[PATCH] commands/acpi: Fix furthering address the tables based upon the Entry field of XSDT

[Qiumiao Zhang]

According to the ACPI specification, the Entry field of XSDT containsts an
array of 64-bit physical addresses that point to other DESCRIPTION_HEADERs.
But entry_ptr is defined as a 32-bit pointer, which result in mistakenly
treating each 64-bit length address as two 32-bit length addresses when
iterating through the Entry field of XSDT.

Fix the issue by using the correct address length during the iteration process.

Signed-off-by: Qiumiao Zhang <zhangqiumiao1@huawei.com>
---
 grub-core/commands/acpi.c | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/grub-core/commands/acpi.c b/grub-core/commands/acpi.c
index 1c034463c..12b4a84eb 100644
--- a/grub-core/commands/acpi.c
+++ b/grub-core/commands/acpi.c
@@ -490,12 +490,12 @@ grub_cmd_acpi (struct grub_extcmd_context *ctxt, int 
argc, char **args)
 
   if (rsdp)
     {
-      grub_uint32_t *entry_ptr;
+      grub_uint8_t *entry_ptr;
       char *exclude = 0;
       char *load_only = 0;
       char *ptr;
-      /* RSDT consists of header and an array of 32-bit pointers. */
-      struct grub_acpi_table_header *rsdt;
+      int offset = 0;
+      struct grub_acpi_table_header *table_head;
 
       exclude = state[0].set ? grub_strdup (state[0].arg) : 0;
       if (exclude)
@@ -515,20 +515,32 @@ grub_cmd_acpi (struct grub_extcmd_context *ctxt, int 
argc, char **args)
       rev1 = ! rsdp->revision;
       rev2 = rsdp->revision;
       if (rev2 && ((struct grub_acpi_table_header *) (grub_addr_t) ((struct 
grub_acpi_rsdp_v20 *) rsdp)->xsdt_addr) != NULL)
-       rsdt = (struct grub_acpi_table_header *) (grub_addr_t) ((struct 
grub_acpi_rsdp_v20 *) rsdp)->xsdt_addr;
+       {
+         /* XSDT consists of header and an array of 64-bit pointers. */
+         table_head = (struct grub_acpi_table_header *) (grub_addr_t) ((struct 
grub_acpi_rsdp_v20 *) rsdp)->xsdt_addr;
+         offset = sizeof(((struct grub_acpi_rsdp_v20 *) rsdp)->xsdt_addr);
+       }
       else
-       rsdt = (struct grub_acpi_table_header *) (grub_addr_t) rsdp->rsdt_addr;
+       {
+         /* RSDT consists of header and an array of 32-bit pointers. */
+         table_head = (struct grub_acpi_table_header *) (grub_addr_t) 
rsdp->rsdt_addr;
+         offset = sizeof(rsdp->rsdt_addr);
+       }
 
       /* Load host tables. */
-      for (entry_ptr = (grub_uint32_t *) (rsdt + 1);
-          entry_ptr < (grub_uint32_t *) (((grub_uint8_t *) rsdt)
-                                         + rsdt->length);
-          entry_ptr++)
+      for (entry_ptr = (grub_uint8_t *) (table_head + 1);
+          entry_ptr < (grub_uint8_t *) (((grub_uint8_t *) table_head)
+                                         + table_head->length);
+          entry_ptr += offset)
        {
          char signature[5];
          struct efiemu_acpi_table *table;
-         struct grub_acpi_table_header *curtable
-           = (struct grub_acpi_table_header *) (grub_addr_t) *entry_ptr;
+         struct grub_acpi_table_header *curtable;
+         if (offset == sizeof(rsdp->rsdt_addr))
+           curtable = (struct grub_acpi_table_header *) (grub_addr_t) 
*((grub_uint32_t *)entry_ptr);
+         else
+           curtable = (struct grub_acpi_table_header *) (grub_addr_t) 
*((grub_uint64_t *)entry_ptr);
+
          signature[4] = 0;
          for (i = 0; i < 4;i++)
            signature[i] = grub_tolower (curtable->signature[i]);
-- 
2.28.0.windows.1