kernel/arch/powerpc/math-emu/math.c, branch linux-4.3.y

powerpc/math-emu: Fix load/store indexed emulation

2013-08-14T04:59:57Z

Load/store indexed instructions where the index register RA=R0, such as "lfdx f1,0,r3", are not illegal. Load/store indexed with update instructions where the index register RA=R0, such as "lfdux f1,0,r3", are invalid, and, to be consistent with existing math-emu behavior for other invalid instruction forms, will signal as illegal. Signed-off-by: James Yang Signed-off-by: Benjamin Herrenschmidt

powerpc: Make flush_fp_to_thread() nop when CONFIG_PPC_FPU is disabled

2013-08-14T04:59:44Z

In the current kernel, the function flush_fp_to_thread() is not dependent on CONFIG_PPC_FPU. So most invocations of this function is not wrapped by CONFIG_PPC_FPU. Even through we don't really save the FPRs to the thread struct if CONFIG_PPC_FPU is not enabled, but there does have some runtime overhead such as the check for tsk->thread.regs and preempt disable and enable. It really make no sense to do that. So make it a nop when CONFIG_PPC_FPU is disabled. Also remove the wrapped #ifdef CONFIG_PPC_FPU when invoking this function. Signed-off-by: Kevin Hao Signed-off-by: Benjamin Herrenschmidt

powerpc: split She math emulation into two parts

2013-08-14T04:59:19Z

For some SoC (such as the FSL BookE) even though there does have a hardware FPU, but not all floating point instructions are implemented. Unfortunately some versions of gcc do use these unimplemented instructions. Then we have to enable the math emulation to workaround this issue. It seems a little redundant to have the support to emulate all the floating point instructions in this case. So split the math emulation into two parts. One is for the SoC which doesn't have FPU at all and the other for the SoC which does have the hardware FPU and only need some special floating point instructions to be emulated. Signed-off-by: Kevin Hao Signed-off-by: Benjamin Herrenschmidt

powerpc/math-emu: Move the flush FPU state function into do_mathemu

2013-08-14T04:59:06Z

By doing this we can make sure that the FPU state is only flushed to the thread struct when it is really needed. Signed-off-by: Kevin Hao Signed-off-by: Benjamin Herrenschmidt

powerpc/math-emu: Remove the unneeded check for CONFIG_MATH_EMULATION in math.c

2013-08-14T04:58:46Z

The math.c is only built when CONFIG_MATH_EMULATION is enabled. So the #ifdef check for CONFIG_MATH_EMULATION in it seems redundant. Drop all of them. Signed-off-by: Kevin Hao Signed-off-by: Benjamin Herrenschmidt

powerpc/math-emu: Remove the dead code in math.c

2013-08-14T04:58:40Z

The math.c is only built when CONFIG_MATH_EMULATION is enabled. So we would never get into the case that CONFIG_MATH_EMULATION is not defined in this file. Signed-off-by: Kevin Hao Signed-off-by: Benjamin Herrenschmidt

powerpc/math-emu: Fix decoding of some instructions

2013-06-20T07:05:05Z

The decoding of some instructions such as fsqrt{s} was incorrect, using the wrong registers, and thus could not work. This fixes it and also adds a couple of place holders for missing instructions. Signed-off-by: Benjamin Herrenschmidt

powerpc/math-emu: Use kernel generic math-emu code

2008-10-01T13:40:07Z

The math emulation code is centered around a set of generic macros that provide the core of the emulation that are shared by the various architectures and other projects (like glibc). Each arch implements its own sfp-machine.h to specific various arch specific details. For historic reasons that are now lost the powerpc math-emu code had its own version of the common headers. This moves us to using the kernel generic version and thus getting fixes when those are updated. Also cleaned up exception/error reporting from the FP emulation functions. Signed-off-by: Kumar Gala

powerpc: Add macros to access floating point registers in thread_struct.

2008-07-01T01:28:43Z

We are going to change where the floating point registers are stored in the thread_struct, so in preparation add some macros to access the floating point registers. Update all code to use these new macros. Signed-off-by: Michael Neuling Signed-off-by: Paul Mackerras

[POWERPC] Fix handling of stfiwx math emulation

2007-10-16T14:05:24Z

Its legal for the stfiwx instruction to have RA = 0 as part of its effective address calculation. This is illegal for all other XE form instructions. Add code to compute the proper effective address for stfiwx if RA = 0 rather than treating it as illegal. Signed-off-by: Kumar Gala