4, but the "struct cpufreq_freqs" (and also the cpufreq notifier machanism) of 4.4~4.19 are different from the upstream kernel. These differences cause build errors, and this patch can fix the build. Cc: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Stable <stable@vger.kernel.org> # 4.4/4.9/4.14/4.19 Signed-off-by: Huacai Chen <chenhc@lemote.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-09MIPS: Add missing EHB in mtc0 -> mfc0 sequence for DSPenHauke Mehrtens1-0/+1
commit fcec538ef8cca0ad0b84432235dccd9059c8e6f8 upstream. This resolves the hazard between the mtc0 in the change_c0_status() and the mfc0 in configure_exception_vector(). Without resolving this hazard configure_exception_vector() could read an old value and would restore this old value again. This would revert the changes change_c0_status() did. I checked this by printing out the read_c0_status() at the end of per_cpu_trap_init() and the ST0_MX is not set without this patch. The hazard is documented in the MIPS Architecture Reference Manual Vol. III: MIPS32/microMIPS32 Privileged Resource Architecture (MD00088), rev 6.03 table 8.1 which includes: Producer | Consumer | Hazard ----------|----------|---------------------------- mtc0 | mfc0 | any coprocessor 0 register I saw this hazard on an Atheros AR9344 rev 2 SoC with a MIPS 74Kc CPU. There the change_c0_status() function would activate the DSPen by setting ST0_MX in the c0_status register. This was reverted and then the system got a DSP exception when the DSP registers were saved in save_dsp() in the first process switch. The crash looks like this: [ 0.089999] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear) [ 0.097796] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear) [ 0.107070] Kernel panic - not syncing: Unexpected DSP exception [ 0.113470] Rebooting in 1 seconds.. We saw this problem in OpenWrt only on the MIPS 74Kc based Atheros SoCs, not on the 24Kc based SoCs. We only saw it with kernel 5.4 not with kernel 4.19, in addition we had to use GCC 8.4 or 9.X, with GCC 8.3 it did not happen. In the kernel I bisected this problem to commit 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING"), but when this was reverted it also happened after commit 172dcd935c34b ("MIPS: Always allocate exception vector for MIPSr2+"). Commit 0b24cae4d535 ("MIPS: Add missing EHB in mtc0 -> mfc0 sequence.") does similar changes to a different file. I am not sure if there are more places affected by this problem. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> Cc: <stable@vger.kernel.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-20MIPS: Fix IRQ tracing when call handle_fpe() and handle_msa_fpe()YuanJunQing1-3/+3
[ Upstream commit 31e1b3efa802f97a17628dde280006c4cee4ce5e ] Register "a1" is unsaved in this function, when CONFIG_TRACE_IRQFLAGS is enabled, the TRACE_IRQS_OFF macro will call trace_hardirqs_off(), and this may change register "a1". The changed register "a1" as argument will be send to do_fpe() and do_msa_fpe(). Signed-off-by: YuanJunQing <yuanjunqing66@163.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-20mips: Add udelay lpj numbers adjustmentSerge Semin1-0/+70
[ Upstream commit ed26aacfb5f71eecb20a51c4467da440cb719d66 ] Loops-per-jiffies is a special number which represents a number of noop-loop cycles per CPU-scheduler quantum - jiffies. As you understand aside from CPU-specific implementation it depends on the CPU frequency. So when a platform has the CPU frequency fixed, we have no problem and the current udelay interface will work just fine. But as soon as CPU-freq driver is enabled and the cores frequency changes, we'll end up with distorted udelay's. In order to fix this we have to accordinly adjust the per-CPU udelay_val (the same as the global loops_per_jiffy) number. This can be done in the CPU-freq transition event handler. We subscribe to that event in the MIPS arch time-inititalization method. Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-20mips: cm: Fix an invalid error code of INTVN_*_ERRSerge Semin1-3/+3
