build: Fix -Werror=array-bounds array subscript 0 is outside array bounds

The GRUB is failing to build with GCC-12 in many places like this:

  In function 'init_cbfsdisk',
      inlined from 'grub_mod_init' at ../../grub-core/fs/cbfs.c:391:3:
  ../../grub-core/fs/cbfs.c:345:7: error: array subscript 0 is outside array bounds of 'grub_uint32_t[0]' {aka 'unsigned int[]'} [-Werror=array-bounds]
    345 |   ptr = *(grub_uint32_t *) 0xfffffffc;
        |   ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is caused by GCC regression in 11/12 [1]. In a nut shell, the
warning is about detected invalid accesses at non-zero offsets to NULL
pointers. Since hardwired constant address is treated as NULL plus an
offset in the same underlying code, the warning is therefore triggered.

Instead of inserting #pragma all over the places where literal pointers
are accessed to avoid diagnosing array-bounds, we can try to borrow the
idea from Linux kernel that the absolute_pointer() macro [2][3] is used
to disconnect a pointer using literal address from it's original object,
hence GCC won't be able to make assumptions on the boundary while doing
pointer arithmetic. With that we can greatly reduce the code we have to
cover up by making initial literal pointer assignment to use the new
wrapper but not having to track everywhere literal pointers are
accessed. This also makes code looks cleaner.

Please note the grub_absolute_pointer() macro requires to be invoked in
a function as long as it is compound expression. Some global variables
with literal pointers has been changed to local ones in order to use
grub_absolute_pointer() to initialize it. The shuffling is basically done
in a selective and careful way that the variable's scope doesn't matter
being local or global, for example, the global variable must not get
modified at run time throughout. For the record, here's the list of
global variables got shuffled in this patch:

  grub-core/commands/i386/pc/drivemap.c:int13slot
  grub-core/term/i386/pc/console.c:bios_data_area
  grub-core/term/ns8250.c:serial_hw_io_addr

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
[2] https://elixir.bootlin.com/linux/v5.16.14/source/include/linux/compiler.h#L180
[3] https://elixir.bootlin.com/linux/v5.16.14/source/include/linux/compiler-gcc.h#L31

Signed-off-by: Michael Chang <mchang@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/grub-core/bus/cs5536.c b/grub-core/bus/cs5536.c
index 8c90ed598d4fef9aae0b093eb920055086b65d88..cd0a45e58a7d7624ad97ab3d4d8c564a1e1c7049 100644 (file)
--- a/grub-core/bus/cs5536.c
+++ b/grub-core/bus/cs5536.c
@@ -331,8 +331,9 @@ grub_cs5536_init_geode (grub_pci_device_t dev)
 
   {
     volatile grub_uint32_t *oc;
-    oc = grub_pci_device_map_range (dev, 0x05022000,
-                                   GRUB_CS5536_USB_OPTION_REGS_SIZE);
+
+    oc = grub_absolute_pointer (grub_pci_device_map_range (dev, 0x05022000,
+                               GRUB_CS5536_USB_OPTION_REGS_SIZE));
 
     oc[GRUB_CS5536_USB_OPTION_REG_UOCMUX] =
       (oc[GRUB_CS5536_USB_OPTION_REG_UOCMUX]

diff --git a/grub-core/commands/acpi.c b/grub-core/commands/acpi.c
index 1215f2a62efb6b4d1bec33e5d9833a253812c665..fda62f4ea98a6da87b16373304cd330c2fe9abca 100644 (file)
--- a/grub-core/commands/acpi.c
+++ b/grub-core/commands/acpi.c
@@ -168,7 +168,7 @@ grub_acpi_create_ebda (void)
   struct grub_acpi_rsdp_v10 *v1;
   struct grub_acpi_rsdp_v20 *v2;
 
