src/arch/x86/postcar_loader.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright 2016 Google Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <arch/cpu.h>
  17 #include <cbmem.h>
  18 #include <console/console.h>
  19 #include <cpu/x86/msr.h>
  20 #include <cpu/x86/mtrr.h>
  21 #include <program_loading.h>
  22 #include <rmodule.h>
  23
  24 static inline void stack_push(struct postcar_frame *pcf, uint32_t val)
  25 {
  26         uint32_t *ptr;
  27
  28         pcf->stack -= sizeof(val);
  29         ptr = (void *)pcf->stack;
  30         *ptr = val;
  31 }
  32
  33 int postcar_frame_init(struct postcar_frame *pcf, size_t stack_size)
  34 {
  35         void *stack;
  36         msr_t msr;
  37
  38         msr = rdmsr(MTRR_CAP_MSR);
  39
  40         stack = cbmem_add(CBMEM_ID_ROMSTAGE_RAM_STACK, stack_size);
  41         if (stack == NULL) {
  42                 printk(BIOS_ERR, "Couldn't add %zd byte stack in cbmem.\n",
  43                         stack_size);
  44                 return -1;
  45         }
  46
  47         pcf->stack = (uintptr_t)stack;
  48         pcf->stack += stack_size;
  49
  50         pcf->upper_mask = (1 << (cpu_phys_address_size() - 32)) - 1;
  51
  52         pcf->max_var_mttrs = msr.lo & MTRR_CAP_VCNT;
  53
  54         pcf->num_var_mttrs = 0;
  55
  56         return 0;
  57 }
  58
  59 void postcar_frame_add_mtrr(struct postcar_frame *pcf,
  60                                 uintptr_t addr, size_t size, int type)
  61 {
  62         size_t align;
  63
  64         if (pcf->num_var_mttrs >= pcf->max_var_mttrs) {
  65                 printk(BIOS_ERR, "No more variable MTRRs: %d\n",
  66                         pcf->max_var_mttrs);
  67                 return;
  68         }
  69
  70         /* Determine address alignment by lowest bit set in address. */
  71         align = addr & (addr ^ (addr - 1));
  72
  73         if (align < size) {
  74                 printk(BIOS_ERR, "Address (%lx) alignment (%zx) < size (%zx)\n",
  75                         addr, align, size);
  76                 size = align;
  77         }
  78
  79         /* Push MTRR mask then base -- upper 32-bits then lower 32-bits. */
  80         stack_push(pcf, pcf->upper_mask);
  81         stack_push(pcf, ~(size - 1) | MTRR_PHYS_MASK_VALID);
  82         stack_push(pcf, 0);
  83         stack_push(pcf, addr | type);
  84         pcf->num_var_mttrs++;
  85 }
  86
  87 void run_postcar_phase(struct postcar_frame *pcf)
  88 {
  89         struct prog prog =
  90                 PROG_INIT(PROG_UNKNOWN, CONFIG_CBFS_PREFIX "/postcar");
  91         struct rmod_stage_load rsl = {
  92                 .cbmem_id = CBMEM_ID_AFTER_CAR,
  93                 .prog = &prog,
  94         };
  95
  96         /*
  97          * Place the number of used variable MTRRs on stack then max number
  98          * of variable MTRRs supported in the system.
  99          */
 100         stack_push(pcf, pcf->num_var_mttrs);
 101         stack_push(pcf, pcf->max_var_mttrs);
 102
 103         if (prog_locate(&prog))
 104                 die("Failed to locate after CAR program.\n");
 105         if (rmodule_stage_load(&rsl))
 106                 die("Failed to load after CAR program.\n");
 107
 108         /* Set the stack pointer within parameters of the program loaded. */
 109         if (rsl.params == NULL)
 110                 die("No parameters found in after CAR program.\n");
 111
 112         *(uintptr_t *)rsl.params = pcf->stack;
 113
 114         /*
 115          * Signal to rest of system that another update was made to the
 116          * postcar program prior to running it.
 117          */
 118         prog_segment_loaded((uintptr_t)rsl.params, sizeof(uintptr_t),
 119                 SEG_FINAL);
 120
 121         prog_run(&prog);
 122 }