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Fixed #181 -- Corrected problems with ARMv7 build under iOS.

Browse Source 
Based on a patch from @fealebenpae, with input from @SolaWing and @rth7680,
and testing from @superdump.
This commit is contained in:
Russell Keith-Magee
2015-12-21 00:37:06 +08:00
parent e3d2812ce4
commit bc4fc07aa5
8 changed files with 323 additions and 517 deletions
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4
doc/libffi.texi
View File

@@ -152,7 +152,7 @@ If the function being called is variadic (varargs) then
@code{ffi_prep_cif_var} must be used instead of @code{ffi_prep_cif}.
@findex ffi_prep_cif_var
@defun ffi_status ffi_prep_cif_var (ffi_cif *@var{cif}, ffi_abi var{abi}, unsigned int @var{nfixedargs}, unsigned int var{ntotalargs}, ffi_type *@var{rtype}, ffi_type **@var{argtypes})
@defun ffi_status ffi_prep_cif_var (ffi_cif *@var{cif}, ffi_abi @var{abi}, unsigned int @var{nfixedargs}, unsigned int @var{ntotalargs}, ffi_type *@var{rtype}, ffi_type **@var{argtypes})
This initializes @var{cif} according to the given parameters for
a call to a variadic function. In general it's operation is the
same as for @code{ffi_prep_cif} except that:
@@ -161,7 +161,7 @@ same as for @code{ffi_prep_cif} except that:
variadic arguments. It must be greater than zero.
@var{ntotalargs} the total number of arguments, including variadic
and fixed arguments.
and fixed arguments. @var{argtypes} must have this many elements.
Note that, different cif's must be prepped for calls to the same
function when different numbers of arguments are passed.

