From d3e021adac7c51a26d9ede167c789fcc1b878467 Mon Sep 17 00:00:00 2001 From: "Chang S. Bae" Date: Wed, 24 Aug 2022 12:12:22 -0700 Subject: x86/fpu: Fix the init_fpstate size check with the actual size The init_fpstate buffer is statically allocated. Thus, the sanity test was established to check whether the pre-allocated buffer is enough for the calculated size or not. The currently measured size is not strictly relevant. Fix to validate the calculated init_fpstate size with the pre-allocated area. Also, replace the sanity check function with open code for clarity. The abstraction itself and the function naming do not tend to represent simply what it does. Fixes: 2ae996e0c1a3 ("x86/fpu: Calculate the default sizes independently") Signed-off-by: Chang S. Bae Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20220824191223.1248-3-chang.seok.bae@intel.com --- arch/x86/kernel/fpu/xstate.c | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-) (limited to 'arch/x86/kernel/fpu') diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index f0ce10620ab0..f5ef78633b4c 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -678,20 +678,6 @@ static unsigned int __init get_xsave_size_user(void) return ebx; } -/* - * Will the runtime-enumerated 'xstate_size' fit in the init - * task's statically-allocated buffer? - */ -static bool __init is_supported_xstate_size(unsigned int test_xstate_size) -{ - if (test_xstate_size <= sizeof(init_fpstate.regs)) - return true; - - pr_warn("x86/fpu: xstate buffer too small (%zu < %d), disabling xsave\n", - sizeof(init_fpstate.regs), test_xstate_size); - return false; -} - static int __init init_xstate_size(void) { /* Recompute the context size for enabled features: */ @@ -717,10 +703,6 @@ static int __init init_xstate_size(void) kernel_default_size = xstate_calculate_size(fpu_kernel_cfg.default_features, compacted); - /* Ensure we have the space to store all default enabled features. */ - if (!is_supported_xstate_size(kernel_default_size)) - return -EINVAL; - if (!paranoid_xstate_size_valid(kernel_size)) return -EINVAL; @@ -879,6 +861,12 @@ void __init fpu__init_system_xstate(unsigned int legacy_size) init_fpstate.size = fpu_kernel_cfg.max_size; init_fpstate.xfeatures = fpu_kernel_cfg.max_features; + if (init_fpstate.size > sizeof(init_fpstate.regs)) { + pr_warn("x86/fpu: init_fpstate buffer too small (%zu < %d), disabling XSAVE\n", + sizeof(init_fpstate.regs), init_fpstate.size); + goto out_disable; + } + setup_init_fpu_buf(); /* -- cgit v1.2.3