Implement thread cancellation for aarch64

2025-01-31 03:27:39 +00:00 · 2023-09-07 08:29:16 -07:00 · 2023-09-07 08:29:16 -07:00 · 032b1f3449
commit 032b1f3449
parent dcda6f7d8d
54 changed files with 297 additions and 167 deletions
--- a/build/definitions.mk
+++ b/build/definitions.mk
@ -155,9 +155,11 @@ SANITIZER =								\
 	-fsanitize=address

 NO_MAGIC =								\
+	-ffreestanding							\
 	-fno-stack-protector						\
 	-fwrapv								\
-	-fno-sanitize=all
+	-fno-sanitize=all						\
+	-fpatchable-function-entry=0,0

 OLD_CODE =								\
 	-fno-strict-aliasing						\
--- a/examples/greenbean.c
+++ b/examples/greenbean.c
@ -186,6 +186,7 @@ void *Worker(void *id) {
    do {
      // parse the incoming http message
      InitHttpMessage(&msg, kHttpRequest);
+      // wait for http message (non-fragmented required)
      // we're not terrible concerned when errors happen here
      unassert(!pthread_setcancelstate(PTHREAD_CANCEL_MASKED, 0));
      if ((got = read(client, inbuf, sizeof(inbuf))) <= 0) break;
@ -198,9 +199,8 @@ void *Worker(void *id) {
 #if LOGGING
      // log the incoming http message
      unsigned clientip = ntohl(clientaddr.sin_addr.s_addr);
-      kprintf("\r\e[K%6P get some %d.%d.%d.%d:%d %#.*s\n",
-              (clientip & 0xff000000) >> 030, (clientip & 0x00ff0000) >> 020,
-              (clientip & 0x0000ff00) >> 010, (clientip & 0x000000ff) >> 000,
+      kprintf("\r\e[K%6P get some %hhu.%hhu.%hhu.%hhu:%hu %#.*s\n",
+              clientip >> 24, clientip >> 16, clientip >> 8, clientip,
              ntohs(clientaddr.sin_port), msg.uri.b - msg.uri.a,
              inbuf + msg.uri.a);
      SomethingHappened();
@ -314,10 +314,8 @@ int main(int argc, char *argv[]) {
  // Cosmo's GetHostIps() API is much easier than ioctl(SIOCGIFCONF)
  uint32_t *hostips;
  for (hostips = gc(GetHostIps()), i = 0; hostips[i]; ++i) {
-    kprintf("listening on http://%d.%d.%d.%d:%d\n",
-            (hostips[i] & 0xff000000) >> 030, (hostips[i] & 0x00ff0000) >> 020,
-            (hostips[i] & 0x0000ff00) >> 010, (hostips[i] & 0x000000ff) >> 000,
-            PORT);
+    kprintf("listening on http://%hhu.%hhu.%hhu.%hhu:%hu\n", hostips[i] >> 24,
+            hostips[i] >> 16, hostips[i] >> 8, hostips[i], PORT);
  }

  // you can pass the number of threads you want as the first command arg
@ -414,7 +412,7 @@ int main(int argc, char *argv[]) {
  while (!a_termsig) {
    PrintStatus();
    unassert(!pthread_cond_wait(&statuscond, &statuslock));
-    usleep(20);
+    usleep(10 * 1000);
  }
  unassert(!pthread_mutex_unlock(&statuslock));