[ Upstream commit 8a0efb8b101665a843205eab3d67ab09cb2d9a8d ] Commit 3885c2b463f6 ("MIPS: CM: Add support for reporting CM cache errors") adds cm2_causes[] array with map of error type ID and pointers to the short description string. There is a mistake in the table, since according to MIPS32 manual CM2_ERROR_TYPE = {17,18} correspond to INTVN_WR_ERR and INTVN_RD_ERR, while the table claims they have {0x17,0x18} codes. This is obviously hex-dec copy-paste bug. Moreover codes {0x18 - 0x1a} indicate L2 ECC errors. Fixes: 3885c2b463f6 ("MIPS: CM: Add support for reporting CM cache errors") Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-pm@vger.kernel.org Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-20MIPS: Make sparse_init() using top-down allocationTiezhu Yang1-0/+10
[ Upstream commit 269b3a9ac538c4ae87f84be640b9fa89914a2489 ] In the current code, if CONFIG_SWIOTLB is set, when failed to get IO TLB memory from the low pages by plat_swiotlb_setup(), it may lead to the boot process failed with kernel panic. (1) On the Loongson and SiByte platform arch/mips/loongson64/dma.c arch/mips/sibyte/common/dma.c void __init plat_swiotlb_setup(void) { swiotlb_init(1); } kernel/dma/swiotlb.c void __init swiotlb_init(int verbose) { ... vstart = memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE); if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose)) return; ... pr_warn("Cannot allocate buffer"); no_iotlb_memory = true; } phys_addr_t swiotlb_tbl_map_single() { ... if (no_iotlb_memory) panic("Can not allocate SWIOTLB buffer earlier ..."); ... } (2) On the Cavium OCTEON platform arch/mips/cavium-octeon/dma-octeon.c void __init plat_swiotlb_setup(void) { ... octeon_swiotlb = memblock_alloc_low(swiotlbsize, PAGE_SIZE); if (!octeon_swiotlb) panic("%s: Failed to allocate %zu bytes align=%lx\n", __func__, swiotlbsize, PAGE_SIZE); ... } Because IO_TLB_DEFAULT_SIZE is 64M, if the rest size of low memory is less than 64M when call plat_swiotlb_setup(), we can easily reproduce the panic case. In order to reduce the possibility of kernel panic when failed to get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate low memory as small as possible before plat_swiotlb_setup(), so make sparse_init() using top-down allocation. Reported-by: Juxin Gao <gaojuxin@loongson.cn> Co-developed-by: Juxin Gao <gaojuxin@loongson.cn> Signed-off-by: Juxin Gao <gaojuxin@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-10MIPS: perf: Remove incorrect odd/even counter handling for I6400Marcin Nowakowski1-1/+5
commit f7a31b5e7874f77464a4eae0a8ba84b9ae0b3a54 upstream. All performance counters on I6400 (odd and even) are capable of counting any of the available events, so drop current logic of using the extra bit to determine which counter to use. Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Fixes: 4e88a8621301 ("MIPS: Add cases for CPU_I6400") Fixes: fd716fca10fc ("MIPS: perf: Fix I6400 event numbers") Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/15991/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10mips/panic: replace smp_send_stop() with kdump friendly version in panic pathHidehiro Kawai2-1/+18
commit 54c721b857fd45f3ad3bda695ee4f472518db02a upstream. Daniel Walker reported problems which happens when crash_kexec_post_notifiers kernel option is enabled (https://lkml.org/lkml/2015/6/24/44). In that case, smp_send_stop() is called before entering kdump routines which assume other CPUs are still online. As the result, kdump routines fail to save other CPUs' registers. Additionally for MIPS OCTEON, it misses to stop the watchdog timer. To fix this problem, call a new kdump friendly function, crash_smp_send_stop(), instead of the smp_send_stop() when crash_kexec_post_notifiers is enabled. crash_smp_send_stop() is a weak function, and it just call smp_send_stop(). Architecture codes should override it so that kdump can work appropriately. This patch provides MIPS version. Fixes: f06e5153f4ae (kernel/panic.c: add "crash_kexec_post_notifiers" option) Link: http://lkml.kernel.org/r/20160810080950.11028.28000.stgit@sysi4-13.yrl.intra.hitachi.co.jp Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Reported-by: Daniel Walker <dwalker@fifo99.com> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Daniel Walker <dwalker@fifo99.com> Cc: Xunlei Pang <xpang@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Daney <david.daney@cavium.com> Cc: Aaro Koskinen <aaro.koskinen@iki.fi> Cc: "Steven J. Hill" <steven.hill@cavium.com> Cc: Corey Minyard <cminyard@mvista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: SMP: Update cpu_foreign_map on CPU disableJames Hogan3-1/+3