-  ebda = (grub_uint8_t *) (grub_addr_t) ((*((grub_uint16_t *)0x40e)) << 4);
+  ebda = (grub_uint8_t *) (grub_addr_t) ((*((grub_uint16_t *) grub_absolute_pointer (0x40e))) << 4);
   grub_dprintf ("acpi", "EBDA @%p\n", ebda);
   if (ebda)
     ebda_kb_len = *(grub_uint16_t *) ebda;
@@ -298,7 +298,7 @@ grub_acpi_create_ebda (void)
       *target = 0;
 
   grub_dprintf ("acpi", "Switching EBDA\n");
-  (*((grub_uint16_t *) 0x40e)) = ((grub_addr_t) targetebda) >> 4;
+  (*((grub_uint16_t *) grub_absolute_pointer (0x40e))) = ((grub_addr_t) targetebda) >> 4;
   grub_dprintf ("acpi", "EBDA switched\n");
 
   return GRUB_ERR_NONE;

diff --git a/grub-core/commands/efi/loadbios.c b/grub-core/commands/efi/loadbios.c
index 5c7725f8bd8f9d2f679bd35d95f0ab88883cdec5..574e4104662737b2335c6a52d8316405cf01a784 100644 (file)
--- a/grub-core/commands/efi/loadbios.c
+++ b/grub-core/commands/efi/loadbios.c
@@ -46,7 +46,7 @@ enable_rom_area (void)
   grub_uint32_t *rom_ptr;
   grub_pci_device_t dev = { .bus = 0, .device = 0, .function = 0};
 
-  rom_ptr = (grub_uint32_t *) VBIOS_ADDR;
+  rom_ptr = grub_absolute_pointer (VBIOS_ADDR);
   if (*rom_ptr != BLANK_MEM)
     {
       grub_puts_ (N_("ROM image is present."));
@@ -96,8 +96,8 @@ fake_bios_data (int use_rom)
   void *acpi, *smbios;
   grub_uint16_t *ebda_seg_ptr, *low_mem_ptr;
 
-  ebda_seg_ptr = (grub_uint16_t *) EBDA_SEG_ADDR;
-  low_mem_ptr = (grub_uint16_t *) LOW_MEM_ADDR;
+  ebda_seg_ptr = grub_absolute_pointer (EBDA_SEG_ADDR);
+  low_mem_ptr = grub_absolute_pointer (LOW_MEM_ADDR);
   if ((*ebda_seg_ptr) || (*low_mem_ptr))
     return;
 
@@ -132,7 +132,8 @@ fake_bios_data (int use_rom)
   *ebda_seg_ptr = FAKE_EBDA_SEG;
   *low_mem_ptr = (FAKE_EBDA_SEG >> 6);
 
-  *((grub_uint16_t *) (FAKE_EBDA_SEG << 4)) = 640 - *low_mem_ptr;
+  /* *((grub_uint16_t *) (FAKE_EBDA_SEG << 4)) = 640 - *low_mem_ptr; */
+  *((grub_uint16_t *) (grub_absolute_pointer (FAKE_EBDA_SEG << 4))) = 640 - *low_mem_ptr;
 
   if (acpi)
     grub_memcpy ((char *) ((FAKE_EBDA_SEG << 4) + 16), acpi, 1024 - 16);

diff --git a/grub-core/commands/i386/pc/drivemap.c b/grub-core/commands/i386/pc/drivemap.c
index 3fb22dc460b7560e311de505bba707d4c9373773..a7ee4c9bdd54bf1cbc49539774cd2987dc0b60d2 100644 (file)
--- a/grub-core/commands/i386/pc/drivemap.c
+++ b/grub-core/commands/i386/pc/drivemap.c
@@ -31,9 +31,6 @@
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
-/* Real mode IVT slot (seg:off far pointer) for interrupt 0x13.  */
-static grub_uint32_t *const int13slot = (grub_uint32_t *) (4 * 0x13);
-
 /* Remember to update enum opt_idxs accordingly.  */
 static const struct grub_arg_option options[] = {
   /* TRANSLATORS: In this file "mapping" refers to a change GRUB makes so if
@@ -280,6 +277,8 @@ install_int13_handler (int noret __attribute__ ((unused)))
   grub_uint8_t *handler_base = 0;
   /* Address of the map within the deployed bundle.  */
   int13map_node_t *handler_map;
+  /* Real mode IVT slot (seg:off far pointer) for interrupt 0x13. */
+  grub_uint32_t *int13slot = (grub_uint32_t *) grub_absolute_pointer (4 * 0x13);
 