--- a/libc/crt/crt.S
+++ b/libc/crt/crt.S
@ -121,6 +121,7 @@ _start:
 	mov	x0,sp

 //	setup the stack
+	mov	x28,#0
 	mov	x29,#0
 	mov	x30,#0
 	ldr	x1,=ape_stack_round
--- a/libc/log/appendresourcereport.c
+++ b/libc/log/appendresourcereport.c
@ -81,15 +81,15 @@ void AppendResourceReport(char **b, struct rusage *ru, const char *nl) {
    ticks = ceill((long double)(utime + stime) / (1000000.L / CLK_TCK));
    if (ru->ru_idrss) {
      AppendMetric(st, "needed ", lroundl(ru->ru_idrss / ticks),
-                   " memory on average");
-    }
-    if (ru->ru_isrss) {
-      AppendMetric(st, "needed ", lroundl(ru->ru_isrss / ticks),
-                   " stack on average");
+                   "kb private on average");
    }
    if (ru->ru_ixrss) {
      AppendMetric(st, "needed ", lroundl(ru->ru_ixrss / ticks),
-                   " shared on average");
+                   "kb shared on average");
+    }
+    if (ru->ru_isrss) {
+      AppendMetric(st, "needed ", lroundl(ru->ru_isrss / ticks),
+                   "kb stack on average");
    }
  }
  if (ru->ru_minflt || ru->ru_majflt) {
--- a/libc/sysv/calls/__sys_accept.S
+++ b/libc/sysv/calls/__sys_accept.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall __sys_accept,0x81e81ea1d281e82b,202,30,globl,hidden
+.scall __sys_accept,0x81e81ea1d281e82b,2250,30,globl,hidden
--- a/libc/sysv/calls/__sys_accept4.S
+++ b/libc/sysv/calls/__sys_accept4.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall __sys_accept4,0xfff85da1dffff920,242,4095,globl,hidden
+.scall __sys_accept4,0xfff85da1dffff920,2290,4095,globl,hidden
--- a/libc/sysv/calls/__sys_clock_nanosleep.S
+++ b/libc/sysv/calls/__sys_clock_nanosleep.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall __sys_clock_nanosleep,0x9ddfff8f4ffff8e6,115,4095,globl,hidden
+.scall __sys_clock_nanosleep,0x9ddfff8f4ffff8e6,2163,4095,globl,hidden
--- a/libc/sysv/calls/__sys_connect.S
+++ b/libc/sysv/calls/__sys_connect.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall __sys_connect,0x862862862286282a,203,98,globl,hidden
+.scall __sys_connect,0x862862862286282a,2251,98,globl,hidden
--- a/libc/sysv/calls/__sys_fcntl_cp.S
+++ b/libc/sysv/calls/__sys_fcntl_cp.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall __sys_fcntl_cp,0x85c85c85c285c848,25,92,globl,hidden
+.scall __sys_fcntl_cp,0x85c85c85c285c848,2073,92,globl,hidden
--- a/libc/sysv/calls/__sys_openat.S
+++ b/libc/sysv/calls/__sys_openat.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall __sys_openat,0x9d49419f329cf901,56,463,globl,hidden
+.scall __sys_openat,0x9d49419f329cf901,2104,463,globl,hidden
--- a/libc/sysv/calls/__sys_wait4.S
+++ b/libc/sysv/calls/__sys_wait4.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall __sys_wait4,0x9c180b807280783d,260,7,globl,hidden
+.scall __sys_wait4,0x9c180b807280783d,2308,7,globl,hidden
--- a/libc/sysv/calls/sys_copy_file_range.S
+++ b/libc/sysv/calls/sys_copy_file_range.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_copy_file_range,0xffffffa39ffff946,285,4095,globl,hidden
+.scall sys_copy_file_range,0xffffffa39ffff946,2333,4095,globl,hidden
--- a/libc/sysv/calls/sys_epoll_pwait.S
+++ b/libc/sysv/calls/sys_epoll_pwait.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_epoll_pwait,0xfffffffffffff919,22,4095,globl,hidden
+.scall sys_epoll_pwait,0xfffffffffffff919,2070,4095,globl,hidden
--- a/libc/sysv/calls/sys_fdatasync.S
+++ b/libc/sysv/calls/sys_fdatasync.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_fdatasync,0x8f185fa2628bb84b,83,187,globl,hidden
+.scall sys_fdatasync,0x8f185fa2628bb84b,2131,187,globl,hidden
--- a/libc/sysv/calls/sys_flock.S
+++ b/libc/sysv/calls/sys_flock.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_flock,0x8838838832883849,32,131,globl,hidden
+.scall sys_flock,0x8838838832883849,2080,131,globl,hidden
--- a/libc/sysv/calls/sys_fstatfs.S
+++ b/libc/sysv/calls/sys_fstatfs.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_fstatfs,0x89e840a2c295a88a,44,346,globl,hidden
+.scall sys_fstatfs,0x89e840a2c295a88a,2092,346,globl,hidden
--- a/libc/sysv/calls/sys_fsync.S
+++ b/libc/sysv/calls/sys_fsync.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_fsync,0x85f85f85f285f84a,82,95,globl,hidden
+.scall sys_fsync,0x85f85f85f285f84a,2130,95,globl,hidden
--- a/libc/sysv/calls/sys_ftruncate.S
+++ b/libc/sysv/calls/sys_ftruncate.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_ftruncate,0x8c98a89e028c984d,46,201,globl,hidden
+.scall sys_ftruncate,0x8c98a89e028c984d,2094,201,globl,hidden
--- a/libc/sysv/calls/sys_futex_cp.S
+++ b/libc/sysv/calls/sys_futex_cp.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_futex_cp,0x8a68539c6ffff8ca,98,4095,globl,hidden
+.scall sys_futex_cp,0x8a68539c6ffff8ca,2146,4095,globl,hidden
--- a/libc/sysv/calls/sys_ioctl_cp.S
+++ b/libc/sysv/calls/sys_ioctl_cp.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_ioctl_cp,0x8368368362836810,29,54,globl,hidden
+.scall sys_ioctl_cp,0x8368368362836810,2077,54,globl,hidden
--- a/libc/sysv/calls/sys_msgrcv.S
+++ b/libc/sysv/calls/sys_msgrcv.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_msgrcv,0x8e38e38e32905846,188,261,globl
+.scall sys_msgrcv,0x8e38e38e32905846,2236,261,globl
--- a/libc/sysv/calls/sys_msgsnd.S
+++ b/libc/sysv/calls/sys_msgsnd.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_msgsnd,0x8e28e28e22904845,189,260,globl
+.scall sys_msgsnd,0x8e28e28e22904845,2237,260,globl
--- a/libc/sysv/calls/sys_msync.S
+++ b/libc/sysv/calls/sys_msync.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_msync,0x915900841284181a,227,65,globl,hidden
+.scall sys_msync,0x915900841284181a,2275,65,globl,hidden
--- a/libc/sysv/calls/sys_nanosleep.S
+++ b/libc/sysv/calls/sys_nanosleep.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_nanosleep,0x9ae85b8f0ffff823,101,4095,globl,hidden
+.scall sys_nanosleep,0x9ae85b8f0ffff823,2149,4095,globl,hidden
--- a/libc/sysv/calls/sys_ppoll.S
