musl/arch/sh/pthread_arch.h

static inline uintptr_t __get_tp()
{
	uintptr_t tp;
	__asm__ ("stc gbr,%0" : "=r" (tp) );
	return tp;
}

#define TLS_ABOVE_TP
#define GAP_ABOVE_TP 8

#define MC_PC pc

#ifdef __FDPIC__
#define MC_GOT gregs[12]
#define CANCEL_GOT (*(uintptr_t *)((char *)__syscall_cp_asm+sizeof(uintptr_t)))
#endif
deduplicate __pthread_self thread pointer adjustment out of each arch the adjustment made is entirely a function of TLS_ABOVE_TP and TP_OFFSET. aside from avoiding repetition of the TP_OFFSET value and arithmetic, this change makes pthread_arch.h independent of the definition of struct __pthread from pthread_impl.h. this in turn will allow inclusion of pthread_arch.h to be moved to the top of pthread_impl.h so that it can influence the definition of the structure. previously, arch files were very inconsistent about the type used for the thread pointer. this change unifies the new __get_tp interface to always use uintptr_t, which is the most correct when performing arithmetic that may involve addresses outside the actual pointed-to object (due to TP_OFFSET). 2020-08-25 02:23:08 +00:00			`static inline uintptr_t __get_tp()`
superh port 2013-10-05 10:13:18 +00:00			`{`
deduplicate __pthread_self thread pointer adjustment out of each arch the adjustment made is entirely a function of TLS_ABOVE_TP and TP_OFFSET. aside from avoiding repetition of the TP_OFFSET value and arithmetic, this change makes pthread_arch.h independent of the definition of struct __pthread from pthread_impl.h. this in turn will allow inclusion of pthread_arch.h to be moved to the top of pthread_impl.h so that it can influence the definition of the structure. previously, arch files were very inconsistent about the type used for the thread pointer. this change unifies the new __get_tp interface to always use uintptr_t, which is the most correct when performing arithmetic that may involve addresses outside the actual pointed-to object (due to TP_OFFSET). 2020-08-25 02:23:08 +00:00			`uintptr_t tp;`
			`__asm__ ("stc gbr,%0" : "=r" (tp) );`
			`return tp;`
superh port 2013-10-05 10:13:18 +00:00			`}`

			`#define TLS_ABOVE_TP`
fix TLS layout of TLS variant I when there is a gap above TP In TLS variant I the TLS is above TP (or above a fixed offset from TP) but on some targets there is a reserved gap above TP before TLS starts. This matters for the local-exec tls access model when the offsets of TLS variables from the TP are hard coded by the linker into the executable, so the libc must compute these offsets the same way as the linker. The tls offset of the main module has to be alignup(GAP_ABOVE_TP, main_tls_align). If there is no TLS in the main module then the gap can be ignored since musl does not use it and the tls access models of shared libraries are not affected. The previous setup only worked if (tls_align & -GAP_ABOVE_TP) == 0 (i.e. TLS did not require large alignment) because the gap was treated as a fixed offset from TP. Now the TP points at the end of the pthread struct (which is aligned) and there is a gap above it (which may also need alignment). The fix required changing TP_ADJ and __pthread_self on affected targets (aarch64, arm and sh) and in the tlsdesc asm the offset to access the dtv changed too. 2018-06-01 23:52:01 +00:00			`#define GAP_ABOVE_TP 8`
superh port 2013-10-05 10:13:18 +00:00
sh: fix incorrect mcontext_t member naming while the layouts match, the member member naming expected by software using mcontext_t omits the sc_ prefix. 2020-12-12 04:30:53 +00:00			`#define MC_PC pc`
fix async thread cancellation on sh-fdpic if __cp_cancel was reached via __syscall_cp, r12 will necessarily still contain a GOT pointer (for libc.so or for the static-linked main program) valid for entering __cancel. however, in the case of async cancellation, r12 may contain any scratch value; it's not necessarily even a valid GOT pointer for the code that was interrupted. unlike in commit 0ec49dab6794166d67fae4764ce7fdea42ea6103 where the corresponding issue was fixed for powerpc64, there is fundamentally no way for fdpic code to recompute its GOT pointer. so a new mechanism is introduced for cancel_handler to write a GOT register value into the interrupted context on archs where it is needed. 2018-08-29 18:01:46 +00:00
			`#ifdef __FDPIC__`
sh: fix incorrect mcontext_t member naming while the layouts match, the member member naming expected by software using mcontext_t omits the sc_ prefix. 2020-12-12 04:30:53 +00:00			`#define MC_GOT gregs[12]`
fix async thread cancellation on sh-fdpic if __cp_cancel was reached via __syscall_cp, r12 will necessarily still contain a GOT pointer (for libc.so or for the static-linked main program) valid for entering __cancel. however, in the case of async cancellation, r12 may contain any scratch value; it's not necessarily even a valid GOT pointer for the code that was interrupted. unlike in commit 0ec49dab6794166d67fae4764ce7fdea42ea6103 where the corresponding issue was fixed for powerpc64, there is fundamentally no way for fdpic code to recompute its GOT pointer. so a new mechanism is introduced for cancel_handler to write a GOT register value into the interrupted context on archs where it is needed. 2018-08-29 18:01:46 +00:00			`#define CANCEL_GOT ((uintptr_t )((char *)__syscall_cp_asm+sizeof(uintptr_t)))`
			`#endif`