ACPI tables translator

Exposes x86 ACPI tables as a netfs on a mount point

* acpi: New directory.
* Makefile (prog-subdirs): Add acpi.
* hurd/hurd_types.h (FSTYPE_ACPI): New macro.

1 files changed, 290 insertions, 0 deletions

diff --git a/acpi/acpi.c b/acpi/acpi.c
new file mode 100644
index 00000000..63066aaf
--- /dev/null
+++ b/acpi/acpi.c
@@ -0,0 +1,290 @@
+/*
+   Copyright (C) 2018 Free Software Foundation, Inc.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the GNU Hurd.  If not, see <<a rel="nofollow" href="http://www.gnu.org/licenses/">http://www.gnu.org/licenses/</a>>.
+*/
+
+#include <sys/mman.h>
+#include <sys/io.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "acpi.h"
+
+int
+mmap_phys_acpi_header(uintptr_t base_addr, struct acpi_header **ptr_to_header,
+                      void **virt_addr, int fd)
+{
+  /* The memory mapping must be done aligned to page size
+   * but we have a known physical address we want to inspect,
+   * therefore we must compute offsets.
+   */
+  uintptr_t pa_acpi = base_addr & ~(sysconf(_SC_PAGE_SIZE) - 1);
+  uintptr_t pa_start = base_addr - pa_acpi;
+
+  /* Map the ACPI table at the nearest page (rounded down) */
+  *virt_addr = 0;
+  *virt_addr = mmap(NULL, ESCD_SIZE, PROT_READ, MAP_SHARED | MAP_FIXED,
+                    fd, (off_t) pa_acpi);
+
+  if (*virt_addr == MAP_FAILED)
+    return errno;
+
+  /* Fabricate a pointer to our magic address */
+  *ptr_to_header = (struct acpi_header *)(*virt_addr + pa_start);
+
+  return 0;
+}
+
+int
+acpi_get_num_tables(size_t *num_tables)
+{
+  int fd_mem;
+  int err;
+  void *virt_addr, *virt_addr2;
+  bool found = false;
+  struct rsdp_descr2 rsdp = { 0 };
+  uintptr_t sdt_base = (uintptr_t)0;
+  bool is_64bit = false;
+  unsigned char *buf;
+  struct acpi_header *root_sdt;
+  struct acpi_header *next;
+
+  if ((fd_mem = open("/dev/mem", O_RDWR)) < 0)
+    return EPERM;
+
+  virt_addr = mmap(NULL, ESCD_SIZE, PROT_READ,
+                   MAP_SHARED | MAP_FIXED, fd_mem, ESCD);
+  if (virt_addr == MAP_FAILED)
+    return errno;
+
+  buf = (unsigned char *)virt_addr;
+  found = false;
+
+  /* RSDP magic string is 16 byte aligned */
+  for (int i = 0; i < ESCD_SIZE; i += 16)
+    {
+      if (!memcmp(&buf[i], RSDP_MAGIC, 8)) {
+        rsdp = *((struct rsdp_descr2 *)(&buf[i]));
+        found = true;
+        break;
+      }
+    }
+
+  if (!found) {
+    munmap(virt_addr, ESCD_SIZE);
+    return ENODEV;
+  }
+
+  if (rsdp.v1.revision == 0) {
+    // ACPI 1.0
+    sdt_base = rsdp.v1.rsdt_addr;
+    is_64bit = false;
+  } else if (rsdp.v1.revision == 2) {
+    // ACPI >= 2.0
+    sdt_base = rsdp.xsdt_addr;
+    is_64bit = true;
+  } else {
+    munmap(virt_addr, ESCD_SIZE);
+    return ENODEV;
+  }
+
+  munmap(virt_addr, ESCD_SIZE);
+
+  /* Now we have the sdt_base address and knowledge of 32/64 bit ACPI */
+
+  err = mmap_phys_acpi_header(sdt_base, &root_sdt, &virt_addr, fd_mem);
+  if (err) {
+    munmap(virt_addr, ESCD_SIZE);
+    return err;
+  }
+
+  /* Get total tables */
+  uint32_t ntables;
+  uint8_t sz_ptr;
+  sz_ptr = is_64bit ? 8 : 4;
+  ntables = (root_sdt->length - sizeof(*root_sdt)) / sz_ptr;
+
+  /* Get pointer to first ACPI table */
+  uintptr_t acpi_ptr = (uintptr_t)root_sdt + sizeof(*root_sdt);
+
+  /* Get number of readable tables */
+  *num_tables = 0;
+  for (int i = 0; i < ntables; i++)
+    {
+      uintptr_t acpi_ptr32 = (uintptr_t)*((uint32_t *)(acpi_ptr + i*sz_ptr));
+      uintptr_t acpi_ptr64 = (uintptr_t)*((uint64_t *)(acpi_ptr + i*sz_ptr));
+      if (is_64bit) {
+        err = mmap_phys_acpi_header(acpi_ptr64, &next, &virt_addr2, fd_mem);
+      } else {
+        err = mmap_phys_acpi_header(acpi_ptr32, &next, &virt_addr2, fd_mem);
+      }
+
+      char name[5] = { 0 };
+      snprintf(name, 5, "%s", &next->signature[0]);