   int i;
   int entries = 0;
@@ -354,6 +353,9 @@ install_int13_handler (int noret __attribute__ ((unused)))
 static grub_err_t
 uninstall_int13_handler (void)
 {
+  /* Real mode IVT slot (seg:off far pointer) for interrupt 0x13. */
+  grub_uint32_t *int13slot = (grub_uint32_t *) grub_absolute_pointer (4 * 0x13);
+
   if (! grub_drivemap_oldhandler)
     return GRUB_ERR_NONE;
 

diff --git a/grub-core/commands/i386/pc/sendkey.c b/grub-core/commands/i386/pc/sendkey.c
index 184befabfbeac98244198c223ff3e9582c50bd96..282bb5d4282b2311498a3a52bcaf098d3bf22019 100644 (file)
--- a/grub-core/commands/i386/pc/sendkey.c
+++ b/grub-core/commands/i386/pc/sendkey.c
@@ -216,12 +216,12 @@ static grub_err_t
 grub_sendkey_postboot (void)
 {
   /* For convention: pointer to flags.  */
-  grub_uint32_t *flags = (grub_uint32_t *) 0x417;
+  grub_uint32_t *flags = grub_absolute_pointer (0x417);
 
   *flags = oldflags;
 
-  *((volatile char *) 0x41a) = 0x1e;
-  *((volatile char *) 0x41c) = 0x1e;
+  *((volatile char *) grub_absolute_pointer (0x41a)) = 0x1e;
+  *((volatile char *) grub_absolute_pointer (0x41c)) = 0x1e;
 
   return GRUB_ERR_NONE;
 }
@@ -231,13 +231,13 @@ static grub_err_t
 grub_sendkey_preboot (int noret __attribute__ ((unused)))
 {
   /* For convention: pointer to flags.  */
-  grub_uint32_t *flags = (grub_uint32_t *) 0x417;
+  grub_uint32_t *flags = grub_absolute_pointer (0x417);
 
   oldflags = *flags;
 
   /* Set the sendkey.  */
-  *((volatile char *) 0x41a) = 0x1e;
-  *((volatile char *) 0x41c) = keylen + 0x1e;
+  *((volatile char *) grub_absolute_pointer (0x41a)) = 0x1e;
+  *((volatile char *) grub_absolute_pointer (0x41c)) = keylen + 0x1e;
   grub_memcpy ((char *) 0x41e, sendkey, 0x20);
 
   /* Transform "any ctrl" to "right ctrl" flag.  */

diff --git a/grub-core/disk/i386/pc/biosdisk.c b/grub-core/disk/i386/pc/biosdisk.c
index 81fd4e832c34a4e7b8e18aaeaf972bbfab698b28..49e4e8a14f8f73c1ca480358779e80def46acb05 100644 (file)
--- a/grub-core/disk/i386/pc/biosdisk.c
+++ b/grub-core/disk/i386/pc/biosdisk.c
@@ -367,7 +367,7 @@ grub_biosdisk_open (const char *name, grub_disk_t disk)
       if (version)
        {
          struct grub_biosdisk_drp *drp
-           = (struct grub_biosdisk_drp *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+           = (struct grub_biosdisk_drp *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
 
