Re: [PATCH 5.10 119/199] x86/mmx: Use KFPU_387 for MMX string operations

2021-01-26 Thread Greg Kroah-Hartman
On Mon, Jan 25, 2021 at 07:24:56PM -0800, Krzysztof Olędzki wrote: > Hi, > > I think for both 5.4-stable and 5.10-stable we also need > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e45122893a9870813f9bd7b4add4f613e6f29008 > - "x86/fpu: Add kernel_fpu_begin_mask()

Re: [PATCH 5.10 119/199] x86/mmx: Use KFPU_387 for MMX string operations

2021-01-26 Thread Krzysztof Olędzki
Hi, I think for both 5.4-stable and 5.10-stable we also need https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e45122893a9870813f9bd7b4add4f613e6f29008 - "x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state" Without this, there is no kernel_fpu_beg

[PATCH 5.10 119/199] x86/mmx: Use KFPU_387 for MMX string operations

2021-01-25 Thread Greg Kroah-Hartman
From: Andy Lutomirski commit 67de8dca50c027ca0fa3b62a488ee5035036a0da upstream. The default kernel_fpu_begin() doesn't work on systems that support XMM but haven't yet enabled CR4.OSFXSR. This causes crashes when _mmx_memcpy() is called too early because LDMXCSR generates #UD when the aforement