+      if (next->signature[0] == '\0' || next->length == 0) {
+        munmap(virt_addr2, ESCD_SIZE);
+        continue;
+      }
+      *num_tables += 1;
+      munmap(virt_addr2, ESCD_SIZE);
+    }
+
+  munmap(virt_addr, ESCD_SIZE);
+
+  return 0;
+}
+
+int
+acpi_get_tables(struct acpi_table **tables)
+{
+  int err;
+  int fd_mem;
+  void *virt_addr, *virt_addr2;
+  uint32_t phys_addr = ESCD;
+  bool found = false;
+  struct rsdp_descr2 rsdp = { 0 };
+  uintptr_t sdt_base = (uintptr_t)0;
+  bool is_64bit = false;
+  unsigned char *buf;
+  struct acpi_header *root_sdt;
+  struct acpi_header *next;
+  size_t ntables_actual;
+  int cur_tab = 0;
+
+  err = acpi_get_num_tables(&ntables_actual);
+  if (err)
+    return err;
+
+  *tables = malloc(ntables_actual * sizeof(**tables));
+  if (!*tables)
+    return ENOMEM;
+
+  if ((fd_mem = open("/dev/mem", O_RDWR)) < 0)
+    return EPERM;
+
+  virt_addr = mmap(NULL, ESCD_SIZE, PROT_READ, MAP_SHARED | MAP_FIXED,
+                   fd_mem, (off_t) phys_addr);
+
+  if (virt_addr == MAP_FAILED)
+    return errno;
+
+  buf = (unsigned char *)virt_addr;
+  found = false;
+
+  /* RSDP magic string is 16 byte aligned */
+  for (int i = 0; i < ESCD_SIZE; i += 16)
+    {
+      if (!memcmp(&buf[i], RSDP_MAGIC, 8)) {
+        rsdp = *((struct rsdp_descr2 *)(&buf[i]));
+        found = true;
+        break;
+      }
+    }
+
+  if (!found) {
+    munmap(virt_addr, ESCD_SIZE);
+    return ENODEV;
+  }
+
+  if (rsdp.v1.revision == 0) {
+    // ACPI 1.0
+    sdt_base = rsdp.v1.rsdt_addr;
+    is_64bit = false;
+  } else if (rsdp.v1.revision == 2) {
+    // ACPI >= 2.0
+    sdt_base = rsdp.xsdt_addr;
+    is_64bit = true;
+  } else {
+    munmap(virt_addr, ESCD_SIZE);
+    return ENODEV;
+  }
+
+  munmap(virt_addr, ESCD_SIZE);
+
+  /* Now we have the sdt_base address and knowledge of 32/64 bit ACPI */
+
+  err = mmap_phys_acpi_header(sdt_base, &root_sdt, &virt_addr, fd_mem);
+  if (err) {
+    munmap(virt_addr, ESCD_SIZE);
+    return err;
+  }
+
+  /* Get total tables */
+  uint32_t ntables;
+  uint8_t sz_ptr;
+  sz_ptr = is_64bit ? 8 : 4;
+  ntables = (root_sdt->length - sizeof(*root_sdt)) / sz_ptr;
+
+  /* Get pointer to first ACPI table */
+  uintptr_t acpi_ptr = (uintptr_t)root_sdt + sizeof(*root_sdt);
+
+  /* Get all tables and data */
+  for (int i = 0; i < ntables; i++)
+    {
+      uintptr_t acpi_ptr32 = (uintptr_t)*((uint32_t *)(acpi_ptr + i*sz_ptr));
+      uintptr_t acpi_ptr64 = (uintptr_t)*((uint64_t *)(acpi_ptr + i*sz_ptr));
+      if (is_64bit) {
+        err = mmap_phys_acpi_header(acpi_ptr64, &next, &virt_addr2, fd_mem);
+        if (err) {
+          munmap(virt_addr, ESCD_SIZE);
+          return err;
+        }
+      } else {
+        err = mmap_phys_acpi_header(acpi_ptr32, &next, &virt_addr2, fd_mem);
+        if (err) {
+          munmap(virt_addr, ESCD_SIZE);
+          return err;
+        }
+      }
+
+      char name[5] = { 0 };
+      snprintf(name, 5, "%s", &next->signature[0]);
+      if (next->signature[0] == '\0' || next->length == 0) {
+        munmap(virt_addr2, ESCD_SIZE);
+        continue;
+      }
+      uint32_t datalen = next->length - sizeof(*next);
+      void *data = (void *)((uintptr_t)next + sizeof(*next));
+
+      /* We now have a pointer to the data,
+       * its length and header.
+       */
+      struct acpi_table *t = *tables + cur_tab;
+      memcpy(&t->h, next, sizeof(*next));
+      t->datalen = 0;
+      t->data = malloc(datalen);
+      if (!t->data) {
+        munmap(virt_addr2, ESCD_SIZE);
+        munmap(virt_addr, ESCD_SIZE);
+        return ENOMEM;
+      }
+      t->datalen = datalen;
+      memcpy(t->data, data, datalen);
+      cur_tab++;
+      munmap(virt_addr2, ESCD_SIZE);
+    }
+
+  munmap(virt_addr, ESCD_SIZE);
+
+  return 0;
+}