247
src/aarch64/ffi.c
View File

@@ -22,6 +22,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <fficonfig.h>
#include <ffi.h>
#include <ffi_common.h>
#include "internal.h"
@@ -70,6 +71,14 @@ ffi_clear_cache (void *start, void *end)
#endif
}
#if FFI_EXEC_TRAMPOLINE_TABLE
#ifdef __MACH__
#include <mach/vm_param.h>
#endif
#endif
/* A subroutine of is_vfp_type. Given a structure type, return the type code
of the first non-structure element. Recurse for structure elements.
Return -1 if the structure is in fact empty, i.e. no nested elements. */
@@ -725,240 +734,6 @@ ffi_call_go (ffi_cif *cif, void (*fn) (void), void *rvalue,
extern void ffi_closure_SYSV (void) FFI_HIDDEN;
extern void ffi_closure_SYSV_V (void) FFI_HIDDEN;
#if FFI_EXEC_TRAMPOLINE_TABLE
#include <mach/mach.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
extern void *ffi_closure_trampoline_table_page;
typedef struct ffi_trampoline_table ffi_trampoline_table;
typedef struct ffi_trampoline_table_entry ffi_trampoline_table_entry;
struct ffi_trampoline_table
{
/* contiguous writable and executable pages */
vm_address_t config_page;
vm_address_t trampoline_page;
/* free list tracking */
uint16_t free_count;
ffi_trampoline_table_entry *free_list;
ffi_trampoline_table_entry *free_list_pool;
ffi_trampoline_table *prev;
ffi_trampoline_table *next;
};
struct ffi_trampoline_table_entry
{
void *(*trampoline) ();
ffi_trampoline_table_entry *next;
};
/* The trampoline configuration is placed a page prior to the trampoline's entry point */
#define FFI_TRAMPOLINE_CODELOC_CONFIG(codeloc) ((void **) (((uint8_t *) codeloc) - PAGE_SIZE));
/* Total number of trampolines that fit in one trampoline table */
#define FFI_TRAMPOLINE_COUNT (PAGE_SIZE / FFI_TRAMPOLINE_SIZE)
static pthread_mutex_t ffi_trampoline_lock = PTHREAD_MUTEX_INITIALIZER;
static ffi_trampoline_table *ffi_trampoline_tables = NULL;
static ffi_trampoline_table *
ffi_trampoline_table_alloc ()
{
ffi_trampoline_table *table = NULL;
/* Loop until we can allocate two contiguous pages */
while (table == NULL)
{
vm_address_t config_page = 0x0;
kern_return_t kt;
/* Try to allocate two pages */
kt =
vm_allocate (mach_task_self (), &config_page, PAGE_SIZE * 2,
VM_FLAGS_ANYWHERE);
if (kt != KERN_SUCCESS)
{
fprintf (stderr, "vm_allocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
break;
}
/* Now drop the second half of the allocation to make room for the trampoline table */
vm_address_t trampoline_page = config_page + PAGE_SIZE;
kt = vm_deallocate (mach_task_self (), trampoline_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
{
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
break;
}
/* Remap the trampoline table to directly follow the config page */
vm_prot_t cur_prot;
vm_prot_t max_prot;
kt =
vm_remap (mach_task_self (), &trampoline_page, PAGE_SIZE, 0x0, FALSE,
mach_task_self (),
(vm_address_t) & ffi_closure_trampoline_table_page, FALSE,
&cur_prot, &max_prot, VM_INHERIT_SHARE);
/* If we lost access to the destination trampoline page, drop our config allocation mapping and retry */
if (kt != KERN_SUCCESS)
{
/* Log unexpected failures */
if (kt != KERN_NO_SPACE)
{
fprintf (stderr, "vm_remap() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
}
vm_deallocate (mach_task_self (), config_page, PAGE_SIZE);
continue;
}
/* We have valid trampoline and config pages */
table = calloc (1, sizeof (ffi_trampoline_table));
table->free_count = FFI_TRAMPOLINE_COUNT;
table->config_page = config_page;
