user/sven/linux.git/arch/arc/kernel, branch v4.9.220

ARC: perf: Accommodate big-endian CPU

2019-11-28T17:29:03Z

commit 5effc09c4907901f0e71e68e5f2e14211d9a203f upstream. 8-letter strings representing ARC perf events are stores in two 32-bit registers as ASCII characters like that: "IJMP", "IALL", "IJMPTAK" etc. And the same order of bytes in the word is used regardless CPU endianness. Which means in case of big-endian CPU core we need to swap bytes to get the same order as if it was on little-endian CPU. Otherwise we're seeing the following error message on boot: ------------------------->8---------------------- ARC perf : 8 counters (32 bits), 40 conditions, [overflow IRQ support] sysfs: cannot create duplicate filename '/devices/arc_pct/events/pmji' CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.18 #3 Stack Trace: arc_unwind_core+0xd4/0xfc dump_stack+0x64/0x80 sysfs_warn_dup+0x46/0x58 sysfs_add_file_mode_ns+0xb2/0x168 create_files+0x70/0x2a0 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at kernel/events/core.c:12144 perf_event_sysfs_init+0x70/0xa0 Failed to register pmu: arc_pct, reason -17 Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.18 #3 Stack Trace: arc_unwind_core+0xd4/0xfc dump_stack+0x64/0x80 __warn+0x9c/0xd4 warn_slowpath_fmt+0x22/0x2c perf_event_sysfs_init+0x70/0xa0 ---[ end trace a75fb9a9837bd1ec ]--- ------------------------->8---------------------- What happens here we're trying to register more than one raw perf event with the same name "PMJI". Why? Because ARC perf events are 4 to 8 letters and encoded into two 32-bit words. In this particular case we deal with 2 events: * "IJMP____" which counts all jump & branch instructions * "IJMPC___" which counts only conditional jumps & branches Those strings are split in two 32-bit words this way "IJMP" + "____" & "IJMP" + "C___" correspondingly. Now if we read them swapped due to CPU core being big-endian then we read "PMJI" + "____" & "PMJI" + "___C". And since we interpret read array of ASCII letters as a null-terminated string on big-endian CPU we end up with 2 events of the same name "PMJI". Signed-off-by: Alexey Brodkin Cc: stable@vger.kernel.org Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: export "abort" for modules

2019-09-21T05:14:23Z

This is a custom patch (no mainline equivalent) for stable backport only to address 0-Day kernel test infra ARC 4.x.y builds errors. The reason for this custom patch as that it is a single patch, touches only ARC, vs. atleast two 7c2c11b208be09c1, dc8635b78cd8669 which touch atleast 3 other arches (one long removed) and could potentially have a fallout. Reported-by: kbuild test robot CC: stable@vger.kernel.org # 4.4, 4.9 Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: hide unused function unw_hdr_alloc

2019-07-21T07:06:07Z

commit fd5de2721ea7d16e2b16c4049ac49f229551b290 upstream. As kernelci.org reports, this function is not used in vdk_hs38_defconfig: arch/arc/kernel/unwind.c:188:14: warning: 'unw_hdr_alloc' defined but not used [-Wunused-function] Fixes: bc79c9a72165 ("ARC: dw2 unwind: Reinstante unwinding out of modules") Link: https://kernelci.org/build/id/5d1cae3f59b514300340c132/logs/ Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: handle gcc generated __builtin_trap for older compiler

2019-07-10T07:55:44Z

commit af1be2e21203867cb958aaceed5366e2e24b88e8 upstream. ARC gcc prior to GNU 2018.03 release didn't have a target specific __builtin_trap() implementation, generating default abort() call. Implement the abort() call - emulating what newer gcc does for the same, as suggested by Arnd. Acked-by: Arnd Bergmann Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: u-boot args: check that magic number is correct

2019-04-20T07:07:45Z

[ Upstream commit edb64bca50cd736c6894cc6081d5263c007ce005 ] In case of devboards we really often disable bootloader and load Linux image in memory via JTAG. Even if kernel tries to verify uboot_tag and uboot_arg there is sill a chance that we treat some garbage in registers as valid u-boot arguments in JTAG case. E.g. it is enough to have '1' in r0 to treat any value in r2 as a boot command line. So check that magic number passed from u-boot is correct and drop u-boot arguments otherwise. That helps to reduce the possibility of using garbage as u-boot arguments in JTAG case. We can safely check U-boot magic value (0x0) in linux passed via r1 register as U-boot pass it from the beginning. So there is no backward-compatibility issues. Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

