kernel/linux.git/arch/mips/include/asm/cpu.h, branch linux-5.9.y

MIPS: handle Loongson-specific GSExc exception

2020-07-31T15:52:47+00:00

Newer Loongson cores (Loongson-3A R2 and newer) use the implementation-dependent ExcCode 16 to signal Loongson-specific exceptions. The extended cause is put in the non-standard CP0.Diag1 register which is CP0 Register 22 Select 1, called GSCause in Loongson manuals. Inside is an exception code bitfield called GSExcCode, only codes 0 to 6 inclusive are documented (so far, in the Loongson 3A3000 User Manual, Volume 2). During experiments, it was found that some undocumented unprivileged instructions can trigger the also-undocumented GSExcCode 8 on Loongson 3A4000. Processor state is not corrupted, but we cannot continue without further knowledge, and Loongson is not providing that information as of this writing. So we send SIGILL on seeing this exception code to thwart easy local DoS attacks. Other exception codes are made fatal, partly because of insufficient knowledge, also partly because they are not as easily reproduced. None of them are encountered in the wild with upstream kernels and userspace so far. Some older cores (Loongson-3A1000 and Loongson-3B1500) have ExcCode 16 too, but the semantic is equivalent to GSExcCode 0. Because the respective manuals did not mention the CP0.Diag1 register or its read behavior, these cores are not covered in this patch, as MFC0 from non-existent CP0 registers is UNDEFINED according to the MIPS architecture spec. Reviewed-by: Huacai Chen Signed-off-by: WANG Xuerui Cc: Huacai Chen Cc: Jiaxun Yang Cc: Tiezhu Yang Signed-off-by: Thomas Bogendoerfer

MIPS: only register FTLBPar exception handler for supported models

2020-07-31T15:52:10+00:00

Previously ExcCode 16 is unconditionally treated as the FTLB parity exception (FTLBPar), but in fact its semantic is implementation- dependent. Looking at various manuals it seems the FTLBPar exception is only present on some recent MIPS Technologies cores, so only register the handler on these. Fixes: 75b5b5e0a262790f ("MIPS: Add support for FTLBs") Reviewed-by: Huacai Chen Signed-off-by: WANG Xuerui Cc: Paul Burton Signed-off-by: Thomas Bogendoerfer

MIPS: X2000: Add X2000 system type.

2020-07-24T09:13:57+00:00

1.Add "PRID_COMP_INGENIC_13" and "PRID_IMP_XBURST2" for X2000. 2.Add X2000 system type for cat /proc/cpuinfo to give out X2000. Signed-off-by: 周琰杰 (Zhou Yanjie) Signed-off-by: Thomas Bogendoerfer

mips: Add CP0 Write Merge config support

2020-05-22T07:11:45+00:00

CP0 config register may indicate whether write-through merging is allowed. Currently there are two types of the merging available: SysAD Valid and Full modes. Whether each of them are supported by the core is implementation dependent. Moreover whether the ability to change the mode also depends on the chip family instance. Taking into account all of this we created a dedicated mm_config() method to detect and enable merging if it's supported. It is called for MIPS-type processors at CPU-probe stage and attempts to detect whether the write merging is available. If it's known to be supported and switchable, then switch on the full mode. Otherwise just perform the CP0.Config.MM field analysis. In addition there are platforms like InterAptiv/ProAptiv, which do have the MM bit field set by default, but having write-through cacheing unsupported makes write-merging also unsupported. In this case we just ignore the MM field value. Co-developed-by: Alexey Malahov Signed-off-by: Alexey Malahov Signed-off-by: Serge Semin Cc: Thomas Bogendoerfer Cc: Paul Burton Cc: Ralf Baechle Cc: Arnd Bergmann Cc: Rob Herring Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer

