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2019-10-10mips: Fix unroll macro when building with ClangNathan Chancellor
Building with Clang errors after commit 6baaeadae911 ("MIPS: Provide unroll() macro, use it for cache ops") since the GCC_VERSION macro is defined in include/linux/compiler-gcc.h, which is only included in compiler.h when using GCC: In file included from arch/mips/kernel/mips-mt.c:20: ./arch/mips/include/asm/r4kcache.h:254:1: error: use of undeclared identifier 'GCC_VERSION'; did you mean 'S_VERSION'? __BUILD_BLAST_CACHE(i, icache, Index_Invalidate_I, Hit_Invalidate_I, 32, ) ^ ./arch/mips/include/asm/r4kcache.h:219:4: note: expanded from macro '__BUILD_BLAST_CACHE' cache_unroll(32, kernel_cache, indexop, ^ ./arch/mips/include/asm/r4kcache.h:203:2: note: expanded from macro 'cache_unroll' unroll(times, _cache_op, insn, op, (addr) + (i++ * (lsize))); ^ ./arch/mips/include/asm/unroll.h:28:15: note: expanded from macro 'unroll' BUILD_BUG_ON(GCC_VERSION >= 40700 && \ ^ Use CONFIG_GCC_VERSION, which will always be set by Kconfig. Additionally, Clang 8 had improvements around __builtin_constant_p so use that as a lower limit for this check with Clang (although MIPS wasn't buildable until Clang 9); building a kernel with Clang 9.0.0 has no issues after this change. Fixes: 6baaeadae911 ("MIPS: Provide unroll() macro, use it for cache ops") Link: https://github.com/ClangBuiltLinux/linux/issues/736 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Cc: Nick Desaulniers <ndesaulniers@google.com>
2019-10-10MIPS: cmdline: Clean up boot_command_line initializationPaul Burton
Our current code to initialize boot_command_line is a mess. Some of this is due to the addition of too many options over the years, and some of this is due to workarounds for early_init_dt_scan_chosen() performing actions specific to options from other architectures that probably shouldn't be in generic code. Clean this up by introducing a new bootcmdline_init() function that simplifies the initialization somewhat. The major changes are: - Because bootcmdline_init() is a function it can return early in the CONFIG_CMDLINE_OVERRIDE case. - We clear boot_command_line rather than inheriting whatever early_init_dt_scan_chosen() may have left us. This means we no longer need to set boot_command_line to a space character in an attempt to prevent early_init_dt_scan_chosen() from copying CONFIG_CMDLINE into boot_command_line without us knowing about it. - Indirection via USE_PROM_CMDLINE, USE_DTB_CMDLINE, EXTEND_WITH_PROM & BUILTIN_EXTEND_WITH_PROM macros is removed; they seemingly served only to obfuscate the code. - The logic is cleaner, clearer & commented. Two minor drawbacks of this approach are: 1) We call of_scan_flat_dt(), which means we scan through the DT again. The overhead is fairly minimal & shouldn't be noticeable. 2) cmdline_scan_chosen() duplicates a small amount of the logic from early_init_dt_scan_chosen(). Alternatives might be to allow the generic FDT code to keep & expose a copy of the arguments taken from the /chosen node's bootargs property, or to introduce a function like early_init_dt_scan_chosen() that retrieves them without modification to handle CONFIG_CMDLINE. Neither of these sounds particularly cleaner though, and this way we at least keep the extra work in arch/mips. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org
2019-10-09MIPS: cmdline: Remove redundant Kconfig defaultsPaul Burton
CMDLINE, CMDLINE_BOOL & CMDLINE_FORCE all explicitly specify default values that are the same as the default value for their respective types anyway (ie. n for booleans, and the empty string for strings). Remove the redundant defaults. Signed-off-by: Paul Burton <paul.burton@mips.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Cc: linux-mips@vger.kernel.org
2019-10-09MIPS: SGI-IP22/28: Use PROM for memory detectionThomas Bogendoerfer
EARLY_PRINTK uses ArcWrite (via prom_putchar) on IP22/28, which needs to not mess up PROMs data structures. ARC PROM gives out a list of memory chunks, which are used and which are free. This fixes the problem of not working early printk. By using XKPHYS spaces more than 256MB memory on Indigo2 R4k machines is working now, too. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-09MIPS: SGI-IP22: set PHYS_OFFSET to memory startThomas Bogendoerfer
IP22 started at physical 0x08000000. To avoid wasting memory for page structs set PHYS_OFFSET. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-09MIPS: fw: arc: workaround 64bit kernel/32bit ARC problemsThomas Bogendoerfer