+++ b/libc/sysv/calls/sys_ppoll.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_ppoll,0xfff86da21ffff90f,73,4095,globl,hidden
+.scall sys_ppoll,0xfff86da21ffff90f,2121,4095,globl,hidden
--- a/libc/sysv/calls/sys_pread.S
+++ b/libc/sysv/calls/sys_pread.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_pread,0x8ad8a99db2899811,67,153,globl,hidden
+.scall sys_pread,0x8ad8a99db2899811,2115,153,globl,hidden
--- a/libc/sysv/calls/sys_preadv.S
+++ b/libc/sysv/calls/sys_preadv.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_preadv,0x9218ab9212a1c927,69,540,globl,hidden
+.scall sys_preadv,0x9218ab9212a1c927,2117,540,globl,hidden
--- a/libc/sysv/calls/sys_pselect.S
+++ b/libc/sysv/calls/sys_pselect.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_pselect,0x9b486ea0a298a90e,72,394,globl,hidden
+.scall sys_pselect,0x9b486ea0a298a90e,2120,394,globl,hidden
--- a/libc/sysv/calls/sys_pwrite.S
+++ b/libc/sysv/calls/sys_pwrite.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_pwrite,0x8ae8aa9dc289a812,68,154,globl,hidden
+.scall sys_pwrite,0x8ae8aa9dc289a812,2116,154,globl,hidden
--- a/libc/sysv/calls/sys_pwritev.S
+++ b/libc/sysv/calls/sys_pwritev.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_pwritev,0x9228ac9222a1d928,70,541,globl,hidden
+.scall sys_pwritev,0x9228ac9222a1d928,2118,541,globl,hidden
--- a/libc/sysv/calls/sys_read.S
+++ b/libc/sysv/calls/sys_read.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_read,0x8038038032803800,63,3,globl,hidden
+.scall sys_read,0x8038038032803800,2111,3,globl,hidden
--- a/libc/sysv/calls/sys_readv.S
+++ b/libc/sysv/calls/sys_readv.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_readv,0x8788788782878813,65,120,globl,hidden
+.scall sys_readv,0x8788788782878813,2113,120,globl,hidden
--- a/libc/sysv/calls/sys_recvfrom.S
+++ b/libc/sysv/calls/sys_recvfrom.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_recvfrom,0x81d81d81d281d82d,207,29,globl,hidden
+.scall sys_recvfrom,0x81d81d81d281d82d,2255,29,globl,hidden
--- a/libc/sysv/calls/sys_recvmsg.S
+++ b/libc/sysv/calls/sys_recvmsg.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_recvmsg,0x81b81b81b281b82f,212,27,globl,hidden
+.scall sys_recvmsg,0x81b81b81b281b82f,2260,27,globl,hidden
--- a/libc/sysv/calls/sys_sendmsg.S
+++ b/libc/sysv/calls/sys_sendmsg.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_sendmsg,0x81c81c81c281c82e,211,28,globl,hidden
+.scall sys_sendmsg,0x81c81c81c281c82e,2259,28,globl,hidden
--- a/libc/sysv/calls/sys_sendto.S
+++ b/libc/sysv/calls/sys_sendto.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_sendto,0x885885885288582c,206,133,globl,hidden
+.scall sys_sendto,0x885885885288582c,2254,133,globl,hidden
--- a/libc/sysv/calls/sys_sigsuspend.S
+++ b/libc/sysv/calls/sys_sigsuspend.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_sigsuspend,0x92686f955286f882,133,111,globl,hidden
+.scall sys_sigsuspend,0x92686f955286f882,2181,111,globl,hidden
--- a/libc/sysv/calls/sys_sigtimedwait.S
+++ b/libc/sysv/calls/sys_sigtimedwait.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_sigtimedwait,0x9affff959ffff880,137,4095,globl,hidden
+.scall sys_sigtimedwait,0x9affff959ffff880,2185,4095,globl,hidden
--- a/libc/sysv/calls/sys_statfs.S
+++ b/libc/sysv/calls/sys_statfs.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_statfs,0x89d83fa2b2959889,43,345,globl,hidden
+.scall sys_statfs,0x89d83fa2b2959889,2091,345,globl,hidden
--- a/libc/sysv/calls/sys_truncate.S
+++ b/libc/sysv/calls/sys_truncate.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_truncate,0x8c88a79df28c884c,45,200,globl,hidden
+.scall sys_truncate,0x8c88a79df28c884c,2093,200,globl,hidden
--- a/libc/sysv/calls/sys_write.S
+++ b/libc/sysv/calls/sys_write.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_write,0x8048048042804801,64,4,globl,hidden
+.scall sys_write,0x8048048042804801,2112,4,globl,hidden
--- a/libc/sysv/calls/sys_writev.S
+++ b/libc/sysv/calls/sys_writev.S
@ -1,2 +1,2 @@
 #include "libc/sysv/macros.internal.h"
-.scall sys_writev,0x8798798792879814,66,121,globl,hidden
+.scall sys_writev,0x8798798792879814,2114,121,globl,hidden
--- a/libc/sysv/macros.internal.h
+++ b/libc/sysv/macros.internal.h
@ -35,62 +35,12 @@
  .endif
 	.endfn	\name,\kw1,\kw2
 #elif defined(__aarch64__)
-  .ifc \arm_linux,4095
-    .ifc \arm_xnu,4095
-//	return enosys();
 	.ftrace1
 \name:	.ftrace2
-	b	enosys
+	mov	x8,#\arm_linux
+	mov	x16,#\arm_xnu
+	b	systemfive
 	.endfn	\name,\kw1,\kw2
-  .else
-//	return IsXnu() ? syscall(x16, ...) : syscall(x8, ...);
-	.ftrace1
-\name:	.ftrace2
-	adrp	x9,__hostos
-	ldr	w9,[x9,#:lo12:__hostos]
-	tbz	x9,#3,1f			// !IsXnu()
-	mov	x16,#\arm_xnu			// apple ordinal
-	mov	x9,#0				// clear carry flag
-	adds	x9,x9,#0			// clear carry flag
-	svc	#0				// issue system call
-	bcs	1f
-	b	_sysret
-1:	neg	x0,x0
-	b	_sysret
-	.hidden	_sysret
-	.endfn	\name,\kw1,\kw2
-    .endif
-  .else
-    .ifc \arm_xnu,4095
-//	return IsLinux() ? syscall(x8, ...) : enosys();
-	.ftrace1
-\name:	.ftrace2
-	adrp	x9,__hostos
-	ldr	w9,[x9,#:lo12:__hostos]
-	tbz	x9,#0,1f			// !IsLinux()
-	mov	x8,#\arm_linux			// systemd ordinal
-	svc	#0				// issue system call
-	mov	x1,#\arm_linux
-	b	_sysret
-	.hidden	_sysret
-1:	b	enosys
-	.endfn	\name,\kw1,\kw2
-  .else
-	.ftrace1
-\name:	.ftrace2
-	mov	x16,#\arm_xnu			// apple ordinal
-	mov	x8,#\arm_linux			// systemd ordinal
-	mov	x9,#0				// clear carry flag
-	adds	x9,x9,#0			// clear carry flag
-	svc	#0				// issue system call
-	bcs	1f
-	b	_sysret
-1:	neg	x0,x0
-	b	_sysret
-	.hidden	_sysret
-	.endfn	\name,\kw1,\kw2
-    .endif
-  .endif
 #else
 #error "architecture unsupported"
 #endif
--- a/libc/sysv/syscalls.sh
+++ b/libc/sysv/syscalls.sh
@ -34,30 +34,30 @@ dir=libc/sysv/calls
 #	                       9.1+│  │  │ │ │  │
 #	Symbol                    ┌┴┐┌┴┐┌┴┐│┬┴┐┌┴┐      Arm64	Directives & Commentary
 scall	sys_exit		0x00100100120010e7	0x05e	globl hidden # a.k.a. exit_group