ARC: U-boot: check arguments paranoidly

2019-02-27T09:07:01Z

commit a66f2e57bd566240d8b3884eedf503928fbbe557 upstream. Handle U-boot arguments paranoidly: * don't allow to pass unknown tag. * try to use external device tree blob only if corresponding tag (TAG_DTB) is set. * don't check uboot_tag if kernel build with no ARC_UBOOT_SUPPORT. NOTE: If U-boot args are invalid we skip them and try to use embedded device tree blob. We can't panic on invalid U-boot args as we really pass invalid args due to bug in U-boot code. This happens if we don't provide external DTB to U-boot and don't set 'bootargs' U-boot environment variable (which is default case at least for HSDK board) In that case we will pass {r0 = 1 (bootargs in r2); r1 = 0; r2 = 0;} to linux which is invalid. While I'm at it refactor U-boot arguments handling code. Cc: stable@vger.kernel.org Tested-by: Corentin LABBE Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARCv2: Enable unaligned access in early ASM code

2019-02-27T09:07:01Z

commit 252f6e8eae909bc075a1b1e3b9efb095ae4c0b56 upstream. It is currently done in arc_init_IRQ() which might be too late considering gcc 7.3.1 onwards (GNU 2018.03) generates unaligned memory accesses by default Cc: stable@vger.kernel.org #4.4+ Signed-off-by: Eugeniy Paltsev Signed-off-by: Vineet Gupta [vgupta: rewrote changelog] Signed-off-by: Greg Kroah-Hartman

ARC: clone syscall to setp r25 as thread pointer

2018-10-13T07:18:57Z

commit c58a584f05e35d1d4342923cd7aac07d9c3d3d16 upstream. Per ARC TLS ABI, r25 is designated TP (thread pointer register). However so far kernel didn't do any special treatment, like setting up usermode r25, even for CLONE_SETTLS. We instead relied on libc runtime to do this, in say clone libc wrapper [1]. This was deliberate to keep kernel ABI agnostic (userspace could potentially change TP, specially for different ARC ISA say ARCompact vs. ARCv2 with different spare registers etc) However userspace setting up r25, after clone syscall opens a race, if child is not scheduled and gets a signal instead. It starts off in userspace not in clone but in a signal handler and anything TP sepcific there such as pthread_self() fails which showed up with uClibc testsuite nptl/tst-kill6 [2] Fix this by having kernel populate r25 to TP value. So this locks in ABI, but it was not going to change anyways, and fwiw is same for both ARCompact (arc700 core) and ARCvs (HS3x cores) [1] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/arc/clone.S [2] https://github.com/wbx-github/uclibc-ng-test/blob/master/test/nptl/tst-kill6.c Fixes: ARC STAR 9001378481 Cc: stable@vger.kernel.org Reported-by: Nikita Sobolev Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: Improve cmpxchg syscall implementation

2018-08-24T11:12:37Z

[ Upstream commit e8708786d4fe21c043d38d760f768949a3d71185 ] This is used in configs lacking hardware atomics to emulate atomic r-m-w for user space, implemented by disabling preemption in kernel. However there are issues in current implementation: 1. Process not terminated if invalid user pointer passed: i.e. __get_user() failed. 2. The reason for this patch was __put_user() failure not being handled either, specifically for the COW break scenario. The zero page is initially wired up and read from __get_user() succeeds. A subsequent write by __put_user() induces a Protection Violation, but COW can't finish as Linux page fault handler is disabled due to preempt disable. And what's worse is we silently return the stale value to user space. Fix this specific case by re-enabling preemption and explicitly fixing up the fault and retrying the whole sequence over. Cc: Max Filippov Cc: linux-arch@vger.kernel.org Signed-off-by: Alexey Brodkin Signed-off-by: Peter Zijlstra Signed-off-by: Vineet Gupta [vgupta: rewrote the changelog] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

ARC: Enable machine_desc->init_per_cpu for !CONFIG_SMP

2018-08-24T11:12:30Z

[ Upstream commit 2f24ef7413a4d91657ef04e77c27ce0b313e6c95 ] machine_desc->init_per_cpu() hook is supposed to be per cpu initialization and would seem to apply equally to UP and/or SMP. Infact the comment in header file seems to suggest it works for UP too, which was not the case and this patch. This enables !CONFIG_SMP build for platforms such as hsdk. Signed-off-by: Alexey Brodkin Signed-off-by: Vineet Gupta [vgupta: trimmeed changelog] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman