musl/arch/powerpc64/pthread_arch.h

static inline uintptr_t __get_tp()
{
	register uintptr_t tp __asm__("r13");
	__asm__ ("" : "=r" (tp) );
	return tp;
}

#define TLS_ABOVE_TP
#define GAP_ABOVE_TP 0

#define TP_OFFSET 0x7000
#define DTP_OFFSET 0x8000

// the kernel calls the ip "nip", it's the first saved value after the 32
// GPRs.
#define MC_PC gp_regs[32]
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()`
add powerpc64 port 2016-05-01 00:18:17 +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			`register uintptr_t tp __asm__("r13");`
make thread-pointer-loading asm non-volatile this will allow the compiler to cache and reuse the result, meaning we no longer have to take care not to load it more than once for the sake of archs where the load may be expensive. depends on commit 1c84c99913bf1cd47b866ed31e665848a0da84a2 for correctness, since otherwise the compiler could hoist loads during stage 3 of dynamic linking before the initial thread-pointer setup. 2018-10-16 18:08:01 +00:00			`__asm__ ("" : "=r" (tp) );`
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			`return tp;`
add powerpc64 port 2016-05-01 00:18:17 +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 0`
add powerpc64 port 2016-05-01 00:18:17 +00:00
deduplicate TP_ADJ logic out of each arch, replace with TP_OFFSET the only part of TP_ADJ that was not uniquely determined by TLS_ABOVE_TP was the 0x7000 adjustment used mainly on mips and powerpc variants. 2020-08-25 02:04:52 +00:00			`#define TP_OFFSET 0x7000`
add powerpc64 port 2016-05-01 00:18:17 +00:00			`#define DTP_OFFSET 0x8000`

			`// the kernel calls the ip "nip", it's the first saved value after the 32`
			`// GPRs.`
			`#define MC_PC gp_regs[32]`