4725c86055
The FPC_VALID_MASK has been used to check the validity of the value to be loaded into the floating-point-control register. With the introduction of the floating-point extension facility and the decimal-floating-point additional bits have been defined which need to be checked in a non straight forward way. So far these bits have been ignored which can cause an incorrect results for decimal- floating-point operations, e.g. an incorrect rounding mode to be set after signal return. The static check with the FPC_VALID_MASK is replaced with a trial load of the floating-point-control value, see test_fp_ctl. In addition an information leak with the padding word between the floating-point-control word and the floating-point registers in the s390_fp_regs is fixed. Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
142 lines
3.6 KiB
C
142 lines
3.6 KiB
C
/*
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* Copyright IBM Corp. 1999, 2009
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*
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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*/
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#ifndef __ASM_SWITCH_TO_H
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#define __ASM_SWITCH_TO_H
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#include <linux/thread_info.h>
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#include <asm/ptrace.h>
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extern struct task_struct *__switch_to(void *, void *);
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extern void update_cr_regs(struct task_struct *task);
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static inline int test_fp_ctl(u32 fpc)
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{
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u32 orig_fpc;
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int rc;
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if (!MACHINE_HAS_IEEE)
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return 0;
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asm volatile(
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" efpc %1\n"
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" sfpc %2\n"
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"0: sfpc %1\n"
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" la %0,0\n"
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"1:\n"
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EX_TABLE(0b,1b)
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: "=d" (rc), "=d" (orig_fpc)
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: "d" (fpc), "0" (-EINVAL));
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return rc;
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}
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static inline void save_fp_ctl(u32 *fpc)
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{
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if (!MACHINE_HAS_IEEE)
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return;
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asm volatile(
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" stfpc %0\n"
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: "+Q" (*fpc));
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}
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static inline int restore_fp_ctl(u32 *fpc)
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{
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int rc;
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if (!MACHINE_HAS_IEEE)
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return 0;
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asm volatile(
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"0: lfpc %1\n"
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" la %0,0\n"
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"1:\n"
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EX_TABLE(0b,1b)
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: "=d" (rc) : "Q" (*fpc), "0" (-EINVAL));
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return rc;
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}
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static inline void save_fp_regs(freg_t *fprs)
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{
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asm volatile("std 0,%0" : "=Q" (fprs[0]));
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asm volatile("std 2,%0" : "=Q" (fprs[2]));
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asm volatile("std 4,%0" : "=Q" (fprs[4]));
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asm volatile("std 6,%0" : "=Q" (fprs[6]));
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if (!MACHINE_HAS_IEEE)
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return;
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asm volatile("std 1,%0" : "=Q" (fprs[1]));
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asm volatile("std 3,%0" : "=Q" (fprs[3]));
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asm volatile("std 5,%0" : "=Q" (fprs[5]));
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asm volatile("std 7,%0" : "=Q" (fprs[7]));
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asm volatile("std 8,%0" : "=Q" (fprs[8]));
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asm volatile("std 9,%0" : "=Q" (fprs[9]));
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asm volatile("std 10,%0" : "=Q" (fprs[10]));
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asm volatile("std 11,%0" : "=Q" (fprs[11]));
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asm volatile("std 12,%0" : "=Q" (fprs[12]));
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asm volatile("std 13,%0" : "=Q" (fprs[13]));
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asm volatile("std 14,%0" : "=Q" (fprs[14]));
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asm volatile("std 15,%0" : "=Q" (fprs[15]));
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}
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static inline void restore_fp_regs(freg_t *fprs)
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{
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asm volatile("ld 0,%0" : : "Q" (fprs[0]));
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asm volatile("ld 2,%0" : : "Q" (fprs[2]));
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asm volatile("ld 4,%0" : : "Q" (fprs[4]));
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asm volatile("ld 6,%0" : : "Q" (fprs[6]));
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if (!MACHINE_HAS_IEEE)
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return;
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asm volatile("ld 1,%0" : : "Q" (fprs[1]));
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asm volatile("ld 3,%0" : : "Q" (fprs[3]));
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asm volatile("ld 5,%0" : : "Q" (fprs[5]));
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asm volatile("ld 7,%0" : : "Q" (fprs[7]));
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asm volatile("ld 8,%0" : : "Q" (fprs[8]));
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asm volatile("ld 9,%0" : : "Q" (fprs[9]));
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asm volatile("ld 10,%0" : : "Q" (fprs[10]));
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asm volatile("ld 11,%0" : : "Q" (fprs[11]));
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asm volatile("ld 12,%0" : : "Q" (fprs[12]));
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asm volatile("ld 13,%0" : : "Q" (fprs[13]));
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asm volatile("ld 14,%0" : : "Q" (fprs[14]));
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asm volatile("ld 15,%0" : : "Q" (fprs[15]));
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}
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static inline void save_access_regs(unsigned int *acrs)
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{
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typedef struct { int _[NUM_ACRS]; } acrstype;
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asm volatile("stam 0,15,%0" : "=Q" (*(acrstype *)acrs));
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}
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static inline void restore_access_regs(unsigned int *acrs)
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{
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typedef struct { int _[NUM_ACRS]; } acrstype;
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asm volatile("lam 0,15,%0" : : "Q" (*(acrstype *)acrs));
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}
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#define switch_to(prev,next,last) do { \
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if (prev->mm) { \
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save_fp_ctl(&prev->thread.fp_regs.fpc); \
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save_fp_regs(prev->thread.fp_regs.fprs); \
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save_access_regs(&prev->thread.acrs[0]); \
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save_ri_cb(prev->thread.ri_cb); \
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} \
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if (next->mm) { \
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restore_fp_ctl(&next->thread.fp_regs.fpc); \
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restore_fp_regs(next->thread.fp_regs.fprs); \
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restore_access_regs(&next->thread.acrs[0]); \
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restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb); \
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update_cr_regs(next); \
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} \
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prev = __switch_to(prev,next); \
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} while (0)
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#define finish_arch_switch(prev) do { \
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set_fs(current->thread.mm_segment); \
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} while (0)
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#endif /* __ASM_SWITCH_TO_H */
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