kernel/linux.git/arch/arc, branch linux-5.9.y

ARC: stack unwinding: don't assume non-current task is sleeping

2020-12-16T09:58:30+00:00

[ Upstream commit e42404fa10fd11fe72d0a0e149a321d10e577715 ] To start stack unwinding (SP, PC and BLINK) are needed. When the explicit execution context (pt_regs etc) is not available, unwinder assumes the task is sleeping (in __switch_to()) and fetches SP and BLINK from kernel mode stack. But this assumption is not true, specially in a SMP system, when top runs on 1 core, there may be active running processes on all cores. So when unwinding non courrent tasks, ensure they are NOT running. And while at it, handle the self unwinding case explicitly. This came out of investigation of a customer reported hang with rcutorture+top Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/31 Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed

2020-12-02T07:51:54+00:00

[ Upstream commit cef397038167ac15d085914493d6c86385773709 ] Stefan Agner reported a bug when using zsram on 32-bit Arm machines with RAM above the 4GB address boundary: Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = a27bd01c [00000000] *pgd=236a0003, *pmd=1ffa64003 Internal error: Oops: 207 [#1] SMP ARM Modules linked in: mdio_bcm_unimac(+) brcmfmac cfg80211 brcmutil raspberrypi_hwmon hci_uart crc32_arm_ce bcm2711_thermal phy_generic genet CPU: 0 PID: 123 Comm: mkfs.ext4 Not tainted 5.9.6 #1 Hardware name: BCM2711 PC is at zs_map_object+0x94/0x338 LR is at zram_bvec_rw.constprop.0+0x330/0xa64 pc : [] lr : [] psr: 60000013 sp : e376bbe0 ip : 00000000 fp : c1e2921c r10: 00000002 r9 : c1dda730 r8 : 00000000 r7 : e8ff7a00 r6 : 00000000 r5 : 02f9ffa0 r4 : e3710000 r3 : 000fdffe r2 : c1e0ce80 r1 : ebf979a0 r0 : 00000000 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 30c5383d Table: 235c2a80 DAC: fffffffd Process mkfs.ext4 (pid: 123, stack limit = 0x495a22e6) Stack: (0xe376bbe0 to 0xe376c000) As it turns out, zsram needs to know the maximum memory size, which is defined in MAX_PHYSMEM_BITS when CONFIG_SPARSEMEM is set, or in MAX_POSSIBLE_PHYSMEM_BITS on the x86 architecture. The same problem will be hit on all 32-bit architectures that have a physical address space larger than 4GB and happen to not enable sparsemem and include asm/sparsemem.h from asm/pgtable.h. After the initial discussion, I suggested just always defining MAX_POSSIBLE_PHYSMEM_BITS whenever CONFIG_PHYS_ADDR_T_64BIT is set, or provoking a build error otherwise. This addresses all configurations that can currently have this runtime bug, but leaves all other configurations unchanged. I looked up the possible number of bits in source code and datasheets, here is what I found: - on ARC, CONFIG_ARC_HAS_PAE40 controls whether 32 or 40 bits are used - on ARM, CONFIG_LPAE enables 40 bit addressing, without it we never support more than 32 bits, even though supersections in theory allow up to 40 bits as well. - on MIPS, some MIPS32r1 or later chips support 36 bits, and MIPS32r5 XPA supports up to 60 bits in theory, but 40 bits are more than anyone will ever ship - On PowerPC, there are three different implementations of 36 bit addressing, but 32-bit is used without CONFIG_PTE_64BIT - On RISC-V, the normal page table format can support 34 bit addressing. There is no highmem support on RISC-V, so anything above 2GB is unused, but it might be useful to eventually support CONFIG_ZRAM for high pages. Fixes: 61989a80fb3a ("staging: zsmalloc: zsmalloc memory allocation library") Fixes: 02390b87a945 ("mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS") Acked-by: Thomas Bogendoerfer Reviewed-by: Stefan Agner Tested-by: Stefan Agner Acked-by: Mike Rapoport Link: https://lore.kernel.org/linux-mm/bdfa44bf1c570b05d6c70898e2bbb0acf234ecdf.1604762181.git.stefan@agner.ch/ Signed-off-by: Arnd Bergmann Signed-off-by: Sasha Levin

