kernel/linux.git/arch/arc/include/asm, 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

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

arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed

2020-11-16T15:57:18+00:00

Stefan Agner reported a bug when using zsram on 32-bit Arm machines with RAM above the 4GB address boundary: Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = a27bd01c [00000000] *pgd=236a0003, *pmd=1ffa64003 Internal error: Oops: 207 [#1] SMP ARM Modules linked in: mdio_bcm_unimac(+) brcmfmac cfg80211 brcmutil raspberrypi_hwmon hci_uart crc32_arm_ce bcm2711_thermal phy_generic genet CPU: 0 PID: 123 Comm: mkfs.ext4 Not tainted 5.9.6 #1 Hardware name: BCM2711 PC is at zs_map_object+0x94/0x338 LR is at zram_bvec_rw.constprop.0+0x330/0xa64 pc : [] lr : [] psr: 60000013 sp : e376bbe0 ip : 00000000 fp : c1e2921c r10: 00000002 r9 : c1dda730 r8 : 00000000 r7 : e8ff7a00 r6 : 00000000 r5 : 02f9ffa0 r4 : e3710000 r3 : 000fdffe r2 : c1e0ce80 r1 : ebf979a0 r0 : 00000000 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 30c5383d Table: 235c2a80 DAC: fffffffd Process mkfs.ext4 (pid: 123, stack limit = 0x495a22e6) Stack: (0xe376bbe0 to 0xe376c000) As it turns out, zsram needs to know the maximum memory size, which is defined in MAX_PHYSMEM_BITS when CONFIG_SPARSEMEM is set, or in MAX_POSSIBLE_PHYSMEM_BITS on the x86 architecture. The same problem will be hit on all 32-bit architectures that have a physical address space larger than 4GB and happen to not enable sparsemem and include asm/sparsemem.h from asm/pgtable.h. After the initial discussion, I suggested just always defining MAX_POSSIBLE_PHYSMEM_BITS whenever CONFIG_PHYS_ADDR_T_64BIT is set, or provoking a build error otherwise. This addresses all configurations that can currently have this runtime bug, but leaves all other configurations unchanged. I looked up the possible number of bits in source code and datasheets, here is what I found: - on ARC, CONFIG_ARC_HAS_PAE40 controls whether 32 or 40 bits are used - on ARM, CONFIG_LPAE enables 40 bit addressing, without it we never support more than 32 bits, even though supersections in theory allow up to 40 bits as well. - on MIPS, some MIPS32r1 or later chips support 36 bits, and MIPS32r5 XPA supports up to 60 bits in theory, but 40 bits are more than anyone will ever ship - On PowerPC, there are three different implementations of 36 bit addressing, but 32-bit is used without CONFIG_PTE_64BIT - On RISC-V, the normal page table format can support 34 bit addressing. There is no highmem support on RISC-V, so anything above 2GB is unused, but it might be useful to eventually support CONFIG_ZRAM for high pages. Fixes: 61989a80fb3a ("staging: zsmalloc: zsmalloc memory allocation library") Fixes: 02390b87a945 ("mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS") Acked-by: Thomas Bogendoerfer Reviewed-by: Stefan Agner Tested-by: Stefan Agner Acked-by: Mike Rapoport Link: https://lore.kernel.org/linux-mm/bdfa44bf1c570b05d6c70898e2bbb0acf234ecdf.1604762181.git.stefan@agner.ch/ Signed-off-by: Arnd Bergmann