Pointer arguments for 32bit ARC PROMs must reside in CKSEG0/1. While the initial stack resides in CKSEG0 the first kernel thread stack is already placed at a XKPHYS address, which ARC32 can't handle. The workaround here is to use static variables, which are placed into BSS and linked to a CKSEG0 address. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-09MIPS: Kconfig: always select ARC_MEMORY and ARC_PROMLIB for platformThomas Bogendoerfer
Instead of having a default y option with depends simply select options for the platforms where they are needed. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-09MIPS: fw: arc: use call_o32 to call ARC prom from 64bit kernelThomas Bogendoerfer
When using a 64bit kernel with generic spaces setup stack is also placed in XKPYHS, which the 32bit PROM can't handle. By using call_o32 for ARC_CALLs a stack placed in KSEG0 is used when calling PROM. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-09MIPS: fw: arc: remove unused ARC codeThomas Bogendoerfer
Current kernel uses only a few ARC calls. Drop all unused ARC functions. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-09MIPS: Drop 32-bit asm string functionsPaul Burton
We have assembly implementations of strcpy(), strncpy(), strcmp() & strncmp() which: - Are simple byte-at-a-time loops with no particular optimizations. As a comment in the code describes, they're "rather naive". - Offer no clear performance advantage over the generic C implementations - in microbenchmarks performed by Alexander Lobakin the asm functions sometimes win & sometimes lose, but generally not by large margins in either direction. - Don't support 64-bit kernels, where we already make use of the generic C implementations. - Tend to bloat kernel code size due to inlining. - Don't support CONFIG_FORTIFY_SOURCE. - Won't support nanoMIPS without rework. For all of these reasons, delete the asm implementations & make use of the generic C implementations for 32-bit kernels just like we already do for 64-bit kernels. Signed-off-by: Paul Burton <paul.burton@mips.com> URL: https://lore.kernel.org/linux-mips/a2a35f1cf58d6db19eb4af9b4ae21e35@dlink.ru/ Cc: Alexander Lobakin <alobakin@dlink.ru> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Cc: linux-mips@vger.kernel.org
2019-10-09MIPS: Provide unroll() macro, use it for cache opsPaul Burton
Currently we have a lot of duplication in asm/r4kcache.h to handle manually unrolling loops of cache ops for various line sizes, and we have to explicitly handle the difference in cache op immediate width between MIPSr6 & earlier ISA revisions with further duplication. Introduce an unroll() macro in asm/unroll.h which expands to a switch statement which is used to call a function or expand a preprocessor macro a compile-time constant number of times in a row - effectively explicitly unrolling a loop. We make use of this here to remove the cache op duplication & will use it further in later patches. A nice side effect of this is that calculating the cache op offset immediate is now the compiler's responsibility, so we're no longer sensitive to the width change of that immediate in MIPSr6 & will be similarly agnostic to immediate width in any future supported ISA. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org
2019-10-08MIPS: generic: Use __initconst for const init dataTiezhu Yang
Fix the following checkpatch errors: $ ./scripts/checkpatch.pl --no-tree -f arch/mips/generic/init.c ERROR: Use of const init definition must use __initconst #23: FILE: arch/mips/generic/init.c:23: +static __initdata const void *fdt; ERROR: Use of const init definition must use __initconst #24: FILE: arch/mips/generic/init.c:24: +static __initdata const struct mips_machine *mach; ERROR: Use of const init definition must use __initconst #25: FILE: arch/mips/generic/init.c:25: +static __initdata const void *mach_match_data; Fixes: eed0eabd12ef ("MIPS: generic: Introduce generic DT-based board support") Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: futex: Restore \n after sync instructionsPaul Burton
Commit 3c1d3f097972 ("MIPS: futex: Emit Loongson3 sync workarounds within asm") inadvertently removed the newlines following __WEAK_LLSC_MB, which causes build failures for configurations in which __WEAK_LLSC_MB expands to a sync instruction: {standard input}: Assembler messages: {standard input}:9346: Error: symbol `sync3' is already defined {standard input}:9380: Error: symbol `sync3' is already defined ... Fix this by restoring the newlines to separate the sync instruction from anything following it (such as the 3: label), preventing inadvertent concatenation. Signed-off-by: Paul Burton <paul.burton@mips.com> Fixes: 3c1d3f097972 ("MIPS: futex: Emit Loongson3 sync workarounds within asm")
