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Commit 4e63f8ed authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

powerpc/math-emu: Allow math-emu to be used for HW FPU 



(Including 64-bit ones)

This allow SW emulation by the kernel of optional instructions
such as fsqrt which aren't implemented on some processors, and
thus fixes some Fedora 19 issues such as Anaconda since the
compiler is set to generate those by default on 64-bit.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 04ae9001

arch/powerpc/Kconfig

+5 −1
Original line number Diff line number Diff line
@@ -298,7 +298,7 @@ config HUGETLB_PAGE_SIZE_VARIABLE 


config MATH_EMULATION

	bool "Math emulation"

	depends on 4xx || 8xx || E200 || PPC_MPC832x || E500

	depends on 4xx || 8xx || PPC_MPC832x || BOOKE

	---help---

	  Some PowerPC chips designed for embedded applications do not have

	  a floating-point unit and therefore do not implement the
@@ -307,6 +307,10 @@ config MATH_EMULATION 
	  unit, which will allow programs that use floating-point

	  instructions to run.



	  This is also useful to emulate missing (optional) instructions

	  such as fsqrt on cores that do have an FPU but do not implement

	  them (such as Freescale BookE).



config PPC_TRANSACTIONAL_MEM

       bool "Transactional Memory support for POWERPC"

       depends on PPC_BOOK3S_64

arch/powerpc/kernel/traps.c

+11 −1
Original line number Diff line number Diff line
@@ -1125,7 +1125,17 @@ void __kprobes program_check_exception(struct pt_regs *regs) 
	 * ESR_DST (!?) or 0.  In the process of chasing this with the

	 * hardware people - not sure if it can happen on any illegal

	 * instruction or only on FP instructions, whether there is a

	 * pattern to occurrences etc. -dgibson 31/Mar/2003 */

	 * pattern to occurrences etc. -dgibson 31/Mar/2003

	 */



	/*

	 * If we support a HW FPU, we need to ensure the FP state

	 * if flushed into the thread_struct before attempting

	 * emulation

	 */

#ifdef CONFIG_PPC_FPU

	flush_fp_to_thread(current);

#endif

	switch (do_mathemu(regs)) {

	case 0:

		emulate_single_step(regs);