ARC: [plat-hsdk] Remap CCMs super early in asm boot trampoline

2020-11-18T18:22:12+00:00

[ Upstream commit 3b57533b460c8dc22a432684b7e8d22571f34d2e ] ARC HSDK platform stopped booting on released v5.10-rc1, getting stuck in startup of non master SMP cores. This was bisected to upstream commit 7fef431be9c9ac25 "(mm/page_alloc: place pages to tail in __free_pages_core())" That commit itself is harmless, it just exposed a subtle assumption in our platform code (hence CC'ing linux-mm just as FYI in case some other arches / platforms trip on it). The upstream commit is semantically disruptive as it reverses the order of page allocations (actually it can be good test for hardware verification to exercise different memory patterns altogether). For ARC HSDK platform that meant a remapped memory region (pertaining to unused Closely Coupled Memory) started getting used early for dynamice allocations, while not effectively remapped on all the cores, triggering memory error exception on those cores. The fix is to move the CCM remapping from early platform code to to early core boot code. And while it is undesirable to riddle common boot code with platform quirks, there is no other way to do this since the faltering code involves setting up stack itself so even function calls are not allowed at that point. If anyone is interested, all the gory details can be found at Link below. Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/32 Cc: David Hildenbrand Cc: linux-mm@kvack.org Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

ARC: stack unwinding: avoid indefinite looping

2020-11-10T11:39:10+00:00

commit 328d2168ca524d501fc4b133d6be076142bd305c upstream. Currently stack unwinder is a while(1) loop which relies on the dwarf unwinder to signal termination, which in turn relies on dwarf info to do so. This in theory could cause an infinite loop if the dwarf info was somehow messed up or the register contents were etc. This fix thus detects the excessive looping and breaks the loop. | Mem: 26184K used, 1009136K free, 0K shrd, 0K buff, 14416K cached | CPU: 0.0% usr 72.8% sys 0.0% nic 27.1% idle 0.0% io 0.0% irq 0.0% sirq | Load average: 4.33 2.60 1.11 2/74 139 | PID PPID USER STAT VSZ %VSZ CPU %CPU COMMAND | 133 2 root SWN 0 0.0 3 22.9 [rcu_torture_rea] | 132 2 root SWN 0 0.0 0 22.0 [rcu_torture_rea] | 131 2 root SWN 0 0.0 3 21.5 [rcu_torture_rea] | 126 2 root RW 0 0.0 2 5.4 [rcu_torture_wri] | 129 2 root SWN 0 0.0 0 0.2 [rcu_torture_fak] | 137 2 root SW 0 0.0 0 0.2 [rcu_torture_cbf] | 127 2 root SWN 0 0.0 0 0.1 [rcu_torture_fak] | 138 115 root R 1464 0.1 2 0.1 top | 130 2 root SWN 0 0.0 0 0.1 [rcu_torture_fak] | 128 2 root SWN 0 0.0 0 0.1 [rcu_torture_fak] | 115 1 root S 1472 0.1 1 0.0 -/bin/sh | 104 1 root S 1464 0.1 0 0.0 inetd | 1 0 root S 1456 0.1 2 0.0 init | 78 1 root S 1456 0.1 0 0.0 syslogd -O /var/log/messages | 134 2 root SW 0 0.0 2 0.0 [rcu_torture_sta] | 10 2 root IW 0 0.0 1 0.0 [rcu_preempt] | 88 2 root IW 0 0.0 1 0.0 [kworker/1:1-eve] | 66 2 root IW 0 0.0 2 0.0 [kworker/2:2-eve] | 39 2 root IW 0 0.0 2 0.0 [kworker/2:1-eve] | unwinder looping too long, aborting ! Cc: Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: perf: redo the pct irq missing in device-tree handling

2020-11-05T10:51:47+00:00

commit 8c42a5c02bec6c7eccf08957be3c6c8fccf9790b upstream. commit feb92d7d3813456c11dce21 "(ARC: perf: don't bail setup if pct irq missing in device-tree)" introduced a silly brown-paper bag bug: The assignment and comparison in an if statement were not bracketed correctly leaving the order of evaluation undefined. | | if (has_interrupts && (irq = platform_get_irq(pdev, 0) >= 0)) { | ^^^ ^^^^ And given such a chance, the compiler will bite you hard, fully entitled to generating this piece of beauty: | | # if (has_interrupts && (irq = platform_get_irq(pdev, 0) >= 0)) { | | bl.d @platform_get_irq <-- irq returned in r0 | | setge r2, r0, 0 <-- r2 is bool 1 or 0 if irq >= 0 true/false | brlt.d r0, 0, @.L114 | | st_s r2,[sp] <-- irq saved is bool 1 or 0, not actual return val | st 1,[r3,160] # arc_pmu.18_29->irq <-- drops bool and assumes 1 | | # return __request_percpu_irq(irq, handler, 0, | | bl.d @__request_percpu_irq; | mov_s r0,1 <-- drops even bool and assumes 1 which fails With the snafu fixed, everything is as expected. | bl.d @platform_get_irq <-- returns irq in r0 | | mov_s r2,r0 | brlt.d r2, 0, @.L112 | | st_s r0,[sp] <-- irq isaved is actual return value above | st r0,[r13,160] #arc_pmu.18_27->irq | | bl.d @__request_percpu_irq <-- r0 unchanged so actual irq returned | add r4,r4,r12 #, tmp363, __ptr Cc: Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: [dts] fix the errors detected by dtbs_check

