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arm-trusted-firmware/common/bl_common.c

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/*
* Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of ARM nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <arch_helpers.h>
#include <console.h>
#include <platform.h>
#include <semihosting.h>
#include <bl_common.h>
/***********************************************************
* Memory for sharing data while changing exception levels.
* Only used by the primary core.
**********************************************************/
unsigned char bl2_el_change_mem_ptr[EL_CHANGE_MEM_SIZE];
unsigned long *get_el_change_mem_ptr(void)
{
return (unsigned long *) bl2_el_change_mem_ptr;
}
unsigned long page_align(unsigned long value, unsigned dir)
{
unsigned long page_size = 1 << FOUR_KB_SHIFT;
/* Round up the limit to the next page boundary */
if (value & (page_size - 1)) {
value &= ~(page_size - 1);
if (dir == UP)
value += page_size;
}
return value;
}
static inline unsigned int is_page_aligned (unsigned long addr) {
const unsigned long page_size = 1 << FOUR_KB_SHIFT;
return (addr & (page_size - 1)) == 0;
}
void change_security_state(unsigned int target_security_state)
{
unsigned long scr = read_scr();
if (target_security_state == SECURE)
scr &= ~SCR_NS_BIT;
else if (target_security_state == NON_SECURE)
scr |= SCR_NS_BIT;
else
assert(0);
write_scr(scr);
}
int drop_el(aapcs64_params *args,
unsigned long spsr,
unsigned long entrypoint)
{
write_spsr(spsr);
write_elr(entrypoint);
eret(args->arg0,
args->arg1,
args->arg2,
args->arg3,
args->arg4,
args->arg5,
args->arg6,
args->arg7);
return -EINVAL;
}
long raise_el(aapcs64_params *args)
{
return smc(args->arg0,
args->arg1,
args->arg2,
args->arg3,
args->arg4,
args->arg5,
args->arg6,
args->arg7);
}
/*
* TODO: If we are not EL3 then currently we only issue an SMC.
* Add support for dropping into EL0 etc. Consider adding support
* for switching from S-EL1 to S-EL0/1 etc.
*/
long change_el(el_change_info *info)
{
unsigned long current_el = read_current_el();
if (GET_EL(current_el) == MODE_EL3) {
/*
* We can go anywhere from EL3. So find where.
* TODO: Lots to do if we are going non-secure.
* Flip the NS bit. Restore NS registers etc.
* Just doing the bare minimal for now.
*/
if (info->security_state == NON_SECURE)
change_security_state(info->security_state);
return drop_el(&info->args, info->spsr, info->entrypoint);
} else
return raise_el(&info->args);
}
/* TODO: add a parameter for DAIF. not needed right now */
unsigned long make_spsr(unsigned long target_el,
unsigned long target_sp,
unsigned long target_rw)
{
unsigned long spsr;
/* Disable all exceptions & setup the EL */
spsr = (DAIF_FIQ_BIT | DAIF_IRQ_BIT | DAIF_ABT_BIT | DAIF_DBG_BIT)
<< PSR_DAIF_SHIFT;
spsr |= PSR_MODE(target_rw, target_el, target_sp);
return spsr;
}
/*******************************************************************************
* The next two functions are the weak definitions. Platform specific
* code can override them if it wishes to.
******************************************************************************/
/*******************************************************************************
* Function that takes a memory layout into which BL31 has been either top or
* bottom loaded. Using this information, it populates bl31_mem_layout to tell
* BL31 how much memory it has access to and how much is available for use. It
* does not need the address where BL31 has been loaded as BL31 will reclaim
* all the memory used by BL2.
* TODO: Revisit if this and init_bl2_mem_layout can be replaced by a single
* routine.
******************************************************************************/
void init_bl31_mem_layout(const meminfo *bl2_mem_layout,
meminfo *bl31_mem_layout,
unsigned int load_type)
{
if (load_type == BOT_LOAD) {
/*
* ------------ ^
* | BL2 | |
* |----------| ^ | BL2
* | | | BL2 free | total
* | | | size | size
* |----------| BL2 free base v |
* | BL31 | |
* ------------ BL2 total base v
*/
unsigned long bl31_size;
bl31_mem_layout->free_base = bl2_mem_layout->free_base;
bl31_size = bl2_mem_layout->free_base - bl2_mem_layout->total_base;
bl31_mem_layout->free_size = bl2_mem_layout->total_size - bl31_size;
} else {
/*
* ------------ ^
* | BL31 | |
* |----------| ^ | BL2
* | | | BL2 free | total
* | | | size | size
* |----------| BL2 free base v |
* | BL2 | |
* ------------ BL2 total base v
*/
unsigned long bl2_size;
bl31_mem_layout->free_base = bl2_mem_layout->total_base;
bl2_size = bl2_mem_layout->free_base - bl2_mem_layout->total_base;
bl31_mem_layout->free_size = bl2_mem_layout->free_size + bl2_size;
}
bl31_mem_layout->total_base = bl2_mem_layout->total_base;
bl31_mem_layout->total_size = bl2_mem_layout->total_size;
bl31_mem_layout->attr = load_type;
flush_dcache_range((unsigned long) bl31_mem_layout, sizeof(meminfo));
return;
}
/*******************************************************************************
* Function that takes a memory layout into which BL2 has been either top or
* bottom loaded along with the address where BL2 has been loaded in it. Using
* this information, it populates bl2_mem_layout to tell BL2 how much memory
* it has access to and how much is available for use.
