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x86/fpu: Add debugging checks to all copy_kernel_to_*() functions

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Copying from in-kernel FPU context buffers to FPU registers are
never supposed to fault.

Add debugging checks to copy_kernel_to_fxregs() and copy_kernel_to_fregs()
to double check this assumption.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2015-05-25 10:59:31 +02:00
parent ce2a1e67f1
commit 43b287b3f4
1 changed files with 20 additions and 8 deletions
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26
arch/x86/include/asm/fpu/internal.h
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@ -143,14 +143,22 @@ static inline int copy_fxregs_to_user(struct fxregs_state __user *fx)
static inline int copy_kernel_to_fxregs(struct fxregs_state *fx)
{
if (config_enabled(CONFIG_X86_32))
return check_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
else if (config_enabled(CONFIG_AS_FXSAVEQ))
return check_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
int err;
if (config_enabled(CONFIG_X86_32)) {
err = check_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
} else {
if (config_enabled(CONFIG_AS_FXSAVEQ)) {
err = check_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
} else {
/* See comment in copy_fxregs_to_kernel() below. */
return check_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx),
"m" (*fx));
err = check_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx), "m" (*fx));
}
}
/* Copying from a kernel buffer to FPU registers should never fail: */
WARN_ON_FPU(err);
return err;
}
static inline int copy_user_to_fxregs(struct fxregs_state __user *fx)
@ -167,7 +175,11 @@ static inline int copy_user_to_fxregs(struct fxregs_state __user *fx)
static inline int copy_kernel_to_fregs(struct fregs_state *fx)
{
return check_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
int err = check_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
WARN_ON_FPU(err);
return err;
}
static inline int copy_user_to_fregs(struct fregs_state __user *fx)