kernel/git/stable/linux.git/arch/mips/vdso, branch linux-5.6.y

MIPS: vdso: Wrap -mexplicit-relocs in cc-option

2020-02-19T18:30:10+00:00

Clang does not support this option and errors out: clang-11: error: unknown argument: '-mexplicit-relocs' Clang does not appear to need this flag like GCC does because the jalr check that was added in commit 976c23af3ee5 ("mips: vdso: add build time check that no 'jalr t9' calls left") passes just fine with $ make ARCH=mips CC=clang CROSS_COMPILE=mipsel-linux-gnu- malta_defconfig arch/mips/vdso/ even before commit d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code"). -mrelax-pic-calls has been supported since clang 9, which is the earliest version that could build a working MIPS kernel, and it is the default for clang so just leave it be. Fixes: d3f703c4359f ("mips: vdso: fix 'jalr t9' crash in vdso code") Link: https://github.com/ClangBuiltLinux/linux/issues/890 Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com

mips: vdso: add build time check that no 'jalr t9' calls left

2020-02-15T20:44:03+00:00

vdso shared object cannot have GOT based PIC 'jalr t9' calls because nobody set GOT table in vdso. Contributing into vdso .o files are compiled in PIC mode and as result for internal static functions calls compiler will generate 'jalr t9' instructions. Those are supposed to be converted into PC relative 'bal' calls by linker when relocation are processed. Mips global GOT entries do have dynamic relocations and they will be caught by cmd_vdso_check Makefile rule. Static PIC calls go through mips local GOT entries that do not have dynamic relocations. For those 'jalr t9' calls could be present but without dynamic relocations and they need to be converted to 'bal' calls by linker. Add additional build time check to make sure that no 'jalr t9' slip through because of some toolchain misconfiguration that prevents 'jalr t9' to 'bal' conversion. Signed-off-by: Victor Kamensky Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle Cc: James Hogan Cc: Vincenzo Frascino Cc: bruce.ashfield@gmail.com Cc: richard.purdie@linuxfoundation.org

MIPS: Disable VDSO time functionality on microMIPS

2020-02-15T20:44:03+00:00

A check we're about to add to pick up on function calls that depend on bogus use of the GOT in the VDSO picked up on instances of such function calls in microMIPS builds. Since the code appears genuinely problematic, and given the relatively small amount of use & testing that microMIPS sees, go ahead & disable the VDSO for microMIPS builds. Signed-off-by: Paul Burton

mips: vdso: fix 'jalr t9' crash in vdso code

2020-02-15T19:04:05+00:00

Observed that when kernel is built with Yocto mips64-poky-linux-gcc, and mips64-poky-linux-gnun32-gcc toolchain, resulting vdso contains 'jalr t9' instructions in its code and since in vdso case nobody sets GOT table code crashes when instruction reached. On other hand observed that when kernel is built mips-poky-linux-gcc toolchain, the same 'jalr t9' instruction are replaced with PC relative function calls using 'bal' instructions. The difference boils down to -mrelax-pic-calls and -mexplicit-relocs gcc options that gets different default values depending on gcc target triplets and corresponding binutils. -mrelax-pic-calls got enabled by default only in mips-poky-linux-gcc case. MIPS binutils ld relies on R_MIPS_JALR relocation to convert 'jalr t9' into 'bal' and such relocation is generated only if -mrelax-pic-calls option is on. Please note 'jalr t9' conversion to 'bal' can happen only to static functions. These static PIC calls use mips local GOT entries that are supposed to be filled with start of DSO value by run-time linker (missing in VDSO case) and they do not have dynamic relocations. Global mips GOT entries must have dynamic relocations and they should be prevented by cmd_vdso_check Makefile rule. Solution call out -mrelax-pic-calls and -mexplicit-relocs options explicitly while compiling MIPS vdso code. That would get correct and consistent between different toolchains behaviour. Reported-by: Bruce Ashfield Signed-off-by: Victor Kamensky Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle Cc: James Hogan Cc: Vincenzo Frascino Cc: richard.purdie@linuxfoundation.org

kbuild: rename hostprogs-y/always to hostprogs/always-y

2020-02-03T16:53:07+00:00

In old days, the "host-progs" syntax was used for specifying host programs. It was renamed to the current "hostprogs-y" in 2004. It is typically useful in scripts/Makefile because it allows Kbuild to selectively compile host programs based on the kernel configuration. This commit renames like follows: always -> always-y hostprogs-y -> hostprogs So, scripts/Makefile will look like this: always-$(CONFIG_BUILD_BIN2C) += ... always-$(CONFIG_KALLSYMS) += ... ... hostprogs := $(always-y) $(always-m) I think this makes more sense because a host program is always a host program, irrespective of the kernel configuration. We want to specify which ones to compile by CONFIG options, so always-y will be handier. The "always", "hostprogs-y", "hostprogs-m" will be kept for backward compatibility for a while. Signed-off-by: Masahiro Yamada

