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drm/i915: Treat stolen memory as DMA addresses 

The conversion of stolen to use phys_addr_t (from essentially u32)
sparked an interesting discussion. We treat stolen memory as only
accessible from the GPU (the DMA device) - an attempt to use it from the
CPU will generate a MCE on gen6 onwards, although it is in theory a
physical address that can be dereferenced from the CPU as demonstrated
by earlier generations. As such, using phys_addr_t has the wrong
connotations and as we pass the address into the DMA device via
dma_addr_t (through the scatterlists used to program the GTT entries),
we should treat it as dma_addr_t throughout.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170127165531.28135-1-chris@chris-wilson.co.uk
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
This commit is contained in:
Chris Wilson 2017-01-27 16:55:30 +00:00
parent 4703b0472e
commit c88473878d
2 changed files with 19 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/gpu/drm/i915/i915_drv.h
View File

@ -1461,7 +1461,7 @@ struct i915_gem_mm {
struct work_struct free_work;
/** Usable portion of the GTT for GEM */
phys_addr_t stolen_base; /* limited to low memory (32-bit) */
dma_addr_t stolen_base; /* limited to low memory (32-bit) */
/** PPGTT used for aliasing the PPGTT with the GTT */
struct i915_hw_ppgtt *aliasing_ppgtt;

36
drivers/gpu/drm/i915/i915_gem_stolen.c
View File

@ -79,12 +79,12 @@ void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,
mutex_unlock(&dev_priv->mm.stolen_lock);
}
static phys_addr_t i915_stolen_to_physical(struct drm_i915_private *dev_priv)
static dma_addr_t i915_stolen_to_dma(struct drm_i915_private *dev_priv)
{
struct pci_dev *pdev = dev_priv->drm.pdev;
struct i915_ggtt *ggtt = &dev_priv->ggtt;
struct resource *r;
phys_addr_t base;
dma_addr_t base;
/* Almost universally we can find the Graphics Base of Stolen Memory
* at register BSM (0x5c) in the igfx configuration space. On a few
@ -196,7 +196,7 @@ static phys_addr_t i915_stolen_to_physical(struct drm_i915_private *dev_priv)
if (INTEL_GEN(dev_priv) <= 4 &&
!IS_G33(dev_priv) && !IS_PINEVIEW(dev_priv) && !IS_G4X(dev_priv)) {
struct {
phys_addr_t start, end;
dma_addr_t start, end;
} stolen[2] = {
{ .start = base, .end = base + ggtt->stolen_size, },
{ .start = base, .end = base + ggtt->stolen_size, },
@ -228,12 +228,12 @@ static phys_addr_t i915_stolen_to_physical(struct drm_i915_private *dev_priv)
if (stolen[0].start != stolen[1].start ||
stolen[0].end != stolen[1].end) {
phys_addr_t end = base + ggtt->stolen_size - 1;
dma_addr_t end = base + ggtt->stolen_size - 1;
DRM_DEBUG_KMS("GTT within stolen memory at 0x%llx-0x%llx\n",
(unsigned long long)ggtt_start,
(unsigned long long)ggtt_end - 1);
DRM_DEBUG_KMS("Stolen memory adjusted to %pa - %pa\n",
DRM_DEBUG_KMS("Stolen memory adjusted to %pad - %pad\n",
&base, &end);
}
}
@ -263,9 +263,9 @@ static phys_addr_t i915_stolen_to_physical(struct drm_i915_private *dev_priv)
* range. Apparently this works.
*/
if (r == NULL && !IS_GEN3(dev_priv)) {
phys_addr_t end = base + ggtt->stolen_size;
dma_addr_t end = base + ggtt->stolen_size;
DRM_ERROR("conflict detected with stolen region: [%pa - %pa]\n",
DRM_ERROR("conflict detected with stolen region: [%pad - %pad]\n",
&base, &end);
base = 0;
}
@ -285,13 +285,13 @@ void i915_gem_cleanup_stolen(struct drm_device *dev)
}
static void g4x_get_stolen_reserved(struct drm_i915_private *dev_priv,
phys_addr_t *base, u32 *size)
dma_addr_t *base, u32 *size)
{
struct i915_ggtt *ggtt = &dev_priv->ggtt;
uint32_t reg_val = I915_READ(IS_GM45(dev_priv) ?
CTG_STOLEN_RESERVED :
ELK_STOLEN_RESERVED);
phys_addr_t stolen_top = dev_priv->mm.stolen_base + ggtt->stolen_size;
dma_addr_t stolen_top = dev_priv->mm.stolen_base + ggtt->stolen_size;
*base = (reg_val & G4X_STOLEN_RESERVED_ADDR2_MASK) << 16;
@ -308,7 +308,7 @@ static void g4x_get_stolen_reserved(struct drm_i915_private *dev_priv,
}
static void gen6_get_stolen_reserved(struct drm_i915_private *dev_priv,
phys_addr_t *base, u32 *size)
dma_addr_t *base, u32 *size)
{
uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
@ -334,7 +334,7 @@ static void gen6_get_stolen_reserved(struct drm_i915_private *dev_priv,
}
static void gen7_get_stolen_reserved(struct drm_i915_private *dev_priv,
phys_addr_t *base, u32 *size)
dma_addr_t *base, u32 *size)
{
uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
@ -354,7 +354,7 @@ static void gen7_get_stolen_reserved(struct drm_i915_private *dev_priv,
}
static void chv_get_stolen_reserved(struct drm_i915_private *dev_priv,
phys_addr_t *base, u32 *size)
dma_addr_t *base, u32 *size)
{
uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
@ -380,11 +380,11 @@ static void chv_get_stolen_reserved(struct drm_i915_private *dev_priv,
}
static void bdw_get_stolen_reserved(struct drm_i915_private *dev_priv,
phys_addr_t *base, u32 *size)
dma_addr_t *base, u32 *size)
{
struct i915_ggtt *ggtt = &dev_priv->ggtt;
uint32_t reg_val = I915_READ(GEN6_STOLEN_RESERVED);
phys_addr_t stolen_top;
dma_addr_t stolen_top;
stolen_top = dev_priv->mm.stolen_base + ggtt->stolen_size;
@ -403,7 +403,7 @@ static void bdw_get_stolen_reserved(struct drm_i915_private *dev_priv,
int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
{
struct i915_ggtt *ggtt = &dev_priv->ggtt;
phys_addr_t reserved_base, stolen_top;
dma_addr_t reserved_base, stolen_top;
u32 reserved_total, reserved_size;
u32 stolen_usable_start;
@ -419,7 +419,7 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
if (ggtt->stolen_size == 0)
return 0;
dev_priv->mm.stolen_base = i915_stolen_to_physical(dev_priv);
dev_priv->mm.stolen_base = i915_stolen_to_dma(dev_priv);
if (dev_priv->mm.stolen_base == 0)
return 0;
@ -468,8 +468,8 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv)
if (reserved_base < dev_priv->mm.stolen_base ||
reserved_base + reserved_size > stolen_top) {
phys_addr_t reserved_top = reserved_base + reserved_size;
DRM_DEBUG_KMS("Stolen reserved area [%pa - %pa] outside stolen memory [%pa - %pa]\n",
dma_addr_t reserved_top = reserved_base + reserved_size;
DRM_DEBUG_KMS("Stolen reserved area [%pad - %pad] outside stolen memory [%pad - %pad]\n",
&reserved_base, &reserved_top,
&dev_priv->mm.stolen_base, &stolen_top);
return 0;