          /* Clear out the DRP.  */
          grub_memset (drp, 0, sizeof (*drp));
@@ -654,7 +654,7 @@ grub_disk_biosdisk_fini (void)
 GRUB_MOD_INIT(biosdisk)
 {
   struct grub_biosdisk_cdrp *cdrp
-    = (struct grub_biosdisk_cdrp *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+    = (struct grub_biosdisk_cdrp *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
   grub_uint8_t boot_drive;
 
   if (grub_disk_firmware_is_tainted)

diff --git a/grub-core/fs/cbfs.c b/grub-core/fs/cbfs.c
index 581215ef1886e7eba6713bd215ce695ae173341a..8ab7106afbb6103e618322ebab86777e1ac6d66c 100644 (file)
--- a/grub-core/fs/cbfs.c
+++ b/grub-core/fs/cbfs.c
@@ -342,7 +342,7 @@ init_cbfsdisk (void)
   grub_uint32_t ptr;
   struct cbfs_header *head;
 
-  ptr = *(grub_uint32_t *) 0xfffffffc;
+  ptr = *((grub_uint32_t *) grub_absolute_pointer (0xfffffffc));
   head = (struct cbfs_header *) (grub_addr_t) ptr;
   grub_dprintf ("cbfs", "head=%p\n", head);
 

diff --git a/grub-core/kern/i386/pc/acpi.c b/grub-core/kern/i386/pc/acpi.c
index 297f5d05f3b04d2a15184b44af53ba5369242ba7..0a69eba7b56ee61f4146a846bdbeeb4c0ac13a3c 100644 (file)
--- a/grub-core/kern/i386/pc/acpi.c
+++ b/grub-core/kern/i386/pc/acpi.c
@@ -27,7 +27,7 @@ grub_machine_acpi_get_rsdpv1 (void)
   grub_uint8_t *ebda, *ptr;
 
   grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
-  ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
+  ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) grub_absolute_pointer (0x40e))) << 4);
   ebda_len = * (grub_uint16_t *) ebda;
   if (! ebda_len) /* FIXME do we really need this check? */
     goto scan_bios;
@@ -55,7 +55,7 @@ grub_machine_acpi_get_rsdpv2 (void)
   grub_uint8_t *ebda, *ptr;
 
   grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
-  ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
+  ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) grub_absolute_pointer (0x40e))) << 4);
   ebda_len = * (grub_uint16_t *) ebda;
   if (! ebda_len) /* FIXME do we really need this check? */
     goto scan_bios;

diff --git a/grub-core/kern/i386/pc/mmap.c b/grub-core/kern/i386/pc/mmap.c
index ef2faa2ab6a5d14b7ef9c89abfd64994f6587dbe..53fcf45af611388f38990fd76d0e2505aca692cd 100644 (file)
--- a/grub-core/kern/i386/pc/mmap.c
+++ b/grub-core/kern/i386/pc/mmap.c
@@ -143,7 +143,7 @@ grub_machine_mmap_iterate (grub_memory_hook_t hook, void *hook_data)
 {
   grub_uint32_t cont = 0;
   struct grub_machine_mmap_entry *entry
-    = (struct grub_machine_mmap_entry *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+    = (struct grub_machine_mmap_entry *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
   int e820_works = 0;
 
   while (1)

diff --git a/grub-core/loader/i386/multiboot_mbi.c b/grub-core/loader/i386/multiboot_mbi.c
index ff1a846af9272d72d1e1d8a7281f35a60550ee7d..11a6e224fff5cd4a59a8c404825182306835c8a8 100644 (file)
--- a/grub-core/loader/i386/multiboot_mbi.c
+++ b/grub-core/loader/i386/multiboot_mbi.c
@@ -293,7 +293,7 @@ fill_vbe_info (struct multiboot_info *mbi, grub_uint8_t *ptrorig,
   struct grub_vbe_mode_info_block *mode_info;
 #if GRUB_MACHINE_HAS_VBE
   grub_vbe_status_t status;
-  void *scratch = (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+  void *scratch = grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
 
