diff options
Diffstat (limited to 'arch/s390/include/asm/fpu/api.h')
| -rw-r--r-- | arch/s390/include/asm/fpu/api.h | 35 |
1 files changed, 21 insertions, 14 deletions
diff --git a/arch/s390/include/asm/fpu/api.h b/arch/s390/include/asm/fpu/api.h index 9acf48e53a87..d6ca8bc6ca68 100644 --- a/arch/s390/include/asm/fpu/api.h +++ b/arch/s390/include/asm/fpu/api.h @@ -46,26 +46,33 @@ #include <linux/preempt.h> #include <asm/asm-extable.h> +#include <asm/fpu/internal.h> void save_fpu_regs(void); void load_fpu_regs(void); void __load_fpu_regs(void); -static inline int test_fp_ctl(u32 fpc) +/** + * sfpc_safe - Set floating point control register safely. + * @fpc: new value for floating point control register + * + * Set floating point control register. This may lead to an exception, + * since a saved value may have been modified by user space (ptrace, + * signal return, kvm registers) to an invalid value. In such a case + * set the floating point control register to zero. + */ +static inline void sfpc_safe(u32 fpc) { - u32 orig_fpc; - int rc; - - asm volatile( - " efpc %1\n" - " sfpc %2\n" - "0: sfpc %1\n" - " la %0,0\n" - "1:\n" - EX_TABLE(0b,1b) - : "=d" (rc), "=&d" (orig_fpc) - : "d" (fpc), "0" (-EINVAL)); - return rc; + asm volatile("\n" + "0: sfpc %[fpc]\n" + "1: nopr %%r7\n" + ".pushsection .fixup, \"ax\"\n" + "2: lghi %[fpc],0\n" + " jg 0b\n" + ".popsection\n" + EX_TABLE(1b, 2b) + : [fpc] "+d" (fpc) + : : "memory"); } #define KERNEL_FPC 1 |