table->trampoline_page = trampoline_page;
/* Create and initialize the free list */
table->free_list_pool =
calloc (FFI_TRAMPOLINE_COUNT, sizeof (ffi_trampoline_table_entry));
uint16_t i;
for (i = 0; i < table->free_count; i++)
{
ffi_trampoline_table_entry *entry = &table->free_list_pool[i];
entry->trampoline =
(void *) (table->trampoline_page + (i * FFI_TRAMPOLINE_SIZE));
if (i < table->free_count - 1)
entry->next = &table->free_list_pool[i + 1];
}
table->free_list = table->free_list_pool;
}
return table;
}
void *
ffi_closure_alloc (size_t size, void **code)
{
/* Create the closure */
ffi_closure *closure = malloc (size);
if (closure == NULL)
return NULL;
pthread_mutex_lock (&ffi_trampoline_lock);
/* Check for an active trampoline table with available entries. */
ffi_trampoline_table *table = ffi_trampoline_tables;
if (table == NULL || table->free_list == NULL)
{
table = ffi_trampoline_table_alloc ();
if (table == NULL)
{
free (closure);
return NULL;
}
/* Insert the new table at the top of the list */
table->next = ffi_trampoline_tables;
if (table->next != NULL)
table->next->prev = table;
ffi_trampoline_tables = table;
}
/* Claim the free entry */
ffi_trampoline_table_entry *entry = ffi_trampoline_tables->free_list;
ffi_trampoline_tables->free_list = entry->next;
ffi_trampoline_tables->free_count--;
entry->next = NULL;
pthread_mutex_unlock (&ffi_trampoline_lock);
/* Initialize the return values */
*code = entry->trampoline;
closure->trampoline_table = table;
closure->trampoline_table_entry = entry;
return closure;
}
void
ffi_closure_free (void *ptr)
{
ffi_closure *closure = ptr;
pthread_mutex_lock (&ffi_trampoline_lock);
/* Fetch the table and entry references */
ffi_trampoline_table *table = closure->trampoline_table;
ffi_trampoline_table_entry *entry = closure->trampoline_table_entry;
/* Return the entry to the free list */
entry->next = table->free_list;
table->free_list = entry;
table->free_count++;
/* If all trampolines within this table are free, and at least one other table exists, deallocate
* the table */
if (table->free_count == FFI_TRAMPOLINE_COUNT
&& ffi_trampoline_tables != table)
{
/* Remove from the list */
if (table->prev != NULL)
table->prev->next = table->next;
if (table->next != NULL)
table->next->prev = table->prev;
/* Deallocate pages */
kern_return_t kt;
kt = vm_deallocate (mach_task_self (), table->config_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
kt =
vm_deallocate (mach_task_self (), table->trampoline_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
/* Deallocate free list */
free (table->free_list_pool);
free (table);
}
else if (ffi_trampoline_tables != table)
{
/* Otherwise, bump this table to the top of the list */
table->prev = NULL;
table->next = ffi_trampoline_tables;
if (ffi_trampoline_tables != NULL)
ffi_trampoline_tables->prev = table;
ffi_trampoline_tables = table;
}
pthread_mutex_unlock (&ffi_trampoline_lock);
/* Free the closure */
free (closure);
}
#endif
ffi_status
ffi_prep_closure_loc (ffi_closure *closure,
ffi_cif* cif,
@@ -977,9 +752,11 @@ ffi_prep_closure_loc (ffi_closure *closure,
start = ffi_closure_SYSV;
#if FFI_EXEC_TRAMPOLINE_TABLE
void **config = FFI_TRAMPOLINE_CODELOC_CONFIG (codeloc);
#ifdef __MACH__
void **config = (void **)((uint8_t *)codeloc - PAGE_MAX_SIZE);
config[0] = closure;
config[1] = start;
#endif
#else
static const unsigned char trampoline[16] = {
0x90, 0x00, 0x00, 0x58, /* ldr x16, tramp+16 */