   status = grub_vbe_bios_get_controller_info (scratch);
   if (status != GRUB_VBE_STATUS_OK)

diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index 6d680d67150c44c7004026ea1e8d6b2ba6c056a6..00a48413c01383991f7efc3e0e8322c540b8fb43 100644 (file)
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -504,7 +504,7 @@ static void
 fill_vbe_tag (struct multiboot_tag_vbe *tag)
 {
   grub_vbe_status_t status;
-  void *scratch = (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+  void *scratch = grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
 
   tag->type = MULTIBOOT_TAG_TYPE_VBE;
   tag->size = 0;
@@ -577,7 +577,7 @@ retrieve_video_parameters (grub_properly_aligned_t **ptrorig)
 #if defined (GRUB_MACHINE_PCBIOS)
       {
        grub_vbe_status_t status;
-       void *scratch = (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+       void *scratch = grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
        status = grub_vbe_bios_get_mode (scratch);
        vbe_mode = *(grub_uint32_t *) scratch;
        if (status != GRUB_VBE_STATUS_OK)

diff --git a/grub-core/mmap/i386/pc/mmap.c b/grub-core/mmap/i386/pc/mmap.c
index 6ab4f6730918859a4ed3e7ed14bb0dc82a1b5db0..b9c5b0a0029415938669f5949e9b2c551c67c2ac 100644 (file)
--- a/grub-core/mmap/i386/pc/mmap.c
+++ b/grub-core/mmap/i386/pc/mmap.c
@@ -80,13 +80,13 @@ preboot (int noreturn __attribute__ ((unused)))
     = min (grub_mmap_get_post64 (), 0xfc000000ULL) >> 16;
 
   /* Correct BDA. */
-  *((grub_uint16_t *) 0x413) = grub_mmap_get_lower () >> 10;
+  *((grub_uint16_t *) grub_absolute_pointer (0x413)) = grub_mmap_get_lower () >> 10;
 
   /* Save old interrupt handlers. */
-  grub_machine_mmaphook_int12offset = *((grub_uint16_t *) 0x48);
-  grub_machine_mmaphook_int12segment = *((grub_uint16_t *) 0x4a);
-  grub_machine_mmaphook_int15offset = *((grub_uint16_t *) 0x54);
-  grub_machine_mmaphook_int15segment = *((grub_uint16_t *) 0x56);
+  grub_machine_mmaphook_int12offset = *((grub_uint16_t *) grub_absolute_pointer (0x48));
+  grub_machine_mmaphook_int12segment = *((grub_uint16_t *) grub_absolute_pointer (0x4a));
+  grub_machine_mmaphook_int15offset = *((grub_uint16_t *) grub_absolute_pointer (0x54));
+  grub_machine_mmaphook_int15segment = *((grub_uint16_t *) grub_absolute_pointer (0x56));
 
   grub_dprintf ("mmap", "hooktarget = %p\n", hooktarget);
 
@@ -94,11 +94,11 @@ preboot (int noreturn __attribute__ ((unused)))
   grub_memcpy (hooktarget, &grub_machine_mmaphook_start,
               &grub_machine_mmaphook_end - &grub_machine_mmaphook_start);
 
-  *((grub_uint16_t *) 0x4a) = ((grub_addr_t) hooktarget) >> 4;
-  *((grub_uint16_t *) 0x56) = ((grub_addr_t) hooktarget) >> 4;
-  *((grub_uint16_t *) 0x48) = &grub_machine_mmaphook_int12
+  *((grub_uint16_t *) grub_absolute_pointer (0x4a)) = ((grub_addr_t) hooktarget) >> 4;
+  *((grub_uint16_t *) grub_absolute_pointer (0x56)) = ((grub_addr_t) hooktarget) >> 4;
+  *((grub_uint16_t *) grub_absolute_pointer (0x48)) = &grub_machine_mmaphook_int12
     - &grub_machine_mmaphook_start;
-  *((grub_uint16_t *) 0x54) = &grub_machine_mmaphook_int15
+  *((grub_uint16_t *) grub_absolute_pointer (0x54)) = &grub_machine_mmaphook_int15
     - &grub_machine_mmaphook_start;
 
