diff options
| author | Ingo Molnar <mingo@kernel.org> | 2015-05-25 10:59:31 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-05-27 14:11:28 +0200 |
| commit | 43b287b3f4d8665cd5a4909132259b663cc1c0e3 (patch) | |
| tree | a782f11d7934e451c57f1b7e9a8f1dd87e1cbd15 /arch/x86/include/asm | |
| parent | ce2a1e67f1738535b011a7b4bd42cc114b1d805f (diff) | |
x86/fpu: Add debugging checks to all copy_kernel_to_*() functions
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>
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index e3bd93c84928..eb8fa0f9d279 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -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; - /* See comment in copy_fxregs_to_kernel() below. */ - return check_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx), - "m" (*fx)); + 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. */ + 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) |