13
src/aarch64/ffitarget.h
View File

@@ -48,14 +48,21 @@ typedef enum ffi_abi
/* ---- Definitions for closures ----------------------------------------- */
#define FFI_CLOSURES 1
#if defined (__APPLE__)
#define FFI_TRAMPOLINE_SIZE 20
#define FFI_NATIVE_RAW_API 0
#if defined (FFI_EXEC_TRAMPOLINE_TABLE) && FFI_EXEC_TRAMPOLINE_TABLE
#ifdef __MACH__
#define FFI_TRAMPOLINE_SIZE 16
#define FFI_TRAMPOLINE_CLOSURE_OFFSET 16
#else
#error "No trampoline table implementation"
#endif
#else
#define FFI_TRAMPOLINE_SIZE 24
#define FFI_TRAMPOLINE_CLOSURE_OFFSET FFI_TRAMPOLINE_SIZE
#endif
#define FFI_NATIVE_RAW_API 0
/* ---- Internal ---- */

20
src/aarch64/sysv.S
View File

@@ -356,16 +356,18 @@ CNAME(ffi_closure_SYSV):
#endif
#if FFI_EXEC_TRAMPOLINE_TABLE
.align 12
#ifdef __MACH__
#include <mach/vm_param.h>
.align PAGE_MAX_SHIFT
CNAME(ffi_closure_trampoline_table_page):
.rept 16384 / FFI_TRAMPOLINE_SIZE
adr x17, -16384
adr x16, -16380
ldr x16, [x16]
ldr x17, [x17]
br x16
.rept PAGE_MAX_SIZE / FFI_TRAMPOLINE_SIZE
adr x16, -PAGE_MAX_SIZE
ldp x17, x16, [x16]
br x16
nop /* each entry in the trampoline config page is 2*sizeof(void*) so the trampoline itself cannot be smaller that 16 bytes */
.endr
.globl CNAME(ffi_closure_trampoline_table_page)
#ifdef __ELF__
.type CNAME(ffi_closure_trampoline_table_page), #function
@@ -374,6 +376,8 @@ CNAME(ffi_closure_trampoline_table_page):
#endif
#endif
#endif /* FFI_EXEC_TRAMPOLINE_TABLE */
#ifdef FFI_GO_CLOSURES
.align 4
CNAME(ffi_go_closure_SYSV_V):

