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| author | Joseph Myers <joseph@codesourcery.com> | 2017-01-19 00:05:34 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2017-01-19 00:05:34 +0000 |
| commit | 3a66b2b0637e439fb0e7a14c6c3d4c58190eec61 (patch) | |
| tree | 04a7b7a3c6680075e33ebb1e503d6d511ff20ffb | |
| parent | cd880aa2ccabecd1a258b39b987160f0e86fd52d (diff) | |
| download | glibc-3a66b2b0637e439fb0e7a14c6c3d4c58190eec61.tar.gz glibc-3a66b2b0637e439fb0e7a14c6c3d4c58190eec61.tar.xz glibc-3a66b2b0637e439fb0e7a14c6c3d4c58190eec61.zip | |
Fix ARM fpu_control.h for assemblers requiring VFP insn names (bug 21047).
Bug 21047 reports that the clang assembler disallows the ARM implementations of _FPU_GETCW and _FPU_SETCW. These are deliberately written the way they are, using generic coprocessor instructions (from the days when VFP was just one possible coprocessor for ARM) that have the right encodings, to handle the case of the instructions being used runtime-conditionally inside glibc, where use of these macros is not meant to result in either the assembler requiring VFP to be enabled at assembly time or in it marking the object as using VFP. However, more recent ARM ARM versions have restricted the definitions of the coprocessor instructions and reportedly the clang assembler follows that in disallowing those names for VFP instructions. In the non-__SOFTFP__ case - which in fact is the only case where these macro definitions can be used outside the build of glibc itself - using VFP instruction names is of course fine, since we know that VFP is enabled for that compilation. Thus, this patch uses the current VFP names for these instructions in that case to improve compatibility for this header file. Tested for hard-float and soft-float builds of glibc, including that installed stripped shared libraries are unchanged by the patch. [BZ #21047] * sysdeps/arm/fpu_control.h [!__SOFTFP__] (_FPU_GETCW): Use VFP name for instruction. [!__SOFTFP__] (_FPU_SETCW): Likewise.
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | sysdeps/arm/fpu_control.h | 11 |
2 files changed, 16 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog index 9961dc420e..e3f3f5f01c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2017-01-19 Joseph Myers <joseph@codesourcery.com> + + [BZ #21047] + * sysdeps/arm/fpu_control.h [!__SOFTFP__] (_FPU_GETCW): Use VFP + name for instruction. + [!__SOFTFP__] (_FPU_SETCW): Likewise. + 2017-01-18 Joseph Myers <joseph@codesourcery.com> * scripts/build-many-glibcs.py (Config.build_cross_tool): Use -j1 diff --git a/sysdeps/arm/fpu_control.h b/sysdeps/arm/fpu_control.h index d49066c473..405d427c84 100644 --- a/sysdeps/arm/fpu_control.h +++ b/sysdeps/arm/fpu_control.h @@ -53,12 +53,19 @@ extern fpu_control_t __fpu_control; typedef unsigned int fpu_control_t; /* Macros for accessing the hardware control word. */ +#ifdef __SOFTFP__ /* This is fmrx %0, fpscr. */ -#define _FPU_GETCW(cw) \ +# define _FPU_GETCW(cw) \ __asm__ __volatile__ ("mrc p10, 7, %0, cr1, cr0, 0" : "=r" (cw)) /* This is fmxr fpscr, %0. */ -#define _FPU_SETCW(cw) \ +# define _FPU_SETCW(cw) \ __asm__ __volatile__ ("mcr p10, 7, %0, cr1, cr0, 0" : : "r" (cw)) +#else +# define _FPU_GETCW(cw) \ + __asm__ __volatile__ ("vmrs %0, fpscr" : "=r" (cw)) +# define _FPU_SETCW(cw) \ + __asm__ __volatile__ ("vmsr fpscr, %0" : : "r" (cw)) +#endif /* Default control word set at startup. */ extern fpu_control_t __fpu_control; |