radeon: Do not directly dereference pointers to BIOS area.

[ Upstream commit f2c9e560b406f2f6b14b345c7da33467dee9cdf2 ]

Use readb() and memcpy_fromio() accessors instead.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/drivers/gpu/drm/radeon/radeon_bios.c b/drivers/gpu/drm/radeon/radeon_bios.c
index 63ccb8f..d27e4cc 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_bios.c
+++ b/drivers/gpu/drm/radeon/radeon_bios.c
@@ -76,7 +76,7 @@ static bool igp_read_bios_from_vram(struct radeon_device *rdev)
 
 static bool radeon_read_bios(struct radeon_device *rdev)
 {
-       uint8_t __iomem *bios;
+       uint8_t __iomem *bios, val1, val2;
        size_t size;
 
        rdev->bios = NULL;
@@ -86,15 +86,19 @@ static bool radeon_read_bios(struct radeon_device *rdev)
                return false;
        }
 
-       if (size == 0 || bios[0] != 0x55 || bios[1] != 0xaa) {
+       val1 = readb(&bios[0]);
+       val2 = readb(&bios[1]);
+
+       if (size == 0 || val1 != 0x55 || val2 != 0xaa) {
                pci_unmap_rom(rdev->pdev, bios);
                return false;
        }
-       rdev->bios = kmemdup(bios, size, GFP_KERNEL);
+       rdev->bios = kzalloc(size, GFP_KERNEL);
        if (rdev->bios == NULL) {
                pci_unmap_rom(rdev->pdev, bios);
                return false;
        }
+       memcpy_fromio(rdev->bios, bios, size);
        pci_unmap_rom(rdev->pdev, bios);
        return true;
 }