-scall	sys_read		0x8038038032803800	0x03f	globl hidden
-scall	sys_write		0x8048048042804801	0x040	globl hidden
+scall	sys_read		0x8038038032803800	0x83f	globl hidden
+scall	sys_write		0x8048048042804801	0x840	globl hidden
 scall	sys_close		0x0060060062006003	0x039	globl hidden
 scall	__sys_stat		0x1b7026fff2152004	0x04f	globl hidden # FreeBSD 11→12 fumble; use sys_fstatat(); blocked on Android
 scall	__sys_fstat		0x1b80352272153005	0x050	globl hidden # needs __stat2linux()
 scall	__sys_lstat		0x1b90280282154006	0xfff	globl hidden # needs __stat2linux(); blocked on Android
 scall	__sys_poll		0x8d18fc8d128e6807	0xfff	globl hidden
-scall	sys_ppoll		0xfff86da21ffff90f	0x049	globl hidden # consider INTON/INTOFF tutorial in examples/unbourne.c
+scall	sys_ppoll		0xfff86da21ffff90f	0x849	globl hidden # consider INTON/INTOFF tutorial in examples/unbourne.c
 scall	sys_lseek		0x0c70a61de20c7008	0x03e	globl hidden # netbsd:evilpad, OpenBSD 7.3+
 scall	__sys_mmap		0x0c50311dd20c5009	0x0de	globl hidden # netbsd:pad, OpenBSD 7.3+
-scall	sys_msync		0x915900841284181a	0x0e3	globl hidden
+scall	sys_msync		0x915900841284181a	0x8e3	globl hidden
 scall	sys_mprotect		0x04a04a04a204a00a	0x0e2	globl hidden
 scall	__sys_munmap		0x049049049204900b	0x0d7	globl hidden
 scall	sys_sigaction		0x15402e1a0202e00d	0x086	globl hidden # rt_sigaction on Lunix; __sigaction_sigtramp() on NetBSD
 scall	__sys_sigprocmask	0x125030154214900e	0x087	globl hidden # a.k.a. rt_sigprocmask, openbsd:byvalue, a.k.a. pthread_sigmask
 scall	sys_ioctl		0x0360360362036010	0x01d	globl hidden
-scall	sys_ioctl_cp		0x8368368362836810	0x01d	globl hidden # intended for TCSBRK
-scall	sys_pread		0x8ad8a99db2899811	0x043	globl hidden # a.k.a. pread64; netbsd:pad, OpenBSD 7.3+
-scall	sys_pwrite		0x8ae8aa9dc289a812	0x044	globl hidden # a.k.a. pwrite64; netbsd:pad, OpenBSD 7.3+
-scall	sys_readv		0x8788788782878813	0x041	globl hidden
-scall	sys_writev		0x8798798792879814	0x042	globl hidden
+scall	sys_ioctl_cp		0x8368368362836810	0x81d	globl hidden # intended for TCSBRK
+scall	sys_pread		0x8ad8a99db2899811	0x843	globl hidden # a.k.a. pread64; netbsd:pad, OpenBSD 7.3+
+scall	sys_pwrite		0x8ae8aa9dc289a812	0x844	globl hidden # a.k.a. pwrite64; netbsd:pad, OpenBSD 7.3+
+scall	sys_readv		0x8788788782878813	0x841	globl hidden
+scall	sys_writev		0x8798798792879814	0x842	globl hidden
 scall	__sys_pipe		0x02a10721e202a016	0x03b	globl hidden # NOTE: pipe2() on FreeBSD and Linux Aarch64; XNU is pipe(void)→eax:edx
 scall	sys_select		0x9a184785d285d817	0xfff	globl hidden
-scall	sys_pselect		0x9b486ea0a298a90e	0x048	globl hidden # pselect6() on gnu/systemd
+scall	sys_pselect		0x9b486ea0a298a90e	0x848	globl hidden # pselect6() on gnu/systemd
 scall	sys_sched_yield		0x15e12a14bf25d018	0x07c	globl hidden # select() on XNU (previously swtch() but removed in 12.4)
 scall	__sys_mremap		0x19bffffffffff019	0x0d8	globl hidden
 scall	sys_mincore		0x04e04e04e204e01b	0x0e8	globl hidden
@ -68,20 +68,20 @@ scall	sys_shmctl		0x1bb128200210701f	0x0c3	globl # no wrapper
 scall	sys_dup			0x0290290292029020	0x017	globl hidden
 scall	sys_dup2		0x05a05a05a205a021	0x018	globl hidden # dup3() on linux aarch64 (doesn't behave same if oldfd==newfd)
 scall	sys_pause		0xfffffffffffff022	0xfff	globl hidden
-scall	sys_nanosleep		0x9ae85b8f0ffff823	0x065	globl hidden
-scall	__sys_clock_nanosleep	0x9ddfff8f4ffff8e6	0x073	globl hidden
+scall	sys_nanosleep		0x9ae85b8f0ffff823	0x865	globl hidden
+scall	__sys_clock_nanosleep	0x9ddfff8f4ffff8e6	0x873	globl hidden
 scall	sys_getitimer		0x1aa0460562056024	0x066	globl hidden
 scall	sys_setitimer		0x1a90450532053026	0x067	globl hidden
 scall	sys_alarm		0xfffffffffffff025	0xfff	globl hidden
 scall	sys_getpid		0x0140140142014027	0x0ac	globl hidden # netbsd returns ppid in edx
 scall	sys_sendfile		0xffffff1892151028	0x047	globl hidden # Linux vs. XNU/BSD ABIs very different
 scall	__sys_socket		0x18a0610612061029	0x0c6	globl hidden
-scall	__sys_connect		0x862862862286282a	0x0cb	globl hidden
-scall	__sys_accept		0x81e81ea1d281e82b	0x0ca	globl hidden # accept4 on freebsd
-scall	sys_sendto		0x885885885288582c	0x0ce	globl hidden
-scall	sys_recvfrom		0x81d81d81d281d82d	0x0cf	globl hidden
-scall	sys_sendmsg		0x81c81c81c281c82e	0x0d3	globl hidden
-scall	sys_recvmsg		0x81b81b81b281b82f	0x0d4	globl hidden
+scall	__sys_connect		0x862862862286282a	0x8cb	globl hidden
+scall	__sys_accept		0x81e81ea1d281e82b	0x8ca	globl hidden # accept4 on freebsd
+scall	sys_sendto		0x885885885288582c	0x8ce	globl hidden
+scall	sys_recvfrom		0x81d81d81d281d82d	0x8cf	globl hidden
+scall	sys_sendmsg		0x81c81c81c281c82e	0x8d3	globl hidden
+scall	sys_recvmsg		0x81b81b81b281b82f	0x8d4	globl hidden
 scall	sys_shutdown		0x0860860862086030	0x0d2	globl hidden
 scall	__sys_bind		0x0680680682068031	0x0c8	globl hidden
 scall	sys_listen		0x06a06a06a206a032	0x0c9	globl hidden
@ -94,14 +94,14 @@ scall	__sys_fork		0x0020020022002039	0xfff	globl hidden # xnu needs eax&=~-edx b
 #scall	vfork			0x042042042204203a	0xfff	globl        # this syscall is from the moon so we implement it by hand in libc/runtime/vfork.S; probably removed from XNU in 12.5
 scall	sys_posix_spawn		0x1daffffff20f4fff	0xfff	globl hidden # good luck figuring out how xnu defines this
 scall	__sys_execve		0x03b03b03b203b03b	0x0dd	globl hidden
-scall	__sys_wait4		0x9c180b807280783d	0x104	globl hidden
+scall	__sys_wait4		0x9c180b807280783d	0x904	globl hidden
 scall	sys_kill		0x02507a025202503e	0x081	globl hidden # kill(pid, sig, 1) b/c xnu
 scall	sys_killpg		0x092fff092fffffff	0xfff	globl hidden
 scall	sys_clone		0x11fffffffffff038	0x0dc	globl hidden
 scall	sys_tkill		0x13e0771b121480c8	0x082	globl hidden # thr_kill() on FreeBSD; _lwp_kill() on NetBSD; thrkill() on OpenBSD where arg3 should be 0 or tcb; __pthread_kill() on XNU
 scall	sys_tgkill		0xffffff1e1ffff0ea	0x083	globl hidden # thr_kill2() on FreeBSD
