linux/drivers/firmware/efi/libstub/arm32-stub.c
Ard Biesheuvel 801820bee9 efi/arm/libstub: Make screen_info accessible to the UEFI stub
In order to hand over the framebuffer described by the GOP protocol and
discovered by the UEFI stub, make struct screen_info accessible by the
stub. This involves allocating a loader data buffer and passing it to the
kernel proper via a UEFI Configuration Table, since the UEFI stub executes
in the context of the decompressor, and cannot access the kernel's copy of
struct screen_info directly.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-22-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28 11:33:59 +02:00

140 lines
4.2 KiB
C

/*
* Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/efi.h>
#include <asm/efi.h>
efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
{
int block;
/* 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) {
pr_efi_err(sys_table_arg, "This LPAE kernel is not supported by your CPU\n");
return EFI_UNSUPPORTED;
}
return EFI_SUCCESS;
}
static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
struct screen_info *alloc_screen_info(efi_system_table_t *sys_table_arg)
{
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_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
sizeof(*si), (void **)&si);
if (status != EFI_SUCCESS)
return NULL;
status = efi_call_early(install_configuration_table,
&screen_info_guid, si);
if (status == EFI_SUCCESS)
return si;
efi_call_early(free_pool, si);
return NULL;
}
void free_screen_info(efi_system_table_t *sys_table_arg, struct screen_info *si)
{
if (!si)
return;
efi_call_early(install_configuration_table, &screen_info_guid, NULL);
efi_call_early(free_pool, si);
}
efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
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)
{
unsigned long nr_pages;
efi_status_t status;
/* Use alloc_addr to tranlsate between types */
efi_physical_addr_t alloc_addr;
/*
* Verify that the DRAM base address is compatible with the ARM
* boot protocol, which determines the base of DRAM by masking
* off the low 27 bits of the address at which the zImage is
* loaded. These assumptions are made by the decompressor,
* before any memory map is available.
*/
dram_base = round_up(dram_base, SZ_128M);
/*
* 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;
*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
nr_pages = round_up(*reserve_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
status = sys_table->boottime->allocate_pages(EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA,
nr_pages, &alloc_addr);
if (status != EFI_SUCCESS) {
*reserve_size = 0;
pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
return status;
}
*reserve_addr = alloc_addr;
/*
* Relocate the zImage, so that it appears in the lowest 128 MB
* memory window.
*/
*image_size = image->image_size;
status = efi_relocate_kernel(sys_table, image_addr, *image_size,
*image_size,
dram_base + MAX_UNCOMP_KERNEL_SIZE, 0);
if (status != EFI_SUCCESS) {
pr_efi_err(sys_table, "Failed to relocate kernel.\n");
efi_free(sys_table, *reserve_size, *reserve_addr);
*reserve_size = 0;
return status;
}
/*
* Check to see if we were able to allocate memory low enough
* in memory. The kernel determines the base of DRAM from the
* address at which the zImage is loaded.
*/
if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
efi_free(sys_table, *reserve_size, *reserve_addr);
*reserve_size = 0;
efi_free(sys_table, *image_size, *image_addr);
*image_size = 0;
return EFI_LOAD_ERROR;
}
return EFI_SUCCESS;
}