Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 27/32] MIPS: Force o32 fp64 support on 32bit MIPS64r6 kernels | Date | Mon, 10 Apr 2017 18:39:17 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: James Hogan <james.hogan@imgtec.com>
commit 2e6c7747730296a6d4fd700894286db1132598c4 upstream.
When a 32-bit kernel is configured to support MIPS64r6 (CPU_MIPS64_R6), MIPS_O32_FP64_SUPPORT won't be selected as it should be because MIPS32_O32 is disabled (o32 is already the default ABI available on 32-bit kernels).
This results in userland FP breakage as CP0_Status.FR is read-only 1 since r6 (when an FPU is present) so __enable_fpu() will fail to clear FR. This causes the FPU emulator to get used which will incorrectly emulate 32-bit FPU registers.
Force o32 fp64 support in this case by also selecting MIPS_O32_FP64_SUPPORT from CPU_MIPS64_R6 if 32BIT.
Fixes: 4e9d324d4288 ("MIPS: Require O32 FP64 support for MIPS64 with O32 compat") Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/15310/ Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/mips/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1412,7 +1412,7 @@ config CPU_MIPS32_R6 select CPU_SUPPORTS_MSA select GENERIC_CSUM select HAVE_KVM - select MIPS_O32_FP64_SUPPORT + select MIPS_O32_FP64_SUPPORT if 32BIT help Choose this option to build a kernel for release 6 or later of the MIPS32 architecture. New MIPS processors, starting with the Warrior
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