1. 09 Aug, 2020 5 commits
    • Alexander A. Klimov's avatar
      kbuild: Replace HTTP links with HTTPS ones · 16a122c7
      Alexander A. Klimov authored
      Rationale:
      Reduces attack surface on kernel devs opening the links for MITM
      as HTTPS traffic is much harder to manipulate.
      
      Deterministic algorithm:
      For each file:
        If not .svg:
          For each line:
            If doesn't contain `\bxmlns\b`:
              For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
      	  If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
                  If both the HTTP and HTTPS versions
                  return 200 OK and serve the same content:
                    Replace HTTP with HTTPS.
      Signed-off-by: default avatarAlexander A. Klimov <grandmaster@al2klimov.de>
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      16a122c7
    • Masahiro Yamada's avatar
      kbuild: trace functions in subdirectories of lib/ · b16838c6
      Masahiro Yamada authored
      ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE)
      
      exists here in sub-directories of lib/ to keep the behavior of
      commit 2464a609 ("ftrace: do not trace library functions").
      
      Since that commit, not only the objects in lib/ but also the ones in
      the sub-directories are excluded from ftrace (although the commit
      description did not explicitly mention this).
      
      However, most of library functions in sub-directories are not so hot.
      Re-add them to ftrace.
      
      Going forward, only the objects right under lib/ will be excluded.
      
      Cc: Ingo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Acked-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      b16838c6
    • Masahiro Yamada's avatar
      kbuild: introduce ccflags-remove-y and asflags-remove-y · 15d5761a
      Masahiro Yamada authored
      CFLAGS_REMOVE_<file>.o filters out flags when compiling a particular
      object, but there is no convenient way to do that for every object in
      a directory.
      
      Add ccflags-remove-y and asflags-remove-y to make it easily.
      
      Use ccflags-remove-y to clean up some Makefiles.
      
      The add/remove order works as follows:
      
       [1] KBUILD_CFLAGS specifies compiler flags used globally
      
       [2] ccflags-y adds compiler flags for all objects in the
           current Makefile
      
       [3] ccflags-remove-y removes compiler flags for all objects in the
           current Makefile (New feature)
      
       [4] CFLAGS_<file> adds compiler flags per file.
      
       [5] CFLAGS_REMOVE_<file> removes compiler flags per file.
      
      Having [3] before [4] allows us to remove flags from most (but not all)
      objects in the current Makefile.
      
      For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE)
      from all objects in the directory, then adds it back to
      trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o
      
      The same applies to lib/livepatch/Makefile.
      
      Please note ccflags-remove-y has no effect to the sub-directories.
      In contrast, the previous notation got rid of compiler flags also from
      all the sub-directories.
      
      The following are not affected because they have no sub-directories:
      
        arch/arm/boot/compressed/
        arch/powerpc/xmon/
        arch/sh/
        kernel/trace/
      
      However, lib/ has several sub-directories.
      
      To keep the behavior, I added ccflags-remove-y to all Makefiles
      in subdirectories of lib/, except the following:
      
        lib/vdso/Makefile        - Kbuild does not descend into this Makefile
        lib/raid/test/Makefile   - This is not used for the kernel build
      
      I think commit 2464a609 ("ftrace: do not trace library functions")
      excluded too much. In the next commit, I will remove ccflags-remove-y
      from the sub-directories of lib/.
      Suggested-by: default avatarSami Tolvanen <samitolvanen@google.com>
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Acked-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
      Acked-by: Brendan Higgins <brendanhiggins@google.com> (KUnit)
      Tested-by: default avatarAnders Roxell <anders.roxell@linaro.org>
      15d5761a
    • Masahiro Yamada's avatar
      kbuild: do not export LDFLAGS_vmlinux · 3ec8a5b3
      Masahiro Yamada authored
      When you clean the build tree for ARCH=arm, you may see the following
      error message from 'nm' command:
      
      $ make -j24 ARCH=arm clean
        CLEAN   arch/arm/crypto
        CLEAN   arch/arm/kernel
        CLEAN   arch/arm/mach-at91
        CLEAN   arch/arm/mach-omap2
        CLEAN   arch/arm/vdso
        CLEAN   certs
        CLEAN   lib
        CLEAN   usr
        CLEAN   net/wireless
        CLEAN   drivers/firmware/efi/libstub
      nm: 'arch/arm/boot/compressed/../../../../vmlinux': No such file
      /bin/sh: 1: arithmetic expression: expecting primary: " "
        CLEAN   arch/arm/boot/compressed
        CLEAN   drivers/scsi
        CLEAN   drivers/tty/vt
        CLEAN   arch/arm/boot
        CLEAN   vmlinux.symvers modules.builtin modules.builtin.modinfo
      
      Even if you rerun the same command, the error message will not be
      shown despite vmlinux is already gone.
      
