From 61b1e75f7d8004461f2e18f171c26c2f545eed32 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 21 Jan 2016 19:28:15 +0000 Subject: overhaul sh atomics for new atomics framework, add j-core cas.l backend sh needs runtime-selected atomic backends since there are a number of supported models that use non-forwards-compatible (non-smp-compatible) atomic mechanisms. previously, the code paths for this were highly inefficient since they involved C function calls with multiple branches in the callee and heavy spills in the caller. the new code performs calls the runtime-selected asm fragment from inline asm with extremely minimal clobbers, rather than using a function call. for the sh4a case where the atomic mechanism is known and there is no forward-compatibility issue, the movli.l and movco.l instructions are provided as a_ll and a_sc, allowing the new shared atomic.h to generate efficient inline versions of all the basic atomic operations without needing a cas loop. --- src/thread/sh/__set_thread_area.c | 40 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 src/thread/sh/__set_thread_area.c (limited to 'src/thread/sh/__set_thread_area.c') diff --git a/src/thread/sh/__set_thread_area.c b/src/thread/sh/__set_thread_area.c new file mode 100644 index 00000000..9c47f78d --- /dev/null +++ b/src/thread/sh/__set_thread_area.c @@ -0,0 +1,40 @@ +#include "pthread_impl.h" +#include "libc.h" +#include + +/* Also perform sh-specific init */ + +#define CPU_HAS_LLSC 0x0040 +#define CPU_HAS_CAS_L 0x0400 + +__attribute__((__visibility__("hidden"))) +extern const char __sh_cas_gusa[], __sh_cas_llsc[], __sh_cas_imask[], __sh_cas_cas_l[]; + +__attribute__((__visibility__("hidden"))) +const void *__sh_cas_ptr; + +__attribute__((__visibility__("hidden"))) +unsigned __sh_nommu; + +int __set_thread_area(void *p) +{ + size_t *aux; + __asm__ __volatile__ ( "ldc %0, gbr" : : "r"(p) : "memory" ); +#ifndef __SH4A__ + __sh_cas_ptr = __sh_cas_gusa; +#if !defined(__SH3__) && !defined(__SH4__) + for (aux=libc.auxv; *aux; aux+=2) { + if (*aux != AT_PLATFORM) continue; + const char *s = (void *)aux[1]; + if (s[0]!='s' || s[1]!='h' || s[2]!='2' || s[3]-'0'<10u) break; + __sh_cas_ptr = __sh_cas_imask; + __sh_nommu = 1; + } +#endif + if (__hwcap & CPU_HAS_CAS_L) + __sh_cas_ptr = __sh_cas_cas_l; + else if (__hwcap & CPU_HAS_LLSC) + __sh_cas_ptr = __sh_cas_llsc; +#endif + return 0; +} -- cgit 1.4.1