2019-10-07mips: check for dsp presence only once before save/restoreAurabindo Jayamohanan
{save,restore}_dsp() internally checks if the cpu has dsp support. Therefore, explicit check is not required before calling them in {save,restore}_processor_state() Signed-off-by: Aurabindo Jayamohanan <mail@aurabindo.in> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: alexios.zavras@intel.com Cc: gregkh@linuxfoundation.org Cc: armijn@tjaldur.nl Cc: allison@lohutok.net Cc: tglx@linutronix.de Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: PCI: use information from 1-wire PROM for IOC3 detectionThomas Bogendoerfer
IOC3 chips in SGI system are conntected to a bridge ASIC, which has a 1-wire prom attached with part number information. This changeset uses this information to create PCI subsystem information, which the MFD driver uses for further platform device setup. Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Lee Jones <lee.jones@linaro.org> Cc: David S. Miller <davem@davemloft.net> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-rtc@vger.kernel.org Cc: linux-serial@vger.kernel.org
2019-10-07nvmem: core: add nvmem_device_findThomas Bogendoerfer
nvmem_device_find provides a way to search for nvmem devices with the help of a match function simlair to bus_find_device. Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Lee Jones <lee.jones@linaro.org> Cc: David S. Miller <davem@davemloft.net> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@vger.kernel.org Cc: netdev@vger.kernel.org Cc: linux-rtc@vger.kernel.org Cc: linux-serial@vger.kernel.org
2019-10-07MIPS: CI20: DTS: Add LedsAlexandre GRIVEAUX
Adding leds and related triggers. Signed-off-by: Alexandre GRIVEAUX <agriveaux@deutnet.info> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: robh+dt@kernel.org Cc: mark.rutland@arm.com Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: devicetree@vger.kernel.org
2019-10-07MIPS: CI20: DTS: Add IW8103 Wifi + bluetoothAlexandre GRIVEAUX
Add IW8103 Wifi + bluetooth module to device tree and related power domain. Signed-off-by: Alexandre GRIVEAUX <agriveaux@deutnet.info> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: robh+dt@kernel.org Cc: mark.rutland@arm.com Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: devicetree@vger.kernel.org
2019-10-07MIPS: CI20: DTS: Add I2C nodesAlexandre GRIVEAUX
Adding missing I2C nodes and some peripheral: - PMU - RTC Signed-off-by: Alexandre GRIVEAUX <agriveaux@deutnet.info> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: robh+dt@kernel.org Cc: mark.rutland@arm.com Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: devicetree@vger.kernel.org
2019-10-07MIPS: JZ4780: DTS: Add I2C nodesAlexandre GRIVEAUX
Add the devicetree nodes for the I2C core of the JZ4780 SoC, disabled by default. Signed-off-by: Alexandre GRIVEAUX <agriveaux@deutnet.info> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: robh+dt@kernel.org Cc: mark.rutland@arm.com Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: devicetree@vger.kernel.org
2019-10-07mips: Kconfig: Add ARCH_HAS_FORTIFY_SOURCEDmitry Korotin
FORTIFY_SOURCE detects various overflows at compile and run time. (6974f0c4555e ("include/linux/string.h: add the option of fortified string.h functions) ARCH_HAS_FORTIFY_SOURCE means that the architecture can be built and run with CONFIG_FORTIFY_SOURCE. Since mips can be built and run with that flag, select ARCH_HAS_FORTIFY_SOURCE as default. Signed-off-by: Dmitry Korotin <dkorotin@wavecomp.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org
2019-10-07MIPS: Loongson-3: Add CSR IPI supportHuacai Chen
CSR IPI and legacy MMIO use the same infrastructure, but CSR IPI is faster than legacy MMIO IPI. This patch enable CSR IPI if possible (except for MailBox, because CSR IPI is too complicated for MailBox). Signed-off-by: Huacai Chen <chenhc@lemote.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: linux-mips@vger.kernel.org Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: Huacai Chen <chenhuacai@gmail.com>
2019-10-07MIPS: Loongson: Add Loongson-3A R4 basic supportHuacai Chen
