linux/drivers/firmware/efi/libstub/arm32-stub.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org>
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
static efi_guid_t cpu_state_guid = LINUX_EFI_ARM_CPU_STATE_TABLE_GUID;
struct efi_arm_entry_state *efi_entry_state;
static void get_cpu_state(u32 *cpsr, u32 *sctlr)
{
asm("mrs %0, cpsr" : "=r"(*cpsr));
if ((*cpsr & MODE_MASK) == HYP_MODE)
asm("mrc p15, 4, %0, c1, c0, 0" : "=r"(*sctlr));
else
asm("mrc p15, 0, %0, c1, c0, 0" : "=r"(*sctlr));
}
efi_status_t check_platform_features(void)
{
efi_status_t status;
u32 cpsr, sctlr;
int block;
get_cpu_state(&cpsr, &sctlr);
efi_info("Entering in %s mode with MMU %sabled\n",
((cpsr & MODE_MASK) == HYP_MODE) ? "HYP" : "SVC",
(sctlr & 1) ? "en" : "dis");
status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
sizeof(*efi_entry_state),
(void **)&efi_entry_state);
if (status != EFI_SUCCESS) {
efi_err("allocate_pool() failed\n");
return status;
}
efi_entry_state->cpsr_before_ebs = cpsr;
efi_entry_state->sctlr_before_ebs = sctlr;
status = efi_bs_call(install_configuration_table, &cpu_state_guid,
efi_entry_state);
if (status != EFI_SUCCESS) {
efi_err("install_configuration_table() failed\n");
goto free_state;
}
/* non-LPAE kernels can run anywhere */
if (!IS_ENABLED(CONFIG_ARM_LPAE))
return EFI_SUCCESS;
/* LPAE kernels need compatible hardware */
block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
if (block < 5) {
efi_err("This LPAE kernel is not supported by your CPU\n");
status = EFI_UNSUPPORTED;
goto drop_table;
}
return EFI_SUCCESS;
drop_table:
efi_bs_call(install_configuration_table, &cpu_state_guid, NULL);
free_state:
efi_bs_call(free_pool, efi_entry_state);
return status;
}
void efi_handle_post_ebs_state(void)
{
get_cpu_state(&efi_entry_state->cpsr_after_ebs,
&efi_entry_state->sctlr_after_ebs);
}
static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
struct screen_info *alloc_screen_info(void)
{
struct screen_info *si;
efi_status_t status;
/*
* Unlike on arm64, where we can directly fill out the screen_info
* structure from the stub, we need to allocate a buffer to hold
* its contents while we hand over to the kernel proper from the
* decompressor.
*/
status = efi_bs_call(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
sizeof(*si), (void **)&si);
if (status != EFI_SUCCESS)
return NULL;
status = efi_bs_call(install_configuration_table,
&screen_info_guid, si);
if (status == EFI_SUCCESS)
return si;
efi_bs_call(free_pool, si);
return NULL;
}
void free_screen_info(struct screen_info *si)
{
if (!si)
return;
efi_bs_call(install_configuration_table, &screen_info_guid, NULL);
efi_bs_call(free_pool, si);
}
static efi_status_t reserve_kernel_base(unsigned long dram_base,
unsigned long *reserve_addr,
unsigned long *reserve_size)
{
efi_physical_addr_t alloc_addr;
efi_memory_desc_t *memory_map;
unsigned long nr_pages, map_size, desc_size, buff_size;
efi_status_t status;
unsigned long l;
struct efi_boot_memmap map = {
.map = &memory_map,
.map_size = &map_size,
.desc_size = &desc_size,
.desc_ver = NULL,
.key_ptr = NULL,
.buff_size = &buff_size,
};
/*
* Reserve memory for the uncompressed kernel image. This is
* all that prevents any future allocations from conflicting
* with the kernel. Since we can't tell from the compressed
* image how much DRAM the kernel actually uses (due to BSS
* size uncertainty) we allocate the maximum possible size.
* Do this very early, as prints can cause memory allocations
* that may conflict with this.
*/
alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE;
nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr);
if (status == EFI_SUCCESS) {
if (alloc_addr == dram_base) {
*reserve_addr = alloc_addr;
*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
return EFI_SUCCESS;
}
/*
* If we end up here, the allocation succeeded but starts below
* dram_base. This can only occur if the real base of DRAM is
* not a multiple of 128 MB, in which case dram_base will have
* been rounded up. Since this implies that a part of the region
* was already occupied, we need to fall through to the code
* below to ensure that the existing allocations don't conflict.
* For this reason, we use EFI_BOOT_SERVICES_DATA above and not
* EFI_LOADER_DATA, which we wouldn't able to distinguish from
* allocations that we want to disallow.
*/
}
/*
* If the allocation above failed, we may still be able to proceed:
* if the only allocations in the region are of types that will be
* released to the OS after ExitBootServices(), the decompressor can
* safely overwrite them.
