common.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <assert.h>
#include <cbmem.h>
#include <fmap.h>
#include <vb2_api.h>
#include <security/vboot/misc.h>
#include <security/vboot/symbols.h>
#include <security/vboot/vboot_common.h>
 
static struct vb2_context *vboot_ctx;
 
static void *vboot_get_workbuf(void)
{
        void *wb = NULL;
 
        if (cbmem_possibly_online())
                wb = cbmem_find(CBMEM_ID_VBOOT_WORKBUF);
 
        if (wb == NULL && !CONFIG(VBOOT_STARTS_IN_ROMSTAGE) && preram_symbols_available())
                wb = _vboot2_work;
 
        assert(wb != NULL);
 
        return wb;
}
 
struct vb2_context *vboot_get_context(void)
{
        void *wb;
 
        /* Return if context has already been initialized/restored. */
        if (vboot_ctx)
                return vboot_ctx;
 
        wb = vboot_get_workbuf();
 
        /* Restore context from a previous stage. */
        if (vboot_logic_executed()) {
                assert(vb2api_reinit(wb, &vboot_ctx) == VB2_SUCCESS);
                return vboot_ctx;
        }
 
        assert(verification_should_run());
 
        /* Initialize vb2_shared_data and friends. */
        assert(vb2api_init(wb, VB2_FIRMWARE_WORKBUF_RECOMMENDED_SIZE,
                           &vboot_ctx) == VB2_SUCCESS);
 
        return vboot_ctx;
}
 
int vboot_locate_firmware(struct vb2_context *ctx, struct region_device *fw)
{
        const char *name;
 
        if (vboot_is_firmware_slot_a(ctx))
                name = "FW_MAIN_A";
        else
                name = "FW_MAIN_B";
 
        int ret = fmap_locate_area_as_rdev(name, fw);
        if (ret)
                return ret;
 
        /* Truncate area to the size that was actually signed by vboot. */
        return rdev_chain(fw, fw, 0, vb2api_get_firmware_size(ctx));
}
 
static void vboot_setup_cbmem(int unused)
{
        vb2_error_t rv;
        const size_t cbmem_size = VB2_KERNEL_WORKBUF_RECOMMENDED_SIZE;
        void *wb_cbmem = cbmem_add(CBMEM_ID_VBOOT_WORKBUF, cbmem_size);
        assert(wb_cbmem != NULL);
        /*
         * On platforms where VBOOT_STARTS_BEFORE_BOOTBLOCK, the verification
         * occurs before the main processor starts running.  The vboot data-
         * structure is available in the _vboot2_work memory area as soon
         * as the main processor is released.
         *
         * For platforms where VBOOT_STARTS_IN_BOOTBLOCK, vboot verification
         * occurs before CBMEM is brought online, using pre-RAM. In order to
         * make vboot data structures available downstream, copy vboot workbuf
         * from SRAM/CAR into CBMEM.
         *
         * For platforms where VBOOT_STARTS_IN_ROMSTAGE, verification occurs
         * after CBMEM is brought online.  Directly initialize vboot data
         * structures in CBMEM, which will also be available downstream.
         */
        if (!CONFIG(VBOOT_STARTS_IN_ROMSTAGE))
                rv = vb2api_relocate(wb_cbmem, _vboot2_work, cbmem_size,
                                     &vboot_ctx);
        else
                rv = vb2api_init(wb_cbmem, cbmem_size, &vboot_ctx);
 
        assert(rv == VB2_SUCCESS);
}
ROMSTAGE_CBMEM_INIT_HOOK(vboot_setup_cbmem)