/**
* imr_fixup_memmap - Tear down IMRs used during bootup.
*
* BIOS and Grub both setup IMRs around compressed kernel, initrd memory
* that need to be removed before the kernel hands out one of the IMR
* encased addresses to a downstream DMA agent such as the SD or Ethernet.
* IMRs on Galileo are setup to immediately reset the system on violation.
* As a result if you're running a root filesystem from SD - you'll need
* the boot-time IMRs torn down or you'll find seemingly random resets when
* using your filesystem.
*
* @idev: pointer to imr_device structure.
* @return:
*/
static void __init imr_fixup_memmap(struct imr_device *idev)
{
phys_addr_t base = virt_to_phys(&_text);
size_t size = virt_to_phys(&__end_rodata) - base;
unsigned long start, end;
int i;
int ret;
/* Tear down all existing unlocked IMRs. */
for (i = 0; i < idev->max_imr; i++)
imr_clear(i);
start = (unsigned long)_text;
end = (unsigned long)__end_rodata - 1;
/*
* Setup an unlocked IMR around the physical extent of the kernel
* from the beginning of the .text secton to the end of the
* .rodata section as one physically contiguous block.
*
* We don't round up @size since it is already PAGE_SIZE aligned.
* See vmlinux.lds.S for details.
*/
ret = imr_add_range(base, size, IMR_CPU, IMR_CPU);
if (ret < 0) {
pr_err("unable to setup IMR for kernel: %zu KiB (%lx - %lx)\n",
size / 1024, start, end);
} else {
pr_info("protecting kernel .text - .rodata: %zu KiB (%lx - %lx)\n",
size / 1024, start, end);
}
}
/**
* imr_self_test
*
* Verify IMR self_test with some simple tests to verify overlap,
* zero sized allocations and 1 KiB sized areas.
*
*/
static void __init imr_self_test(void)
{
phys_addr_t base = virt_to_phys((void *)ktla_ktva((unsigned long)_text));
size_t size = virt_to_phys(&__end_rodata) - base;
const char *fmt_over = "overlapped IMR @ (0x%08lx - 0x%08lx)\n";
int ret;
/* Test zero zero. */
ret = imr_add_range(0, 0, 0, 0, false);
imr_self_test_result(ret < 0, "zero sized IMR\n");
/* Test exact overlap. */
ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
imr_self_test_result(ret < 0, fmt_over, __va(base), __va(base + size));
/* Test overlap with base inside of existing. */
base += size - IMR_ALIGN;
ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
imr_self_test_result(ret < 0, fmt_over, __va(base), __va(base + size));
/* Test overlap with end inside of existing. */
base -= size + IMR_ALIGN * 2;
ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
imr_self_test_result(ret < 0, fmt_over, __va(base), __va(base + size));
/* Test that a 1 KiB IMR @ zero with read/write all will bomb out. */
ret = imr_add_range(0, IMR_ALIGN, IMR_READ_ACCESS_ALL,
IMR_WRITE_ACCESS_ALL, false);
imr_self_test_result(ret < 0, "1KiB IMR @ 0x00000000 - access-all\n");
/* Test that a 1 KiB IMR @ zero with CPU only will work. */
ret = imr_add_range(0, IMR_ALIGN, IMR_CPU, IMR_CPU, false);
imr_self_test_result(ret >= 0, "1KiB IMR @ 0x00000000 - cpu-access\n");
if (ret >= 0) {
ret = imr_remove_range(0, IMR_ALIGN);
imr_self_test_result(ret == 0, "teardown - cpu-access\n");
}
/* Test 2 KiB works. */
size = IMR_ALIGN * 2;
ret = imr_add_range(0, size, IMR_READ_ACCESS_ALL,
IMR_WRITE_ACCESS_ALL, false);
imr_self_test_result(ret >= 0, "2KiB IMR @ 0x00000000\n");
if (ret >= 0) {
ret = imr_remove_range(0, size);
imr_self_test_result(ret == 0, "teardown 2KiB\n");
}
}