      To reproduce it, the parallel option -j is needed. Single thread
      cleaning always executes 'archclean', 'vmlinuxclean' in this order,
      so vmlinux still exists when arch/arm/boot/compressed/ is cleaned.
      
      Looking at arch/arm/boot/compressed/Makefile does not help understand
      the reason of the error message. Both KBSS_SZ and LDFLAGS_vmlinux are
      assigned with '=' operator, hence, they are not expanded unless used.
      Obviously, 'make clean' does not use them.
      
      In fact, the root cause exists in the top Makefile:
      
        export LDFLAGS_vmlinux
      
      Since LDFLAGS_vmlinux is an exported variable, LDFLAGS_vmlinux in
      arch/arm/boot/compressed/Makefile is expanded when scripts/Makefile.clean
      has a command to execute. This is why the error message shows up only
      when there exist build artifacts in arch/arm/boot/compressed/.
      
      Adding 'unexport LDFLAGS_vmlinux' to arch/arm/boot/compressed/Makefile
      will fix it as far as ARCH=arm is concerned, but I think the proper fix
      is to get rid of 'export LDFLAGS_vmlinux' from the top Makefile.
      
      LDFLAGS_vmlinux in the top Makefile contains linker flags for the top
      vmlinux. LDFLAGS_vmlinux in arch/arm/boot/compressed/Makefile is for
      arch/arm/boot/compressed/vmlinux. They just happen to have the same
      variable name, but are used for different purposes. Stop shadowing
      LDFLAGS_vmlinux.
      
      This commit passes LDFLAGS_vmlinux to scripts/link-vmlinux.sh via a
      command line parameter instead of via an environment variable. LD and
      KBUILD_LDFLAGS are exported, but I did the same for consistency. Anyway,
      they must be included in cmd_link-vmlinux to allow if_changed to detect
      the changes in LD or KBUILD_LDFLAGS.
      
      The following Makefiles are not affected:
      
        arch/arm/boot/compressed/Makefile
        arch/h8300/boot/compressed/Makefile
        arch/nios2/boot/compressed/Makefile
        arch/parisc/boot/compressed/Makefile
        arch/s390/boot/compressed/Makefile
        arch/sh/boot/compressed/Makefile
        arch/sh/boot/romimage/Makefile
        arch/x86/boot/compressed/Makefile
      
      They use ':=' or '=' to clear the LDFLAGS_vmlinux inherited from the
      top Makefile.
      
      We need to take a closer look at the impact to unicore32 and xtensa.
      
      arch/unicore32/boot/compressed/Makefile only uses '+=' operator for
      LDFLAGS_vmlinux. So, the decompressor previously inherited the linker
      flags from the top Makefile.
      
      However, commit 70fac51f ("unicore32 additional architecture files:
      boot process") was merged before commit 1f2bfbd0 ("kbuild: link of
      vmlinux moved to a script"). So, I rather consider this is a bug fix of
      1f2bfbd0.
      
      arch/xtensa/boot/boot-elf/Makefile is also affected, but this is also
      considered a fix for the same reason. It did not inherit LDFLAGS_vmlinux
      when commit 4bedea94 ("[PATCH] xtensa: Architecture support for
      Tensilica Xtensa Part 2") was merged. I deleted $(LDFLAGS_vmlinux),
      which is now empty.
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      Tested-by: default avatarNick Desaulniers <ndesaulniers@google.com>
      3ec8a5b3
    • Masahiro Yamada's avatar
      kbuild: always create directories of targets · cc8a51ca
      Masahiro Yamada authored
      Currently, the directories of objects are automatically created
      only for O= builds.
      
      It should not hurt to cater to this for in-tree builds too.
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      cc8a51ca
  2. 22 Jul, 2020 1 commit
  3. 07 Jul, 2020 5 commits
  4. 05 Jul, 2020 14 commits
    • Linus Torvalds's avatar
      Linux 5.8-rc4 · dcb7fd82
      Linus Torvalds authored
      dcb7fd82
    • Linus Torvalds's avatar
      x86/ldt: use "pr_info_once()" instead of open-coding it badly · bb5a93aa
      Linus Torvalds authored
      Using a mutex for "print this warning only once" is so overdesigned as
      to be actively offensive to my sensitive stomach.
      