All Loongson-3 CPU family: Code-name Brand-name PRId Loongson-3A R1 Loongson-3A1000 0x6305 Loongson-3A R2 Loongson-3A2000 0x6308 Loongson-3A R2.1 Loongson-3A2000 0x630c Loongson-3A R3 Loongson-3A3000 0x6309 Loongson-3A R3.1 Loongson-3A3000 0x630d Loongson-3A R4 Loongson-3A4000 0xc000 Loongson-3B R1 Loongson-3B1000 0x6306 Loongson-3B R2 Loongson-3B1500 0x6307 Features of R4 revision of Loongson-3A: - All R2/R3 features, including SFB, V-Cache, FTLB, RIXI, DSP, etc. - Support variable ASID bits. - Support MSA and VZ extensions. - Support CPUCFG (CPU config) and CSR (Control and Status Register) extensions. - 64 entries of VTLB (classic TLB), 2048 entries of FTLB (8-way set-associative). Now 64-bit Loongson processors has three types of PRID.IMP: 0x6300 is the classic one so we call it PRID_IMP_LOONGSON_64C (e.g., Loongson-2E/ 2F/3A1000/3B1000/3B1500/3A2000/3A3000), 0x6100 is for some processors which has reduced capabilities so we call it PRID_IMP_LOONGSON_64R (e.g., Loongson-2K), 0xc000 is supposed to cover all new processors in general (e.g., Loongson-3A4000+) so we call it PRID_IMP_LOONGSON_64G. Signed-off-by: Huacai Chen <chenhc@lemote.com> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: linux-mips@vger.kernel.org Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: Huacai Chen <chenhuacai@gmail.com>
2019-10-07MIPS: Loongson: Add CFUCFG&CSR supportHuacai Chen
Loongson-3A R4+ (Loongson-3A4000 and newer) has CPUCFG (CPU config) and CSR (Control and Status Register) extensions. This patch add read/write functionalities for them. Signed-off-by: Huacai Chen <chenhc@lemote.com> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@linux-mips.org Cc: linux-mips@vger.kernel.org Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Cc: Huacai Chen <chenhuacai@gmail.com>
2019-10-07mips: sgi-ip27: switch from DISCONTIGMEM to SPARSEMEMMike Rapoport
The memory initialization of SGI-IP27 is already half-way to support SPARSEMEM. It only had free_bootmem_with_active_regions() left-overs interfering with sparse_memory_present_with_active_regions(). Replace these calls with simpler memblocks_present() call in prom_meminit() and adjust arch/mips/Kconfig to enable SPARSEMEM and SPARSEMEM_EXTREME for SGI-IP27. Co-developed-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: Check Loongson3 LL/SC errata workaround correctnessPaul Burton
When Loongson3 LL/SC errata workarounds are enabled (ie. CONFIG_CPU_LOONGSON3_WORKAROUNDS=y) run a tool to scan through the compiled kernel & ensure that the workaround is applied correctly. That is, ensure that: - Every LL or LLD instruction is preceded by a sync instruction. - Any branches from within an LL/SC loop to outside of that loop target a sync instruction. Reasoning for these conditions can be found by reading the comment above the definition of __SYNC_loongson3_war in arch/mips/include/asm/sync.h. This tool will help ensure that we don't inadvertently introduce code paths that miss the required workarounds. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: genex: Don't reload address unnecessarilyPaul Burton
In ejtag_debug_handler() we must reload the address of ejtag_debug_buffer_spinlock if an sc fails, since the address in k0 will have been clobbered by the result of the sc instruction. In the case where we simply load a non-zero value (ie. there's contention for the lock) the address will not be clobbered & we can simply branch back to repeat the load from memory without reloading the address into k0. The primary motivation for this change is that it moves the target of the bnez instruction to an instruction within the LL/SC loop (the LL itself), which we know contains no other memory accesses & therefore isn't affected by Loongson3 LL/SC errata. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: genex: Add Loongson3 LL/SC workaround to ejtag_debug_handlerPaul Burton
In ejtag_debug_handler we use LL & SC instructions to acquire & release an open-coded spinlock. For Loongson3 systems affected by LL/SC errata this requires that we insert a sync instruction prior to the LL in order to ensure correct behavior of the LL/SC loop. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: barrier: Make __smp_mb__before_atomic() a no-op for Loongson3Paul Burton
Loongson3 systems with CONFIG_CPU_LOONGSON3_WORKAROUNDS enabled already emit a full completion barrier as part of the inline assembly containing LL/SC loops for atomic operations. As such the barrier emitted by __smp_mb__before_atomic() is redundant, and we can remove it. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: barrier: Remove loongson_llsc_mb()Paul Burton
The loongson_llsc_mb() macro is no longer used - instead barriers are emitted as part of inline asm using the __SYNC() macro. Remove the now-defunct loongson_llsc_mb() macro. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: syscall: Emit Loongson3 sync workarounds within asmPaul Burton
