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Remove some legacy cruft

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Function trace logs will report stack usage accurately. It won't include
the argv/environ block. Our clone() polyfill is now simpler and does not
use as much stack memory. Function call tracing on x86 is now faster too
This commit is contained in:
Justine Tunney 2025-01-02 18:44:07 -08:00
parent 8db646f6b2
commit a15958edc6
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GPG key ID: BE714B4575D6E328
21 changed files with 291 additions and 467 deletions
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67
libc/runtime/ftracer.c
View file

@ -31,11 +31,7 @@
#include "libc/thread/tls.h"
/**
* @fileoverview Plain-text function call logging.
*
* Able to log ~2 million function calls per second, which is mostly
* bottlenecked by system call overhead. Log size is reasonable if piped
* into gzip.
* @fileoverview plain-text function call logging
*/
#define MAX_NESTING 512
@ -49,7 +45,7 @@
static struct CosmoFtrace g_ftrace;
__funline int GetNestingLevelImpl(struct StackFrame *frame) {
int nesting = -2;
int nesting = -1;
while (frame && !kisdangerous(frame)) {
++nesting;
frame = frame->next;
@ -82,38 +78,63 @@ privileged void ftracer(void) {
struct StackFrame *sf;
struct CosmoFtrace *ft;
struct PosixThread *pt;
// get interesting values
sf = __builtin_frame_address(0);
st = (uintptr_t)__argv - sizeof(uintptr_t);
if (__ftrace <= 0)
return;
// determine top of stack
// main thread won't consider kernel provided argblock
if (__tls_enabled) {
tib = __get_tls_privileged();
if (tib->tib_ftrace <= 0)
return;
ft = &tib->tib_ftracer;
if ((char *)sf >= tib->tib_sigstack_addr &&
(char *)sf <= tib->tib_sigstack_addr + tib->tib_sigstack_size) {
st = (uintptr_t)tib->tib_sigstack_addr + tib->tib_sigstack_size;
} else if ((pt = (struct PosixThread *)tib->tib_pthread) &&
pt->pt_attr.__stacksize) {
st = (uintptr_t)pt->pt_attr.__stackaddr + pt->pt_attr.__stacksize;
pt = (struct PosixThread *)tib->tib_pthread;
if (pt != &_pthread_static) {
if ((char *)sf >= tib->tib_sigstack_addr &&
(char *)sf <= tib->tib_sigstack_addr + tib->tib_sigstack_size) {
st = (uintptr_t)tib->tib_sigstack_addr + tib->tib_sigstack_size;
} else if (pt && pt->pt_attr.__stacksize) {
st = (uintptr_t)pt->pt_attr.__stackaddr + pt->pt_attr.__stacksize;
}
}
} else {
ft = &g_ftrace;
}
stackuse = st - (intptr_t)sf;
if (_cmpxchg(&ft->ft_once, false, true)) {
// estimate stack pointer of hooked function
uintptr_t usp = (uintptr_t)sf;
usp += sizeof(struct StackFrame); // overhead of this function
#if defined(__x86_64__)
usp += 8; // ftrace_hook() stack aligning
usp += 8 * 8; // ftrace_hook() pushed 8x regs
usp += 8 * 16; // ftrace_hook() pushed 8x xmms
#elif defined(__aarch64__)
usp += 384; // overhead of ftrace_hook()
#else
#error "unsupported architecture"
#endif
// determine how much stack hooked function is using
stackuse = st - usp;
// log function call
//
// FUN $PID $TID $STARTNANOS $STACKUSE $SYMBOL
//
if (!ft->ft_once) {
ft->ft_lastaddr = -1;
ft->ft_skew = GetNestingLevelImpl(sf);
ft->ft_once = true;
}
if (_cmpxchg(&ft->ft_noreentry, false, true)) {
sf = sf->next;
fn = sf->addr + DETOUR_SKEW;
if (fn != ft->ft_lastaddr) {
kprintf("%rFUN %6P %6H %'18T %'*ld %*s%t\n", ftrace_stackdigs, stackuse,
GetNestingLevel(ft, sf) * 2, "", fn);
ft->ft_lastaddr = fn;
}
ft->ft_noreentry = false;
sf = sf->next;
fn = sf->addr + DETOUR_SKEW;
if (fn != ft->ft_lastaddr) {
kprintf("%rFUN %6P %6H %'18T %'*ld %*s%t\n", ftrace_stackdigs, stackuse,
GetNestingLevel(ft, sf) * 2, "", fn);
ft->ft_lastaddr = fn;
}
}