From 84e4dccc8fce20b497388d756e12de5c9006eb48 Mon Sep 17 00:00:00 2001 From: "Chang S. Bae" Date: Thu, 21 Oct 2021 15:55:07 -0700 Subject: [PATCH] x86/fpu/xstate: Provide xstate_calculate_size() Split out the size calculation from the paranoia check so it can be used for recalculating buffer sizes when dynamically enabled features are supported. Signed-off-by: Chang S. Bae [ tglx: Adopted to changed base code ] Signed-off-by: Thomas Gleixner Signed-off-by: Chang S. Bae Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20211021225527.10184-4-chang.seok.bae@intel.com --- arch/x86/kernel/fpu/xstate.c | 46 +++++++++++++++++++++++++++----------------- 1 file changed, 28 insertions(+), 18 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index cbba3812a160..310c4201e056 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -549,6 +549,33 @@ static bool __init check_xstate_against_struct(int nr) return true; } +static unsigned int xstate_calculate_size(u64 xfeatures, bool compacted) +{ + unsigned int size = FXSAVE_SIZE + XSAVE_HDR_SIZE; + int i; + + for_each_extended_xfeature(i, xfeatures) { + /* Align from the end of the previous feature */ + if (xfeature_is_aligned(i)) + size = ALIGN(size, 64); + /* + * In compacted format the enabled features are packed, + * i.e. disabled features do not occupy space. + * + * In non-compacted format the offsets are fixed and + * disabled states still occupy space in the memory buffer. + */ + if (!compacted) + size = xfeature_uncompacted_offset(i); + /* + * Add the feature size even for non-compacted format + * to make the end result correct + */ + size += xfeature_size(i); + } + return size; +} + /* * This essentially double-checks what the cpu told us about * how large the XSAVE buffer needs to be. We are recalculating @@ -575,25 +602,8 @@ static bool __init paranoid_xstate_size_valid(unsigned int kernel_size) XSTATE_WARN_ON(1); return false; } - - /* Align from the end of the previous feature */ - if (xfeature_is_aligned(i)) - size = ALIGN(size, 64); - /* - * In compacted format the enabled features are packed, - * i.e. disabled features do not occupy space. - * - * In non-compacted format the offsets are fixed and - * disabled states still occupy space in the memory buffer. - */ - if (!compacted) - size = xfeature_uncompacted_offset(i); - /* - * Add the feature size even for non-compacted format - * to make the end result correct - */ - size += xfeature_size(i); } + size = xstate_calculate_size(fpu_kernel_cfg.max_features, compacted); XSTATE_WARN_ON(size != kernel_size); return size == kernel_size; } -- 2.11.0