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// SPDX-License-Identifier: GPL-2.0
#include <linux/efi.h>
#include <linux/screen_info.h>
#include <asm/efi.h>
#include "efistub.h"
/*
* There are two ways of populating the core kernel's struct screen_info via the stub:
* - using a configuration table, like below, which relies on the EFI init code
* to locate the table and copy the contents;
* - by linking directly to the core kernel's copy of the global symbol.
*
* The latter is preferred because it makes the EFIFB earlycon available very
* early, but it only works if the EFI stub is part of the core kernel image
* itself. The zboot decompressor can only use the configuration table
* approach.
*/
static efi_guid_t screen_info_guid = LINUX_EFI_SCREEN_INFO_TABLE_GUID;
struct screen_info *__alloc_screen_info(void)
{
struct screen_info *si;
efi_status_t status;
status = efi_bs_call(allocate_pool, EFI_ACPI_RECLAIM_MEMORY,
sizeof(*si), (void **)&si);
if (status != EFI_SUCCESS)
return NULL;
memset(si, 0, sizeof(*si));
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);
}
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