From 354d17523f599746a84e5b22fa670c9910137947 Mon Sep 17 00:00:00 2001 From: Paul Sokolovsky Date: Mon, 6 Jul 2015 00:08:33 +0300 Subject: [PATCH] modmachine: Implement physical memory access using /dev/mem (Linux, etc). This requires root access. And on recent Linux kernels, with CONFIG_STRICT_DEVMEM option enabled, only address ranges listed in /proc/iomem can be accessed. The above compiled-time option can be however overriden with boot-time option "iomem=relaxed". This also removed separate read/write paths - there unlikely would be a case when they're different. --- extmod/modmachine.c | 42 +++++++++++++++++++++++++-------- tests/extmod/machine1.py | 14 ----------- tests/extmod/machine1.py.exp | 3 --- tests/extmod/machine_mem.py | 16 +++++++++++++ tests/extmod/machine_mem.py.exp | 1 + unix/mpconfigport.h | 5 ++++ 6 files changed, 54 insertions(+), 27 deletions(-) create mode 100644 tests/extmod/machine_mem.py create mode 100644 tests/extmod/machine_mem.py.exp diff --git a/extmod/modmachine.c b/extmod/modmachine.c index 721978796..b9ebee120 100644 --- a/extmod/modmachine.c +++ b/extmod/modmachine.c @@ -29,22 +29,44 @@ #include "py/nlr.h" #include "py/obj.h" +#if MICROPY_PLAT_DEV_MEM +#include +#include +#include +#endif #if MICROPY_PY_MACHINE -STATIC mp_uint_t get_read_addr(mp_obj_t addr_o, uint align) { - mp_uint_t addr = mp_obj_int_get_truncated(addr_o); - if ((addr & (align - 1)) != 0) { - nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "address %08x is not aligned to %d bytes", addr, align)); - } - return addr; -} +#define PAGE_SIZE 4096 +#define PAGE_MASK (PAGE_SIZE - 1) -STATIC mp_uint_t get_write_addr(mp_obj_t addr_o, uint align) { +STATIC mp_uint_t get_addr(mp_obj_t addr_o, uint align) { mp_uint_t addr = mp_obj_int_get_truncated(addr_o); if ((addr & (align - 1)) != 0) { nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "address %08x is not aligned to %d bytes", addr, align)); } + #if MICROPY_PLAT_DEV_MEM + { + // Not thread-safe + static int fd; + static mp_uint_t last_base = (mp_uint_t)-1; + static mp_uint_t map_page; + if (!fd) { + fd = open("/dev/mem", O_RDWR | O_SYNC); + if (fd == -1) { + nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(errno))); + } + } + + mp_uint_t cur_base = addr & ~PAGE_MASK; + if (cur_base != last_base) { + map_page = (mp_uint_t)mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, cur_base); + last_base = cur_base; + } + addr = map_page + (addr & PAGE_MASK); + } + #endif + return addr; } @@ -67,7 +89,7 @@ STATIC mp_obj_t machine_mem_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t va return MP_OBJ_NULL; // op not supported } else if (value == MP_OBJ_SENTINEL) { // load - mp_uint_t addr = get_read_addr(index, self->elem_size); + mp_uint_t addr = get_addr(index, self->elem_size); uint32_t val; switch (self->elem_size) { case 1: val = (*(uint8_t*)addr); break; @@ -77,7 +99,7 @@ STATIC mp_obj_t machine_mem_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t va return mp_obj_new_int(val); } else { // store - mp_uint_t addr = get_write_addr(index, self->elem_size); + mp_uint_t addr = get_addr(index, self->elem_size); uint32_t val = mp_obj_get_int(value); switch (self->elem_size) { case 1: (*(uint8_t*)addr) = val; break; diff --git a/tests/extmod/machine1.py b/tests/extmod/machine1.py index e7fd40d4d..af4dacd03 100644 --- a/tests/extmod/machine1.py +++ b/tests/extmod/machine1.py @@ -7,22 +7,8 @@ except ImportError: import sys sys.exit() -import uctypes - print(machine.mem8) -buf = bytearray(8) -addr = uctypes.addressof(buf) - -machine.mem8[addr] = 123 -print(machine.mem8[addr]) - -machine.mem16[addr] = 12345 -print(machine.mem16[addr]) - -machine.mem32[addr] = 123456789 -print(machine.mem32[addr]) - try: machine.mem16[1] except ValueError: diff --git a/tests/extmod/machine1.py.exp b/tests/extmod/machine1.py.exp index e46afc752..bb421ea5c 100644 --- a/tests/extmod/machine1.py.exp +++ b/tests/extmod/machine1.py.exp @@ -1,7 +1,4 @@ <8-bit memory> -123 -12345 -123456789 ValueError ValueError TypeError diff --git a/tests/extmod/machine_mem.py b/tests/extmod/machine_mem.py new file mode 100644 index 000000000..7d8a9ac01 --- /dev/null +++ b/tests/extmod/machine_mem.py @@ -0,0 +1,16 @@ +# This test requires root privilege, so is usually skipped +# It also assumes x86 legacy hardware (with Video BIOS present). + +try: + import machine +except ImportError: + print("SKIP") + import sys + sys.exit() + +try: + print(hex(machine.mem16[0xc0000])) +except OSError: + print("SKIP") + import sys + sys.exit() diff --git a/tests/extmod/machine_mem.py.exp b/tests/extmod/machine_mem.py.exp new file mode 100644 index 000000000..371f8fa44 --- /dev/null +++ b/tests/extmod/machine_mem.py.exp @@ -0,0 +1 @@ +0xaa55 diff --git a/unix/mpconfigport.h b/unix/mpconfigport.h index a0e7bf467..9f65bc929 100644 --- a/unix/mpconfigport.h +++ b/unix/mpconfigport.h @@ -179,6 +179,11 @@ void mp_unix_mark_exec(void); #define MP_PLAT_PRINT_STRN(str, len) fwrite(str, 1, len, stdout) +#ifdef __linux__ +// Can access physical memory using /dev/mem +#define MICROPY_PLAT_DEV_MEM (1) +#endif + extern const struct _mp_obj_fun_builtin_t mp_builtin_input_obj; extern const struct _mp_obj_fun_builtin_t mp_builtin_open_obj; #define MICROPY_PORT_BUILTINS \