******************************************************************************/
void init_bl2_mem_layout(meminfo *bl1_mem_layout,
meminfo *bl2_mem_layout,
unsigned int load_type,
unsigned long bl2_base)
{
unsigned tmp;
if (load_type == BOT_LOAD) {
bl2_mem_layout->total_base = bl2_base;
tmp = bl1_mem_layout->free_base - bl2_base;
bl2_mem_layout->total_size = bl1_mem_layout->free_size + tmp;
} else {
bl2_mem_layout->total_base = bl1_mem_layout->free_base;
tmp = bl1_mem_layout->total_base + bl1_mem_layout->total_size;
bl2_mem_layout->total_size = tmp - bl1_mem_layout->free_base;
}
bl2_mem_layout->free_base = bl1_mem_layout->free_base;
bl2_mem_layout->free_size = bl1_mem_layout->free_size;
bl2_mem_layout->attr = load_type;
flush_dcache_range((unsigned long) bl2_mem_layout, sizeof(meminfo));
return;
}
static void dump_load_info(unsigned long image_load_addr,
unsigned long image_size,
const meminfo *mem_layout)
{
#if DEBUG
printf("Trying to load image at address 0x%lx, size = 0x%lx\r\n",
image_load_addr, image_size);
printf("Current memory layout:\r\n");
printf(" total region = [0x%lx, 0x%lx]\r\n", mem_layout->total_base,
mem_layout->total_base + mem_layout->total_size);
printf(" free region = [0x%lx, 0x%lx]\r\n", mem_layout->free_base,
mem_layout->free_base + mem_layout->free_size);
#endif
}
/*******************************************************************************
* Generic function to load an image into the trusted RAM using semihosting
* given a name, extents of free memory & whether the image should be loaded at
* the bottom or top of the free memory. It updates the memory layout if the
* load is successful.
******************************************************************************/
unsigned long load_image(meminfo *mem_layout,
const char *image_name,
unsigned int load_type,
unsigned long fixed_addr)
{
unsigned long temp_image_base, image_base;
long offset;
int image_flen;
/* Find the size of the image */
image_flen = semihosting_get_flen(image_name);
if (image_flen < 0) {
printf("ERROR: Cannot access '%s' file (%i).\r\n",
image_name, image_flen);
return 0;
}
/* See if we have enough space */
if (image_flen > mem_layout->free_size) {
printf("ERROR: Cannot load '%s' file: Not enough space.\r\n",
image_name);
dump_load_info(0, image_flen, mem_layout);
return 0;
}
switch (load_type) {
case TOP_LOAD:
/* Load the image in the top of free memory */
temp_image_base = mem_layout->free_base + mem_layout->free_size;
temp_image_base -= image_flen;
/* Page align base address and check whether the image still fits */
image_base = page_align(temp_image_base, DOWN);
assert(image_base <= temp_image_base);
if (image_base < mem_layout->free_base) {
printf("ERROR: Cannot load '%s' file: Not enough space.\r\n",
image_name);
dump_load_info(image_base, image_flen, mem_layout);
return 0;
}
/* Calculate the amount of extra memory used due to alignment */
offset = temp_image_base - image_base;
break;
case BOT_LOAD:
/* Load the BL2 image in the bottom of free memory */
temp_image_base = mem_layout->free_base;
image_base = page_align(temp_image_base, UP);
assert(image_base >= temp_image_base);
/* Page align base address and check whether the image still fits */
if (image_base + image_flen >
mem_layout->free_base + mem_layout->free_size) {
printf("ERROR: Cannot load '%s' file: Not enough space.\r\n",
image_name);
dump_load_info(image_base, image_flen, mem_layout);
return 0;
}
/* Calculate the amount of extra memory used due to alignment */
offset = image_base - temp_image_base;
break;
default:
assert(0);
}
/*
* Some images must be loaded at a fixed address, not a dynamic one.
*
* This has been implemented as a hack on top of the existing dynamic
* loading mechanism, for the time being. If the 'fixed_addr' function
* argument is different from zero, then it will force the load address.
