5.4-stable review patch. If anyone has any objections, please let me know.
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From: Feng Tang feng.tang@intel.com
commit 2c66ca3949dc701da7f4c9407f2140ae425683a5 upstream.
0-Day found a 34.6% regression in stress-ng's 'af-alg' test case, and bisected it to commit b81fac906a8f ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()"), which optimizes the FPU init order, and moves the CR4_OSXSAVE enabling into a later place:
arch_cpu_finalize_init identify_boot_cpu identify_cpu generic_identify get_cpu_cap --> setup cpu capability ... fpu__init_cpu fpu__init_cpu_xstate cr4_set_bits(X86_CR4_OSXSAVE);
As the FPU is not yet initialized the CPU capability setup fails to set X86_FEATURE_OSXSAVE. Many security module like 'camellia_aesni_avx_x86_64' depend on this feature and therefore fail to load, causing the regression.
Cure this by setting X86_FEATURE_OSXSAVE feature right after OSXSAVE enabling.
[ tglx: Moved it into the actual BSP FPU initialization code and added a comment ]
Fixes: b81fac906a8f ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()") Reported-by: kernel test robot oliver.sang@intel.com Signed-off-by: Feng Tang feng.tang@intel.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/202307192135.203ac24e-oliver.sang@intel.com Link: https://lore.kernel.org/lkml/20230823065747.92257-1-feng.tang@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/fpu/xstate.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -805,6 +805,14 @@ void __init fpu__init_system_xstate(void fpu__init_prepare_fx_sw_frame(); setup_init_fpu_buf(); setup_xstate_comp(); + + /* + * CPU capabilities initialization runs before FPU init. So + * X86_FEATURE_OSXSAVE is not set. Now that XSAVE is completely + * functional, set the feature bit so depending code works. + */ + setup_force_cpu_cap(X86_FEATURE_OSXSAVE); + print_xstate_offset_size();
pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",