musl/arch/x32/pthread_arch.h

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

#define MC_PC gregs[REG_RIP]

#define CANARY_PAD

#define tls_mod_off_t unsigned long long
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()`
import vanilla x86_64 code as x32 2014-01-07 21:43:34 +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__ ("mov %%fs:0,%0" : "=r" (tp) );`
			`return tp;`
import vanilla x86_64 code as x32 2014-01-07 21:43:34 +00:00			`}`

properly access mcontext_t program counter in cancellation handler using the actual mcontext_t definition rather than an overlaid pointer array both improves correctness/readability and eliminates some ugly hacks for archs with 64-bit registers bit 32-bit program counter. also fix UB due to comparison of pointers not in a common array object. 2015-11-02 17:39:28 +00:00			`#define MC_PC gregs[REG_RIP]`
fix stack protector crashes on x32 & powerpc due to misplaced TLS canary i386, x86_64, x32, and powerpc all use TLS for stack protector canary values in the default stack protector ABI, but the location only matched the ABI on i386 and x86_64. on x32, the expected location for the canary contained the tid, thus producing spurious mismatches (resulting in process termination) upon fork. on powerpc, the expected location contained the stdio_locks list head, so returning from a function after calling flockfile produced spurious mismatches. in both cases, the random canary was not present, and a predictable value was used instead, making the stack protector hardening much less effective than it should be. in the current fix, the thread structure has been expanded to have canary fields at all three possible locations, and archs that use a non-default location must define a macro in pthread_arch.h to choose which location is used. for most archs (which lack TLS canary ABI) the choice does not matter. 2015-05-06 22:37:19 +00:00
remove redundant pthread struct members repeated for layout purposes dtv_copy, canary2, and canary_at_end existed solely to match multiple ABI and asm-accessed layouts simultaneously. now that pthread_arch.h can be included before struct __pthread is defined, the struct layout can depend on macros defined by pthread_arch.h. 2020-08-25 02:45:51 +00:00			`#define CANARY_PAD`
fix crashes in x32 __tls_get_addr x32 has another gratuitous difference to all other archs: it passes an array of 64bit values to __tls_get_addr(). usually it is an array of size_t. 2017-01-13 10:28:46 +00:00
			`#define tls_mod_off_t unsigned long long`