Mark pointers in cpu registers as in use.

This prevents bugs where gc_collect is called from C code that did
a recent allocation.
crypto-aes
Scott Shawcroft 5 years ago
parent 252aacdddf
commit ec78d3cefd
No known key found for this signature in database
GPG Key ID: 0DFD512649C052DA

@ -44,6 +44,7 @@
#include "lib/utils/pyexec.h"
#include "mpconfigboard.h"
#include "supervisor/cpu.h"
#include "supervisor/port.h"
#include "supervisor/filesystem.h"
// TODO(tannewt): Figure out how to choose language at compile time.
@ -381,16 +382,17 @@ int __attribute__((used)) main(void) {
}
void gc_collect(void) {
// WARNING: This gc_collect implementation doesn't try to get root
// pointers from CPU registers, and thus may function incorrectly.
void *dummy;
gc_collect_start();
mp_uint_t regs[10];
mp_uint_t sp = cpu_get_regs_and_sp(regs);
// This collects root pointers from the VFS mount table. Some of them may
// have lost their references in the VM even though they are mounted.
gc_collect_root((void**)&MP_STATE_VM(vfs_mount_table), sizeof(mp_vfs_mount_t) / sizeof(mp_uint_t));
// This naively collects all object references from an approximate stack
// range.
gc_collect_root(&dummy, ((mp_uint_t)&_estack - (mp_uint_t)&dummy) / sizeof(mp_uint_t));
gc_collect_root((void**)sp, ((uint32_t)&_estack - sp) / sizeof(uint32_t));
gc_collect_end();
}

@ -412,6 +412,8 @@ endif
SRC_SHARED_MODULE_EXPANDED = $(addprefix shared-bindings/, $(SRC_SHARED_MODULE)) \
$(addprefix shared-module/, $(SRC_SHARED_MODULE))
SRC_O = supervisor/$(CHIP_FAMILY)_cpu.o
OBJ = $(PY_O) $(SUPERVISOR_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
OBJ += $(addprefix $(BUILD)/, $(SRC_ASF:.c=.o))
OBJ += $(addprefix $(BUILD)/, $(SRC_COMMON_HAL_EXPANDED:.c=.o))
@ -419,6 +421,7 @@ OBJ += $(addprefix $(BUILD)/, $(SRC_SHARED_MODULE_EXPANDED:.c=.o))
ifeq ($(INTERNAL_LIBM),1)
OBJ += $(addprefix $(BUILD)/, $(SRC_LIBM:.c=.o))
endif
OBJ += $(addprefix $(BUILD)/, $(SRC_O))
SRC_QSTR += $(SRC_C) $(SRC_SUPERVISOR) $(SRC_COMMON_HAL_EXPANDED) $(SRC_SHARED_MODULE_EXPANDED) $(STM_SRC_C)

@ -0,0 +1,35 @@
.syntax unified
.cpu cortex-m0
.thumb
.text
.align 2
@ uint cpu_get_regs_and_sp(r0=uint regs[10])
.global cpu_get_regs_and_sp
.thumb
.thumb_func
.type cpu_get_regs_and_sp, %function
cpu_get_regs_and_sp:
@ store registers into given array
str r4, [r0, #0]
str r5, [r0, #4]
str r6, [r0, #8]
str r7, [r0, #12]
push {r1}
mov r1, r8
str r1, [r0, #16]
mov r1, r9
str r1, [r0, #20]
mov r1, r10
str r1, [r0, #24]
mov r1, r11
str r1, [r0, #28]
mov r1, r12
str r1, [r0, #32]
mov r1, r13
str r1, [r0, #36]
pop {r1}
@ return the sp
mov r0, sp
bx lr

@ -0,0 +1,27 @@
.syntax unified
.cpu cortex-m4
.thumb
.text
.align 2
@ uint cpu_get_regs_and_sp(r0=uint regs[10])
.global cpu_get_regs_and_sp
.thumb
.thumb_func
.type cpu_get_regs_and_sp, %function
cpu_get_regs_and_sp:
@ store registers into given array
str r4, [r0], #4
str r5, [r0], #4
str r6, [r0], #4
str r7, [r0], #4
str r8, [r0], #4
str r9, [r0], #4
str r10, [r0], #4
str r11, [r0], #4
str r12, [r0], #4
str r13, [r0], #4
@ return the sp
mov r0, sp
bx lr

@ -0,0 +1,34 @@
/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef MICROPY_INCLUDED_SUPERVISOR_CPU_H
#define MICROPY_INCLUDED_SUPERVISOR_CPU_H
// Adds up to 10 pointers from the CPUs registers to regs. This is used to make sure no actively
// used heap memory is freed. Its usually implemented in assembly.
mp_uint_t cpu_get_regs_and_sp(mp_uint_t *regs);
#endif // MICROPY_INCLUDED_SUPERVISOR_CPU_H
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