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

Source file repositories/reference/linux-study-clean/drivers/firmware/efi/libstub/arm32-stub.c

File Facts

System
Linux kernel
Corpus path
drivers/firmware/efi/libstub/arm32-stub.c
Extension
.c
Size
3766 bytes
Lines
135
Domain
Driver Families
Bucket
drivers/firmware
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// 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);
}

efi_status_t handle_kernel_image(unsigned long *image_addr,
				 unsigned long *image_size,
				 unsigned long *reserve_addr,
				 unsigned long *reserve_size,
				 efi_loaded_image_t *image,
				 efi_handle_t image_handle)
{
	const int slack = TEXT_OFFSET - 5 * PAGE_SIZE;
	int alloc_size = MAX_UNCOMP_KERNEL_SIZE + EFI_PHYS_ALIGN;
	unsigned long alloc_base, kernel_base;
	efi_status_t status;

Annotation

Implementation Notes