mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-09 11:25:00 +00:00
Bug 773903 - ~1s shutdown delay in xpcshell in xpcom shutdown. r=ted.
This just updates mach_override.c to a version that has a faster search for an available spot to put the branch island.
This commit is contained in:
parent
30e0f551ce
commit
bdf274f8f7
@ -1,4 +1,5 @@
|
||||
/* copied from https://github.com/rentzsch/mach_star */
|
||||
/* Copied from https://github.com/rentzsch/mach_star at revision
|
||||
* 498e0ba31461ac6bada7fa75ce1a7009734d5a4c */
|
||||
|
||||
/*******************************************************************************
|
||||
mach_override.c
|
||||
@ -25,6 +26,7 @@
|
||||
#pragma mark -
|
||||
#pragma mark (Constants)
|
||||
|
||||
#define kPageSize 4096
|
||||
#if defined(__ppc__) || defined(__POWERPC__)
|
||||
|
||||
long kIslandTemplate[] = {
|
||||
@ -78,9 +80,6 @@ char kIslandTemplate[] = {
|
||||
|
||||
#endif
|
||||
|
||||
#define kAllocateHigh 1
|
||||
#define kAllocateNormal 0
|
||||
|
||||
/**************************
|
||||
*
|
||||
* Data Types
|
||||
@ -91,7 +90,6 @@ char kIslandTemplate[] = {
|
||||
|
||||
typedef struct {
|
||||
char instructions[sizeof(kIslandTemplate)];
|
||||
int allocatedHigh;
|
||||
} BranchIsland;
|
||||
|
||||
/**************************
|
||||
@ -105,7 +103,6 @@ typedef struct {
|
||||
mach_error_t
|
||||
allocateBranchIsland(
|
||||
BranchIsland **island,
|
||||
int allocateHigh,
|
||||
void *originalFunctionAddress);
|
||||
|
||||
mach_error_t
|
||||
@ -160,12 +157,10 @@ fixupInstructions(
|
||||
#if defined(__i386__) || defined(__x86_64__)
|
||||
mach_error_t makeIslandExecutable(void *address) {
|
||||
mach_error_t err = err_none;
|
||||
vm_size_t pageSize;
|
||||
host_page_size( mach_host_self(), &pageSize );
|
||||
uintptr_t page = (uintptr_t)address & ~(uintptr_t)(pageSize-1);
|
||||
uintptr_t page = (uintptr_t)address & ~(uintptr_t)(kPageSize-1);
|
||||
int e = err_none;
|
||||
e |= mprotect((void *)page, pageSize, PROT_EXEC | PROT_READ | PROT_WRITE);
|
||||
e |= msync((void *)page, pageSize, MS_INVALIDATE );
|
||||
e |= mprotect((void *)page, kPageSize, PROT_EXEC | PROT_READ | PROT_WRITE);
|
||||
e |= msync((void *)page, kPageSize, MS_INVALIDATE );
|
||||
if (e) {
|
||||
err = err_cannot_override;
|
||||
}
|
||||
@ -243,7 +238,7 @@ mach_override_ptr(
|
||||
// Allocate and target the escape island to the overriding function.
|
||||
BranchIsland *escapeIsland = NULL;
|
||||
if( !err )
|
||||
err = allocateBranchIsland( &escapeIsland, kAllocateHigh, originalFunctionAddress );
|
||||
err = allocateBranchIsland( &escapeIsland, originalFunctionAddress );
|
||||
if (err) fprintf(stderr, "err = %x %s:%d\n", err, __FILE__, __LINE__);
|
||||
|
||||
|
||||
@ -285,7 +280,7 @@ mach_override_ptr(
|
||||
// technically our original function.
|
||||
BranchIsland *reentryIsland = NULL;
|
||||
if( !err && originalFunctionReentryIsland ) {
|
||||
err = allocateBranchIsland( &reentryIsland, kAllocateHigh, escapeIsland);
|
||||
err = allocateBranchIsland( &reentryIsland, escapeIsland);
|
||||
if( !err )
|
||||
*originalFunctionReentryIsland = reentryIsland;
|
||||
}
|
||||
@ -369,9 +364,6 @@ mach_override_ptr(
|
||||
Implementation: Allocates memory for a branch island.
|
||||
|
||||
@param island <- The allocated island.
|
||||
@param allocateHigh -> Whether to allocate the island at the end of the
|
||||
address space (for use with the branch absolute
|
||||
instruction).
|
||||
@result <- mach_error_t
|
||||
|
||||
***************************************************************************/
|
||||
@ -379,63 +371,63 @@ mach_override_ptr(
|
||||
mach_error_t
|
||||
allocateBranchIsland(
|
||||
BranchIsland **island,
|
||||
int allocateHigh,
|
||||
void *originalFunctionAddress)
|
||||
{
|
||||
assert( island );
|
||||
|
||||
mach_error_t err = err_none;
|
||||
|
||||
if( allocateHigh ) {
|
||||
vm_size_t pageSize;
|
||||
err = host_page_size( mach_host_self(), &pageSize );
|
||||
if( !err ) {
|
||||
assert( sizeof( BranchIsland ) <= pageSize );
|
||||
#if defined(__ppc__) || defined(__POWERPC__)
|
||||
vm_address_t first = 0xfeffffff;
|
||||
vm_address_t last = 0xfe000000 + pageSize;
|
||||
#elif defined(__x86_64__)
|
||||
vm_address_t first = (uint64_t)originalFunctionAddress & ~(uint64_t)(((uint64_t)1 << 31) - 1) | ((uint64_t)1 << 31); // start in the middle of the page?