commit 826e99be6ab5189dbfb096389016ffb8d20a683e upstream. When a CPU is disabled via CPU hotplug, cpu_foreign_map is not updated. This could result in cache management SMP calls being sent to offline CPUs instead of online siblings in the same core. Add a call to calculate_cpu_foreign_map() in the various MIPS cpu disable callbacks after set_cpu_online(). All cases are updated for consistency and to keep cpu_foreign_map strictly up to date, not just those which may support hardware multithreading. Fixes: cccf34e9411c ("MIPS: c-r4k: Fix cache flushing for MT cores") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: David Daney <david.daney@cavium.com> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: Hongliang Tao <taohl@lemote.com> Cc: Hua Yan <yanh@lemote.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13799/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: perf: Fix I6400 event numbersJames Hogan1-2/+52
commit fd716fca10fc3dc0f18b8c16d4ecfa6d93f010d2 upstream. Fix perf hardware performance counter event numbers for I6400. This core does not follow the performance event numbering scheme of previous MIPS cores. All performance counters (both odd and even) are capable of counting any of the available events. Fixes: 4e88a8621301 ("MIPS: Add cases for CPU_I6400") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13259/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: Fix BC1{EQ,NE}Z return offset calculationPaul Burton1-15/+3
commit ac1496980f1d2752f26769f5db63afbc9ac2b603 upstream. The conditions for branching when emulating the BC1EQZ & BC1NEZ instructions were backwards, leading to each of those instructions being treated as the other. Fix this by reversing the conditions, and clear up the code a little for readability & checkpatch. Fixes: c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions") Signed-off-by: Paul Burton <paul.burton@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13151/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: BMIPS: Pretty print BMIPS5200 processor nameFlorian Fainelli1-1/+4
commit 37808d62afcdc420d98875c4b514c178d56f6815 upstream. Just to ease debugging of multiplatform kernel, make sure we print "Broadcom BMIPS5200" for the BMIPS5200 implementation instead of Broadcom BMIPS5000. Fixes: 68e6a78373a6d ("MIPS: BMIPS: Add PRId for BMIPS5200 (Whirlwind)") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13014/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: scall: Handle seccomp filters which redirect syscallsMatt Redfearn4-18/+24
commit a400bed6d105c23d3673f763596e4b85de14e41a upstream. Commit d218af78492a ("MIPS: scall: Always run the seccomp syscall filters") modified the syscall code to always call the seccomp filters, but missed the case where a filter may redirect the syscall, as revealed by the seccomp_bpf self test. The syscall path now restores the syscall from the stack after the filter rather than saving it locally. Syscall number checking and syscall function table lookup is done after the filter may have run such that redirected syscalls are also checked, and executed. The regular path of syscall number checking and pointer lookup is also made more consistent between ABIs with scall64-64.S being the reference. With this patch in place, the seccomp_bpf self test now passes TRACE_syscall.syscall_redirected and TRACE_syscall.syscall_dropped on all MIPS ABIs. Fixes: d218af78492a ("MIPS: scall: Always run the seccomp syscall filters") Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Eric B Munson <emunson@akamai.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mips@linux-mips.org Cc: IMG-MIPSLinuxKerneldevelopers@imgtec.com Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12916/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: smp-cps: Stop printing EJTAG exceptions to UARTPaul Burton1-1/+0
