kernel.git/arch/mips/kernel/r4k_switch.S, branch linux-4.15.y

MIPS: Move r4k FP code from r4k_switch.S to r4k_fpu.S

2017-08-29T13:21:51Z

Move _save_fp(), _restore_fp(), _save_msa(), _restore_msa(), _init_msa_upper() & _init_fpu() out of r4k_switch.S & into r4k_fpu.S. This allows us to clean up the way in which Octeon includes the default r4k implementations of these FP functions despite replacing resume(), and makes CONFIG_R4K_FPU more straightforwardly represent all configurations that have an R4K-style FPU, including Octeon. Besides cleaning up this will be useful for later patches which disable FP support. [ralf@linux-mips.org: Fixed build issues reported by Arnd Bergmann ] Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16237/ Signed-off-by: Ralf Baechle

MIPS: Remove dead define of ST_OFF

2017-04-12T11:52:21Z

Commit 1a3d59579b9f ("MIPS: Tidy up FPU context switching") removed the last usage of the macro ST_OFF. Remove the dead code. Signed-off-by: Matt Redfearn Cc: James Hogan Cc: Paul Burton Cc: trivial@kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15898/ Signed-off-by: Ralf Baechle

MIPS: Export _save_fp & _save_msa alongside their definitions

2017-01-03T15:34:49Z

Now that EXPORT_SYMBOL can be used from assembly source, move the EXPORT_SYMBOL invocations for _save_fp & _save_msa to be alongside their definitions. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14509/ Signed-off-by: Ralf Baechle

MIPS: Remove redundant asm/pgtable-bits.h inclusions

2016-05-13T13:30:25Z

asm/pgtable-bits.h is included in 2 assembly files and thus has to ifdef around C code, however nothing defined by the header is used in either of the assembly files that include it. Remove the redundant inclusions such that asm/pgtable-bits.h doesn't need to #ifdef around C code, for cleanliness and in preparation for later patches which will add more C. Signed-off-by: Paul Burton Reviewed-by: James Hogan Cc: Maciej W. Rozycki Cc: Jonas Gorski Cc: Alex Smith Cc: Kirill A. Shutemov Cc: Andrew Morton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13114/ Signed-off-by: Ralf Baechle

MIPS: Tidy up FPU context switching

2015-09-03T10:08:05Z

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: Respect the ISA level in FCSR handling

2015-04-07T23:10:37Z

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: kernel: r4k_switch: Add support for MIPS R6

2015-02-17T15:37:27Z

Add the MIPS R6 related preprocessor definitions for save/restore FPU related functions. We also set the appropriate ISA level so the final return instruction "jr ra" will produce the correct opcode on R6. Signed-off-by: Leonid Yegoshin Signed-off-by: Markos Chandras

MIPS: Fix build with binutils 2.24.51+

2014-11-07T14:07:36Z

Starting with version 2.24.51.20140728 MIPS binutils complain loudly about mixing soft-float and hard-float object files, leading to this build failure since GCC is invoked with "-msoft-float" on MIPS: {standard input}: Warning: .gnu_attribute 4,3 requires `softfloat' LD arch/mips/alchemy/common/built-in.o mipsel-softfloat-linux-gnu-ld: Warning: arch/mips/alchemy/common/built-in.o uses -msoft-float (set by arch/mips/alchemy/common/prom.o), arch/mips/alchemy/common/sleeper.o uses -mhard-float To fix this, we detect if GAS is new enough to support "-msoft-float" command option, and if it does, we can let GCC pass it to GAS; but then we also need to sprinkle the files which make use of floating point registers with the necessary ".set hardfloat" directives. Signed-off-by: Manuel Lauss Cc: Linux-MIPS Cc: Matthew Fortune Cc: Markos Chandras Cc: Maciej W. Rozycki Patchwork: https://patchwork.linux-mips.org/patch/8355/ Signed-off-by: Ralf Baechle

MIPS: init upper 64b of vector registers when MSA is first used

2014-08-01T22:06:44Z

When a task first makes use of MSA we need to ensure that the upper 64b of the vector registers are set to some value such that no information can be leaked to it from the previous task to use MSA context on the CPU. The architecture formerly specified that these bits would be cleared to 0 when a scalar FP instructions wrote to the aliased FP registers, which would have implicitly handled this as the kernel restored scalar FP context. However more recent versions of the specification now state that the value of the bits in such cases is unpredictable. Initialise them explictly to be sure, and set all the bits to 1 rather than 0 for consistency with the least significant 64b. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7497/ Signed-off-by: Ralf Baechle

MIPS: preserve scalar FP CSR when switching vector context

2014-08-01T22:06:43Z

Switching the vector context implicitly saves & restores the state of the aliased scalar FP data registers, however the scalar FP control & status register is distinct from the MSA control & status register. In order to allow scalar FP to function correctly in programs using MSA, the scalar CSR needs to be saved & restored along with the MSA vector context. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7301/ Signed-off-by: Ralf Baechle