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Always initialize thread local storage

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We had previously not enabled TLS in MODE=tiny in order to keep the
smallest example programs (e.g. life.com) just 16kb in size. But it
was error prone doing that, so now we just always enable it because
this change uses hacks to ensure it won't increase life.com's size.

This change also fixes a bug on NetBSD, where signal handlers would
break thread local storage if SA_SIGINFO was being used. This looks
like it might be a bug in NetBSD, but it's got a simple workaround.
This commit is contained in:
Justine Tunney 2022-07-18 22:26:11 -07:00
parent 057e8f5b54
commit 69f4152f38
33 changed files with 174 additions and 123 deletions
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41
libc/runtime/morph.greg.c
View file

@ -17,6 +17,7 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#define ShouldUseMsabiAttribute() 1
#include "libc/assert.h"
#include "libc/bits/asmflag.h"
#include "libc/calls/internal.h"
#include "libc/calls/strace.internal.h"
@ -58,10 +59,28 @@ static privileged void __morph_mprotect(void *addr, size_t size, int prot,
* @return 0 on success, or -1 w/ errno
*/
privileged void __morph_begin(void) {
int ax;
bool cf;
intptr_t dx;
sigset_t ss = {{-1, -1}};
STRACE("__morph_begin()");
if (!IsWindows()) {
sys_sigprocmask(SIG_BLOCK, &ss, &oldss);
if (!IsOpenbsd()) {
asm volatile("mov\t$8,%%r10d\n\t"
"syscall"
: "=a"(ax), "=d"(dx)
: "0"(__NR_sigprocmask), "D"(SIG_BLOCK), "S"(&ss),
"1"(&oldss)
: "rcx", "r10", "r11", "memory", "cc");
assert(!ax);
} else {
asm volatile(CFLAG_ASM("syscall")
: CFLAG_CONSTRAINT(cf), "=a"(ax), "=d"(dx)
: "1"(__NR_sigprocmask), "D"(SIG_BLOCK), "S"(-1u)
: "rcx", "r11", "memory");
oldss.__bits[0] = ax & 0xffffffff;
assert(!cf);
}
}
__morph_mprotect(_base, __privileged_addr - _base, PROT_READ | PROT_WRITE,
kNtPageWritecopy);
@ -71,10 +90,28 @@ privileged void __morph_begin(void) {
* Begins code morphing execuatble.
*/
privileged void __morph_end(void) {
int ax;
long dx;
bool cf;
__morph_mprotect(_base, __privileged_addr - _base, PROT_READ | PROT_EXEC,
kNtPageExecuteRead);
if (!IsWindows()) {
sys_sigprocmask(SIG_SETMASK, &oldss, 0);
if (!IsOpenbsd()) {
asm volatile("mov\t$8,%%r10d\n\t"
"syscall"
: "=a"(ax), "=d"(dx)
: "0"(__NR_sigprocmask), "D"(SIG_SETMASK), "S"(&oldss),
"1"(0)
: "rcx", "r10", "r11", "memory", "cc");
assert(!ax);
} else {
asm volatile(CFLAG_ASM("syscall")
: CFLAG_CONSTRAINT(cf), "=a"(ax), "=d"(dx)
: "1"(__NR_sigprocmask), "D"(SIG_SETMASK),
"S"(oldss.__bits[0])
: "rcx", "r11", "memory");
assert(!cf);
}
}
STRACE("__morph_end()");
}