commit 6609ccdc852f7bfbfa54300dd5b3cd89eb4ced6f upstream. When CONFIG_MIPS_CPS_NS16550 is enabled, some register state is dumped to the UART when an exception is taken via the BEV on secondary cores. EJTAG exceptions are architecturally expected to be handled by the BEV even when Status.BEV is 0. This effectively means that if userland executes an sdbbp instruction on a secondary core then the kernel dumps register state to the UART even though the exception is perfectly normal & expected. Prevent this by simply not dumping information to the UART for EJTAG exceptions. Fixes: 609cf6f2291a ("MIPS: CPS: Early debug using an ns16550-compatible UART") Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12341/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: BMIPS: Fix PRID_IMP_BMIPS5000 masking for BMIPS5200Florian Fainelli1-2/+7
commit cbbda6e7c9c3e4532bd70a73ff9d5e6655c894dc upstream. BMIPS5000 have a PrID value of 0x5A00 and BMIPS5200 have a PrID value of 0x5B00, which, masked with 0x5A00, returns 0x5A00. Update all conditionals on the PrID to cover both variants since we are going to need this to enable BMIPS5200 SMP. The existing check, masking with 0xFF00 would not cover BMIPS5200 at all. Fixes: 68e6a78373a6d ("MIPS: BMIPS: Add PRId for BMIPS5200 (Whirlwind)") Fixes: 6465460c92a85 ("MIPS: BMIPS: change compile time checks to runtime checks") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Cc: john@phrozen.org Cc: cernekee@gmail.com Cc: jogo@openwrt.org Cc: jaedon.shin@gmail.com Cc: jfraser@broadcom.com Cc: pgynther@google.com Cc: dragan.stancevic@gmail.com Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12279/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: ptrace: Drop cp0_tcstatus from regoffset_table[]James Hogan1-3/+0
commit 555fae60b2bbb2d6282d82c5321d3adfa85b22ae upstream. The cp0_tcstatus member of struct pt_regs was removed along with the rest of SMTC in v3.16, commit b633648c5ad3 ("MIPS: MT: Remove SMTC support"), however recent uprobes support in v4.3 added back a reference to it in the regoffset_table[] in ptrace.c. Remove it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Fixes: 40e084a506eb ("MIPS: Add uprobes support.") Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11920/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-10MIPS: Fix macro typoJaedon Shin1-1/+1
commit 2549cc967ebb4043f3507b55e3dc579f44d3b516 upstream. Change the CONFIG_MIPS_CMDLINE_EXTEND to CONFIG_MIPS_CMDLINE_DTB_EXTEND to resolve the EXTEND_WITH_PROM macro. Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com> Fixes: 2024972ef533 ("MIPS: Make the kernel arguments from dtb available") Reviewed-by: Alexander Sverdlin <alexander.svedlin@gmail.com> Cc: Jonas Gorski <jogo@openwrt.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Aaro Koskinen <aaro.koskinen@nokia.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11909/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-11MIPS: VPE: Fix a double free and a memory leak in 'release_vpe()'Christophe JAILLET1-1/+1
commit bef8e2dfceed6daeb6ca3e8d33f9c9d43b926580 upstream. Pointer on the memory allocated by 'alloc_progmem()' is stored in 'v->load_addr'. So this is this memory that should be freed by 'release_progmem()'. 'release_progmem()' is only a call to 'kfree()'. With the current code, there is both a double free and a memory leak. Fix it by passing the correct pointer to 'release_progmem()'. Fixes: e01402b115ccc ("More AP / SP bits for the 34K, the Malta bits and things. Still wants") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Paul Burton <paulburton@kernel.org> Cc: ralf@linux-mips.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: kernel-janitors@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-29mips: avoid explicit UB in assignment of mips_io_port_baseNick Desaulniers1-1/+1
[ Upstream commit 12051b318bc3ce5b42d6d786191008284b067d83 ] The code in question is modifying a variable declared const through pointer manipulation. Such code is explicitly undefined behavior, and is the lone issue preventing malta_defconfig from booting when built with Clang: If an attempt is made to modify an object defined with a const-qualified type through use of an lvalue with non-const-qualified type, the behavior is undefined. LLVM is removing such assignments. A simple fix is to not declare variables const that you plan on modifying. Limiting the scope would be a better method of preventing unwanted writes to such a variable. Further, the code