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authorEric Anholt <[email protected]>2016-07-02 10:03:05 -0700
committerEric Anholt <[email protected]>2016-07-12 17:42:38 -0700
commite2d7760df5a65ce6ab119e026725c809b8e8bfe3 (patch)
treed41ab18b9fab376840bf954950cf96d815ebc435 /src/gallium
parent24095c8b3bf20a5b667f3f7e7245a4d5739ad951 (diff)
vc4: Add a bitmap of branch targets in kernel validation.
This isn't used yet, it's just a first step toward loop validation. During the main parsing of instructions, we need to know when we hit a new basic block so that we can reset validated state.
Diffstat (limited to 'src/gallium')
-rw-r--r--src/gallium/drivers/vc4/kernel/vc4_validate_shaders.c114
-rw-r--r--src/gallium/drivers/vc4/vc4_qpu_defines.h3
-rw-r--r--src/gallium/drivers/vc4/vc4_simulator_validate.h18
3 files changed, 133 insertions, 2 deletions
diff --git a/src/gallium/drivers/vc4/kernel/vc4_validate_shaders.c b/src/gallium/drivers/vc4/kernel/vc4_validate_shaders.c
index 9c77f9e6a7e..0ea6d073a99 100644
--- a/src/gallium/drivers/vc4/kernel/vc4_validate_shaders.c
+++ b/src/gallium/drivers/vc4/kernel/vc4_validate_shaders.c
@@ -60,6 +60,13 @@ struct vc4_shader_validation_state {
*/
uint32_t live_min_clamp_offsets[32 + 32 + 4];
bool live_max_clamp_regs[32 + 32 + 4];
+
+ /* Bitfield of which IPs are used as branch targets.
+ *
+ * Used for validation that the uniform stream is updated at the right
+ * points and clearing the texturing/clamping state.
+ */
+ unsigned long *branch_targets;
};
static uint32_t
@@ -419,13 +426,104 @@ check_instruction_reads(uint64_t inst,
return true;
}
+/* Make sure that all branches are absolute and point within the shader, and
+ * note their targets for later.
+ */
+static bool
+vc4_validate_branches(struct vc4_shader_validation_state *validation_state)
+{
+ uint32_t max_branch_target = 0;
+ bool found_shader_end = false;
+ int ip;
+ int shader_end_ip = 0;
+ int last_branch = -2;
+
+ for (ip = 0; ip < validation_state->max_ip; ip++) {
+ uint64_t inst = validation_state->shader[ip];
+ int32_t branch_imm = QPU_GET_FIELD(inst, QPU_BRANCH_TARGET);
+ uint32_t sig = QPU_GET_FIELD(inst, QPU_SIG);
+ uint32_t after_delay_ip = ip + 4;
+ uint32_t branch_target_ip;
+
+ if (sig == QPU_SIG_PROG_END) {
+ shader_end_ip = ip;
+ found_shader_end = true;
+ continue;
+ }
+
+ if (sig != QPU_SIG_BRANCH)
+ continue;
+
+ if (ip - last_branch < 4) {
+ DRM_ERROR("Branch at %d during delay slots\n", ip);
+ return false;
+ }
+ last_branch = ip;
+
+ if (inst & QPU_BRANCH_REG) {
+ DRM_ERROR("branching from register relative "
+ "not supported\n");
+ return false;
+ }
+
+ if (!(inst & QPU_BRANCH_REL)) {
+ DRM_ERROR("relative branching required\n");
+ return false;
+ }
+
+ /* The actual branch target is the instruction after the delay
+ * slots, plus whatever byte offset is in the low 32 bits of
+ * the instruction. Make sure we're not branching beyond the
+ * end of the shader object.
+ */
+ if (branch_imm % sizeof(inst) != 0) {
+ DRM_ERROR("branch target not aligned\n");
+ return false;
+ };
+
+ branch_target_ip = after_delay_ip + (branch_imm >> 3);
+ if (branch_target_ip >= validation_state->max_ip) {
+ DRM_ERROR("Branch at %d outside of shader (ip %d/%d)\n",
+ ip, branch_target_ip,
+ validation_state->max_ip);
+ return false;
+ }
+ set_bit(branch_target_ip, validation_state->branch_targets);
+
+ /* Make sure that the non-branching path is also not outside
+ * the shader.