Merge tag 'mips_5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

2020-01-31T19:28:31+00:00

Pull MIPS changes from Paul Burton: "Nothing too big or scary in here: - Support mremap() for the VDSO, primarily to allow CRIU to restore the VDSO to its checkpointed location. - Restore the MIPS32 cBPF JIT, after having reverted the enablement of the eBPF JIT for MIPS32 systems in the 5.5 cycle. - Improve cop0 counter synchronization behaviour whilst onlining CPUs by running with interrupts disabled. - Better match FPU behaviour when emulating multiply-accumulate instructions on pre-r6 systems that implement IEEE754-2008 style MACs. - Loongson64 kernels now build using the MIPS64r2 ISA, allowing them to take advantage of instructions introduced by r2. - Support for the Ingenic X1000 SoC & the really nice little CU Neo development board that's using it. - Support for WMAC on GARDENA Smart Gateway devices. - Lots of cleanup & refactoring of SGI IP27 (Origin 2*) support in preparation for introducing IP35 (Origin 3*) support. - Various Kconfig & Makefile cleanups" * tag 'mips_5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (60 commits) MIPS: PCI: Add detection of IOC3 on IO7, IO8, IO9 and Fuel MIPS: Loongson64: Disable exec hazard MIPS: Loongson64: Bump ISA level to MIPSR2 MIPS: Make DIEI support as a config option MIPS: OCTEON: octeon-irq: fix spelling mistake "to" -> "too" MIPS: asm: local: add barriers for Loongson MIPS: Loongson64: Select mac2008 only feature MIPS: Add MAC2008 Support Revert "MIPS: Add custom serial.h with BASE_BAUD override for generic kernel" MIPS: sort MIPS and MIPS_GENERIC Kconfig selects alphabetically (again) MIPS: make CPU_HAS_LOAD_STORE_LR opt-out MIPS: generic: don't unconditionally select PINCTRL MIPS: don't explicitly select LIBFDT in Kconfig MIPS: sync-r4k: do slave counter synchronization with disabled HW interrupts MIPS: SGI-IP30: Check for valid pointer before using it MIPS: syscalls: fix indentation of the 'SYSNR' message MIPS: boot: fix typo in 'vmlinux.lzma.its' target MIPS: fix indentation of the 'RELOCS' message dt-bindings: Document loongson vendor-prefix MIPS: CU1000-Neo: Refresh defconfig to support HWMON and WiFi. ...

MIPS: vdso: Define BUILD_VDSO32 when building a 32bit kernel

2020-01-16T20:24:25+00:00

The confinement of the 32bit specific VDSO functions missed to define BUILD_VDSO32 when building a 32bit MIPS kernel: arch/mips/vdso/vgettimeofday.c: In function __vdso_clock_gettime: arch/mips/vdso/vgettimeofday.c:17:9: error: implicit declaration of function __cvdso_clock_gettime32 arch/mips/vdso/vgettimeofday.c: In function __vdso_clock_getres: arch/mips/vdso/vgettimeofday.c:39:9: error: implicit declaration of function __cvdso_clock_getres_time32 Force the define for 32bit builds in the VDSO Makefile. Fixes: bf279849ad59 ("lib/vdso: Build 32 bit specific functions in the right context") Reported-by: kbuild test robot Signed-off-by: Thomas Gleixner Acked-by: Paul Burton Link: https://lore.kernel.org/r/87d0bjfaqa.fsf@nanos.tec.linutronix.de

mips/vdso: Support mremap() for vDSO

2020-01-15T18:44:14+00:00

vDSO VMA address is saved in mm_context for the purpose of using restorer from vDSO page to return to userspace after signal handling. In Checkpoint Restore in Userspace (CRIU) project we place vDSO VMA on restore back to the place where it was on the dump. Make vDSO code track the VMA address by supplying .mremap() fops the same way it's done for x86 and arm by: commit b059a453b1cf ("x86/vdso: Add mremap hook to vm_special_mapping") commit 739586951b8a ("arm64/vdso: Support mremap() for vDSO"). Signed-off-by: Guoyun Sun Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: Allison Randal Cc: Thomas Gleixner Cc: Greg Kroah-Hartman Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

mips: Fix gettimeofday() in the vdso library

2019-12-02T18:50:37+00:00

The libc provides a discovery mechanism for vDSO library and its symbols. When a symbol is not exposed by the vDSOs the libc falls back on the system calls. With the introduction of the unified vDSO library on mips this behavior is not honored anymore by the kernel in the case of gettimeofday(). The issue has been noticed and reported due to a dhclient failure on the CI20 board: root@letux:~# dhclient ../../../../lib/isc/unix/time.c:200: Operation not permitted root@letux:~# Restore the original behavior fixing gettimeofday() in the vDSO library. Reported-by: H. Nikolaus Schaller Tested-by: H. Nikolaus Schaller # CI20 with JZ4780 Signed-off-by: Vincenzo Frascino Signed-off-by: Paul Burton Cc: mips-creator-ci20-dev@googlegroups.com Cc: letux-kernel@openphoenux.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

MIPS: allow building with kcov coverage

2019-11-11T18:46:53+00:00

Add ARCH_HAS_KCOV and HAVE_GCC_PLUGINS to MIPS config. Disable instrumentation of vdso to avoid build failure. Signed-off-by: Alexey Khoroshilov Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org