in question mentions "compiler bugs" without any links to bug reports, so it is difficult to know if the issue is resolved in GCC. The patch was authored in 2006, which would have been GCC 4.0.3 or 4.1.1. The minimal supported version of GCC in the Linux kernel is currently 4.6. For what its worth, there was UB before the commit in question, it just added a barrier and got lucky IRT codegen. I don't think there's any actual compiler bugs related, just runtime bugs due to UB. Link: https://github.com/ClangBuiltLinux/linux/issues/610 Fixes: 966f4406d903 ("[MIPS] Work around bad code generation for <asm/io.h>.") Reported-by: Nathan Chancellor <natechancellor@gmail.com> Debugged-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Eli Friedman <efriedma@quicinc.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: Maciej W. Rozycki <macro@linux-mips.org> Cc: Hassan Naveed <hnaveed@wavecomp.com> Cc: Stephen Kitt <steve@sk2.org> Cc: Serge Semin <fancer.lancer@gmail.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-10MIPS: bmips: mark exception vectors as char arraysJonas Gorski1-4/+4
[ Upstream commit e4f5cb1a9b27c0f94ef4f5a0178a3fde2d3d0e9e ] The vectors span more than one byte, so mark them as arrays. Fixes the following build error when building when using GCC 8.3: In file included from ./include/linux/string.h:19, from ./include/linux/bitmap.h:9, from ./include/linux/cpumask.h:12, from ./arch/mips/include/asm/processor.h:15, from ./arch/mips/include/asm/thread_info.h:16, from ./include/linux/thread_info.h:38, from ./include/asm-generic/preempt.h:5, from ./arch/mips/include/generated/asm/preempt.h:1, from ./include/linux/preempt.h:81, from ./include/linux/spinlock.h:51, from ./include/linux/mmzone.h:8, from ./include/linux/bootmem.h:8, from arch/mips/bcm63xx/prom.c:10: arch/mips/bcm63xx/prom.c: In function 'prom_init': ./arch/mips/include/asm/string.h:162:11: error: '__builtin_memcpy' forming offset [2, 32] is out of the bounds [0, 1] of object 'bmips_smp_movevec' with type 'char' [-Werror=array-bounds] __ret = __builtin_memcpy((dst), (src), __len); \ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/mips/bcm63xx/prom.c:97:3: note: in expansion of macro 'memcpy' memcpy((void *)0xa0000200, &bmips_smp_movevec, 0x20); ^~~~~~ In file included from arch/mips/bcm63xx/prom.c:14: ./arch/mips/include/asm/bmips.h:80:13: note: 'bmips_smp_movevec' declared here extern char bmips_smp_movevec; Fixes: 18a1eef92dcd ("MIPS: BMIPS: Introduce bmips.h") Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Paul Burton <paulburton@kernel.org> Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-06MIPS: kernel: only use i8253 clocksource with periodic clockeventThomas Bogendoerfer1-1/+2
[ Upstream commit a07e3324538a989b7cdbf2c679be6a7f9df2544f ] i8253 clocksource needs a free running timer. This could only be used, if i8253 clockevent is set up as periodic. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-10MIPS: uprobes: remove set but not used variable 'epc'YueHaibing1-3/+0
[ Upstream commit f532beeeff0c0a3586cc15538bc52d249eb19e7c ] Fixes gcc '-Wunused-but-set-variable' warning: arch/mips/kernel/uprobes.c: In function 'arch_uprobe_pre_xol': arch/mips/kernel/uprobes.c:115:17: warning: variable 'epc' set but not used [-Wunused-but-set-variable] It's never used since introduction in commit 40e084a506eb ("MIPS: Add uprobes support.") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: <ralf@linux-mips.org> Cc: <jhogan@kernel.org> Cc: <linux-kernel@vger.kernel.org> Cc: <linux-mips@vger.kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-05-16MIPS: scall64-o32: Fix indirect syscall number loadAurelien Jarno1-1/+1
commit 79b4a9cf0e2ea8203ce777c8d5cfa86c71eae86e upstream. Commit 4c21b8fd8f14 (MIPS: seccomp: Handle indirect system calls (o32)) added indirect syscall detection for O32 processes running on MIPS64, but it did not work correctly for big endian kernel/processes. The reason is that the syscall number is loaded from ARG1 using the lw instruction while this is a 64-bit value, so zero is loaded instead of the syscall number. Fix the code by using the ld instruction instead. When running a 32-bit processes on a 64 bit CPU, the values are properly sign-extended, so it ensures the value passed to syscall_trace_enter is correct. Recent systemd versions with seccomp enabled whitelist the getpid syscall for their internal processes (e.g. systemd-journald), but call it through syscall(SYS_getpid). This fix therefore allows O32 big endian systems with a 64-bit kernel to run recent systemd versions. Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> Cc: <stable@vger.kernel.org> # v3.15+ Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-23MIPS: Remove function size check in get_frame_info()Jun-Ru Chang1-4/+3
