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| author |   H. Peter Anvin <hpa@zytor.com> | 2012-09-25 15:42:18 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2012-09-25 15:42:18 -0700 |
| commit | e139e95590dfebab81841bf7a3ac46500f51a47c (patch) | |
| tree | 2094d5154d34ce212c7110ed3a30d975026e5c75 /arch/x86 | |
| parent | Merge branch 'x86/fpu' into x86/smap (diff) | |
| download | linux-dev-e139e95590dfebab81841bf7a3ac46500f51a47c.tar.xz linux-dev-e139e95590dfebab81841bf7a3ac46500f51a47c.zip | |
x86, smap: Do not abuse the [f][x]rstor_checking() functions for user space
With SMAP, the [f][x]rstor_checking() functions are no longer usable
for user-space pointers by applying a simple __force cast. Instead,
create new [f][x]rstor_user() functions which do the proper SMAP
magic.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1343171129-2747-3-git-send-email-suresh.b.siddha@intel.com
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/fpu-internal.h | 17 | ||||
| -rw-r--r-- | arch/x86/kernel/xsave.c | 6 |
2 files changed, 20 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 409b9ccf5518..831dbb9c6c02 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -181,11 +181,28 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx) "m" (*fx)); } +static inline int fxrstor_user(struct i387_fxsave_struct __user *fx) +{ + if (config_enabled(CONFIG_X86_32)) + return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); + else if (config_enabled(CONFIG_AS_FXSAVEQ)) + return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); + + /* See comment in fpu_fxsave() below. */ + return user_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx), + "m" (*fx)); +} + static inline int frstor_checking(struct i387_fsave_struct *fx) { return check_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); } +static inline int frstor_user(struct i387_fsave_struct __user *fx) +{ + return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + static inline void fpu_fxsave(struct fpu *fpu) { if (config_enabled(CONFIG_X86_32)) diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 4e89b3dd408d..ada87a329edc 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -315,7 +315,7 @@ static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only) if ((unsigned long)buf % 64 || fx_only) { u64 init_bv = pcntxt_mask & ~XSTATE_FPSSE; xrstor_state(init_xstate_buf, init_bv); - return fxrstor_checking((__force void *) buf); + return fxrstor_user(buf); } else { u64 init_bv = pcntxt_mask & ~xbv; if (unlikely(init_bv)) @@ -323,9 +323,9 @@ static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only) return xrestore_user(buf, xbv); } } else if (use_fxsr()) { - return fxrstor_checking((__force void *) buf); + return fxrstor_user(buf); } else - return frstor_checking((__force void *) buf); + return frstor_user(buf); } int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) |