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x86/fpu/signal: Remove the legacy alignment check

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Checking for the XSTATE buffer being 64-byte aligned, and if not,
deciding just to restore the FXSR state is daft.

If user space provides an unaligned math frame and has the extended state
magic set in the FX software reserved bytes, then it really can keep the
pieces.

If the frame is unaligned and the FX software magic is not set, then
fx_only is already set and the restore will use fxrstor.

Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121457.184149902@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-06-23 14:02:26 +02:00 committed by Borislav Petkov
parent 99a5901951
commit 9ba589f9cd
1 changed files with 0 additions and 3 deletions
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3
arch/x86/kernel/fpu/signal.c
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@ -306,9 +306,6 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx,
}
}
if ((unsigned long)buf_fx % 64)
fx_only = 1;
if (!ia32_fxstate) {
/*
* Attempt to restore the FPU registers directly from user