[ Upstream commit 2b424cfc69728224fcb5fad138ea7260728e0901 ] Patch (b6c7a324df37b "MIPS: Fix get_frame_info() handling of microMIPS function size.") introduces additional function size check for microMIPS by only checking insn between ip and ip + func_size. However, func_size in get_frame_info() is always 0 if KALLSYMS is not enabled. This causes get_frame_info() to return immediately without calculating correct frame_size, which in turn causes "Can't analyze schedule() prologue" warning messages at boot time. This patch removes func_size check, and let the frame_size check run up to 128 insns for both MIPS and microMIPS. Signed-off-by: Jun-Ru Chang <jrjang@realtek.com> Signed-off-by: Tony Wu <tonywu@realtek.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: b6c7a324df37b ("MIPS: Fix get_frame_info() handling of microMIPS function size.") Cc: <ralf@linux-mips.org> Cc: <jhogan@kernel.org> Cc: <macro@mips.com> Cc: <yamada.masahiro@socionext.com> Cc: <peterz@infradead.org> Cc: <mingo@kernel.org> Cc: <linux-mips@vger.kernel.org> Cc: <linux-kernel@vger.kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-03-23MIPS: irq: Allocate accurate order pages for irq stackLiu Xiang1-2/+2
commit 72faa7a773ca59336f3c889e878de81445c5a85c upstream. The irq_pages is the number of pages for irq stack, but not the order which is needed by __get_free_pages(). We can use get_order() to calculate the accurate order. Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn> Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: fe8bd18ffea5 ("MIPS: Introduce irq_stack") Cc: linux-mips@vger.kernel.org Cc: stable@vger.kernel.org # v4.11+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-20mips: cm: reprime error causeVladimir Kondratiev1-1/+1
commit 05dc6001af0630e200ad5ea08707187fe5537e6d upstream. Accordingly to the documentation ---cut--- The GCR_ERROR_CAUSE.ERR_TYPE field and the GCR_ERROR_MULT.ERR_TYPE fields can be cleared by either a reset or by writing the current value of GCR_ERROR_CAUSE.ERR_TYPE to the GCR_ERROR_CAUSE.ERR_TYPE register. ---cut--- Do exactly this. Original value of cm_error may be safely written back; it clears error cause and keeps other bits untouched. Fixes: 3885c2b463f6 ("MIPS: CM: Add support for reporting CM cache errors") Signed-off-by: Vladimir Kondratiev <vladimir.kondratiev@linux.intel.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v4.3+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-21MIPS: kexec: Mark CPU offline before disabling local IRQDengcheng Zhu2-0/+6
[ Upstream commit dc57aaf95a516f70e2d527d8287a0332c481a226 ] After changing CPU online status, it will not be sent any IPIs such as in __flush_cache_all() on software coherency systems. Do this before disabling local IRQ. Signed-off-by: Dengcheng Zhu <dzhu@wavecomp.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Patchwork: https://patchwork.linux-mips.org/patch/20571/ Cc: pburton@wavecomp.com Cc: ralf@linux-mips.org Cc: linux-mips@linux-mips.org Cc: rachel.mozes@intel.com Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-10MIPS: microMIPS: Fix decoding of swsp16 instructionMatt Redfearn1-1/+1
[ Upstream commit cea8cd498f4f1c30ea27e3664b3c671e495c4fce ] When the immediate encoded in the instruction is accessed, it is sign extended due to being a signed value being assigned to a signed integer. The ISA specifies that this operation is an unsigned operation. The sign extension leads us to incorrectly decode: 801e9c8e: cbf1 sw ra,68(sp) As having an immediate of 1073741809. Since the instruction format does not specify signed/unsigned, and this is currently the only location to use this instuction format, change it to an unsigned immediate. Fixes: bb9bc4689b9c ("MIPS: Calculate microMIPS ra properly when unwinding the stack") Suggested-by: Paul Burton <paul.burton@imgtec.com> Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: Miodrag Dinic <miodrag.dinic@imgtec.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16957/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-11-10MIPS: Handle non word sized instructions when examining frameMatt Redfearn1-3/+6