Generate the sync instructions required to workaround Loongson3 LL/SC errata within inline asm blocks, which feels a little safer than doing it from C where strictly speaking the compiler would be well within its rights to insert a memory access between the separate asm statements we previously had, containing sync & ll instructions respectively. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: futex: Emit Loongson3 sync workarounds within asmPaul Burton
Generate the sync instructions required to workaround Loongson3 LL/SC errata within inline asm blocks, which feels a little safer than doing it from C where strictly speaking the compiler would be well within its rights to insert a memory access between the separate asm statements we previously had, containing sync & ll instructions respectively. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: cmpxchg: Omit redundant barriers for Loongson3Paul Burton
When building a kernel configured to support Loongson3 LL/SC workarounds (ie. CONFIG_CPU_LOONGSON3_WORKAROUNDS=y) the inline assembly in __xchg_asm() & __cmpxchg_asm() already emits completion barriers, and as such we don't need to emit extra barriers from the xchg() or cmpxchg() macros. Add compile-time constant checks causing us to omit the redundant memory barriers. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: cmpxchg: Emit Loongson3 sync workarounds within asmPaul Burton
Generate the sync instructions required to workaround Loongson3 LL/SC errata within inline asm blocks, which feels a little safer than doing it from C where strictly speaking the compiler would be well within its rights to insert a memory access between the separate asm statements we previously had, containing sync & ll instructions respectively. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Use smp_mb__before_atomic in test_* opsPaul Burton
Use smp_mb__before_atomic() rather than smp_mb__before_llsc() in test_and_set_bit(), test_and_clear_bit() & test_and_change_bit(). The _atomic() versions make semantic sense in these cases, and will allow a later patch to omit redundant barriers for Loongson3 systems that already include a barrier within __test_bit_op(). Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Emit Loongson3 sync workarounds within asmPaul Burton
Generate the sync instructions required to workaround Loongson3 LL/SC errata within inline asm blocks, which feels a little safer than doing it from C where strictly speaking the compiler would be well within its rights to insert a memory access between the separate asm statements we previously had, containing sync & ll instructions respectively. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Use BIT_WORD() & BITS_PER_LONGPaul Burton
Rather than using custom SZLONG_LOG & SZLONG_MASK macros to shift & mask a bit index to form word & bit offsets respectively, make use of the standard BIT_WORD() & BITS_PER_LONG macros for the same purpose. volatile is added to the definition of pointers to the long-sized word we'll operate on, in order to prevent the compiler complaining that we cast away the volatile qualifier of the addr argument. This should have no effect on generated code, which in the LL/SC case is inline asm anyway & in the non-LLSC case access is constrained by compiler barriers provided by raw_local_irq_{save,restore}(). Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Abstract LL/SC loopsPaul Burton
Introduce __bit_op() & __test_bit_op() macros which abstract away the implementation of LL/SC loops. This cuts down on a lot of duplicate boilerplate code, and also allows R10000_LLSC_WAR to be handled outside of the individual bitop functions. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Avoid redundant zero-comparison for non-LLSCPaul Burton
The IRQ-disabling non-LLSC fallbacks for bitops on UP systems already return a zero or one, so there's no need to perform another comparison against zero. Move these comparisons into the LLSC paths to avoid the redundant work. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Use the BIT() macroPaul Burton
Use the BIT() macro in asm/bitops.h rather than open-coding its equivalent. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Allow immediates in test_and_{set,clear,change}_bitPaul Burton
