kernel/linux.git/arch/arc, branch v6.6.132

arc: Fix fls() const-foldability via builtin_clzl()

2025-11-24T09:29:18+00:00

[ Upstream commit a3fecb9160482367365cc384c59dd220b162b066 ] While tracking down a problem where constant expressions used by BUILD_BUG_ON() suddenly stopped working[1], we found that an added static initializer was convincing the compiler that it couldn't track the state of the prior statically initialized value. Tracing this down found that ffs() was used in the initializer macro, but since it wasn't marked with __attribute__const__, the compiler had to assume the function might change variable states as a side-effect (which is not true for ffs(), which provides deterministic math results). For arc architecture with CONFIG_ISA_ARCV2=y, the __fls() function uses __builtin_arc_fls() which lacks GCC's const attribute, preventing compile-time constant folding, and KUnit testing of ffs/fls fails on arc[3]. A patch[2] to GCC to solve this has been sent. Add a fix for this by handling compile-time constants with the standard __builtin_clzl() builtin (which has const attribute) while preserving the optimized arc-specific builtin for runtime cases. This has the added benefit of skipping runtime calculation of compile-time constant values. Even with the GCC bug fixed (which is about "attribute const") this is a good change to avoid needless runtime costs, and should be done regardless of the state of GCC's bug. Build tested ARCH=arc allyesconfig with GCC arc-linux 15.2.0. Link: https://github.com/KSPP/linux/issues/364 [1] Link: https://gcc.gnu.org/pipermail/gcc-patches/2025-August/693273.html Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202508031025.doWxtzzc-lkp@intel.com/ [3] Signed-off-by: Kees Cook Acked-by: Vineet Gupta Signed-off-by: Yury Norov (NVIDIA) Signed-off-by: Sasha Levin

arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c

2025-11-02T13:14:41+00:00

[ Upstream commit 35561bab768977c9e05f1f1a9bc00134c85f3e28 ] The include/generated/asm-offsets.h is generated in Kbuild during compiling from arch/SRCARCH/kernel/asm-offsets.c. When we want to generate another similar offset header file, circular dependency can happen. For example, we want to generate a offset file include/generated/test.h, which is included in include/sched/sched.h. If we generate asm-offsets.h first, it will fail, as include/sched/sched.h is included in asm-offsets.c and include/generated/test.h doesn't exist; If we generate test.h first, it can't success neither, as include/generated/asm-offsets.h is included by it. In x86_64, the macro COMPILE_OFFSETS is used to avoid such circular dependency. We can generate asm-offsets.h first, and if the COMPILE_OFFSETS is defined, we don't include the "generated/test.h". And we define the macro COMPILE_OFFSETS for all the asm-offsets.c for this purpose. Signed-off-by: Menglong Dong Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Sasha Levin

ARC: build: Try to guess GCC variant of cross compiler

2025-01-09T12:32:05+00:00

[ Upstream commit 824927e88456331c7a999fdf5d9d27923b619590 ] ARC GCC compiler is packaged starting from Fedora 39i and the GCC variant of cross compile tools has arc-linux-gnu- prefix and not arc-linux-. This is causing that CROSS_COMPILE variable is left unset. This change allows builds without need to supply CROSS_COMPILE argument if distro package is used. Before this change: $ make -j 128 ARCH=arc W=1 drivers/infiniband/hw/mlx4/ gcc: warning: ‘-mcpu=’ is deprecated; use ‘-mtune=’ or ‘-march=’ instead gcc: error: unrecognized command-line option ‘-mmedium-calls’ gcc: error: unrecognized command-line option ‘-mlock’ gcc: error: unrecognized command-line option ‘-munaligned-access’ [1] https://packages.fedoraproject.org/pkgs/cross-gcc/gcc-arc-linux-gnu/index.html Signed-off-by: Leon Romanovsky Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

of/fdt: add dt_phys arg to early_init_dt_scan and early_init_dt_verify

2024-12-09T09:31:56+00:00

[ Upstream commit b2473a359763e27567993e7d8f37de82f57a0829 ] __pa() is only intended to be used for linear map addresses and using it for initial_boot_params which is in fixmap for arm64 will give an incorrect value. Hence save the physical address when it is known at boot time when calling early_init_dt_scan for arm64 and use it at kexec time instead of converting the virtual address using __pa(). Note that arm64 doesn't need the FDT region reserved in the DT as the kernel explicitly reserves the passed in FDT. Therefore, only a debug warning is fixed with this change. Reported-by: Breno Leitao Suggested-by: Mark Rutland Signed-off-by: Usama Arif Fixes: ac10be5cdbfa ("arm64: Use common of_kexec_alloc_and_setup_fdt()") Link: https://lore.kernel.org/r/20241023171426.452688-1-usamaarif642@gmail.com Signed-off-by: Rob Herring (Arm) Signed-off-by: Sasha Levin