   return GRUB_ERR_NONE;
@@ -108,10 +108,10 @@ static grub_err_t
 preboot_rest (void)
 {
   /* Restore old interrupt handlers. */
-  *((grub_uint16_t *) 0x48) = grub_machine_mmaphook_int12offset;
-  *((grub_uint16_t *) 0x4a) = grub_machine_mmaphook_int12segment;
-  *((grub_uint16_t *) 0x54) = grub_machine_mmaphook_int15offset;
-  *((grub_uint16_t *) 0x56) = grub_machine_mmaphook_int15segment;
+  *((grub_uint16_t *) grub_absolute_pointer (0x48)) = grub_machine_mmaphook_int12offset;
+  *((grub_uint16_t *) grub_absolute_pointer (0x4a)) = grub_machine_mmaphook_int12segment;
+  *((grub_uint16_t *) grub_absolute_pointer (0x54)) = grub_machine_mmaphook_int15offset;
+  *((grub_uint16_t *) grub_absolute_pointer (0x56)) = grub_machine_mmaphook_int15segment;
 
   return GRUB_ERR_NONE;
 }

diff --git a/grub-core/net/drivers/i386/pc/pxe.c b/grub-core/net/drivers/i386/pc/pxe.c
index 997010cf1526b4a1a06eae3e1cabdcc62b6c3f97..db17186ee7dc695a16e6c8ed365f0d4b42c42d64 100644 (file)
--- a/grub-core/net/drivers/i386/pc/pxe.c
+++ b/grub-core/net/drivers/i386/pc/pxe.c
@@ -174,7 +174,7 @@ grub_pxe_recv (struct grub_net_card *dev __attribute__ ((unused)))
   grub_uint8_t *ptr, *end;
   struct grub_net_buff *buf;
 
-  isr = (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+  isr = (void *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
 
   if (!in_progress)
     {
@@ -256,11 +256,11 @@ grub_pxe_send (struct grub_net_card *dev __attribute__ ((unused)),
   struct grub_pxe_undi_tbd *tbd;
   char *buf;
 
-  trans = (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+  trans = (void *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
   grub_memset (trans, 0, sizeof (*trans));
-  tbd = (void *) (GRUB_MEMORY_MACHINE_SCRATCH_ADDR + 128);
+  tbd = (void *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR + 128);
   grub_memset (tbd, 0, sizeof (*tbd));
-  buf = (void *) (GRUB_MEMORY_MACHINE_SCRATCH_ADDR + 256);
+  buf = (void *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR + 256);
   grub_memcpy (buf, pack->data, pack->tail - pack->data);
 
   trans->tbd = SEGOFS ((grub_addr_t) tbd);
@@ -287,7 +287,7 @@ static grub_err_t
 grub_pxe_open (struct grub_net_card *dev __attribute__ ((unused)))
 {
   struct grub_pxe_undi_open *ou;
-  ou = (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+  ou = (void *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
   grub_memset (ou, 0, sizeof (*ou));
   ou->pkt_filter = 4;
   grub_pxe_call (GRUB_PXENV_UNDI_OPEN, ou, pxe_rm_entry);
@@ -382,7 +382,7 @@ GRUB_MOD_INIT(pxe)
   if (! pxenv)
     return;
 