 scall	sys_futex		0x0a60531c6ffff0ca	0x062	globl hidden # raises SIGSYS on NetBSD; _umtx_op() on FreeBSD
-scall	sys_futex_cp		0x8a68539c6ffff8ca	0x062	globl hidden # intended for futex wait ops
+scall	sys_futex_cp		0x8a68539c6ffff8ca	0x862	globl hidden # intended for futex wait ops
 scall	sys_set_robust_list	0x0a7ffffffffff111	0x063	globl # no wrapper
 scall	sys_get_robust_list	0x0a8ffffffffff112	0x064	globl # no wrapper
 scall	sys_uname		0x0a4fff0a4ffff03f	0x0a0	globl hidden
@ -110,16 +110,16 @@ scall	sys_semop		0x0de1220de2100041	0x0c1	globl # no wrapper
 scall	sys_semctl		0xfff1271fe20fe042	0x0bf	globl # no wrapper
 scall	sys_shmdt		0x0e60e60e62108043	0x0c5	globl # no wrapper
 scall	sys_msgget		0x0e10e10e12103044	0x0ba	globl # no wrapper
-scall	sys_msgsnd		0x8e28e28e22904845	0x0bd	globl # no wrapper
-scall	sys_msgrcv		0x8e38e38e32905846	0x0bc	globl # no wrapper
+scall	sys_msgsnd		0x8e28e28e22904845	0x8bd	globl # no wrapper
+scall	sys_msgrcv		0x8e38e38e32905846	0x8bc	globl # no wrapper
 scall	sys_msgctl		0x1bc1291ff2102047	0x0bb	globl # no wrapper
 scall	__sys_fcntl		0x05c05c05c205c048	0x019	globl hidden
-scall	__sys_fcntl_cp		0x85c85c85c285c848	0x019	globl hidden # intended for F_SETLKW and F_OFD_SETLKW
-scall	sys_flock		0x8838838832883849	0x020	globl hidden
-scall	sys_fsync		0x85f85f85f285f84a	0x052	globl hidden
-scall	sys_fdatasync		0x8f185fa2628bb84b	0x053	globl hidden # fsync() on openbsd
-scall	sys_truncate		0x8c88a79df28c884c	0x02d	globl hidden # netbsd:pad, OpenBSD 7.3+
-scall	sys_ftruncate		0x8c98a89e028c984d	0x02e	globl hidden # netbsd:pad, OpenBSD 7.3+
+scall	__sys_fcntl_cp		0x85c85c85c285c848	0x819	globl hidden # intended for F_SETLKW and F_OFD_SETLKW
+scall	sys_flock		0x8838838832883849	0x820	globl hidden
+scall	sys_fsync		0x85f85f85f285f84a	0x852	globl hidden
+scall	sys_fdatasync		0x8f185fa2628bb84b	0x853	globl hidden # fsync() on openbsd
+scall	sys_truncate		0x8c88a79df28c884c	0x82d	globl hidden # netbsd:pad, OpenBSD 7.3+
+scall	sys_ftruncate		0x8c98a89e028c984d	0x82e	globl hidden # netbsd:pad, OpenBSD 7.3+
 scall	sys_getcwd		0x128130146ffff04f	0x011	globl hidden
 scall	sys_chdir		0x00c00c00c200c050	0x031	globl hidden
 scall	sys_fchdir		0x00d00d00d200d051	0x032	globl hidden
@ -154,14 +154,14 @@ scall	sys_setresgid		0xfff11c138ffff077	0x095	globl hidden # polyfilled for xnu
 scall	sys_getresuid		0xfff119168ffff076	0x094	globl hidden # semantics aren't well-defined
 scall	sys_getresgid		0xfff11b169ffff078	0x096	globl hidden # semantics aren't well-defined
 scall	sys_sigpending		0x124034157203407f	0x088	globl hidden # a.k.a. rt_sigpending on linux
-scall	sys_sigsuspend		0x92686f955286f882	0x085	globl hidden # a.k.a. rt_sigsuspend on Linux; openbsd:byvalue, sigsuspend_nocancel on XNU
+scall	sys_sigsuspend		0x92686f955286f882	0x885	globl hidden # a.k.a. rt_sigsuspend on Linux; openbsd:byvalue, sigsuspend_nocancel on XNU
 scall	sys_sigaltstack		0x1191200352035083	0x084	globl hidden
 scall	sys_mknod		0x1c200e00e200e085	0xfff	globl hidden
 scall	sys_mknodat		0x1cc14022fffff103	0x021	globl # no wrapper; FreeBSD 12+
 scall	sys_mkfifo		0x0840840842084fff	0xfff	globl hidden
 scall	sys_mkfifoat		0x1cb13f1f1fffffff	0xfff	globl # no wrapper
-scall	sys_statfs		0x89d83fa2b2959889	0x02b	globl hidden
-scall	sys_fstatfs		0x89e840a2c295a88a	0x02c	globl hidden
+scall	sys_statfs		0x89d83fa2b2959889	0x82b	globl hidden
+scall	sys_fstatfs		0x89e840a2c295a88a	0x82c	globl hidden
 scall	sys_getpriority		0x064064064206408c	0x08d	globl hidden
 scall	sys_setpriority		0x060060060206008d	0x08c	globl hidden # modern nice()
 scall	sys_mlock		0x0cb0cb0cb20cb095	0x0e4	globl # no wrapper
@ -182,7 +182,7 @@ scall	sys_setfsuid		0xfffffffffffff07a	0x097	globl hidden
 scall	sys_setfsgid		0xfffffffffffff07b	0x098	globl hidden
 scall	sys_capget		0xfffffffffffff07d	0x05a	globl # no wrapper
 scall	sys_capset		0xfffffffffffff07e	0x05b	globl # no wrapper
-scall	sys_sigtimedwait	0x9affff959ffff880	0x089	globl hidden
+scall	sys_sigtimedwait	0x9affff959ffff880	0x889	globl hidden
 scall	sys_sigqueue		0xffffff1c8fffffff	0xfff	globl hidden
 scall	sys_sigqueueinfo	0x0f5ffffffffff081	0x08a	globl hidden # a.k.a. rt_sigqueueinfo on linux
 scall	sys_personality		0xfffffffffffff087	0x05c	globl # no wrapper
@ -272,7 +272,7 @@ scall	sys_ioprio_get		0xfffffffffffff0fc	0x01f	globl
 scall	sys_inotify_init	0xfffffffffffff0fd	0xfff	globl # no wrapper
 scall	sys_inotify_add_watch	0xfffffffffffff0fe	0xfff	globl # no wrapper
 scall	sys_inotify_rm_watch	0xfffffffffffff0ff	0xfff	globl # no wrapper
-scall	__sys_openat		0x9d49419f329cf901	0x038	globl hidden # Linux 2.6.16+ (c. 2007)
+scall	__sys_openat		0x9d49419f329cf901	0x838	globl hidden # Linux 2.6.16+ (c. 2007)
 scall	__sys_openat_nc		0x1d41411f321d0101	0x038	globl hidden # openat_nocancel() on xnu
 scall	sys_mkdirat		0x1cd13e1f021db102	0x022	globl hidden
 scall	sys_fchownat		0x1d013b1eb21d4104	0x036	globl hidden # @asyncsignalsafe
@ -296,15 +296,15 @@ scall	sys_vmsplice		0xfffffffffffff116	0x04b	globl hidden
 scall	sys_migrate_pages	0xfffffffffffff100	0x0ee	globl        # no wrapper; numa numa yay
 scall	sys_move_pages		0xfffffffffffff117	0x0ef	globl        # no wrapper; NOTE: We view Red Hat versions as "epochs" for all distros.
 #──────────────────────RHEL 5.0 LIMIT────────────────────────────────        # ←┬─ last distro with gplv2 licensed compiler c. 2007
-scall	sys_preadv		0x9218ab9212a1c927	0x045	globl hidden #  ├─ last distro with system v shell script init
-scall	sys_pwritev		0x9228ac9222a1d928	0x046	globl hidden #  ├─ rob landley unleashes busybox gpl lawsuits
+scall	sys_preadv		0x9218ab9212a1c927	0x845	globl hidden #  ├─ last distro with system v shell script init
+scall	sys_pwritev		0x9228ac9222a1d928	0x846	globl hidden #  ├─ rob landley unleashes busybox gpl lawsuits
 scall	__sys_utimensat		0x1d3054223ffff118	0x058	globl hidden #  ├─ python modules need this due to pep513
 scall	sys_fallocate		0xfffffffffffff91d	0x02f	globl        #  ├─ end of life 2020-11-30 (extended)
