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.

arch/powerpc/pthread_arch.h

@@ -14,5 +14,3 @@ static inline uintptr_t __get_tp()
 // the kernel calls the ip "nip", it's the first saved value after the 32
 // GPRs.
 #define MC_PC gregs[32]
-
-#define CANARY canary_at_end

arch/powerpc64/pthread_arch.h

@@ -14,5 +14,3 @@ static inline uintptr_t __get_tp()
 // the kernel calls the ip "nip", it's the first saved value after the 32
 // GPRs.
 #define MC_PC gp_regs[32]
-
-#define CANARY canary_at_end

arch/x32/pthread_arch.h

@@ -7,6 +7,6 @@ static inline uintptr_t __get_tp()
 
 #define MC_PC gregs[REG_RIP]
 
-#define CANARY canary2
+#define CANARY_PAD
 
 #define tls_mod_off_t unsigned long long

ldso/dynlink.c

@@ -1579,7 +1579,7 @@ static void install_new_tls(void)
 
 	/* Install new dtv for each thread. */
 	for (j=0, td=self; !j || td!=self; j++, td=td->next) {
-		td->dtv = td->dtv_copy = newdtv[j];
+		td->dtv = newdtv[j];
 	}
 
 	__tl_unlock();

src/env/__init_tls.c

@@ -67,7 +67,7 @@ void *__copy_tls(unsigned char *mem)
 	}
 #endif
 	dtv[0] = libc.tls_cnt;
-	td->dtv = td->dtv_copy = dtv;
+	td->dtv = dtv;
 	return td;
 }
 

src/env/__stack_chk_fail.c

@@ -9,7 +9,7 @@ void __init_ssp(void *entropy)
 	if (entropy) memcpy(&__stack_chk_guard, entropy, sizeof(uintptr_t));
 	else __stack_chk_guard = (uintptr_t)&__stack_chk_guard * 1103515245;
 
-	__pthread_self()->CANARY = __stack_chk_guard;
+	__pthread_self()->canary = __stack_chk_guard;
 }
 
 void __stack_chk_fail(void)

src/internal/pthread_impl.h

@@ -11,16 +11,25 @@
 #include "atomic.h"
 #include "futex.h"
 
+#include "pthread_arch.h"
+
 #define pthread __pthread
 
 struct pthread {
 	/* Part 1 -- these fields may be external or
 	 * internal (accessed via asm) ABI. Do not change. */
 	struct pthread *self;
+#ifndef TLS_ABOVE_TP
 	uintptr_t *dtv;
+#endif
 	struct pthread *prev, *next; /* non-ABI */
 	uintptr_t sysinfo;
-	uintptr_t canary, canary2;
+#ifndef TLS_ABOVE_TP
+#ifdef CANARY_PAD
+	uintptr_t canary_pad;
+#endif
+	uintptr_t canary;
+#endif
 
 	/* Part 2 -- implementation details, non-ABI. */
 	int tid;
@@ -52,8 +61,10 @@ struct pthread {
 
 	/* Part 3 -- the positions of these fields relative to
 	 * the end of the structure is external and internal ABI. */
-	uintptr_t canary_at_end;
-	uintptr_t *dtv_copy;
+#ifdef TLS_ABOVE_TP
+	uintptr_t canary;
+	uintptr_t *dtv;
+#endif
 };
 
 enum {
@@ -99,12 +110,6 @@ struct __timer {
 #define _b_waiters2 __u.__vi[4]
 #define _b_inst __u.__p[3]
 
-#include "pthread_arch.h"
-
-#ifndef CANARY
-#define CANARY canary
-#endif
-
 #ifndef TP_OFFSET
 #define TP_OFFSET 0
 #endif

src/thread/pthread_create.c

@@ -314,7 +314,7 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
 		new->detach_state = DT_JOINABLE;
 	}
 	new->robust_list.head = &new->robust_list.head;
-	new->CANARY = self->CANARY;
+	new->canary = self->canary;
 	new->sysinfo = self->sysinfo;
 
 	/* Setup argument structure for the new thread on its stack.