-  ui = (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+  ui = (void *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
   grub_memset (ui, 0, sizeof (*ui));
   grub_pxe_call (GRUB_PXENV_UNDI_GET_INFORMATION, ui, pxe_rm_entry);
 

diff --git a/grub-core/term/i386/pc/console.c b/grub-core/term/i386/pc/console.c
index d44937c30592197b07f7ae7079e938ae74bd926e..9403390f1fa3a49d7059b70f625654cce80dc37e 100644 (file)
--- a/grub-core/term/i386/pc/console.c
+++ b/grub-core/term/i386/pc/console.c
@@ -238,12 +238,11 @@ grub_console_getkey (struct grub_term_input *term __attribute__ ((unused)))
   return (regs.eax & 0xff) + (('a' - 1) | GRUB_TERM_CTRL);
 }
 
-static const struct grub_machine_bios_data_area *bios_data_area =
-  (struct grub_machine_bios_data_area *) GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR;
-
 static int
 grub_console_getkeystatus (struct grub_term_input *term __attribute__ ((unused)))
 {
+  const struct grub_machine_bios_data_area *bios_data_area =
+  (struct grub_machine_bios_data_area *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR);
   /* conveniently GRUB keystatus is modelled after BIOS one.  */
   return bios_data_area->keyboard_flag_lower & ~0x80;
 }

diff --git a/grub-core/term/i386/pc/vga_text.c b/grub-core/term/i386/pc/vga_text.c
index 88fecc5ea530f2f6c7a437196803909177869851..669d06fad765756e22ac9ffb0247f25df15a2523 100644 (file)
--- a/grub-core/term/i386/pc/vga_text.c
+++ b/grub-core/term/i386/pc/vga_text.c
@@ -45,15 +45,15 @@ GRUB_MOD_LICENSE ("GPLv3+");
 static struct grub_term_coordinate grub_curr_pos;
 
 #ifdef __mips__
-#define VGA_TEXT_SCREEN                ((grub_uint16_t *) 0xb00b8000)
+#define VGA_TEXT_SCREEN                ((grub_uint16_t *) grub_absolute_pointer (0xb00b8000))
 #define cr_read grub_vga_cr_read
 #define cr_write grub_vga_cr_write
 #elif defined (MODE_MDA)
-#define VGA_TEXT_SCREEN                ((grub_uint16_t *) 0xb0000)
+#define VGA_TEXT_SCREEN                ((grub_uint16_t *) grub_absolute_pointer (0xb0000))
 #define cr_read grub_vga_cr_bw_read
 #define cr_write grub_vga_cr_bw_write
 #else
-#define VGA_TEXT_SCREEN                ((grub_uint16_t *) 0xb8000)
+#define VGA_TEXT_SCREEN                ((grub_uint16_t *) grub_absolute_pointer (0xb8000))
 #define cr_read grub_vga_cr_read
 #define cr_write grub_vga_cr_write
 #endif

diff --git a/grub-core/term/ns8250.c b/grub-core/term/ns8250.c
index 59801839bdb3c1f6952cd6a8379056af7ff90673..83b25990c2a87257b111ce716936befc160414e7 100644 (file)
--- a/grub-core/term/ns8250.c
+++ b/grub-core/term/ns8250.c
@@ -28,7 +28,6 @@
 
 #ifdef GRUB_MACHINE_PCBIOS
 #include <grub/machine/memory.h>
-static const unsigned short *serial_hw_io_addr = (const unsigned short *) GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR;
 #define GRUB_SERIAL_PORT_NUM 4
 #else
 #include <grub/machine/serial.h>
@@ -237,6 +236,9 @@ static struct grub_serial_port com_ports[GRUB_SERIAL_PORT_NUM];
 void
 grub_ns8250_init (void)
 {
+#ifdef GRUB_MACHINE_PCBIOS
+  const unsigned short *serial_hw_io_addr = (const unsigned short *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR);
+#endif
   unsigned i;
   for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
     if (serial_hw_io_addr[i])
@@ -272,6 +274,9 @@ grub_ns8250_init (void)
 grub_port_t
 grub_ns8250_hw_get_port (const unsigned int unit)
 {
+#ifdef GRUB_MACHINE_PCBIOS
+  const unsigned short *serial_hw_io_addr = (const unsigned short *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR);
+#endif
   if (unit < GRUB_SERIAL_PORT_NUM
       && !(dead_ports & (1 << unit)))
     return serial_hw_io_addr[unit];