 scall	sys_posix_fallocate	0x9dffffa12fffffff	0xfff	globl hidden #  └─ cosmopolitan supports rhel5+
-scall	__sys_accept4		0xfff85da1dffff920	0x0f2	globl hidden # Linux 2.6.28+
+scall	__sys_accept4		0xfff85da1dffff920	0x8f2	globl hidden # Linux 2.6.28+
 scall	__sys_dup3		0x1c6066fffffff124	0x018	globl hidden # Linux 2.6.27+
 scall	__sys_pipe2		0x1c506521effff125	0x03b	globl hidden # Linux 2.6.27+
-scall	sys_epoll_pwait		0xfffffffffffff919	0x016	globl hidden
+scall	sys_epoll_pwait		0xfffffffffffff919	0x816	globl hidden
 scall	sys_epoll_create1	0xfffffffffffff123	0x014	globl hidden
 scall	sys_perf_event_open	0xfffffffffffff12a	0x0f1	globl # no wrapper
 scall	sys_inotify_init1	0xfffffffffffff126	0x01a	globl # no wrapper
@ -345,7 +345,7 @@ scall	sys_execveat		0xfffffffffffff142	0x119	globl # no wrapper
 scall	sys_userfaultfd		0xfffffffffffff143	0x11a	globl # no wrapper; Linux 4.3+ (c. 2015)
 scall	sys_membarrier		0xfffffffffffff144	0x11b	globl # no wrapper; Linux 4.3+ (c. 2015)
 scall	sys_mlock2		0xfffffffffffff145	0x11c	globl # no wrapper; Linux 4.5+ (c. 2016)
-scall	sys_copy_file_range	0xffffffa39ffff946	0x11d	globl hidden # Linux 4.5+ (c. 2016), FreeBSD 13+
+scall	sys_copy_file_range	0xffffffa39ffff946	0x91d	globl hidden # Linux 4.5+ (c. 2016), FreeBSD 13+
 scall	sys_preadv2		0xfffffffffffff147	0x11e	globl # no wrapper
 scall	sys_pwritev2		0xfffffffffffff148	0x11f	globl # no wrapper
 scall	sys_pkey_mprotect	0xfffffffffffff149	0x120	globl # no wrapper
--- a/libc/sysv/sysv.c
+++ b/libc/sysv/sysv.c
@ -0,0 +1,157 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/syscall-sysv.internal.h"
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/intrin/atomic.h"
+#include "libc/intrin/weaken.h"
+#include "libc/thread/posixthread.internal.h"
+#include "libc/thread/tls.h"
+#ifndef __x86_64__
+
+// todo(jart): dismal llvm
+register long x0 asm("x0");
+register long x1 asm("x1");
+register long x2 asm("x2");
+register long x3 asm("x3");
+register long x4 asm("x4");
+register long x5 asm("x5");
+register long sysv_ordinal asm("x8");
+register long xnu_ordinal asm("x16");
+register long cosmo_tls_register asm("x28");
+
+void report_cancellation_point(void);
+
+dontinline long systemfive_cancel(void) {
+  return _pthread_cancel_sys();
+}
+
+// special region of executable memory where cancellation is safe
+dontinline long systemfive_cancellable(void) {
+
+  // check (1) this is a cancellation point
+  // plus (2) cancellations aren't disabled
+  struct PosixThread *pth = 0;
+  struct CosmoTib *tib = __get_tls();
+  if (cosmo_tls_register &&               //
+      _weaken(_pthread_cancel_sys) &&     //
+      !(tib->tib_flags & PT_NOCANCEL) &&  //
+      (pth = (struct PosixThread *)tib->tib_pthread)) {
+    // check if cancellation is already pending
+    if (atomic_load_explicit(&pth->cancelled, memory_order_acquire)) {
+      return systemfive_cancel();
+    }
+#if IsModeDbg()
+    if (!(tib->tib_flags & PT_INCANCEL)) {
+      if (_weaken(report_cancellation_point)) {
+        _weaken(report_cancellation_point)();
+      }
+      __builtin_trap();
+    }
+#endif
+  }
+
+  // invoke cancellable system call
+  // this works for both linux and bsd
+  asm volatile("mov\tx9,0\n\t"      // clear carry flag
+               "adds\tx9,x9,0\n\t"  // clear carry flag
+               "svc\t0\n"
+               "systemfive_cancellable_end:\n\t"
+               ".globl\tsystemfive_cancellable_end\n\t"
+               "bcs\t1f\n\t"
+               "b\t2f\n1:\t"
+               "neg\tx0,x0\n2:"
+               : /* global output */
+               : /* global inputs */
+               : "x9", "memory");
+
+  // if it succeeded then we're done
+  if (x0 < -4095ul) {
+    return x0;
+  }
+
+  // check if i/o call was interrupted by sigthr
+  if (pth && x0 == -EINTR &&
+      atomic_load_explicit(&pth->cancelled, memory_order_acquire)) {
+    return systemfive_cancel();
+  }
+
+  // otherwise go down error path
+  return _sysret(x0);
+}
+
+/**
+ * System Five System Call Support.
+ *
+ * This supports POSIX thread cancellation only when the caller flips a
+ * bit in TLS storage that indicates we're inside a cancellation point.
+ *
+ * @param x0 is first argument
+ * @param x1 is second argument
+ * @param x2 is third argument
+ * @param x3 is fourth argument
+ * @param x4 is fifth argument
+ * @param x5 is sixth argument
+ * @param sysv_ordinal is linux ordinal
+ * @param xnu_ordinal is xnu ordinal
+ * @return x0
+ */
+long systemfive(void) {
+
+  // handle special cases
+  if (IsLinux()) {
+    if (sysv_ordinal == 0xfff) {
+      return _sysret(-ENOSYS);
+    }
+    if (sysv_ordinal & 0x800) {
+      sysv_ordinal &= ~0x800;
+      return systemfive_cancellable();
+    }
+  }
+  if (IsXnu()) {
+    if (xnu_ordinal == 0xfff) {
+      return _sysret(-ENOSYS);
+    }
+    if (xnu_ordinal & 0x800) {
+      xnu_ordinal &= ~0x800;
+      return systemfive_cancellable();
+    }
+  }
+
+  // invoke non-blocking system call
+  // this works for both linux and bsd
+  asm volatile("mov\tx9,0\n\t"      // clear carry flag
+               "adds\tx9,x9,0\n\t"  // clear carry flag
+               "svc\t0\n\t"
+               "bcs\t1f\n\t"
+               "b\t2f\n1:\t"
+               "neg\tx0,x0\n2:"
+               : /* global output */
+               : /* global inputs */
+               : "x9", "memory");
+
+  // check result
+  if (x0 < -4095ul) {
+    return x0;
+  } else {
+    return _sysret(x0);
+  }
+}
+
+#endif /* __x86_64__ */
--- a/libc/sysv/sysv.mk
+++ b/libc/sysv/sysv.mk
@ -41,6 +41,7 @@ LIBC_SYSV_A_FILES :=					\
 	libc/sysv/syscall.S				\
 	libc/sysv/systemfive.S				\
 	libc/sysv/sysret.c				\
+	libc/sysv/sysv.c				\
 	libc/sysv/errno.c				\
 	libc/sysv/errfun.S				\
 	libc/sysv/errfun2.c				\
@ -73,6 +74,7 @@ $(LIBC_SYSV_A).pkg:					\
 		$(LIBC_SYSV_A_OBJS)			\
 		$(foreach x,$(LIBC_SYSV_A_DIRECTDEPS),$($(x)_A).pkg)

