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x86/fpu: Fix the init_fpstate size check with the actual size

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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: 2ae996e0c1 ("x86/fpu: Calculate the default sizes independently")
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220824191223.1248-3-chang.seok.bae@intel.com
This commit is contained in:
Chang S. Bae
2022-08-24 12:12:22 -07:00
committed by Thomas Gleixner
parent c32d7cab57
commit d3e021adac
1 changed files with 6 additions and 18 deletions
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24
arch/x86/kernel/fpu/xstate.c
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@@ -678,20 +678,6 @@ static unsigned int __init get_xsave_size_user(void)
return ebx; 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) static int __init init_xstate_size(void)
{ {
/* Recompute the context size for enabled features: */ /* Recompute the context size for enabled features: */
@@ -717,10 +703,6 @@ static int __init init_xstate_size(void)
kernel_default_size = kernel_default_size =
xstate_calculate_size(fpu_kernel_cfg.default_features, compacted); 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)) if (!paranoid_xstate_size_valid(kernel_size))
return -EINVAL; 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.size = fpu_kernel_cfg.max_size;
init_fpstate.xfeatures = fpu_kernel_cfg.max_features; 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(); setup_init_fpu_buf();
/* /*