diff --git a/grub-core/video/i386/pc/vbe.c b/grub-core/video/i386/pc/vbe.c
index 0e65b5206c8a91e939125478c686de5a68b75027..a0bb9af0980ca3d2241496a75c038794536acf4b 100644 (file)
--- a/grub-core/video/i386/pc/vbe.c
+++ b/grub-core/video/i386/pc/vbe.c
@@ -514,7 +514,7 @@ grub_vbe_probe (struct grub_vbe_info_block *info_block)
 
       /* Use low memory scratch area as temporary storage
          for VESA BIOS call.  */
-      vbe_ib = (struct grub_vbe_info_block *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+      vbe_ib = (struct grub_vbe_info_block *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
 
       /* Prepare info block.  */
       grub_memset (vbe_ib, 0, sizeof (*vbe_ib));
@@ -574,7 +574,7 @@ grub_vbe_get_preferred_mode (unsigned int *width, unsigned int *height)
 
   /* Use low memory scratch area as temporary storage for VESA BIOS calls.  */
   flat_panel_info = (struct grub_vbe_flat_panel_info *)
-    (GRUB_MEMORY_MACHINE_SCRATCH_ADDR + sizeof (struct grub_video_edid_info));
+    grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR + sizeof (struct grub_video_edid_info));
 
   if (controller_info.version >= 0x200
       && (grub_vbe_bios_get_ddc_capabilities (&ddc_level) & 0xff)
@@ -676,7 +676,7 @@ grub_vbe_set_video_mode (grub_uint32_t vbe_mode,
          == GRUB_VBE_MEMORY_MODEL_PACKED_PIXEL)
        {
          struct grub_vbe_palette_data *palette
-           = (struct grub_vbe_palette_data *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
+           = (struct grub_vbe_palette_data *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_SCRATCH_ADDR);
          unsigned i;
 
          /* Make sure that the BIOS can reach the palette.  */

diff --git a/include/grub/types.h b/include/grub/types.h
index 0a3ff15913611614ed1981fb20cc87505cc1324d..5ae0ced388289e7657037faaf9e1f02840ea3a61 100644 (file)
--- a/include/grub/types.h
+++ b/include/grub/types.h
@@ -340,4 +340,28 @@ static inline void grub_set_unaligned64 (void *ptr, grub_uint64_t val)
   dd->d = val;
 }
 
+/*
+ * The grub_absolute_pointer() macro borrows the idea from Linux kernel of using
+ * RELOC_HIDE() macro to stop GCC from checking the result of pointer arithmetic
+ * and also it's conversion to be inside the symbol's boundary [1]. The check
+ * is sometimes false positive, especially it is controversial to emit the array
+ * bounds [-Warray-bounds] warning on all hardwired literal pointers since GCC
+ * 11/12 [2]. Unless a good solution can be settled, for the time being we
+ * would be in favor of the macro instead of GCC pragmas which cannot match the
+ * places the warning needs to be ignored in an exact way.
+ *
+ * [1] https://lists.linuxcoding.com/kernel/2006-q3/msg17979.html
+ * [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
+ */
+#if defined(__GNUC__)
+# define grub_absolute_pointer(val)                                    \
+({                                                                     \
+       grub_addr_t __ptr;                                              \
+       asm ("" : "=r" (__ptr) : "0" ((void *) (val)));                 \
+       (void *) (__ptr);                                               \
+})
+#else
+# define grub_absolute_pointer(val) ((void *) (val))
+#endif
+
 #endif /* ! GRUB_TYPES_HEADER */