69 lines
2.4 KiB
Diff
69 lines
2.4 KiB
Diff
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From 57b0774967d7ea8d4173f82387100a84e4ba05d8 Mon Sep 17 00:00:00 2001
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From: Eric Anholt <eric@anholt.net>
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Date: Thu, 20 Oct 2016 16:48:12 -0700
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Subject: [PATCH] drm/vc4: Fix termination of the initial scan for branch
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targets.
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The loop is scanning until the original max_ip (size of the BO), but
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we want to not examine any code after the PROG_END's delay slots.
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There was a block trying to do that, except that we had some early
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continue statements if the signal wasn't a PROG_END or a BRANCH.
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The failure mode would be that a valid shader is rejected because some
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undefined memory after the PROG_END slots is parsed as a branch and
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the rest of its setup is illegal. I haven't seen this in the wild,
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but valgrind was complaining when about this up in the userland
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simulator mode.
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Signed-off-by: Eric Anholt <eric@anholt.net>
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(cherry picked from commit 457e67a728696c4f8e6423c64e93def50530db9a)
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---
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drivers/gpu/drm/vc4/vc4_validate_shaders.c | 19 ++++++++-----------
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1 file changed, 8 insertions(+), 11 deletions(-)
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--- a/drivers/gpu/drm/vc4/vc4_validate_shaders.c
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+++ b/drivers/gpu/drm/vc4/vc4_validate_shaders.c
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@@ -608,9 +608,7 @@ static bool
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vc4_validate_branches(struct vc4_shader_validation_state *validation_state)
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{
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uint32_t max_branch_target = 0;
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- bool found_shader_end = false;
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int ip;
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- int shader_end_ip = 0;
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int last_branch = -2;
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for (ip = 0; ip < validation_state->max_ip; ip++) {
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@@ -621,8 +619,13 @@ vc4_validate_branches(struct vc4_shader_
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uint32_t branch_target_ip;
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if (sig == QPU_SIG_PROG_END) {
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- shader_end_ip = ip;
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- found_shader_end = true;
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+ /* There are two delay slots after program end is
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+ * signaled that are still executed, then we're
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+ * finished. validation_state->max_ip is the
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+ * instruction after the last valid instruction in the
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+ * program.
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+ */
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+ validation_state->max_ip = ip + 3;
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continue;
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}
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@@ -676,15 +679,9 @@ vc4_validate_branches(struct vc4_shader_
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}
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set_bit(after_delay_ip, validation_state->branch_targets);
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max_branch_target = max(max_branch_target, after_delay_ip);
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-
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- /* There are two delay slots after program end is signaled
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- * that are still executed, then we're finished.
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- */
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- if (found_shader_end && ip == shader_end_ip + 2)
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- break;
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}
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- if (max_branch_target > shader_end_ip) {
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+ if (max_branch_target > validation_state->max_ip - 3) {
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DRM_ERROR("Branch landed after QPU_SIG_PROG_END");
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return false;
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}
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