*/
status = efi_get_memory_map(&map);
if (status != EFI_SUCCESS) {
efi_err("reserve_kernel_base(): Unable to retrieve memory map.\n");
return status;
}
for (l = 0; l < map_size; l += desc_size) {
efi_memory_desc_t *desc;
u64 start, end;
desc = (void *)memory_map + l;
start = desc->phys_addr;
end = start + desc->num_pages * EFI_PAGE_SIZE;
/* Skip if entry does not intersect with region */
if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE ||
end <= dram_base)
continue;
switch (desc->type) {
case EFI_BOOT_SERVICES_CODE:
case EFI_BOOT_SERVICES_DATA:
/* Ignore types that are released to the OS anyway */
continue;
case EFI_CONVENTIONAL_MEMORY:
/* Skip soft reserved conventional memory */
if (efi_soft_reserve_enabled() &&
(desc->attribute & EFI_MEMORY_SP))
continue;
/*
* Reserve the intersection between this entry and the
* region.
*/
start = max(start, (u64)dram_base);
end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE);
status = efi_bs_call(allocate_pages,
EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA,
(end - start) / EFI_PAGE_SIZE,
&start);
if (status != EFI_SUCCESS) {
efi_err("reserve_kernel_base(): alloc failed.\n");
goto out;
}
break;
case EFI_LOADER_CODE:
case EFI_LOADER_DATA:
/*
* These regions may be released and reallocated for
* another purpose (including EFI_RUNTIME_SERVICE_DATA)
* at any time during the execution of the OS loader,
* so we cannot consider them as safe.
*/
default:
/*
* Treat any other allocation in the region as unsafe */
status = EFI_OUT_OF_RESOURCES;
goto out;
}
}
status = EFI_SUCCESS;
out:
efi_bs_call(free_pool, memory_map);
return status;
}
efi_status_t handle_kernel_image(unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,
unsigned long *reserve_size,
unsigned long dram_base,
efi_loaded_image_t *image)
{
efi: libstub/arm: Account for firmware reserved memory at the base of RAM The EFI stubloader for ARM starts out by allocating a 32 MB window at the base of RAM, in order to ensure that the decompressor (which blindly copies the uncompressed kernel into that window) does not overwrite other allocations that are made while running in the context of the EFI firmware. In some cases, (e.g., U-Boot running on the Raspberry Pi 2), this is causing boot failures because this initial allocation conflicts with a page of reserved memory at the base of RAM that contains the SMP spin tables and other pieces of firmware data and which was put there by the bootloader under the assumption that the TEXT_OFFSET window right below the kernel is only used partially during early boot, and will be left alone once the memory reservations are processed and taken into account. So let's permit reserved memory regions to exist in the region starting at the base of RAM, and ending at TEXT_OFFSET - 5 * PAGE_SIZE, which is the window below the kernel that is not touched by the early boot code. Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Chester Lin <clin@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-30 01:37:53 +08:00
unsigned long kernel_base;
efi_status_t status;
/* use a 16 MiB aligned base for the decompressed kernel */
kernel_base = round_up(dram_base, SZ_16M) + TEXT_OFFSET;
efi: libstub/arm: Account for firmware reserved memory at the base of RAM The EFI stubloader for ARM starts out by allocating a 32 MB window at the base of RAM, in order to ensure that the decompressor (which blindly copies the uncompressed kernel into that window) does not overwrite other allocations that are made while running in the context of the EFI firmware. In some cases, (e.g., U-Boot running on the Raspberry Pi 2), this is causing boot failures because this initial allocation conflicts with a page of reserved memory at the base of RAM that contains the SMP spin tables and other pieces of firmware data and which was put there by the bootloader under the assumption that the TEXT_OFFSET window right below the kernel is only used partially during early boot, and will be left alone once the memory reservations are processed and taken into account. So let's permit reserved memory regions to exist in the region starting at the base of RAM, and ending at TEXT_OFFSET - 5 * PAGE_SIZE, which is the window below the kernel that is not touched by the early boot code. Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Chester Lin <clin@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-30 01:37:53 +08:00
/*
* Note that some platforms (notably, the Raspberry Pi 2) put
* spin-tables and other pieces of firmware at the base of RAM,
* abusing the fact that the window of TEXT_OFFSET bytes at the
* base of the kernel image is only partially used at the moment.
* (Up to 5 pages are used for the swapper page tables)
*/
status = reserve_kernel_base(kernel_base - 5 * PAGE_SIZE, reserve_addr,
reserve_size);
if (status != EFI_SUCCESS) {
efi_err("Unable to allocate memory for uncompressed kernel.\n");
return status;
}
*image_addr = kernel_base;
*image_size = 0;
return EFI_SUCCESS;
}