      Just use "pr_info_once()" that already does this, although in a
      (harmlessly) racy manner that can in theory cause the message to be
      printed twice if more than one CPU races on that "is this the first
      time" test.
      
      [ If somebody really cares about that harmless data race (which sounds
        very unlikely indeed), that person can trivially fix printk_once() by
        using a simple atomic access, preferably with an optimistic non-atomic
        test first before even bothering to treat the pointless "make sure it
        is _really_ just once" case.
      
        A mutex is most definitely never the right primitive to use for
        something like this. ]
      
      Yes, this is a small and meaningless detail in a code path that hardly
      matters.  But let's keep some code quality standards here, and not
      accept outrageously bad code.
      
      Link: https://lore.kernel.org/lkml/CAHk-=wgV9toS7GU3KmNpj8hCS9SeF+A0voHS8F275_mgLhL4Lw@mail.gmail.com/
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bb5a93aa
    • Linus Torvalds's avatar
      Merge tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 72674d48
      Linus Torvalds authored
      Pull x86 fixes from Thomas Gleixner:
       "A series of fixes for x86:
      
         - Reset MXCSR in kernel_fpu_begin() to prevent using a stale user
           space value.
      
         - Prevent writing MSR_TEST_CTRL on CPUs which are not explicitly
           whitelisted for split lock detection. Some CPUs which do not
           support it crash even when the MSR is written to 0 which is the
           default value.
      
         - Fix the XEN PV fallout of the entry code rework
      
         - Fix the 32bit fallout of the entry code rework
      
         - Add more selftests to ensure that these entry problems don't come
           back.
      
         - Disable 16 bit segments on XEN PV. It's not supported because XEN
           PV does not implement ESPFIX64"
      
      * tag 'x86-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        x86/ldt: Disable 16-bit segments on Xen PV
        x86/entry/32: Fix #MC and #DB wiring on x86_32
        x86/entry/xen: Route #DB correctly on Xen PV
        x86/entry, selftests: Further improve user entry sanity checks
        x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER
        selftests/x86: Consolidate and fix get/set_eflags() helpers
        selftests/x86/syscall_nt: Clear weird flags after each test
        selftests/x86/syscall_nt: Add more flag combinations
        x86/entry/64/compat: Fix Xen PV SYSENTER frame setup
        x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C
        x86/entry: Assert that syscalls are on the right stack
        x86/split_lock: Don't write MSR_TEST_CTRL on CPUs that aren't whitelisted
        x86/fpu: Reset MXCSR to default in kernel_fpu_begin()
      72674d48
    • Linus Torvalds's avatar
      Merge tag 'irq-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · f23dbe18
      Linus Torvalds authored
      Pull irq fixes from Thomas Gleixner:
       "A set of interrupt chip driver fixes:
      
         - Ensure the atomicity of affinity updates in the GIC driver
      
         - Don't try to sleep in atomic context when waiting for the GICv4.1
           to respond. Use polling instead.
      
         - Typo fixes in Kconfig and warnings"
      
      * tag 'irq-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        irqchip/gic: Atomically update affinity
        irqchip/riscv-intc: Fix a typo in a pr_warn()
        irqchip/gic-v4.1: Use readx_poll_timeout_atomic() to fix sleep in atomic
        irqchip/loongson-pci-msi: Fix a typo in Kconfig
      f23dbe18
    • Linus Torvalds's avatar
      Merge tag 'core-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 5465a324
      Linus Torvalds authored
      Pull rcu fixlet from Thomas Gleixner:
       "A single fix for a printk format warning in RCU"
      
      * tag 'core-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        rcuperf: Fix printk format warning
      5465a324
    • Linus Torvalds's avatar
      Merge tag 'kbuild-fixes-v5.8-2' of... · 4bc92736
      Linus Torvalds authored
      Merge tag 'kbuild-fixes-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
      
      Pull Kbuild fixes frin Masahiro Yamada:
      
       - fix various bugs in xconfig
      
       - fix some issues in cross-compilation using Clang
      
       - fix documentation
      
      * tag 'kbuild-fixes-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
        .gitignore: Do not track `defconfig` from `make savedefconfig`
        kbuild: make Clang build userprogs for target architecture
        kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang
        kconfig: qconf: parse newer types at debug info
        kconfig: qconf: navigate menus on hyperlinks
        kconfig: qconf: don't show goback button on splitMode
        kconfig: qconf: simplify the goBack() logic
        kconfig: qconf: re-implement setSelected()
        kconfig: qconf: make debug links work again
        kconfig: qconf: make search fully work again on split mode
        kconfig: qconf: cleanup includes
        docs: kbuild: fix ReST formatting
        gcc-plugins: fix gcc-plugins directory path in documentation
      4bc92736
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 19a61a75
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "Four small fixes in three drivers.
      