* So we still have this principle of top/bottom loading but the code
* determining the load address is bypassed and the load address is
* forced to the fixed one.
*
* This can result in quite a lot of wasted space because we still use
* 1 sole meminfo structure to represent the extents of free memory,
* where we should use some sort of linked list.
*
* E.g. we want to load BL2 at address 0x04020000, the resulting memory
* layout should look as follows:
* ------------ 0x04040000
* | | <- Free space (1)
* |----------|
* | BL2 |
* |----------| 0x04020000
* | | <- Free space (2)
* |----------|
* | BL1 |
* ------------ 0x04000000
*
* But in the current hacky implementation, we'll need to specify
* whether BL2 is loaded at the top or bottom of the free memory.
* E.g. if BL2 is considered as top-loaded, the meminfo structure
* will give the following view of the memory, hiding the chunk of
* free memory above BL2:
* ------------ 0x04040000
* | |
* | |
* | BL2 |
* |----------| 0x04020000
* | | <- Free space (2)
* |----------|
* | BL1 |
* ------------ 0x04000000
*/
if (fixed_addr != 0) {
/* Load the image at the given address. */
image_base = fixed_addr;
/* Check whether the image fits. */
if ((image_base < mem_layout->free_base) ||
(image_base + image_flen >
mem_layout->free_base + mem_layout->free_size)) {
printf("ERROR: Cannot load '%s' file: Not enough space.\r\n",
image_name);
dump_load_info(image_base, image_flen, mem_layout);
return 0;
}
/* Check whether the fixed load address is page-aligned. */
if (!is_page_aligned(image_base)) {
printf("ERROR: Cannot load '%s' file at unaligned address 0x%lx.\r\n",
image_name, fixed_addr);
return 0;
}
/*
* Calculate the amount of extra memory used due to fixed
* loading.
*/
if (load_type == TOP_LOAD) {
unsigned long max_addr, space_used;
/*
* ------------ max_addr
* | /wasted/ | | offset
* |..........|..............................
* | image | | image_flen
* |----------| fixed_addr
* | |
* | |
* ------------ total_base
*/
max_addr = mem_layout->total_base + mem_layout->total_size;
/*
* Compute the amount of memory used by the image.
* Corresponds to all space above the image load
* address.
*/
space_used = max_addr - fixed_addr;
/*
* Calculate the amount of wasted memory within the
* amount of memory used by the image.
*/
offset = space_used - image_flen;
} else /* BOT_LOAD */
/*
* ------------
* | |
* | |
* |----------|
* | image |
* |..........| fixed_addr
* | /wasted/ | | offset
* ------------ total_base
*/
offset = fixed_addr - mem_layout->total_base;
}
/* We have enough space so load the image now */
image_flen = semihosting_download_file(image_name,
image_flen,
(void *) image_base);
if (image_flen <= 0) {
printf("ERROR: Failed to load '%s' file from semihosting (%i).\r\n",
image_name, image_flen);
return 0;
}
/*
* File has been successfully loaded. Update the free memory
* data structure & flush the contents of the TZRAM so that
* the next EL can see it.
*/
/* Update the memory contents */
flush_dcache_range(image_base, image_flen);
mem_layout->free_size -= image_flen + offset;
/* Update the base of free memory since its moved up */
if (load_type == BOT_LOAD)
mem_layout->free_base += offset + image_flen;
return image_base;
}
/*******************************************************************************
* Run a loaded image from the given entry point. This could result in either
* dropping into a lower exception level or jumping to a higher exception level.
* The only way of doing the latter is through an SMC. In either case, setup the
* parameters for the EL change request correctly.
******************************************************************************/
int run_image(unsigned long entrypoint,
unsigned long spsr,
unsigned long target_security_state,
meminfo *mem_layout,
void *data)
{
el_change_info run_image_info;
unsigned long current_el = read_current_el();
/* Tell next EL what we want done */
run_image_info.args.arg0 = RUN_IMAGE;
run_image_info.entrypoint = entrypoint;
run_image_info.spsr = spsr;
run_image_info.security_state = target_security_state;
run_image_info.next = 0;
/*
* If we are EL3 then only an eret can take us to the desired
* exception level. Else for the time being assume that we have
* to jump to a higher EL and issue an SMC. Contents of argY
* will go into the general purpose register xY e.g. arg0->x0
*/
if (GET_EL(current_el) == MODE_EL3) {
run_image_info.args.arg1 = (unsigned long) mem_layout;
run_image_info.args.arg2 = (unsigned long) data;
} else {
run_image_info.args.arg1 = entrypoint;
run_image_info.args.arg2 = spsr;
run_image_info.args.arg3 = (unsigned long) mem_layout;
run_image_info.args.arg4 = (unsigned long) data;
}
return change_el(&run_image_info);
}
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