[PATCH 37/88] drm/amdgpu: Do not directly dereference pointers to BIOS area.

[Alex Deucher]

Use readb() and memcpy_fromio() accessors instead.

Ported from radeon commit:
f2c9e560b406f2f6b14b345c7da33467dee9cdf2

Acked-by: Christian König <christian.koenig at amd.com>
Acked-by: Jammy Zhou <Jammy.Zhou at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
index d7a3ab2..ceb444f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
@@ -75,7 +75,7 @@ static bool igp_read_bios_from_vram(struct amdgpu_device 
*adev)

 bool amdgpu_read_bios(struct amdgpu_device *adev)
 {
-       uint8_t __iomem *bios;
+       uint8_t __iomem *bios, val1, val2;
        size_t size;

        adev->bios = NULL;
@@ -85,15 +85,19 @@ bool amdgpu_read_bios(struct amdgpu_device *adev)
                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(adev->pdev, bios);
                return false;
        }
-       adev->bios = kmemdup(bios, size, GFP_KERNEL);
+       adev->bios = kzalloc(size, GFP_KERNEL);
        if (adev->bios == NULL) {
                pci_unmap_rom(adev->pdev, bios);
                return false;
        }
+       memcpy_fromio(adev->bios, bios, size);
        pci_unmap_rom(adev->pdev, bios);
        return true;
 }
-- 
1.8.3.1