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