+ */
+ if (after_delay_ip >= validation_state->max_ip) {
+ DRM_ERROR("Branch at %d continues past shader end "
+ "(%d/%d)\n",
+ ip, after_delay_ip, validation_state->max_ip);
+ return false;
+ }
+ set_bit(after_delay_ip, validation_state->branch_targets);
+ max_branch_target = max(max_branch_target, after_delay_ip);
+
+ /* There are two delay slots after program end is signaled
+ * that are still executed, then we're finished.
+ */
+ if (found_shader_end && ip == shader_end_ip + 2)
+ break;
+ }
+
+ if (max_branch_target > shader_end_ip) {
+ DRM_ERROR("Branch landed after QPU_SIG_PROG_END");
+ return false;
+ }
+
+ return true;
+}
+
struct vc4_validated_shader_info *
vc4_validate_shader(struct drm_gem_cma_object *shader_obj)
{
bool found_shader_end = false;
int shader_end_ip = 0;
uint32_t ip;
- struct vc4_validated_shader_info *validated_shader;
+ struct vc4_validated_shader_info *validated_shader = NULL;
struct vc4_shader_validation_state validation_state;
int i;
@@ -438,9 +536,18 @@ vc4_validate_shader(struct drm_gem_cma_object *shader_obj)
for (i = 0; i < ARRAY_SIZE(validation_state.live_min_clamp_offsets); i++)
validation_state.live_min_clamp_offsets[i] = ~0;
+ validation_state.branch_targets =
+ kcalloc(BITS_TO_LONGS(validation_state.max_ip),
+ sizeof(unsigned long), GFP_KERNEL);
+ if (!validation_state.branch_targets)
+ goto fail;
+
validated_shader = kcalloc(1, sizeof(*validated_shader), GFP_KERNEL);
if (!validated_shader)
- return NULL;
+ goto fail;
+
+ if (!vc4_validate_branches(&validation_state))
+ goto fail;
for (ip = 0; ip < validation_state.max_ip; ip++) {
uint64_t inst = validation_state.shader[ip];
@@ -509,9 +616,12 @@ vc4_validate_shader(struct drm_gem_cma_object *shader_obj)
(validated_shader->uniforms_size +
4 * validated_shader->num_texture_samples);
+ kfree(validation_state.branch_targets);
+
return validated_shader;
fail:
+ kfree(validation_state.branch_targets);
if (validated_shader) {
kfree(validated_shader->texture_samples);
kfree(validated_shader);
diff --git a/src/gallium/drivers/vc4/vc4_qpu_defines.h b/src/gallium/drivers/vc4/vc4_qpu_defines.h
index 2ffa68663b1..c0b7c56c007 100644
--- a/src/gallium/drivers/vc4/vc4_qpu_defines.h
+++ b/src/gallium/drivers/vc4/vc4_qpu_defines.h
@@ -301,6 +301,9 @@ enum qpu_unpack {
#define QPU_OP_ADD_SHIFT 24
#define QPU_OP_ADD_MASK QPU_MASK(28, 24)
+#define QPU_LOAD_IMM_SHIFT 0
+#define QPU_LOAD_IMM_MASK QPU_MASK(31, 0)
+
#define QPU_BRANCH_TARGET_SHIFT 0
#define QPU_BRANCH_TARGET_MASK QPU_MASK(31, 0)
diff --git a/src/gallium/drivers/vc4/vc4_simulator_validate.h b/src/gallium/drivers/vc4/vc4_simulator_validate.h
index e1f8b5a305e..1352c9bafd2 100644
--- a/src/gallium/drivers/vc4/vc4_simulator_validate.h
+++ b/src/gallium/drivers/vc4/vc4_simulator_validate.h
@@ -47,6 +47,24 @@ struct vc4_exec_info;
#define max(x, y) MAX2(x, y)
#define min(x, y) MIN2(x, y)
#define BUG_ON(condition) assert(!(condition))
+#define BIT(bit) (1u << bit)
+
+/* Unsigned long-based bitmap interface in the linux kernel */
+#define BITMAP_WORDBITS (sizeof(unsigned long) * 8)
+#define BITS_TO_LONGS(bits) (roundup(bits, BITMAP_WORDBITS) / \
+ sizeof(unsigned long))
+static inline bool
+test_bit(unsigned int bit, unsigned long *addr)
+{
+ return addr[bit / BITMAP_WORDBITS] & (1ul << (bit % BITMAP_WORDBITS));
+}
+
+static inline bool
+set_bit(unsigned int bit, unsigned long *addr)
+{
+ return addr[bit / BITMAP_WORDBITS] |= (1ul << (bit % BITMAP_WORDBITS));
+}
+
static inline int
copy_from_user(void *dst, void *src, size_t size)