+o/$(MODE)/libc/sysv/sysv.o				\
 o/$(MODE)/libc/sysv/errno.o				\
 o/$(MODE)/libc/sysv/sysret.o				\
 o/$(MODE)/libc/sysv/errfun2.o				\
@ -80,6 +82,22 @@ o/$(MODE)/libc/sysv/sysret.o: private			\
 		CFLAGS +=				\
 			$(NO_MAGIC)

+ifeq ($(ARCH),aarch64)
+o/$(MODE)/libc/sysv/sysv.o: private			\
+		CFLAGS +=				\
+			-ffixed-x0			\
+			-ffixed-x1			\
+			-ffixed-x2			\
+			-ffixed-x3			\
+			-ffixed-x4			\
+			-ffixed-x5			\
+			-ffixed-x8			\
+			-ffixed-x16			\
+			-fomit-frame-pointer		\
+			-foptimize-sibling-calls	\
+			-Os
+endif
+
 #───────────────────────────────────────────────────────────────────────────────

 LIBC_SYSV_CALLS =					\
--- a/libc/thread/posixthread.internal.h
+++ b/libc/thread/posixthread.internal.h
@ -97,8 +97,8 @@ void _pthread_free(struct PosixThread *);
 void _pthread_onfork_prepare(void);
 void _pthread_onfork_parent(void);
 void _pthread_onfork_child(void);
+long _pthread_cancel_sys(void);
 void _pthread_ungarbage(void);
-int _pthread_cancel_sys(void);

 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
--- a/libc/thread/pthread_cancel.c
+++ b/libc/thread/pthread_cancel.c
@ -21,11 +21,13 @@
 #include "libc/calls/struct/sigaction.h"
 #include "libc/calls/struct/siginfo.h"
 #include "libc/calls/struct/sigset.h"
+#include "libc/calls/struct/ucontext.internal.h"
 #include "libc/calls/syscall_support-sysv.internal.h"
 #include "libc/calls/ucontext.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
 #include "libc/intrin/atomic.h"
+#include "libc/intrin/kprintf.h"
 #include "libc/runtime/runtime.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/sa.h"
@ -34,14 +36,13 @@
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
-#ifdef __x86_64__

 int systemfive_cancel(void);

 extern const char systemfive_cancellable[];
 extern const char systemfive_cancellable_end[];