ARC: [plat-hsdk]: Remove misplaced interrupt-cells property

2024-05-02T14:32:33+00:00

[ Upstream commit 61231eb8113ce47991f35024f9c20810b37996bf ] "gmac" node stands for just an ordinary Ethernet controller, which is by no means a provider of interrupts, i.e. it doesn't serve as an interrupt controller, thus "#interrupt-cells" property doesn't belong to it and so we remove it. Fixes: ------------>8------------ DTC arch/arc/boot/dts/hsdk.dtb arch/arc/boot/dts/hsdk.dts:207.23-235.5: Warning (interrupt_provider): /soc/ethernet@8000: '#interrupt-cells' found, but node is not an interrupt provider arch/arc/boot/dts/hsdk.dtb: Warning (interrupt_map): Failed prerequisite 'interrupt_provider' ------------>8------------ Reported-by: Vineet Gupta Signed-off-by: Alexey Brodkin Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

work around gcc bugs with 'asm goto' with outputs

2024-02-23T08:24:47+00:00

commit 4356e9f841f7fbb945521cef3577ba394c65f3fc upstream. We've had issues with gcc and 'asm goto' before, and we created a 'asm_volatile_goto()' macro for that in the past: see commits 3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation bug") and a9f180345f53 ("compiler/gcc4: Make quirk for asm_volatile_goto() unconditional"). Then, much later, we ended up removing the workaround in commit 43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR 58670") because we no longer supported building the kernel with the affected gcc versions, but we left the macro uses around. Now, Sean Christopherson reports a new version of a very similar problem, which is fixed by re-applying that ancient workaround. But the problem in question is limited to only the 'asm goto with outputs' cases, so instead of re-introducing the old workaround as-is, let's rename and limit the workaround to just that much less common case. It looks like there are at least two separate issues that all hit in this area: (a) some versions of gcc don't mark the asm goto as 'volatile' when it has outputs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 which is easy to work around by just adding the 'volatile' by hand. (b) Internal compiler errors: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 which are worked around by adding the extra empty 'asm' as a barrier, as in the original workaround. but the problem Sean sees may be a third thing since it involves bad code generation (not an ICE) even with the manually added 'volatile'. but the same old workaround works for this case, even if this feels a bit like voodoo programming and may only be hiding the issue. Reported-and-tested-by: Sean Christopherson Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Cc: Nick Desaulniers Cc: Uros Bizjak Cc: Jakub Jelinek Cc: Andrew Pinski Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: Introduce flush_cache_vmap_early()

2024-02-16T18:10:52+00:00

[ Upstream commit 7a92fc8b4d20680e4c20289a670d8fca2d1f2c1b ] The pcpu setup when using the page allocator sets up a new vmalloc mapping very early in the boot process, so early that it cannot use the flush_cache_vmap() function which may depend on structures not yet initialized (for example in riscv, we currently send an IPI to flush other cpus TLB). But on some architectures, we must call flush_cache_vmap(): for example, in riscv, some uarchs can cache invalid TLB entries so we need to flush the new established mapping to avoid taking an exception. So fix this by introducing a new function flush_cache_vmap_early() which is called right after setting the new page table entry and before accessing this new mapping. This new function implements a local flush tlb on riscv and is no-op for other architectures (same as today). Signed-off-by: Alexandre Ghiti Acked-by: Geert Uytterhoeven Signed-off-by: Dennis Zhou Stable-dep-of: d9807d60c145 ("riscv: mm: execute local TLB flush after populating vmemmap") Signed-off-by: Sasha Levin

ARC: fix smatch warning

2024-01-20T10:51:44+00:00

[ Upstream commit 4eb69d00fe967699b9d93f7e74a990fe813e8d2b ] Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/r/202311280906.VAIwEAfT-lkp@intel.com/ Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

ARC: fix spare error

2024-01-20T10:51:44+00:00

[ Upstream commit aca02d933f63ba8bc84258bf35f9ffaf6b664336 ] Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202312082320.VDN5A9hb-lkp@intel.com/ Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

Merge tag 'arc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

2023-09-04T22:38:24+00:00

Pull ARC updates from Vineet Gupta: - fixes for -Wmissing-prototype warnings - missing compiler barrier in relaxed atomics - some uaccess simplification, declutter - removal of massive glocal struct cpuinfo_arc from bootlog code - __switch_to consolidation (removal of inline asm variant) - use GP to cache task pointer (vs. r25) - misc rework of entry code * tag 'arc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (24 commits) ARC: boot log: fix warning arc: Explicitly include correct DT includes ARC: pt_regs: create seperate type for ecr ARCv2: entry: rearrange pt_regs slightly ARC: entry: replace 8 byte ADD.ne with 4 byte ADD2.ne ARC: entry: replace 8 byte OR with 4 byte BSET ARC: entry: Add more common chores to EXCEPTION_PROLOGUE ARC: entry: EV_MachineCheck dont re-read ECR ARC: entry: ARcompact EV_ProtV to use r10 directly ARC: entry: rework (non-functional) ARC: __switch_to: move ksp to thread_info from thread_struct ARC: __switch_to: asm with dwarf ops (vs. inline asm) ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp ARC: entry: use gp to cache task pointer (vs. r25) ARC: boot log: eliminate struct cpuinfo_arc #4: boot log per ISA ARC: boot log: eliminate struct cpuinfo_arc #3: don't export ARC: boot log: eliminate struct cpuinfo_arc #2: cache ARC: boot log: eliminate struct cpuinfo_arc #1: mm ARCv2: memset: don't prefetch for len == 0 which happens a alot ARC: uaccess: elide unaliged handling if hardware supports ...

kernel/linux.git/arch/arc, branch v6.6.132

arc: Fix __fls() const-foldability via __builtin_clzl()

arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c

ARC: build: Try to guess GCC variant of cross compiler

of/fdt: add dt_phys arg to early_init_dt_scan and early_init_dt_verify

ARC: [plat-hsdk]: Remove misplaced interrupt-cells property

work around gcc bugs with 'asm goto' with outputs

mm: Introduce flush_cache_vmap_early()

ARC: fix smatch warning

ARC: fix spare error

Merge tag 'arc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

arc: Fix fls() const-foldability via builtin_clzl()