mips: Add MIPS Release 5 support

2020-05-22T07:09:01+00:00

There are five MIPS32/64 architecture releases currently available: from 1 to 6 except fourth one, which was intentionally skipped. Three of them can be called as major: 1st, 2nd and 6th, that not only have some system level alterations, but also introduced significant core/ISA level updates. The rest of the MIPS architecture releases are minor. Even though they don't have as much ISA/system/core level changes as the major ones with respect to the previous releases, they still provide a set of updates (I'd say they were intended to be the intermediate releases before a major one) that might be useful for the kernel and user-level code, when activated by the kernel or compiler. In particular the following features were introduced or ended up being available at/after MIPS32/64 Release 5 architecture: + the last release of the misaligned memory access instructions, + virtualisation - VZ ASE - is optional component of the arch, + SIMD - MSA ASE - is optional component of the arch, + DSP ASE is optional component of the arch, + CP0.Status.FR=1 for CP1.FIR.F64=1 (pure 64-bit FPU general registers) must be available if FPU is implemented, + CP1.FIR.Has2008 support is required so CP1.FCSR.{ABS2008,NAN2008} bits are available. + UFR/UNFR aliases to access CP0.Status.FR from user-space by means of ctc1/cfc1 instructions (enabled by CP0.Config5.UFR), + CP0.COnfig5.LLB=1 and eretnc instruction are implemented to without accidentally clearing LL-bit when returning from an interrupt, exception, or error trap, + XPA feature together with extended versions of CPx registers is introduced, which needs to have mfhc0/mthc0 instructions available. So due to these changes GNU GCC provides an extended instructions set support for MIPS32/64 Release 5 by default like eretnc/mfhc0/mthc0. Even though the architecture alteration isn't that big, it still worth to be taken into account by the kernel software. Finally we can't deny that some optimization/limitations might be found in future and implemented on some level in kernel or compiler. In this case having even intermediate MIPS architecture releases support would be more than useful. So the most of the changes provided by this commit can be split into either compile- or runtime configs related. The compile-time related changes are caused by adding the new CONFIG_CPU_MIPS32_R5/CONFIG_CPU_MIPSR5 configs and concern the code activating MIPSR2 or MIPSR6 already implemented features (like eretnc/LLbit, mthc0/mfhc0). In addition CPU_HAS_MSA can be now freely enabled for MIPS32/64 release 5 based platforms as this is done for CPU_MIPS32_R6 CPUs. The runtime changes concerns the features which are handled with respect to the MIPS ISA revision detected at run-time by means of CP0.Config.{AT,AR} bits. Alas these fields can be used to detect either r1 or r2 or r6 releases. But since we know which CPUs in fact support the R5 arch, we can manually set MIPS_CPU_ISA_M32R5/MIPS_CPU_ISA_M64R5 bit of c->isa_level and then use cpu_has_mips32r5/cpu_has_mips64r5 where it's appropriate. Since XPA/EVA provide too complex alterationss and to have them used with MIPS32 Release 2 charged kernels (for compatibility with current platform configs) they are left to be setup as a separate kernel configs. Co-developed-by: Alexey Malahov Signed-off-by: Alexey Malahov Signed-off-by: Serge Semin Cc: Thomas Bogendoerfer Cc: Paul Burton Cc: Ralf Baechle Cc: Arnd Bergmann Cc: Rob Herring Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer

MIPS: Kernel: Identify Loongson-2K processors

2020-04-26T16:29:01+00:00

Loongson-2K (Loongson64 Reduced) is a family of SoC shipped with gs264e core. Signed-off-by: Jiaxun Yang Signed-off-by: Thomas Bogendoerfer

MIPS: Add MAC2008 Support

2020-01-22T23:56:08+00:00

MAC2008 means the processor implemented IEEE754 style Fused MADD instruction. It was introduced in Release3 but removed in Release5. The toolchain support of MAC2008 have never landed except for Loongson processors. This patch aimed to disabled the MAC2008 if it's optional. For MAC2008 only processors, we corrected math-emu behavior to align with actual hardware behavior. Signed-off-by: Jiaxun Yang [paulburton@kernel.org: Fixup MIPSr2-r5 check in cpu_set_fpu_2008.] Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: chenhc@lemote.com Cc: paul.burton@mips.com Cc: linux-kernel@vger.kernel.org

MIPS: X1830: Add X1830 system type.

2020-01-09T17:48:42+00:00

1.Add X1830 system type for cat /proc/cpuinfo to give out X1830. 2.Change "PRID_IMP_XBURST" to "PRID_IMP_XBURST_REV1" and add a new "PRID_IMP_XBURST_REV2" for new Ingenic CPUs which has XBurst with MXU2 SIMD ISA. Notice: 1."PRID_IMP_XBURST_REV2" is corresponds to the latest XBurst processor with 128bit MXU2 SIMD instruction set, not the upcoming XBurst2 processor. This version of the processors fixes issues such as BTB and HPTLB. 2.In order to simplify and reuse the code, the "c->cputype" and the "c->writecombine" and the "__cpu_name[cpu]" in the original "PRID_IMP_XBURST" (now is "PRID_IMP_XBURST_REV1") are removed, and the corresponding settings are abtained through fall-through to "PRID_IMP_XBURST_REV2", which will cause the name that was previously mistakenly called "JZRISC" to become to the real name "XBurst". Signed-off-by: 周琰杰 (Zhou Yanjie) Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: yamada.masahiro@socionext.com Cc: tglx@linutronix.de Cc: chenhc@lemote.com Cc: tbogendoerfer@suse.de Cc: paul.burton@mips.com Cc: paul@crapouillou.net Cc: jhogan@kernel.org Cc: fancer.lancer@gmail.com Cc: ralf@linux-mips.org Cc: jiaxun.yang@flygoat.com

MIPS: Loongson: Rename LOONGSON1 to LOONGSON32

2019-11-11T18:43:13+00:00

Now old Loongson-2E/2F use LOONGSON2EF and will be removed in future, newer Loongson-2/3 use LOONGSON64. So rename LOONGSON1 to LOONGSON32 will make the naming style more unified. Signed-off-by: Huacai Chen [paulburton@kernel.org: Fix checkpatch whitespace warning in irqflags.h] Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: linux-mips@vger.kernel.org Cc: Fuxin Zhang Cc: Zhangjin Wu Cc: Huacai Chen

MIPS: Loongson64: Rename CPU TYPES

2019-10-31T22:03:10+00:00

CPU_LOONGSON2 -> CPU_LOONGSON2EF CPU_LOONGSON3 -> CPU_LOONGSON64 As newer loongson-2 products (2G/2H/2K1000) can share kernel implementation with loongson-3 while 2E/2F are less similar with other LOONGSON64 products. Signed-off-by: Jiaxun Yang Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: chenhc@lemote.com Cc: paul.burton@mips.com