File 0001-Fix-Werror-array-bounds-array-subscript-0-is-outside.patch of Package trustedgrub2
From 04de53cb4adc0ae6429b0715c3f1dd8a62ff9a0f Mon Sep 17 00:00:00 2001
From: Michael Chang <mchang@suse.com>
Date: Wed, 16 Mar 2022 17:05:01 +0800
Subject: [PATCH 1/2] 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.
[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>
---
grub-core/bus/cs5536.c | 4 ++--
grub-core/commands/acpi.c | 4 ++--
grub-core/commands/efi/loadbios.c | 9 +++++----
grub-core/commands/i386/pc/drivemap.c | 9 ++++++---
grub-core/commands/i386/pc/sendkey.c | 12 ++++++------
grub-core/disk/i386/pc/biosdisk.c | 4 ++--
grub-core/fs/cbfs.c | 2 +-
grub-core/kern/i386/pc/acpi.c | 4 ++--
grub-core/kern/i386/pc/mmap.c | 2 +-
grub-core/loader/i386/multiboot_mbi.c | 2 +-
grub-core/loader/multiboot_mbi2.c | 4 ++--
grub-core/mmap/i386/pc/mmap.c | 26 +++++++++++++-------------
grub-core/net/drivers/i386/pc/pxe.c | 12 ++++++------
grub-core/term/i386/pc/console.c | 5 ++---
grub-core/term/i386/pc/vga_text.c | 6 +++---
grub-core/term/ns8250.c | 7 ++++++-
grub-core/video/i386/pc/vbe.c | 6 +++---
include/grub/compiler.h | 11 +++++++++++
18 files changed, 74 insertions(+), 55 deletions(-)
--- a/grub-core/bus/cs5536.c
+++ b/grub-core/bus/cs5536.c
@@ -331,8 +331,8 @@
{
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]
--- a/grub-core/commands/acpi.c
+++ b/grub-core/commands/acpi.c
@@ -167,7 +167,7 @@
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;
@@ -297,7 +297,7 @@
*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;
--- a/grub-core/commands/efi/loadbios.c
+++ b/grub-core/commands/efi/loadbios.c
@@ -46,7 +46,7 @@
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 @@
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 @@
*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);
--- 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 +277,9 @@
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 +354,9 @@
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;
--- a/grub-core/commands/i386/pc/sendkey.c
+++ b/grub-core/commands/i386/pc/sendkey.c
@@ -216,12 +216,12 @@
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;
- *((char *) 0x41a) = 0x1e;
- *((char *) 0x41c) = 0x1e;
+ *((char *) grub_absolute_pointer (0x41a)) = 0x1e;
+ *((char *) grub_absolute_pointer (0x41c)) = 0x1e;
return GRUB_ERR_NONE;
}
@@ -231,13 +231,13 @@
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. */
- *((char *) 0x41a) = 0x1e;
- *((char *) 0x41c) = keylen + 0x1e;
+ *((char *) grub_absolute_pointer (0x41a)) = 0x1e;
+ *((char *) grub_absolute_pointer (0x41c)) = keylen + 0x1e;
grub_memcpy ((char *) 0x41e, sendkey, 0x20);
/* Transform "any ctrl" to "right ctrl" flag. */
--- a/grub-core/disk/i386/pc/biosdisk.c
+++ b/grub-core/disk/i386/pc/biosdisk.c
@@ -367,7 +367,7 @@
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_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)
--- a/grub-core/fs/cbfs.c
+++ b/grub-core/fs/cbfs.c
@@ -342,7 +342,7 @@
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);
--- a/grub-core/kern/i386/pc/acpi.c
+++ b/grub-core/kern/i386/pc/acpi.c
@@ -27,7 +27,7 @@
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_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;
--- a/grub-core/kern/i386/pc/mmap.c
+++ b/grub-core/kern/i386/pc/mmap.c
@@ -143,7 +143,7 @@
{
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)
--- a/grub-core/loader/i386/multiboot_mbi.c
+++ b/grub-core/loader/i386/multiboot_mbi.c
@@ -284,7 +284,7 @@
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)
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -445,7 +445,7 @@
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;
@@ -518,7 +518,7 @@
#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)
--- a/grub-core/mmap/i386/pc/mmap.c
+++ b/grub-core/mmap/i386/pc/mmap.c
@@ -88,13 +88,13 @@
= 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);
@@ -102,11 +102,11 @@
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;
@@ -116,10 +116,10 @@
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;
}
--- a/grub-core/net/drivers/i386/pc/pxe.c
+++ b/grub-core/net/drivers/i386/pc/pxe.c
@@ -174,7 +174,7 @@
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 @@
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 @@
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 @@
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);
--- a/grub-core/term/i386/pc/console.c
+++ b/grub-core/term/i386/pc/console.c
@@ -238,12 +238,11 @@
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;
}
--- a/grub-core/term/i386/pc/vga_text.c
+++ b/grub-core/term/i386/pc/vga_text.c
@@ -45,15 +45,15 @@
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
--- 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 @@
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_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];
--- a/grub-core/video/i386/pc/vbe.c
+++ b/grub-core/video/i386/pc/vbe.c
@@ -514,7 +514,7 @@
/* 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 @@
/* 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_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. */
--- a/include/grub/compiler.h
+++ b/include/grub/compiler.h
@@ -48,4 +48,15 @@
# define WARN_UNUSED_RESULT
#endif
+#if defined(__GNUC__)
+# define grub_absolute_pointer(val) \
+({ \
+ unsigned long __ptr; \
+ __asm__ ("" : "=r"(__ptr) : "0"((void *)(val))); \
+ (void *) (__ptr); \
+})
+#else
+# define grub_absolute_pointer(val) ((void *)(val))
+#endif
+
#endif /* ! GRUB_COMPILER_HEADER */