        The mptfusion one has actually caused user visible issues in certain
        kernel configurations"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: mptfusion: Don't use GFP_ATOMIC for larger DMA allocations
        scsi: libfc: Skip additional kref updating work event
        scsi: libfc: Handling of extra kref
        scsi: qla2xxx: Fix a condition in qla2x00_find_all_fabric_devs()
      19a61a75
    • Linus Torvalds's avatar
      Merge tag 'block-5.8-2020-07-05' of git://git.kernel.dk/linux-block · 29206c63
      Linus Torvalds authored
      Pull block fixes from Jens Axboe:
      
       - NVMe fixes from Christoph:
          - Fix crash in multi-path disk add (Christoph)
          - Fix ignore of identify error (Sagi)
      
       - Fix a compiler complaint that a function should be static (Wei)
      
      * tag 'block-5.8-2020-07-05' of git://git.kernel.dk/linux-block:
        block: make function __bio_integrity_free() static
        nvme: fix a crash in nvme_mpath_add_disk
        nvme: fix identify error status silent ignore
      29206c63
    • Linus Torvalds's avatar
      Merge tag 'io_uring-5.8-2020-07-05' of git://git.kernel.dk/linux-block · 9fbe565c
      Linus Torvalds authored
      Pull io_uring fix from Jens Axboe:
       "Andres reported a regression with the fix that was merged earlier this
        week, where his setup of using signals to interrupt io_uring CQ waits
        no longer worked correctly.
      
        Fix this, and also limit our use of TWA_SIGNAL to the case where we
        need it, and continue using TWA_RESUME for task_work as before.
      
        Since the original is marked for 5.7 stable, let's flush this one out
        early"
      
      * tag 'io_uring-5.8-2020-07-05' of git://git.kernel.dk/linux-block:
        io_uring: fix regression with always ignoring signals in io_cqring_wait()
      9fbe565c
    • Linus Torvalds's avatar
      Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux · 77834854
      Linus Torvalds authored
      Pull i2c fixes from Wolfram Sang:
       "The usual driver fixes and documentation updates"
      
      * 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
        i2c: mlxcpld: check correct size of maximum RECV_LEN packet
        i2c: add Kconfig help text for slave mode
        i2c: slave-eeprom: update documentation
        i2c: eg20t: Load module automatically if ID matches
        i2c: designware: platdrv: Set class based on DMI
        i2c: algo-pca: Add 0x78 as SCL stuck low status for PCA9665
      77834854
    • Linus Torvalds's avatar
      Merge tag 'mips_fixes_5.8_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux · 45a5ac7a
      Linus Torvalds authored
      Pull MIPS fixes from Thomas Bogendoerfer:
      
       - fix for missing hazard barrier
      
       - DT fix for ingenic
      
       - DT fix of GPHY names for lantiq
      
       - fix usage of smp_processor_id() while preemption is enabled
      
      * tag 'mips_fixes_5.8_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
        MIPS: Do not use smp_processor_id() in preemptible code
        MIPS: Add missing EHB in mtc0 -> mfc0 sequence for DSPen
        MIPS: ingenic: gcw0: Fix HP detection GPIO.
        MIPS: lantiq: xway: sysctrl: fix the GPHY clock alias names
      45a5ac7a
    • Xingxing Su's avatar
      MIPS: Do not use smp_processor_id() in preemptible code · 5868347a
      Xingxing Su authored
      Use preempt_disable() to fix the following bug under CONFIG_DEBUG_PREEMPT.
      