2020-11-05T10:51:25+00:00

[ Upstream commit 05b1be68c4d6d76970025e6139bfd735c2256ee5 ] xxx/arc/boot/dts/axs101.dt.yaml: dw-apb-ictl@e0012000: $nodename:0: \ 'dw-apb-ictl@e0012000' does not match '^interrupt-controller(@[0-9a-f,]+)*$' From schema: xxx/interrupt-controller/snps,dw-apb-ictl.yaml The node name of the interrupt controller must start with "interrupt-controller" instead of "dw-apb-ictl". Signed-off-by: Zhen Lei Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

arc: plat-hsdk: fix kconfig dependency warning when !RESET_CONTROLLER

2020-10-29T09:11:40+00:00

[ Upstream commit 63bcf87cb1c57956e1179f1a78dde625c7e3cba7 ] When ARC_SOC_HSDK is enabled and RESET_CONTROLLER is disabled, it results in the following Kbuild warning: WARNING: unmet direct dependencies detected for RESET_HSDK Depends on [n]: RESET_CONTROLLER [=n] && HAS_IOMEM [=y] && (ARC_SOC_HSDK [=y] || COMPILE_TEST [=n]) Selected by [y]: - ARC_SOC_HSDK [=y] && ISA_ARCV2 [=y] The reason is that ARC_SOC_HSDK selects RESET_HSDK without depending on or selecting RESET_CONTROLLER while RESET_HSDK is subordinate to RESET_CONTROLLER. Honor the kconfig menu hierarchy to remove kconfig dependency warnings. Fixes: a528629dfd3b ("ARC: [plat-hsdk] select CONFIG_RESET_HSDK from Kconfig") Signed-off-by: Necip Fazil Yildiran Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

Merge tag 'arc-5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

2020-09-05T20:46:14+00:00

Pull ARC fixes from Vineet Gupta: - HSDK-4xd Dev system: perf driver updates for sampling interrupt - HSDK* Dev System: Ethernet broken [Evgeniy Didin] - HIGHMEM broken (2 memory banks) [Mike Rapoport] - show_regs() rewrite once and for all - Other minor fixes * tag 'arc-5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: ARC: [plat-hsdk]: Switch ethernet phy-mode to rgmii-id arc: fix memory initialization for systems with two memory banks irqchip/eznps: Fix build error for !ARC700 builds ARC: show_regs: fix r12 printing and simplify ARC: HSDK: wireup perf irq ARC: perf: don't bail setup if pct irq missing in device-tree ARC: pgalloc.h: delete a duplicated word + other fixes

ARC: [plat-hsdk]: Switch ethernet phy-mode to rgmii-id

2020-09-01T18:59:04+00:00

HSDK board has Micrel KSZ9031, recent commit bcf3440c6dd ("net: phy: micrel: add phy-mode support for the KSZ9031 PHY") caused a breakdown of Ethernet. Using 'phy-mode = "rgmii"' is not correct because accodring RGMII specification it is necessary to have delay on RX (PHY to MAX) which is not generated in case of "rgmii". Using "rgmii-id" adds necessary delay and solves the issue. Also adding name of PHY placed on HSDK board. Signed-off-by: Evgeniy Didin Cc: Eugeniy Paltsev Cc: Alexey Brodkin Signed-off-by: Vineet Gupta

arc: fix memory initialization for systems with two memory banks

2020-09-01T18:23:50+00:00

Rework of memory map initialization broke initialization of ARC systems with two memory banks. Before these changes, memblock was not aware of nodes configuration and the memory map was always allocated from the "lowmem" bank. After the addition of node information to memblock, the core mm attempts to allocate the memory map for the "highmem" bank from its node. The access to this memory using __va() fails because it can be only accessed using kmap. Anther problem that was uncovered is that {min,max}_high_pfn are calculated from u64 high_mem_start variable which prevents truncation to 32-bit physical address and the PFN values are above the node and zone boundaries. Use phys_addr_t type for high_mem_start and high_mem_size to ensure correspondence between PFNs and highmem zone boundaries and reserve the entire highmem bank until mem_init() to avoid accesses to it before highmem is enabled. To test this: 1. Enable HIGHMEM in ARC config 2. Enable 2 memory banks in haps_hs.dts (uncomment the 2nd bank) Fixes: 51930df5801e ("mm: free_area_init: allow defining max_zone_pfn in descending order") Cc: stable@vger.kernel.org [5.8] Signed-off-by: Mike Rapoport Signed-off-by: Vineet Gupta [vgupta: added instructions to test highmem]