259
src/arm/ffi.c
View File

@@ -28,11 +28,22 @@
DEALINGS IN THE SOFTWARE.
----------------------------------------------------------------------- */
#include <fficonfig.h>
#include <ffi.h>
#include <ffi_common.h>
#include <stdlib.h>
#include "internal.h"
#if FFI_EXEC_TRAMPOLINE_TABLE
#ifdef __MACH__
#include <mach/vm_param.h>
#endif
#else
extern unsigned int ffi_arm_trampoline[2] FFI_HIDDEN;
#endif
/* Forward declares. */
static int vfp_type_p (const ffi_type *);
static void layout_vfp_args (ffi_cif *);
@@ -530,252 +541,6 @@ void ffi_closure_VFP (void) FFI_HIDDEN;
void ffi_go_closure_SYSV (void) FFI_HIDDEN;
void ffi_go_closure_VFP (void) FFI_HIDDEN;
#if FFI_EXEC_TRAMPOLINE_TABLE
#include <mach/mach.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
extern void *ffi_closure_trampoline_table_page;
typedef struct ffi_trampoline_table ffi_trampoline_table;
typedef struct ffi_trampoline_table_entry ffi_trampoline_table_entry;
struct ffi_trampoline_table
{
/* contiguous writable and executable pages */
vm_address_t config_page;
vm_address_t trampoline_page;
/* free list tracking */
uint16_t free_count;
ffi_trampoline_table_entry *free_list;
ffi_trampoline_table_entry *free_list_pool;
ffi_trampoline_table *prev;
ffi_trampoline_table *next;
};
struct ffi_trampoline_table_entry
{
void *(*trampoline) ();
ffi_trampoline_table_entry *next;
};
/* Override the standard architecture trampoline size */
// XXX TODO - Fix
#undef FFI_TRAMPOLINE_SIZE
#define FFI_TRAMPOLINE_SIZE 12
/* The trampoline configuration is placed at 4080 bytes prior to the trampoline's entry point */
#define FFI_TRAMPOLINE_CODELOC_CONFIG(codeloc) ((void **) (((uint8_t *) codeloc) - 4080));
/* The first 16 bytes of the config page are unused, as they are unaddressable from the trampoline page. */
#define FFI_TRAMPOLINE_CONFIG_PAGE_OFFSET 16
/* Total number of trampolines that fit in one trampoline table */
#define FFI_TRAMPOLINE_COUNT ((PAGE_SIZE - FFI_TRAMPOLINE_CONFIG_PAGE_OFFSET) / FFI_TRAMPOLINE_SIZE)
static pthread_mutex_t ffi_trampoline_lock = PTHREAD_MUTEX_INITIALIZER;
static ffi_trampoline_table *ffi_trampoline_tables = NULL;
static ffi_trampoline_table *
ffi_trampoline_table_alloc ()
{
ffi_trampoline_table *table = NULL;
/* Loop until we can allocate two contiguous pages */
while (table == NULL)
{
vm_address_t config_page = 0x0;
kern_return_t kt;
/* Try to allocate two pages */
kt =
vm_allocate (mach_task_self (), &config_page, PAGE_SIZE * 2,
VM_FLAGS_ANYWHERE);
if (kt != KERN_SUCCESS)
{
fprintf (stderr, "vm_allocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
break;
}
/* Now drop the second half of the allocation to make room for the trampoline table */
vm_address_t trampoline_page = config_page + PAGE_SIZE;
kt = vm_deallocate (mach_task_self (), trampoline_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
{
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
break;
}
/* Remap the trampoline table to directly follow the config page */
vm_prot_t cur_prot;
vm_prot_t max_prot;
kt =
vm_remap (mach_task_self (), &trampoline_page, PAGE_SIZE, 0x0, FALSE,
mach_task_self (),
(vm_address_t) & ffi_closure_trampoline_table_page, FALSE,
&cur_prot, &max_prot, VM_INHERIT_SHARE);
/* If we lost access to the destination trampoline page, drop our config allocation mapping and retry */
if (kt != KERN_SUCCESS)
{
/* Log unexpected failures */
if (kt != KERN_NO_SPACE)
{
fprintf (stderr, "vm_remap() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
}
vm_deallocate (mach_task_self (), config_page, PAGE_SIZE);
continue;