[ Upstream commit 11887ed172a6960673f130dad8f8fb42778f64d7 ] Commit 34c2f668d0f6b ("MIPS: microMIPS: Add unaligned access support.") added fairly broken support for handling 16bit microMIPS instructions in get_frame_info(). It adjusts the instruction pointer by 16bits in the case of a 16bit sp move instruction, but not any other 16bit instruction. Commit b6c7a324df37 ("MIPS: Fix get_frame_info() handling of microMIPS function size") goes some way to fixing get_frame_info() to iterate over microMIPS instuctions, but the instruction pointer is still manipulated using a postincrement, and is of union mips_instruction type. Since the union is sized to the largest member (a word), but microMIPS instructions are a mix of halfword and word sizes, the function does not always iterate correctly, ending up misaligned with the instruction stream and interpreting it incorrectly. Since the instruction modifying the stack pointer is usually the first in the function, that one is usually handled correctly. But the instruction which saves the return address to the sp is some variable number of instructions into the frame and is frequently missed due to not being on a word boundary, leading to incomplete walking of the stack. Fix this by incrementing the instruction pointer based on the size of the previously decoded instruction (& remove the hack introduced by commit 34c2f668d0f6b ("MIPS: microMIPS: Add unaligned access support.") which adjusts the instruction pointer in the case of a 16bit sp move instruction, but not any other). Fixes: 34c2f668d0f6b ("MIPS: microMIPS: Add unaligned access support.") Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16953/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-11-10MIPS: Fix FCSR Cause bit handling for correct SIGFPE issueMaciej W. Rozycki3-42/+47
[ Upstream commit 5a1aca4469fdccd5b74ba0b4e490173b2b447895 ] Sanitize FCSR Cause bit handling, following a trail of past attempts: * commit 4249548454f7 ("MIPS: ptrace: Fix FP context restoration FCSR regression"), * commit 443c44032a54 ("MIPS: Always clear FCSR cause bits after emulation"), * commit 64bedffe4968 ("MIPS: Clear [MSA]FPE CSR.Cause after notify_die()"), * commit b1442d39fac2 ("MIPS: Prevent user from setting FCSR cause bits"), * commit b54d2901517d ("Properly handle branch delay slots in connection with signals."). Specifically do not mask these bits out in ptrace(2) processing and send a SIGFPE signal instead whenever a matching pair of an FCSR Cause and Enable bit is seen as execution of an affected context is about to resume. Only then clear Cause bits, and even then do not clear any bits that are set but masked with the respective Enable bits. Adjust Cause bit clearing throughout code likewise, except within the FPU emulator proper where they are set according to IEEE 754 exceptions raised as the operation emulated executed. Do so so that any IEEE 754 exceptions subject to their default handling are recorded like with operations executed by FPU hardware. Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14460/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-09-26MIPS: VDSO: Match data page cache colouring when D$ aliasesPaul Burton1-0/+20
commit 0f02cfbc3d9e413d450d8d0fd660077c23f67eff upstream. When a system suffers from dcache aliasing a user program may observe stale VDSO data from an aliased cache line. Notably this can break the expectation that clock_gettime(CLOCK_MONOTONIC, ...) is, as its name suggests, monotonic. In order to ensure that users observe updates to the VDSO data page as intended, align the user mappings of the VDSO data page such that their cache colouring matches that of the virtual address range which the kernel will use to update the data page - typically its unmapped address within kseg0. This ensures that we don't introduce aliasing cache lines for the VDSO data page, and therefore that userland will observe updates without requiring cache invalidation. Signed-off-by: Paul Burton <paul.burton@mips.com> Reported-by: Hauke Mehrtens <hauke@hauke-m.de> Reported-by: Rene Nielsen <rene.nielsen@microsemi.com> Reported-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Patchwork: https://patchwork.linux-mips.org/patch/20344/ Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Tested-by: Hauke Mehrtens <hauke@hauke-m.de> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-19kthread: fix boot hang (regression) on MIPS/OpenRISCVegard Nossum1-1/+0