-int _pthread_cancel_sys(void) {
+long _pthread_cancel_sys(void) {
  struct PosixThread *pt;
  pt = (struct PosixThread *)__get_tls()->tib_pthread;
  if (!(pt->flags & (PT_NOCANCEL | PT_MASKED)) || (pt->flags & PT_ASYNC)) {
@ -60,9 +61,9 @@ static void OnSigThr(int sig, siginfo_t *si, void *ctx) {
      !(pt->flags & PT_NOCANCEL) &&
      atomic_load_explicit(&pt->cancelled, memory_order_acquire)) {
    sigaddset(&uc->uc_sigmask, sig);
-    if (systemfive_cancellable <= (char *)uc->uc_mcontext.rip &&
-        (char *)uc->uc_mcontext.rip < systemfive_cancellable_end) {
-      uc->uc_mcontext.rip = (intptr_t)systemfive_cancel;
+    if (systemfive_cancellable <= (char *)uc->uc_mcontext.PC &&
+        (char *)uc->uc_mcontext.PC < systemfive_cancellable_end) {
+      uc->uc_mcontext.PC = (intptr_t)systemfive_cancel;
    } else if (pt->flags & PT_ASYNC) {
      pthread_exit(PTHREAD_CANCELED);
    } else {
@ -302,8 +303,6 @@ errno_t pthread_cancel(pthread_t thread) {
  return rc;
 }

-#endif /* __x86_64__ */
-
 /**
 * Creates cancellation point in calling thread.
 *
--- a/libc/thread/pthread_create.c
+++ b/libc/thread/pthread_create.c
@ -17,6 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/assert.h"
+#include "libc/atomic.h"
 #include "libc/calls/blocksigs.internal.h"
 #include "libc/calls/calls.h"
 #include "libc/calls/struct/sigaltstack.h"
@ -28,6 +29,7 @@
 #include "libc/intrin/bits.h"
 #include "libc/intrin/bsr.h"
 #include "libc/intrin/dll.h"
+#include "libc/intrin/popcnt.h"
 #include "libc/log/internal.h"
 #include "libc/macros.internal.h"
 #include "libc/mem/mem.h"
@ -58,6 +60,7 @@ static unsigned long roundup2pow(unsigned long x) {
 }

 void _pthread_free(struct PosixThread *pt) {
+  static atomic_uint freed;
  if (pt->flags & PT_STATIC) return;
  free(pt->tls);
  if ((pt->flags & PT_OWNSTACK) &&  //
@ -69,6 +72,9 @@ void _pthread_free(struct PosixThread *pt) {
    free(pt->altstack);
  }
  free(pt);
+  if (popcnt(atomic_fetch_add_explicit(&freed, 1, memory_order_acq_rel)) == 1) {
+    malloc_trim(0);
+  }
 }

 void pthread_kill_siblings_np(void) {
--- a/libc/thread/pthread_decimate_np.c
+++ b/libc/thread/pthread_decimate_np.c
@ -16,19 +16,18 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/atomic.h"
 #include "libc/intrin/atomic.h"
 #include "libc/intrin/dll.h"
 #include "libc/runtime/runtime.h"
 #include "libc/thread/posixthread.internal.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/tls.h"
-#include "third_party/dlmalloc/dlmalloc.h"

 /**
 * Releases memory of detached threads that have terminated.
 */
 void pthread_decimate_np(void) {
-  bool empty;
  struct Dll *e;
  struct PosixThread *pt;
  enum PosixThreadStatus status;
@ -46,9 +45,5 @@ StartOver:
      goto StartOver;
    }
  }
-  empty = dll_is_empty(_pthread_list);
  pthread_spin_unlock(&_pthread_lock);
-  if (empty) {
-    dlmalloc_trim(0);
-  }
 }
--- a/libc/thread/thread.mk
+++ b/libc/thread/thread.mk
@ -34,7 +34,6 @@ LIBC_THREAD_A_DIRECTDEPS =				\
 	LIBC_STR					\
 	LIBC_SYSV					\
 	LIBC_SYSV_CALLS					\
-	THIRD_PARTY_DLMALLOC				\
 	THIRD_PARTY_NSYNC				\
 	THIRD_PARTY_NSYNC_MEM

--- a/libc/thread/tls.h
+++ b/libc/thread/tls.h
@ -44,9 +44,15 @@ extern unsigned __tls_index;
 #ifdef __x86_64__
 extern bool __tls_enabled;
 #define __tls_enabled_set(x) __tls_enabled = x
-#else
-#define __tls_enabled        true
+#elif defined(__aarch64__)
+#define __tls_enabled                        \
+  ({                                         \
+    register struct CosmoTib *_t asm("x28"); \
+    !!_t;                                    \
+  })
 #define __tls_enabled_set(x) (void)0
+#else
+#error "unsupported architecture"
 #endif

 void __require_tls(void);
--- a/test/libc/thread/pthread_cancel_test.c
+++ b/test/libc/thread/pthread_cancel_test.c
@ -21,6 +21,7 @@
 #include "libc/calls/calls.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
+#include "libc/intrin/kprintf.h"
 #include "libc/mem/gc.h"
 #include "libc/mem/mem.h"
 #include "libc/nexgen32e/nexgen32e.h"
@ -29,7 +30,6 @@
 #include "libc/testlib/testlib.h"
 #include "libc/thread/thread.h"
 #include "libc/thread/thread2.h"
-#ifdef __x86_64__

 int pfds[2];
 pthread_cond_t cv;
@ -229,12 +229,14 @@ void *CpuBoundWorker(void *arg) {
  (void)wontleak2;
  ASSERT_EQ(0, pthread_setspecific(key, (void *)31337));
  ASSERT_EQ(0, pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, 0));
-#ifdef __x86_64__
  for (;;) {
+#ifdef __x86_64__
    TortureStack();
+#else
+    CheckStackIsAligned();
+#endif
    is_in_infinite_loop = true;
  }
-#endif
  pthread_cleanup_pop(1);
  free(wouldleak);
  return 0;
@ -282,5 +284,3 @@ TEST(pthread_cancel, self_asynchronous_takesImmediateEffect) {
  ASSERT_SYS(0, 0, close(pfds[1]));
  ASSERT_SYS(0, 0, close(pfds[0]));
 }
-
-#endif /* __x86_64__ */
--- a/tool/emacs/cosmo-c-keywords.el
+++ b/tool/emacs/cosmo-c-keywords.el
@ -204,7 +204,6 @@
           "__vector_size__"
           "__ms_abi__"
           "__sysv_abi__"
-           "systemfive"
           "__mode__"
           "__seg_fs"
           "__seg_gs"))