}
/* We have valid trampoline and config pages */
table = calloc (1, sizeof (ffi_trampoline_table));
table->free_count = FFI_TRAMPOLINE_COUNT;
table->config_page = config_page;
table->trampoline_page = trampoline_page;
/* Create and initialize the free list */
table->free_list_pool =
calloc (FFI_TRAMPOLINE_COUNT, sizeof (ffi_trampoline_table_entry));
uint16_t i;
for (i = 0; i < table->free_count; i++)
{
ffi_trampoline_table_entry *entry = &table->free_list_pool[i];
entry->trampoline =
(void *) (table->trampoline_page + (i * FFI_TRAMPOLINE_SIZE));
if (i < table->free_count - 1)
entry->next = &table->free_list_pool[i + 1];
}
table->free_list = table->free_list_pool;
}
return table;
}
void *
ffi_closure_alloc (size_t size, void **code)
{
/* Create the closure */
ffi_closure *closure = malloc (size);
if (closure == NULL)
return NULL;
pthread_mutex_lock (&ffi_trampoline_lock);
/* Check for an active trampoline table with available entries. */
ffi_trampoline_table *table = ffi_trampoline_tables;
if (table == NULL || table->free_list == NULL)
{
table = ffi_trampoline_table_alloc ();
if (table == NULL)
{
free (closure);
return NULL;
}
/* Insert the new table at the top of the list */
table->next = ffi_trampoline_tables;
if (table->next != NULL)
table->next->prev = table;
ffi_trampoline_tables = table;
}
/* Claim the free entry */
ffi_trampoline_table_entry *entry = ffi_trampoline_tables->free_list;
ffi_trampoline_tables->free_list = entry->next;
ffi_trampoline_tables->free_count--;
entry->next = NULL;
pthread_mutex_unlock (&ffi_trampoline_lock);
/* Initialize the return values */
*code = entry->trampoline;
closure->trampoline_table = table;
closure->trampoline_table_entry = entry;
return closure;
}
void
ffi_closure_free (void *ptr)
{
ffi_closure *closure = ptr;
pthread_mutex_lock (&ffi_trampoline_lock);
/* Fetch the table and entry references */
ffi_trampoline_table *table = closure->trampoline_table;
ffi_trampoline_table_entry *entry = closure->trampoline_table_entry;
/* Return the entry to the free list */
entry->next = table->free_list;
table->free_list = entry;
table->free_count++;
/* If all trampolines within this table are free, and at least one other table exists, deallocate
* the table */
if (table->free_count == FFI_TRAMPOLINE_COUNT
&& ffi_trampoline_tables != table)
{
/* Remove from the list */
if (table->prev != NULL)
table->prev->next = table->next;
if (table->next != NULL)
table->next->prev = table->prev;
/* Deallocate pages */
kern_return_t kt;
kt = vm_deallocate (mach_task_self (), table->config_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
kt =
vm_deallocate (mach_task_self (), table->trampoline_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
/* Deallocate free list */
free (table->free_list_pool);
free (table);
}
else if (ffi_trampoline_tables != table)
{
/* Otherwise, bump this table to the top of the list */
table->prev = NULL;
table->next = ffi_trampoline_tables;
if (ffi_trampoline_tables != NULL)
ffi_trampoline_tables->prev = table;
ffi_trampoline_tables = table;
}
pthread_mutex_unlock (&ffi_trampoline_lock);
/* Free the closure */
free (closure);
}
#else
extern unsigned int ffi_arm_trampoline[2] FFI_HIDDEN;
#endif
/* the cif must already be prep'ed */
ffi_status
@@ -796,7 +561,7 @@ ffi_prep_closure_loc (ffi_closure * closure,
return FFI_BAD_ABI;
#if FFI_EXEC_TRAMPOLINE_TABLE
void **config = FFI_TRAMPOLINE_CODELOC_CONFIG (codeloc);
void **config = (void **)((uint8_t *)codeloc - PAGE_MAX_SIZE);
config[0] = closure;
config[1] = closure_func;
#else

