misc.h

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#ifndef __VBOOT_MISC_H__
#define __VBOOT_MISC_H__
 
#include <assert.h>
#include <security/vboot/vboot_common.h>
#include <vb2_api.h>
 
/*
 * Source: security/vboot/common.c
 */
struct vb2_context *vboot_get_context(void);
 
/*
 * Returns 1 if firmware slot A is used, 0 if slot B is used.
 */
static inline int vboot_is_firmware_slot_a(struct vb2_context *ctx)
{
        return !(ctx->flags & VB2_CONTEXT_FW_SLOT_B);
}
 
/*
 * Check if given flag is set in the flags field in GBB header.
 * Return value:
 * true: Flag is set.
 * false: Flag is not set.
 */
static inline bool vboot_is_gbb_flag_set(enum vb2_gbb_flag flag)
{
        return !!(vb2api_gbb_get_flags(vboot_get_context()) & flag);
}
 
/*
 * Locates firmware as a region device. Returns 0 on success, -1 on failure.
 */
int vboot_locate_firmware(struct vb2_context *ctx, struct region_device *fw);
 
/*
 * The stage loading code is compiled and entered from multiple stages. The
 * helper functions below attempt to provide more clarity on when certain
 * code should be called. They are implemented inline for better compile-time
 * code elimination.
 */
 
static inline int verification_should_run(void)
{
        if (CONFIG(VBOOT_SEPARATE_VERSTAGE))
                return ENV_SEPARATE_VERSTAGE;
        else if (CONFIG(VBOOT_STARTS_IN_ROMSTAGE))
                return ENV_ROMSTAGE;
        else if (CONFIG(VBOOT_STARTS_IN_BOOTBLOCK))
                return ENV_BOOTBLOCK;
        else
                dead_code();
}
 
static inline int verstage_should_load(void)
{
        if (CONFIG(VBOOT_SEPARATE_VERSTAGE) && !CONFIG(VBOOT_STARTS_BEFORE_BOOTBLOCK))
                return ENV_BOOTBLOCK;
        else
                return 0;
}
 
static inline int vboot_logic_executed(void)
{
        extern int vboot_executed;      /* should not be globally accessible */
 
        /* If we are in the stage that runs verification, or in the stage that
           both loads the verstage and is returned to from it afterwards, we
           need to check a global to see if verification has run. */
        if (verification_should_run() ||
            (verstage_should_load() && CONFIG(VBOOT_RETURN_FROM_VERSTAGE)))
                return vboot_executed;
 
        if (CONFIG(VBOOT_STARTS_IN_BOOTBLOCK)) {
                /* All other stages are "after the bootblock" */
                return !ENV_BOOTBLOCK;
        } else if (CONFIG(VBOOT_STARTS_IN_ROMSTAGE)) {
                /* Post-RAM stages are "after the romstage" */
                return !ENV_ROMSTAGE_OR_BEFORE;
        } else if (CONFIG(VBOOT_STARTS_BEFORE_BOOTBLOCK)) {
                return !ENV_SEPARATE_VERSTAGE;
        } else {
                dead_code();
        }
}
 
#endif /* __VBOOT_MISC_H__ */