https://github.com/python/cpython/commit/85f48038aac108e0a2434ae88819a6c94e1ea3af commit: 85f48038aac108e0a2434ae88819a6c94e1ea3af branch: 3.13 author: Sam Gross <[email protected]> committer: colesbury <[email protected]> date: 2025-12-09T14:13:35Z summary:
[3.13] gh-142342: Fix m68k assembler operand constraints for `%fpcr` access (gh-142343) (#142459) On m68k, an fmove instruction accessing %fpcr may only move from or to a data register or a memory operand. The constraint "g" also permits the use of address registers, which is invalid. The correct constraint is "dm". Beginning with GCC 15, the register allocator picks an address register in the code which causes SIGILL during runtime. (cherry picked from commit 02c085d48b59c00fb7f4454fb13933e1c2c0b01a) Co-authored-by: John Paul Adrian Glaubitz <[email protected]> Co-authored-by: Michael Karcher <[email protected]> files: A Misc/NEWS.d/next/Core and Builtins/2025-12-08-13-04-37.gh-issue-142343.BTAyML.rst M Include/internal/pycore_pymath.h M configure M configure.ac diff --git a/Include/internal/pycore_pymath.h b/Include/internal/pycore_pymath.h index 7a4e1c1eb714f7..12d3efc33c6f03 100644 --- a/Include/internal/pycore_pymath.h +++ b/Include/internal/pycore_pymath.h @@ -146,17 +146,17 @@ extern void _Py_set_387controlword(unsigned short); unsigned int old_fpcr, new_fpcr #define _Py_SET_53BIT_PRECISION_START \ do { \ - __asm__ ("fmove.l %%fpcr,%0" : "=g" (old_fpcr)); \ + __asm__ ("fmove.l %%fpcr,%0" : "=dm" (old_fpcr)); \ /* Set double precision / round to nearest. */ \ new_fpcr = (old_fpcr & ~0xf0) | 0x80; \ if (new_fpcr != old_fpcr) { \ - __asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (new_fpcr));\ + __asm__ volatile ("fmove.l %0,%%fpcr" : : "dm" (new_fpcr)); \ } \ } while (0) #define _Py_SET_53BIT_PRECISION_END \ do { \ if (new_fpcr != old_fpcr) { \ - __asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (old_fpcr)); \ + __asm__ volatile ("fmove.l %0,%%fpcr" : : "dm" (old_fpcr)); \ } \ } while (0) #endif diff --git a/Misc/NEWS.d/next/Core and Builtins/2025-12-08-13-04-37.gh-issue-142343.BTAyML.rst b/Misc/NEWS.d/next/Core and Builtins/2025-12-08-13-04-37.gh-issue-142343.BTAyML.rst new file mode 100644 index 00000000000000..9da936c2a6f3bd --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2025-12-08-13-04-37.gh-issue-142343.BTAyML.rst @@ -0,0 +1 @@ +Fix SIGILL crash on m68k due to incorrect assembly constraint. diff --git a/configure b/configure index 901a26c9602e92..9c5b8c717eb144 100755 --- a/configure +++ b/configure @@ -24105,8 +24105,8 @@ main (void) { unsigned int fpcr; - __asm__ __volatile__ ("fmove.l %%fpcr,%0" : "=g" (fpcr)); - __asm__ __volatile__ ("fmove.l %0,%%fpcr" : : "g" (fpcr)); + __asm__ __volatile__ ("fmove.l %%fpcr,%0" : "=dm" (fpcr)); + __asm__ __volatile__ ("fmove.l %0,%%fpcr" : : "dm" (fpcr)); ; return 0; diff --git a/configure.ac b/configure.ac index 597a44b331a02f..5bd98df87f336b 100644 --- a/configure.ac +++ b/configure.ac @@ -6040,8 +6040,8 @@ AS_VAR_IF([ac_cv_gcc_asm_for_x87], [yes], [ AC_CACHE_CHECK([whether we can use gcc inline assembler to get and set mc68881 fpcr], [ac_cv_gcc_asm_for_mc68881], [ AC_LINK_IFELSE( [AC_LANG_PROGRAM([[]], [[ unsigned int fpcr; - __asm__ __volatile__ ("fmove.l %%fpcr,%0" : "=g" (fpcr)); - __asm__ __volatile__ ("fmove.l %0,%%fpcr" : : "g" (fpcr)); + __asm__ __volatile__ ("fmove.l %%fpcr,%0" : "=dm" (fpcr)); + __asm__ __volatile__ ("fmove.l %0,%%fpcr" : : "dm" (fpcr)); ]])],[ac_cv_gcc_asm_for_mc68881=yes],[ac_cv_gcc_asm_for_mc68881=no]) ]) AS_VAR_IF([ac_cv_gcc_asm_for_mc68881], [yes], [ _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
