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LibC: Communicate malloc() and free() operations to UserspaceEmulator

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Use the sneaky SALC secret mechanism of UserspaceEmulator to inform it
about malloc operations.
This commit is contained in:
Andreas Kling 2020-07-15 21:54:18 +02:00
parent c314292319
commit 4aa81a4fd9
Notes: sideshowbarker 2024-07-19 04:47:30 +09:00 
Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/4aa81a4fd93
2 changed files with 24 additions and 0 deletions
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7
Libraries/LibC/malloc.cpp
View file

@ -281,6 +281,10 @@ static void* malloc_impl(size_t size)
#ifdef MALLOC_DEBUG
dbgprintf("LibC: allocated %p (chunk in block %p, size %zu)\n", ptr, block, block->bytes_per_chunk());
#endif
// Tell UserspaceEmulator about this malloc()
send_secret_data_to_userspace_emulator(1, size, reinterpret_cast<FlatPtr>(ptr));
if (s_scrub_malloc)
memset(ptr, MALLOC_SCRUB_BYTE, block->m_size);
return ptr;
@ -382,6 +386,9 @@ void free(void* ptr)
if (s_profiling)
perf_event(PERF_EVENT_FREE, reinterpret_cast<FlatPtr>(ptr), 0);
free_impl(ptr);
// Tell UserspaceEmulator about this free()
send_secret_data_to_userspace_emulator(2, reinterpret_cast<FlatPtr>(ptr), 0);
}
void* calloc(size_t count, size_t size)

17
Libraries/LibC/serenity.h
View file

@ -70,4 +70,21 @@ int perf_event(int type, uintptr_t arg1, uintptr_t arg2);
int get_stack_bounds(uintptr_t* user_stack_base, size_t* user_stack_size);
ALWAYS_INLINE void send_secret_data_to_userspace_emulator(uintptr_t data1, uintptr_t data2, uintptr_t data3)
{
asm volatile(
".byte 0xd6\n"
".byte 0xd6\n" ::
: "eax");
asm volatile(
"push %%eax\n"
"push %%ecx\n"
"push %%edx\n"
"pop %%edx\n"
"pop %%ecx\n"
"pop %%eax\n" ::"a"(data1),
"c"(data2), "d"(data3)
: "memory");
}
__END_DECLS