The logical operations or & xor used in the test_and_set_bit_lock(), test_and_clear_bit() & test_and_change_bit() functions currently force the value 1<<bit to be placed in a register. If the bit is compile-time constant & fits within the immediate field of an or/xor instruction (ie. 16 bits) then we can make use of the ori/xori instruction variants & avoid the use of an extra register. Add the extra "i" constraints in order to allow use of these immediate encodings. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Implement test_and_set_bit() in terms of _lock variantPaul Burton
The only difference between test_and_set_bit() & test_and_set_bit_lock() is memory ordering barrier semantics - the former provides a full barrier whilst the latter only provides acquire semantics. We can therefore implement test_and_set_bit() in terms of test_and_set_bit_lock() with the addition of the extra memory barrier. Do this in order to avoid duplicating logic. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: ins start position is always an immediatePaul Burton
The start position for an ins instruction is always encoded as an immediate, so allowing registers to be used by the inline asm makes no sense. It should never happen anyway since a bit index should always be small enough to be treated as an immediate, but remove the nonsensical "r" for sanity. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Use MIPS_ISA_REV, not #ifdefsPaul Burton
Rather than #ifdef on CONFIG_CPU_* to determine whether the ins instruction is supported we can simply check MIPS_ISA_REV to discover whether we're targeting MIPSr2 or higher. Do so in order to clean up the code. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Only use ins for bit 16 or higherPaul Burton
set_bit() can set bits 0-15 using an ori instruction, rather than loading the value -1 into a register & then using an ins instruction. That is, rather than the following: li t0, -1 ll t1, 0(t2) ins t1, t0, 4, 1 sc t1, 0(t2) We can have the simpler: ll t1, 0(t2) ori t1, t1, 0x10 sc t1, 0(t2) The or path already allows immediates to be used, so simply restricting the ins path to bits that don't fit in immediates is sufficient to take advantage of this. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: bitops: Handle !kernel_uses_llsc firstPaul Burton
Reorder conditions in our various bitops functions that check kernel_uses_llsc such that they handle the !kernel_uses_llsc case first. This allows us to avoid the need to duplicate the kernel_uses_llsc check in all the other cases. For functions that don't involve barriers common to the various implementations, we switch to returning from within each if block making each case easier to read in isolation. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: atomic: Deduplicate 32b & 64b read, set, xchg, cmpxchgPaul Burton
Remove the remaining duplication between 32b & 64b in asm/atomic.h by making use of an ATOMIC_OPS() macro to generate: - atomic_read()/atomic64_read() - atomic_set()/atomic64_set() - atomic_cmpxchg()/atomic64_cmpxchg() - atomic_xchg()/atomic64_xchg() This is consistent with the way all other functions in asm/atomic.h are generated, and ensures consistency between the 32b & 64b functions. Of note is that this results in the above now being static inline functions rather than macros. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: atomic: Unify 32b & 64b sub_if_positivePaul Burton
Unify the definitions of atomic_sub_if_positive() & atomic64_sub_if_positive() using a macro like we do for most other atomic functions. This allows us to share the implementation ensuring consistency between the two. Notably this provides the appropriate loongson3_war barriers in the atomic64_sub_if_positive() case which were previously missing. The code is rearranged a little to handle the !kernel_uses_llsc case first in order to de-indent the LL/SC case & allow us not to go over 80 characters per line. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: atomic: Use _atomic barriers in atomic_sub_if_positive()Paul Burton
Use smp_mb__before_atomic() & smp_mb__after_atomic() in atomic_sub_if_positive() rather than the equivalent smp_mb__before_llsc() & smp_llsc_mb(). The former are more standard & this preps us for avoiding redundant duplicate barriers on Loongson3 in a later patch. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org
2019-10-07MIPS: atomic: Emit Loongson3 sync workarounds within asmPaul Burton
Generate the sync instructions required to workaround Loongson3 LL/SC errata within inline asm blocks, which feels a little safer than doing it from C where strictly speaking the compiler would be well within its rights to insert a memory access between the separate asm statements we previously had, containing sync & ll instructions respectively. Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org