commit b0f5a8f32e8bbdaae1abb8abe2d3cbafaba57e08 upstream. This fixes a regression in commit 4d6501dce079 where I didn't notice that MIPS and OpenRISC were reinitialising p->{set,clear}_child_tid to NULL after our initialisation in copy_process(). We can simply get rid of the arch-specific initialisation here since it is now always done in copy_process() before hitting copy_thread{,_tls}(). Review notes: - As far as I can tell, copy_process() is the only user of copy_thread_tls(), which is the only caller of copy_thread() for architectures that don't implement copy_thread_tls(). - After this patch, there is no arch-specific code touching p->set_child_tid or p->clear_child_tid whatsoever. - It may look like MIPS/OpenRISC wanted to always have these fields be NULL, but that's not true, as copy_process() would unconditionally set them again _after_ calling copy_thread_tls() before commit 4d6501dce079. Fixes: 4d6501dce079c1eb6bf0b1d8f528a5e81770109e ("kthread: Fix use-after-free if kthread fork fails") Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> # MIPS only Acked-by: Stafford Horne <shorne@gmail.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Jonas Bonn <jonas@southpole.se> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: openrisc@lists.librecores.org Cc: Jamie Iles <jamie.iles@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-05MIPS: Correct the 64-bit DSP accumulator register sizeMaciej W. Rozycki2-2/+2
commit f5958b4cf4fc38ed4583ab83fb7c4cd1ab05f47b upstream. Use the `unsigned long' rather than `__u32' type for DSP accumulator registers, like with the regular MIPS multiply/divide accumulator and general-purpose registers, as all are 64-bit in 64-bit implementations and using a 32-bit data type leads to contents truncation on context saving. Update `arch_ptrace' and `compat_arch_ptrace' accordingly, removing casts that are similarly not used with multiply/divide accumulator or general-purpose register accesses. Signed-off-by: Maciej W. Rozycki <macro@mips.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.") Patchwork: https://patchwork.linux-mips.org/patch/19329/ Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # 2.6.15+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-22MIPS: Use async IPIs for arch_trigger_cpumask_backtrace()Paul Burton1-1/+28
commit b63e132b6433a41cf311e8bc382d33fd2b73b505 upstream. The current MIPS implementation of arch_trigger_cpumask_backtrace() is broken because it attempts to use synchronous IPIs despite the fact that it may be run with interrupts disabled. This means that when arch_trigger_cpumask_backtrace() is invoked, for example by the RCU CPU stall watchdog, we may: - Deadlock due to use of synchronous IPIs with interrupts disabled, causing the CPU that's attempting to generate the backtrace output to hang itself. - Not succeed in generating the desired output from remote CPUs. - Produce warnings about this from smp_call_function_many(), for example: [42760.526910] INFO: rcu_sched detected stalls on CPUs/tasks: [42760.535755] 0-...!: (1 GPs behind) idle=ade/140000000000000/0 softirq=526944/526945 fqs=0 [42760.547874] 1-...!: (0 ticks this GP) idle=e4a/140000000000000/0 softirq=547885/547885 fqs=0 [42760.559869] (detected by 2, t=2162 jiffies, g=266689, c=266688, q=33) [42760.568927] ------------[ cut here ]------------ [42760.576146] WARNING: CPU: 2 PID: 1216 at kernel/smp.c:416 smp_call_function_many+0x88/0x20c [42760.587839] Modules linked in: [42760.593152] CPU: 2 PID: 1216 Comm: sh Not tainted 4.15.4-00373-gee058bb4d0c2 #2 [42760.603767] Stack : 8e09bd20 8e09bd20 8e09bd20 fffffff0 00000007 00000006 00000000 8e09bca8 [42760.616937] 95b2b379 95b2b379 807a0080 00000007 81