kernel/linux.git/arch/arc/include, branch v5.10.257

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

2025-12-06T21:08:09+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

ARC: define ASM_NL and __ALIGN(_STR) outside #ifdef ASSEMBLY guard

2023-07-27T06:44:00+00:00

[ Upstream commit 92e2921eeafdfca9acd9b83f07d2b7ca099bac24 ] ASM_NL is useful not only in *.S files but also in .c files for using inline assembler in C code. On ARC, however, ASM_NL is evaluated inconsistently. It is expanded to a backquote (`) in *.S files, but a semicolon (;) in *.c files because arch/arc/include/asm/linkage.h defines it inside #ifdef __ASSEMBLY__, so the definition for C code falls back to the default value defined in include/linux/linkage.h. If ASM_NL is used in inline assembler in .c files, it will result in wrong assembly code because a semicolon is not an instruction separator, but the start of a comment for ARC. Move ASM_NL (also __ALIGN and __ALIGN_STR) out of the #ifdef. Fixes: 9df62f054406 ("arch: use ASM_NL instead of ';' for assembler new line character in the macro") Fixes: 8d92e992a785 ("ARC: define __ALIGN_STR and __ALIGN symbols for ARC") Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

arc: add support for TIF_NOTIFY_SIGNAL

2023-01-04T10:39:18+00:00

[ Upstream commit 53855e12588743ea128ee31f913d1c6e2f1d32c8 ] Wire up TIF_NOTIFY_SIGNAL handling for arc. Cc: linux-snps-arc@lists.infradead.org Acked-by: Vineet Gupta Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

arc: iounmap() arg is volatile

2022-11-03T14:57:51+00:00

[ Upstream commit c44f15c1c09481d50fd33478ebb5b8284f8f5edb ] Add 'volatile' to iounmap()'s argument to prevent build warnings. This make it the same as other major architectures. Placates these warnings: (12 such warnings) ../drivers/video/fbdev/riva/fbdev.c: In function 'rivafb_probe': ../drivers/video/fbdev/riva/fbdev.c:2067:42: error: passing argument 1 of 'iounmap' discards 'volatile' qualifier from pointer target type [-Werror=discarded-qualifiers] 2067 | iounmap(default_par->riva.PRAMIN); Fixes: 1162b0701b14b ("ARC: I/O and DMA Mappings") Signed-off-by: Randy Dunlap Cc: Vineet Gupta Cc: linux-snps-arc@lists.infradead.org Cc: Arnd Bergmann Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

ARCv2: save ABI registers across signal handling

2021-06-23T12:42:51+00:00

commit 96f1b00138cb8f04c742c82d0a7c460b2202e887 upstream. ARCv2 has some configuration dependent registers (r30, r58, r59) which could be targetted by the compiler. To keep the ABI stable, these were unconditionally part of the glibc ABI (sysdeps/unix/sysv/linux/arc/sys/ucontext.h:mcontext_t) however we missed populating them (by saving/restoring them across signal handling). This patch fixes the issue by - adding arcv2 ABI regs to kernel struct sigcontext - populating them during signal handling Change to struct sigcontext might seem like a glibc ABI change (although it primarily uses ucontext_t:mcontext_t) but the fact is - it has only been extended (existing fields are not touched) - the old sigcontext was ABI incomplete to begin with anyways Fixes: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/53 Cc: Tested-by: kernel test robot Reported-by: Vladimir Isaev Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

ARC: mm: PAE: use 40-bit physical page mask

2021-05-19T08:13:10+00:00

commit c5f756d8c6265ebb1736a7787231f010a3b782e5 upstream. 32-bit PAGE_MASK can not be used as a mask for physical addresses when PAE is enabled. PAGE_MASK_PHYS must be used for physical addresses instead of PAGE_MASK. Without this, init gets SIGSEGV if pte_modify was called: | potentially unexpected fatal signal 11. | Path: /bin/busybox | CPU: 0 PID: 1 Comm: init Not tainted 5.12.0-rc5-00003-g1e43c377a79f-dirty | Insn could not be fetched | @No matching VMA found | ECR: 0x00040000 EFA: 0x00000000 ERET: 0x00000000 | STAT: 0x80080082 [IE U ] BTA: 0x00000000 | SP: 0x5f9ffe44 FP: 0x00000000 BLK: 0xaf3d4 | LPS: 0x000d093e LPE: 0x000d0950 LPC: 0x00000000 | r00: 0x00000002 r01: 0x5f9fff14 r02: 0x5f9fff20 | ... | Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Signed-off-by: Vladimir Isaev Reported-by: kernel test robot Cc: Vineet Gupta Cc: stable@vger.kernel.org Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman

arch/arc: add copy_user_page() to to fix build error on ARC

2021-01-19T17:27:26+00:00

[ Upstream commit 8a48c0a3360bf2bf4f40c980d0ec216e770e58ee ] fs/dax.c uses copy_user_page() but ARC does not provide that interface, resulting in a build error. Provide copy_user_page() in . ../fs/dax.c: In function 'copy_cow_page_dax': ../fs/dax.c:702:2: error: implicit declaration of function 'copy_user_page'; did you mean 'copy_to_user_page'? [-Werror=implicit-function-declaration] Reported-by: kernel test robot Signed-off-by: Randy Dunlap Cc: Vineet Gupta Cc: linux-snps-arc@lists.infradead.org Cc: Dan Williams #Acked-by: Vineet Gupta # v1 Cc: Andrew Morton Cc: Matthew Wilcox Cc: Jan Kara Cc: linux-fsdevel@vger.kernel.org Cc: linux-nvdimm@lists.01.org #Reviewed-by: Ira Weiny # v2 Signed-off-by: Vineet Gupta Signed-off-by: Sasha Levin

local64.h: make mandatory

2021-01-12T19:18:16+00:00

[ Upstream commit 87dbc209ea04645fd2351981f09eff5d23f8e2e9 ] Make mandatory in include/asm-generic/Kbuild and remove all arch/*/include/asm/local64.h arch-specific files since they only #include . This fixes build errors on arch/c6x/ and arch/nios2/ for block/blk-iocost.c. Build-tested on 21 of 25 arch-es. (tools problems on the others) Yes, we could even rename to and change all #includes to use instead. Link: https://lkml.kernel.org/r/20201227024446.17018-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Suggested-by: Christoph Hellwig Reviewed-by: Masahiro Yamada Cc: Jens Axboe Cc: Ley Foon Tan Cc: Mark Salter Cc: Aurelien Jacquiot Cc: Peter Zijlstra Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

Merge tag 'asm-generic-fixes-5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2020-11-27T23:00:35+00:00

Pull asm-generic fix from Arnd Bergmann: "Add correct MAX_POSSIBLE_PHYSMEM_BITS setting to asm-generic. This is a single bugfix for a bug that Stefan Agner found on 32-bit Arm, but that exists on several other architectures" * tag 'asm-generic-fixes-5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed

ARC: bitops: Remove unecessary operation and value

2020-11-18T04:10:21+00:00

The 1-bit shift rotation to the left on x variable located on 4 last if statement can be removed because the computed value is will not be used afront. Signed-off-by: Gustavo Pimentel Signed-off-by: Vineet Gupta