|
||||
vm_address_t last = 0x0;
|
||||
#else
|
||||
vm_address_t first = 0xffc00000;
|
||||
vm_address_t last = 0xfffe0000;
|
||||
#endif
|
||||
assert( sizeof( BranchIsland ) <= kPageSize );
|
||||
|
||||
vm_address_t page = first;
|
||||
int allocated = 0;
|
||||
vm_map_t task_self = mach_task_self();
|
||||
|
||||
while( !err && !allocated && page != last ) {
|
||||
vm_map_t task_self = mach_task_self();
|
||||
vm_address_t original_address = (vm_address_t) originalFunctionAddress;
|
||||
static vm_address_t last_allocated = 0;
|
||||
vm_address_t address =
|
||||
last_allocated ? last_allocated : original_address;
|
||||
|
||||
err = vm_allocate( task_self, &page, pageSize, 0 );
|
||||
if( err == err_none )
|
||||
allocated = 1;
|
||||
else if( err == KERN_NO_SPACE ) {
|
||||
#if defined(__x86_64__)
|
||||
page -= pageSize;
|
||||
for (;;) {
|
||||
vm_size_t vmsize = 0;
|
||||
memory_object_name_t object = 0;
|
||||
kern_return_t kr = 0;
|
||||
vm_region_flavor_t flavor = VM_REGION_BASIC_INFO;
|
||||
// Find the page the address is in.
|
||||
#if __WORDSIZE == 32
|
||||
vm_region_basic_info_data_t info;
|
||||
mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;
|
||||
kr = vm_region(task_self, &address, &vmsize, flavor,
|
||||
(vm_region_info_t)&info, &info_count, &object);
|
||||
#else
|
||||
page += pageSize;
|
||||
vm_region_basic_info_data_64_t info;
|
||||
mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT_64;
|
||||
kr = vm_region_64(task_self, &address, &vmsize, flavor,
|
||||
(vm_region_info_t)&info, &info_count, &object);
|
||||
#endif
|
||||
err = err_none;
|
||||
}
|
||||
}
|
||||
if( allocated )
|
||||
*island = (BranchIsland*) page;
|
||||
else if( !allocated && !err )
|
||||
err = KERN_NO_SPACE;
|
||||
if (kr != KERN_SUCCESS)
|
||||
return kr;
|
||||
|
||||
// Don't underflow. This could be made to work, but this is a
|
||||
// convenient place to give up.
|
||||
assert((address & (kPageSize - 1)) == 0);
|
||||
if (address == 0)
|
||||
break;
|
||||
|
||||
// Go back one page.
|
||||
vm_address_t new_address = address - kPageSize;
|
||||
#if __WORDSIZE == 64
|
||||
if(original_address - new_address - 5 > INT32_MAX)
|
||||
break;
|
||||
#endif
|
||||
address = new_address;
|
||||
|
||||
// Try to allocate this page.
|
||||
kr = vm_allocate(task_self, &address, kPageSize, 0);
|
||||
if (kr == KERN_SUCCESS) {
|
||||
*island = (BranchIsland*) address;
|
||||
last_allocated = address;
|
||||
return err_none;
|
||||
}
|
||||
} else {
|
||||
void *block = malloc( sizeof( BranchIsland ) );
|
||||
if( block )
|
||||
*island = block;
|
||||
else
|
||||
err = KERN_NO_SPACE;
|
||||
if (kr != KERN_NO_SPACE)
|
||||
return kr;
|
||||
}
|
||||
if( !err )
|
||||
(**island).allocatedHigh = allocateHigh;
|
||||
|
||||
return err;
|
||||
|
||||
return KERN_NO_SPACE;
|
||||
}
|
||||
|
||||
/***************************************************************************//**
|
||||
@ -452,24 +444,9 @@ freeBranchIsland(
|
||||
{
|
||||
assert( island );
|
||||
assert( (*(long*)&island->instructions[0]) == kIslandTemplate[0] );
|
||||
assert( island->allocatedHigh );
|
||||
|
||||
mach_error_t err = err_none;
|
||||
|
||||
if( island->allocatedHigh ) {
|
||||
vm_size_t pageSize;
|
||||
err = host_page_size( mach_host_self(), &pageSize );
|
||||
if( !err ) {
|
||||
assert( sizeof( BranchIsland ) <= pageSize );
|
||||
err = vm_deallocate(
|
||||
mach_task_self(),
|
||||
(vm_address_t) island, pageSize );
|
||||
}
|
||||
} else {
|
||||
free( island );
|
||||
}
|
||||
|
||||
return err;
|
||||
assert( sizeof( BranchIsland ) <= kPageSize );
|
||||
return vm_deallocate( mach_task_self(), (vm_address_t) island,
|
||||
kPageSize );
|
||||
}
|
||||
|
||||
/***************************************************************************//**
|
||||
@ -601,6 +578,7 @@ static AsmInstructionMatch possibleInstructions[] = {
|
||||
{ 0x5, {0xF8, 0x00, 0x00, 0x00, 0x00}, {0xB8, 0x00, 0x00, 0x00, 0x00} }, // mov $imm, %reg
|
||||
{ 0x3, {0xFF, 0xFF, 0x00}, {0xFF, 0x77, 0x00} }, // pushq $imm(%rdi)
|
||||
{ 0x2, {0xFF, 0xFF}, {0x31, 0xC0} }, // xor %eax, %eax
|
||||
{ 0x2, {0xFF, 0xFF}, {0x89, 0xF8} }, // mov %edi, %eax
|
||||
{ 0x0 }
|
||||
};
|
||||
#endif
|
||||
|
Loading…
Reference in New Issue
Block a user