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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-10-24 08:37:14 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-12-19 15:12:34 -0300 |
| commit | ecb1e7220ddc7a4845bbd1b6fd7fcf17aba566bd (patch) | |
| tree | 5e38bda17e720b93e0a50273c75c3acb27efd8f8 /sysdeps/powerpc/fpu | |
| parent | f94446c38fb3f4ad26183984c490a9590cd05282 (diff) | |
| download | glibc-ecb1e7220ddc7a4845bbd1b6fd7fcf17aba566bd.zip glibc-ecb1e7220ddc7a4845bbd1b6fd7fcf17aba566bd.tar.gz glibc-ecb1e7220ddc7a4845bbd1b6fd7fcf17aba566bd.tar.bz2 | |
powerpc: Do not raise exception traps for fesetexcept/fesetexceptflag (BZ 30988)
According to ISO C23 (7.6.4.4), fesetexcept is supposed to set
floating-point exception flags without raising a trap (unlike
feraiseexcept, which is supposed to raise a trap if feenableexcept was
called with the appropriate argument).
This is a side-effect of how we implement the GNU extension
feenableexcept, where feenableexcept/fesetenv/fesetmode/feupdateenv
might issue prctl (PR_SET_FPEXC, PR_FP_EXC_PRECISE) depending of the
argument. And on PR_FP_EXC_PRECISE, setting a floating-point exception
flag triggers a trap.
To make the both functions follow the C23, fesetexcept and
fesetexceptflag now fail if the argument may trigger a trap.
The math tests now check for an value different than 0, instead
of bail out as unsupported for EXCEPTION_SET_FORCES_TRAP.
Checked on powerpc64le-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'sysdeps/powerpc/fpu')
| -rw-r--r-- | sysdeps/powerpc/fpu/fesetexcept.c | 5 | ||||
| -rw-r--r-- | sysdeps/powerpc/fpu/fsetexcptflg.c | 9 |
2 files changed, 13 insertions, 1 deletions
diff --git a/sysdeps/powerpc/fpu/fesetexcept.c b/sysdeps/powerpc/fpu/fesetexcept.c index 609a148..2850156 100644 --- a/sysdeps/powerpc/fpu/fesetexcept.c +++ b/sysdeps/powerpc/fpu/fesetexcept.c @@ -31,6 +31,11 @@ fesetexcept (int excepts) & FE_INVALID_SOFTWARE)); if (n.l != u.l) { + if (n.l & fenv_exceptions_to_reg (excepts)) + /* Setting the exception flags may trigger a trap. ISO C 23 § 7.6.4.4 + does not allow it. */ + return -1; + fesetenv_register (n.fenv); /* Deal with FE_INVALID_SOFTWARE not being implemented on some chips. */ diff --git a/sysdeps/powerpc/fpu/fsetexcptflg.c b/sysdeps/powerpc/fpu/fsetexcptflg.c index 2b22f91..6517e8e 100644 --- a/sysdeps/powerpc/fpu/fsetexcptflg.c +++ b/sysdeps/powerpc/fpu/fsetexcptflg.c @@ -44,7 +44,14 @@ __fesetexceptflag (const fexcept_t *flagp, int excepts) This may cause floating-point exceptions if the restored state requests it. */ if (n.l != u.l) - fesetenv_register (n.fenv); + { + if (n.l & fenv_exceptions_to_reg (excepts)) + /* Setting the exception flags may trigger a trap. ISO C 23 § 7.6.4.4 + does not allow it. */ + return -1; + + fesetenv_register (n.fenv); + } /* Deal with FE_INVALID_SOFTWARE not being implemented on some chips. */ if (flag & FE_INVALID) |