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author | Fenghua Yu <fenghua.yu@intel.com> | 2016-05-20 10:47:05 -0700 |
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committer | Ingo Molnar <mingo@kernel.org> | 2016-06-18 10:10:18 +0200 |
commit | a1141e0b5ca6ee3e5e35d5f1a310a5ecb9c96ce5 (patch) | |
tree | 3f6562ed55d70ddb83adcdcada133b57c3aa9cf7 /arch/x86/kernel/fpu/signal.c | |
parent | d1898b733619bd46194bd25aa6452d238ff2dc4e (diff) | |
download | linux-a1141e0b5ca6ee3e5e35d5f1a310a5ecb9c96ce5.tar.gz linux-a1141e0b5ca6ee3e5e35d5f1a310a5ecb9c96ce5.tar.bz2 linux-a1141e0b5ca6ee3e5e35d5f1a310a5ecb9c96ce5.zip |
x86/fpu/xstate: Define and use 'fpu_user_xstate_size'
The kernel xstate area can be in standard or compacted format;
it is always in standard format for user mode. When XSAVES is
enabled, the kernel uses the compacted format and it is necessary
to use a separate fpu_user_xstate_size for signal/ptrace frames.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
[ Rebased the patch and cleaned up the naming. ]
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8756ec34dabddfc727cda5743195eb81e8caf91c.1463760376.git.yu-cheng.yu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/fpu/signal.c')
-rw-r--r-- | arch/x86/kernel/fpu/signal.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index c6f2a3cee2c2..0d29d4de4209 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -32,7 +32,7 @@ static inline int check_for_xstate(struct fxregs_state __user *buf, /* Check for the first magic field and other error scenarios. */ if (fx_sw->magic1 != FP_XSTATE_MAGIC1 || fx_sw->xstate_size < min_xstate_size || - fx_sw->xstate_size > xstate_size || + fx_sw->xstate_size > fpu_user_xstate_size || fx_sw->xstate_size > fx_sw->extended_size) return -1; @@ -89,7 +89,8 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame) if (!use_xsave()) return err; - err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size)); + err |= __put_user(FP_XSTATE_MAGIC2, + (__u32 *)(buf + fpu_user_xstate_size)); /* * Read the xfeatures which we copied (directly from the cpu or @@ -126,7 +127,7 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) else err = copy_fregs_to_user((struct fregs_state __user *) buf); - if (unlikely(err) && __clear_user(buf, xstate_size)) + if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size)) err = -EFAULT; return err; } @@ -176,8 +177,19 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) if (ia32_fxstate) copy_fxregs_to_kernel(&tsk->thread.fpu); } else { + /* + * It is a *bug* if kernel uses compacted-format for xsave + * area and we copy it out directly to a signal frame. It + * should have been handled above by saving the registers + * directly. + */ + if (boot_cpu_has(X86_FEATURE_XSAVES)) { + WARN_ONCE(1, "x86/fpu: saving compacted-format xsave area to a signal frame!\n"); + return -1; + } + fpstate_sanitize_xstate(&tsk->thread.fpu); - if (__copy_to_user(buf_fx, xsave, xstate_size)) + if (__copy_to_user(buf_fx, xsave, fpu_user_xstate_size)) return -1; } @@ -344,7 +356,8 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) static inline int xstate_sigframe_size(void) { - return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size; + return use_xsave() ? fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE : + fpu_user_xstate_size; } /* @@ -388,12 +401,12 @@ fpu__alloc_mathframe(unsigned long sp, int ia32_frame, */ void fpu__init_prepare_fx_sw_frame(void) { - int size = xstate_size + FP_XSTATE_MAGIC2_SIZE; + int size = fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE; fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1; fx_sw_reserved.extended_size = size; fx_sw_reserved.xfeatures = xfeatures_mask; - fx_sw_reserved.xstate_size = xstate_size; + fx_sw_reserved.xstate_size = fpu_user_xstate_size; if (config_enabled(CONFIG_IA32_EMULATION) || config_enabled(CONFIG_X86_32)) { |