      [   21.915305] BUG: using smp_processor_id() in preemptible [00000000] code: qemu-system-mip/1056
      [   21.923996] caller is do_ri+0x1d4/0x690
      [   21.927921] CPU: 0 PID: 1056 Comm: qemu-system-mip Not tainted 5.8.0-rc2 #3
      [   21.934913] Stack : 0000000000000001 ffffffff81370000 ffffffff8071cd60 a80f926d5ac95694
      [   21.942984]         a80f926d5ac95694 0000000000000000 98000007f0043c88 ffffffff80f2fe40
      [   21.951054]         0000000000000000 0000000000000000 0000000000000001 0000000000000000
      [   21.959123]         ffffffff802d60cc 98000007f0043dd8 ffffffff81f4b1e8 ffffffff81f60000
      [   21.967192]         ffffffff81f60000 ffffffff80fe0000 ffff000000000000 0000000000000000
      [   21.975261]         fffffffff500cce1 0000000000000001 0000000000000002 0000000000000000
      [   21.983331]         ffffffff80fe1a40 0000000000000006 ffffffff8077f940 0000000000000000
      [   21.991401]         ffffffff81460000 98000007f0040000 98000007f0043c80 000000fffba8cf20
      [   21.999471]         ffffffff8071cd60 0000000000000000 0000000000000000 0000000000000000
      [   22.007541]         0000000000000000 0000000000000000 ffffffff80212ab4 a80f926d5ac95694
      [   22.015610]         ...
      [   22.018086] Call Trace:
      [   22.020562] [<ffffffff80212ab4>] show_stack+0xa4/0x138
      [   22.025732] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
      [   22.030903] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
      [   22.037375] [<ffffffff80213b84>] do_ri+0x1d4/0x690
      [   22.042198] [<ffffffff8020b828>] handle_ri_int+0x44/0x5c
      [   24.359386] BUG: using smp_processor_id() in preemptible [00000000] code: qemu-system-mip/1072
      [   24.368204] caller is do_ri+0x1a8/0x690
      [   24.372169] CPU: 4 PID: 1072 Comm: qemu-system-mip Not tainted 5.8.0-rc2 #3
      [   24.379170] Stack : 0000000000000001 ffffffff81370000 ffffffff8071cd60 a80f926d5ac95694
      [   24.387246]         a80f926d5ac95694 0000000000000000 98001007ef06bc88 ffffffff80f2fe40
      [   24.395318]         0000000000000000 0000000000000000 0000000000000001 0000000000000000
      [   24.403389]         ffffffff802d60cc 98001007ef06bdd8 ffffffff81f4b818 ffffffff81f60000
      [   24.411461]         ffffffff81f60000 ffffffff80fe0000 ffff000000000000 0000000000000000
      [   24.419533]         fffffffff500cce1 0000000000000001 0000000000000002 0000000000000000
      [   24.427603]         ffffffff80fe0000 0000000000000006 ffffffff8077f940 0000000000000020
      [   24.435673]         ffffffff81460020 98001007ef068000 98001007ef06bc80 000000fffbbbb370
      [   24.443745]         ffffffff8071cd60 0000000000000000 0000000000000000 0000000000000000
      [   24.451816]         0000000000000000 0000000000000000 ffffffff80212ab4 a80f926d5ac95694
      [   24.459887]         ...
      [   24.462367] Call Trace:
      [   24.464846] [<ffffffff80212ab4>] show_stack+0xa4/0x138
      [   24.470029] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
      [   24.475208] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
      [   24.481682] [<ffffffff80213b58>] do_ri+0x1a8/0x690
      [   24.486509] [<ffffffff8020b828>] handle_ri_int+0x44/0x5c
      Signed-off-by: default avatarXingxing Su <suxingxing@loongson.cn>
      Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      5868347a
    • Hauke Mehrtens's avatar
      MIPS: Add missing EHB in mtc0 -> mfc0 sequence for DSPen · fcec538e
      Hauke Mehrtens authored
      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 9012d011 ("compiler:
      allow all arches to enable CONFIG_OPTIMIZE_INLINING"), but when this was
      reverted it also happened after commit 172dcd93 ("MIPS: Always
      allocate exception vector for MIPSr2+").
      
      Commit 0b24cae4 ("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: default avatarHauke Mehrtens <hauke@hauke-m.de>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
      fcec538e
    • Paul Menzel's avatar
      .gitignore: Do not track `defconfig` from `make savedefconfig` · ba77dca5
      Paul Menzel authored
      Running `make savedefconfig` creates by default `defconfig`, which is,
      currently, on git’s radar, for example, `git status` lists this file as
      untracked.
      
      So, add the file to `.gitignore`, so it’s ignored by git.
      Signed-off-by: default avatarPaul Menzel <pmenzel@molgen.mpg.de>
      Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      ba77dca5
  5. 04 Jul, 2020 15 commits