diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0537-drm-vc4-Fix-termination-of-the-initial-scan-for-bran.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0537-drm-vc4-Fix-termination-of-the-initial-scan-for-bran.patch | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0537-drm-vc4-Fix-termination-of-the-initial-scan-for-bran.patch b/target/linux/brcm2708/patches-4.4/0537-drm-vc4-Fix-termination-of-the-initial-scan-for-bran.patch new file mode 100644 index 0000000000..c31307278b --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0537-drm-vc4-Fix-termination-of-the-initial-scan-for-bran.patch @@ -0,0 +1,68 @@ +From 1f42fbc79dea3529dd919249ee6e58f157704aaf Mon Sep 17 00:00:00 2001 +From: Eric Anholt <eric@anholt.net> +Date: Thu, 20 Oct 2016 16:48:12 -0700 +Subject: [PATCH] drm/vc4: Fix termination of the initial scan for branch + targets. + +The loop is scanning until the original max_ip (size of the BO), but +we want to not examine any code after the PROG_END's delay slots. +There was a block trying to do that, except that we had some early +continue statements if the signal wasn't a PROG_END or a BRANCH. + +The failure mode would be that a valid shader is rejected because some +undefined memory after the PROG_END slots is parsed as a branch and +the rest of its setup is illegal. I haven't seen this in the wild, +but valgrind was complaining when about this up in the userland +simulator mode. + +Signed-off-by: Eric Anholt <eric@anholt.net> +(cherry picked from commit 457e67a728696c4f8e6423c64e93def50530db9a) +--- + drivers/gpu/drm/vc4/vc4_validate_shaders.c | 19 ++++++++----------- + 1 file changed, 8 insertions(+), 11 deletions(-) + +--- a/drivers/gpu/drm/vc4/vc4_validate_shaders.c ++++ b/drivers/gpu/drm/vc4/vc4_validate_shaders.c +@@ -608,9 +608,7 @@ 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++) { +@@ -621,8 +619,13 @@ vc4_validate_branches(struct vc4_shader_ + uint32_t branch_target_ip; + + if (sig == QPU_SIG_PROG_END) { +- shader_end_ip = ip; +- found_shader_end = true; ++ /* There are two delay slots after program end is ++ * signaled that are still executed, then we're ++ * finished. validation_state->max_ip is the ++ * instruction after the last valid instruction in the ++ * program. ++ */ ++ validation_state->max_ip = ip + 3; + continue; + } + +@@ -676,15 +679,9 @@ vc4_validate_branches(struct vc4_shader_ + } + 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) { ++ if (max_branch_target > validation_state->max_ip - 3) { + DRM_ERROR("Branch landed after QPU_SIG_PROG_END"); + return false; + } |