15
src/arm/ffitarget.h
View File

@@ -63,7 +63,20 @@ typedef enum ffi_abi {
#define FFI_CLOSURES 1
#define FFI_GO_CLOSURES 1
#define FFI_TRAMPOLINE_SIZE 12
#define FFI_NATIVE_RAW_API 0
#if defined (FFI_EXEC_TRAMPOLINE_TABLE) && FFI_EXEC_TRAMPOLINE_TABLE
#ifdef __MACH__
#define FFI_TRAMPOLINE_SIZE 12
#define FFI_TRAMPOLINE_CLOSURE_OFFSET 8
#else
#error "No trampoline table implementation"
#endif
#else
#define FFI_TRAMPOLINE_SIZE 12
#define FFI_TRAMPOLINE_CLOSURE_OFFSET FFI_TRAMPOLINE_SIZE
#endif
#endif

41
src/arm/sysv.S
View File

@@ -228,9 +228,13 @@ ARM_FUNC_START(ffi_closure_SYSV)
cfi_startproc
stmdb sp!, {r0-r3} @ save argument regs
cfi_adjust_cfa_offset(16)
ldr r0, [ip, #FFI_TRAMPOLINE_SIZE] @ load cif
ldr r1, [ip, #FFI_TRAMPOLINE_SIZE+4] @ load fun
ldr r2, [ip, #FFI_TRAMPOLINE_SIZE+8] @ load user_data
#if FFI_EXEC_TRAMPOLINE_TABLE
ldr ip, [ip] @ ip points to the config page, dereference to get the ffi_closure*
#endif
ldr r0, [ip, #FFI_TRAMPOLINE_CLOSURE_OFFSET] @ load cif
ldr r1, [ip, #FFI_TRAMPOLINE_CLOSURE_OFFSET+4] @ load fun
ldr r2, [ip, #FFI_TRAMPOLINE_CLOSURE_OFFSET+8] @ load user_data
0:
add ip, sp, #16 @ compute entry sp
sub sp, sp, #64+32 @ allocate frame
@@ -271,9 +275,13 @@ ARM_FUNC_START(ffi_closure_VFP)
cfi_startproc
stmdb sp!, {r0-r3} @ save argument regs
cfi_adjust_cfa_offset(16)
ldr r0, [ip, #FFI_TRAMPOLINE_SIZE] @ load cif
ldr r1, [ip, #FFI_TRAMPOLINE_SIZE+4] @ load fun
ldr r2, [ip, #FFI_TRAMPOLINE_SIZE+8] @ load user_data
#if FFI_EXEC_TRAMPOLINE_TABLE
ldr ip, [ip] @ ip points to the config page, dereference to get the ffi_closure*
#endif
ldr r0, [ip, #FFI_TRAMPOLINE_CLOSURE_OFFSET] @ load cif
ldr r1, [ip, #FFI_TRAMPOLINE_CLOSURE_OFFSET+4] @ load fun
ldr r2, [ip, #FFI_TRAMPOLINE_CLOSURE_OFFSET+8] @ load user_data
0:
add ip, sp, #16
sub sp, sp, #64+32 @ allocate frame
@@ -347,23 +355,18 @@ ARM_FUNC_END(ffi_closure_ret)
#if FFI_EXEC_TRAMPOLINE_TABLE
/* ??? The iOS support should be updated. The first insn used to
be STMFD, but that's been moved into ffi_closure_SYSV. If the
writable page is put after this one we can make use of the
pc+8 feature of the architecture. We can also reduce the size
of the thunk to 8 and pack more of these into the page.
#ifdef __MACH__
#include <mach/vm_param.h>
In the meantime, simply replace the STMFD with a NOP so as to
keep all the magic numbers the same within ffi.c. */
.align 12
.align PAGE_MAX_SHIFT
ARM_FUNC_START(ffi_closure_trampoline_table_page)
.rept 4096 / 12
nop
ldr ip, [pc, #-4092]
ldr pc, [pc, #-4092]
.rept PAGE_MAX_SIZE / FFI_TRAMPOLINE_SIZE
adr ip, #-PAGE_MAX_SIZE @ the config page is PAGE_MAX_SIZE behind the trampoline page
sub ip, #8 @ account for pc bias
ldr pc, [ip, #4] @ jump to ffi_closure_SYSV or ffi_closure_VFP
.endr
ARM_FUNC_END(ffi_closure_trampoline_table_page)
#endif
#else

