kernel/linux.git/arch/mips/include/asm/fpu.h, branch linux-4.4.y

MIPS: Tidy up FPU context switching

2015-09-03T10:08:05+00:00

Rather than saving the scalar FP or vector context in the assembly resume function, reuse the existing C code we have in fpu.h to do exactly that. This reduces duplication, results in a much easier to read resume function & should allow the compiler to optimise out more MSA code due to is_msa_enabled()/cpu_has_msa being known-zero at compile time for kernels without MSA support. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: Leonid Yegoshin Cc: Maciej W. Rozycki Cc: linux-kernel@vger.kernel.org Cc: James Hogan Cc: Markos Chandras Cc: Manuel Lauss Patchwork: https://patchwork.linux-mips.org/patch/10830/ Signed-off-by: Ralf Baechle

MIPS: fpu.h: Allow 64-bit FPU on a 64-bit MIPS R6 CPU

2015-07-19T09:31:24+00:00

Commit 6134d94923d0 ("MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6") added support for 64-bit FPU on a 32-bit MIPS R6 processor but it missed the 64-bit CPU case leading to FPU failures when requesting FR=1 mode (which is always the case for MIPS R6 userland) when running a 32-bit kernel on a 64-bit CPU. We also fix the MIPS R2 case. Signed-off-by: Markos Chandras Fixes: 6134d94923d0 ("MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6") Reviewed-by: Paul Burton Cc: # 4.0+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10734/ Signed-off-by: Ralf Baechle

Merge branch '4.1-fp' into mips-for-linux-next

2015-04-13T14:01:37+00:00

MIPS: Respect the ISA level in FCSR handling

2015-04-07T23:10:37+00:00

Define the central place the default FCSR value is set from, initialised in `cpu_probe'. Determine the FCSR mask applied to values written to the register with CTC1 in the full emulation mode and via ptrace(2), according to the ISA level of processor hardware or the writability of bits 31:18 if actual FPU hardware is used. Software may rely on FCSR bits whose functions our emulator does not implement, so it should not allow them to be set or software may get confused. For ptrace(2) it's just sanity. [ralf@linux-mips.org: Fixed double inclusion of .] Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9711/ Signed-off-by: Ralf Baechle

MIPS: disable FPU if the mode is unsupported

2015-03-27T18:42:47+00:00

The expected semantics of __enable_fpu are for the FPU to be enabled in the given mode if possible, otherwise for the FPU to be left disabled and SIGFPE returned. The FPU was incorrectly being left enabled in cases where the desired value for FR was unavailable. Without ensuring the FPU is disabled in this case, it would be possible for userland to go on to execute further FP instructions natively in the incorrect mode, rather than those instructions being trapped & emulated as they need to be. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9167/ Signed-off-by: Ralf Baechle

MIPS: lose_fpu(): Disable FPU when MSA enabled

2015-03-27T18:39:42+00:00

The lose_fpu() function only disables the FPU in CP0_Status.CU1 if the FPU is in use and MSA isn't enabled. This isn't necessarily a problem because KSTK_STATUS(current), the version of CP0_Status stored on the kernel stack on entry from user mode, does always get updated and gets restored when returning to user mode, but I don't think it was intended, and it is inconsistent with the case of only the FPU being in use. Sometimes leaving the FPU enabled may also mask kernel bugs where FPU operations are executed when the FPU might not be enabled. So lets disable the FPU in the MSA case too. Fixes: 33c771ba5c5d ("MIPS: save/disable MSA in lose_fpu") Signed-off-by: James Hogan Cc: Ralf Baechle Cc: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9323/ Signed-off-by: Ralf Baechle

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2015-02-22T03:41:38+00:00

Pull MIPS updates from Ralf Baechle: "This is the main pull request for MIPS: - a number of fixes that didn't make the 3.19 release. - a number of cleanups. - preliminary support for Cavium's Octeon 3 SOCs which feature up to 48 MIPS64 R3 cores with FPU and hardware virtualization. - support for MIPS R6 processors. Revision 6 of the MIPS architecture is a major revision of the MIPS architecture which does away with many of original sins of the architecture such as branch delay slots. This and other changes in R6 require major changes throughout the entire MIPS core architecture code and make up for the lion share of this pull request. - finally some preparatory work for eXtendend Physical Address support, which allows support of up to 40 bit of physical address space on 32 bit processors" [ Ahh, MIPS can't leave the PAE brain damage alone. It's like every CPU architect has to make that mistake, but pee in the snow by changing the TLA. But whether it's called PAE, LPAE or XPA, it's horrid crud - Linus ] * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (114 commits) MIPS: sead3: Corrected get_c0_perfcount_int MIPS: mm: Remove dead macro definitions MIPS: OCTEON: irq: add CIB and other fixes MIPS: OCTEON: Don't do acknowledge operations for level triggered irqs. MIPS: OCTEON: More OCTEONIII support MIPS: OCTEON: Remove setting of processor specific CVMCTL icache bits. MIPS: OCTEON: Core-15169 Workaround and general CVMSEG cleanup. MIPS: OCTEON: Update octeon-model.h code for new SoCs. MIPS: OCTEON: Implement DCache errata workaround for all CN6XXX MIPS: OCTEON: Add little-endian support to asm/octeon/octeon.h MIPS: OCTEON: Implement the core-16057 workaround MIPS: OCTEON: Delete unused COP2 saving code MIPS: OCTEON: Use correct instruction to read 64-bit COP0 register MIPS: OCTEON: Save and restore CP2 SHA3 state MIPS: OCTEON: Fix FP context save. MIPS: OCTEON: Save/Restore wider multiply registers in OCTEON III CPUs MIPS: boot: Provide more uImage options MIPS: Remove unneeded #ifdef __KERNEL__ from asm/processor.h MIPS: ip22-gio: Remove legacy suspend/resume support mips: pci: Add ifdef around pci_proc_domain ...

MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6

2015-02-17T15:37:38+00:00

MIPS32 R6 has a 64-bit FPU so add the necessary MIPS R6 definition. Signed-off-by: Markos Chandras

MIPS: FRE: Use set/clear_c0_config5 instead of open coded sequences.

2015-01-13T14:53:08+00:00

Signed-off-by: Ralf Baechle

MIPS: Do not fiddle with FRE unless FRE is actually available.

2015-01-13T14:53:08+00:00

Commit 4227a2d4efc9c84f35826dc4d1e6dc183f6c1c05 (MIPS: Support for hybrid FPRs) changes the kernel to execute read_c0_config5() even on processors that don't have a Config5 register. According to the arch spec the behaviour of trying to read or write this register is UNDEFINED where this register doesn't exist, that is merely looking at this register is already cruel because that might kill a kitten. In case of Qemu older than v2.2 Qemu has elected to implement this UNDEFINED behaviour by taking a RI exception - which then fries the kernel: [...] Freeing YAMON memory: 956k freed Freeing unused kernel memory: 240K (80674000 - 806b0000) Reserved instruction in kernel code[#1]: CPU: 0 PID: 1 Comm: init Not tainted 3.18.0-rc6-00058-g4227a2d #26 task: 86047588 ti: 86048000 task.ti: 86048000 $ 0 : 00000000 77a638cc 00000000 00000000 [...] For qemu v2.2.0 commit f31b035a9f10dc9b57f01c426110af845d453ce2 (target-mips: correctly handle access to unimplemented CP0 register) changed the behaviour to returning zero on read and ignoring writes which more matches how typical hardware implementations actually behave. Signed-off-by: Ralf Baechle