241
src/closures.c
View File

@@ -30,6 +30,7 @@
#define _GNU_SOURCE 1
#endif
#include <fficonfig.h>
#include <ffi.h>
#include <ffi_common.h>
@@ -64,11 +65,247 @@
#if FFI_CLOSURES
# if FFI_EXEC_TRAMPOLINE_TABLE
#if FFI_EXEC_TRAMPOLINE_TABLE
#ifdef __MACH__
#include <mach/mach.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
extern void *ffi_closure_trampoline_table_page;
typedef struct ffi_trampoline_table ffi_trampoline_table;
typedef struct ffi_trampoline_table_entry ffi_trampoline_table_entry;
struct ffi_trampoline_table
{
/* contiguous writable and executable pages */
vm_address_t config_page;
vm_address_t trampoline_page;
/* free list tracking */
uint16_t free_count;
ffi_trampoline_table_entry *free_list;
ffi_trampoline_table_entry *free_list_pool;
ffi_trampoline_table *prev;
ffi_trampoline_table *next;
};
struct ffi_trampoline_table_entry
{
void *(*trampoline) ();
ffi_trampoline_table_entry *next;
};
/* Total number of trampolines that fit in one trampoline table */
#define FFI_TRAMPOLINE_COUNT (PAGE_MAX_SIZE / FFI_TRAMPOLINE_SIZE)
static pthread_mutex_t ffi_trampoline_lock = PTHREAD_MUTEX_INITIALIZER;
static ffi_trampoline_table *ffi_trampoline_tables = NULL;
static ffi_trampoline_table *
ffi_trampoline_table_alloc ()
{
ffi_trampoline_table *table = NULL;
/* Loop until we can allocate two contiguous pages */
while (table == NULL)
{
vm_address_t config_page = 0x0;
kern_return_t kt;
/* Try to allocate two pages */
kt =
vm_allocate (mach_task_self (), &config_page, PAGE_MAX_SIZE * 2,
VM_FLAGS_ANYWHERE);
if (kt != KERN_SUCCESS)
{
fprintf (stderr, "vm_allocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
break;
}
/* Now drop the second half of the allocation to make room for the trampoline table */
vm_address_t trampoline_page = config_page + PAGE_MAX_SIZE;
kt = vm_deallocate (mach_task_self (), trampoline_page, PAGE_MAX_SIZE);
if (kt != KERN_SUCCESS)
{
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
break;
}
/* Remap the trampoline table to directly follow the config page */
vm_prot_t cur_prot;
vm_prot_t max_prot;
vm_address_t trampoline_page_template = (vm_address_t)&ffi_closure_trampoline_table_page;
#ifdef __arm__
/* ffi_closure_trampoline_table_page can be thumb-biased on some ARM archs */
trampoline_page_template &= ~1UL;
#endif
kt =
vm_remap (mach_task_self (), &trampoline_page, PAGE_MAX_SIZE, 0x0, FALSE,
mach_task_self (), trampoline_page_template, FALSE,
&cur_prot, &max_prot, VM_INHERIT_SHARE);
/* If we lost access to the destination trampoline page, drop our config allocation mapping and retry */
if (kt != KERN_SUCCESS)
{
/* Log unexpected failures */
if (kt != KERN_NO_SPACE)
{
fprintf (stderr, "vm_remap() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
}
vm_deallocate (mach_task_self (), config_page, PAGE_SIZE);
continue;
}
/* We have valid trampoline and config pages */
table = calloc (1, sizeof (ffi_trampoline_table));
table->free_count = FFI_TRAMPOLINE_COUNT;
table->config_page = config_page;
table->trampoline_page = trampoline_page;
/* Create and initialize the free list */
table->free_list_pool =
calloc (FFI_TRAMPOLINE_COUNT, sizeof (ffi_trampoline_table_entry));
uint16_t i;
for (i = 0; i < table->free_count; i++)
{
ffi_trampoline_table_entry *entry = &table->free_list_pool[i];
entry->trampoline =
(void *) (table->trampoline_page + (i * FFI_TRAMPOLINE_SIZE));
if (i < table->free_count - 1)
entry->next = &table->free_list_pool[i + 1];
}
table->free_list = table->free_list_pool;
}
return table;
}
void *
ffi_closure_alloc (size_t size, void **code)
{
/* Create the closure */
ffi_closure *closure = malloc (size);
if (closure == NULL)
return NULL;
pthread_mutex_lock (&ffi_trampoline_lock);
/* Check for an active trampoline table with available entries. */
ffi_trampoline_table *table = ffi_trampoline_tables;
if (table == NULL || table->free_list == NULL)
{
table = ffi_trampoline_table_alloc ();
if (table == NULL)
{
free (closure);
return NULL;
}
/* Insert the new table at the top of the list */
table->next = ffi_trampoline_tables;
if (table->next != NULL)
table->next->prev = table;
ffi_trampoline_tables = table;
}
/* Claim the free entry */
ffi_trampoline_table_entry *entry = ffi_trampoline_tables->free_list;
ffi_trampoline_tables->free_list = entry->next;
ffi_trampoline_tables->free_count--;
entry->next = NULL;
pthread_mutex_unlock (&ffi_trampoline_lock);
/* Initialize the return values */
*code = entry->trampoline;
closure->trampoline_table = table;
closure->trampoline_table_entry = entry;
return closure;
}
void
ffi_closure_free (void *ptr)
{
ffi_closure *closure = ptr;
pthread_mutex_lock (&ffi_trampoline_lock);
/* Fetch the table and entry references */
ffi_trampoline_table *table = closure->trampoline_table;
ffi_trampoline_table_entry *entry = closure->trampoline_table_entry;
/* Return the entry to the free list */
entry->next = table->free_list;
table->free_list = entry;
table->free_count++;
/* If all trampolines within this table are free, and at least one other table exists, deallocate
* the table */
if (table->free_count == FFI_TRAMPOLINE_COUNT
&& ffi_trampoline_tables != table)
{
/* Remove from the list */
if (table->prev != NULL)
table->prev->next = table->next;
if (table->next != NULL)
table->next->prev = table->prev;
/* Deallocate pages */
kern_return_t kt;
kt = vm_deallocate (mach_task_self (), table->config_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
kt =
vm_deallocate (mach_task_self (), table->trampoline_page, PAGE_SIZE);
if (kt != KERN_SUCCESS)
fprintf (stderr, "vm_deallocate() failure: %d at %s:%d\n", kt,
__FILE__, __LINE__);
/* Deallocate free list */
free (table->free_list_pool);
free (table);
}
else if (ffi_trampoline_tables != table)
{
/* Otherwise, bump this table to the top of the list */
table->prev = NULL;
table->next = ffi_trampoline_tables;
if (ffi_trampoline_tables != NULL)
ffi_trampoline_tables->prev = table;
ffi_trampoline_tables = table;
}
pthread_mutex_unlock (&ffi_trampoline_lock);
/* Free the closure */
free (closure);
}
#endif
// Per-target implementation; It's unclear what can reasonable be shared between two OS/architecture implementations.
# elif FFI_MMAP_EXEC_WRIT /* !FFI_EXEC_TRAMPOLINE_TABLE */
#elif FFI_MMAP_EXEC_WRIT /* !FFI_EXEC_TRAMPOLINE_TABLE */
#define USE_LOCKS 1
#define USE_DL_PREFIX 1