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authorLancelot SIX <lancelot.six@amd.com>2025-01-28 19:16:49 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-02-27 04:34:13 -0800
commit3eedb45fa474cfbda5b48357e9a5d72cd52b9dcc (patch)
tree2f6d2446519930a90f002877ba08a2b3e51a23be
parentb871ca494c88d00ce6860063ea068d5b6c54407e (diff)
drm/amdkfd: Ensure consistent barrier state saved in gfx12 trap handler
[ Upstream commit d584198a6fe4c51f4aa88ad72f258f8961a0f11c ] It is possible for some waves in a workgroup to finish their save sequence before the group leader has had time to capture the workgroup barrier state. When this happens, having those waves exit do impact the barrier state. As a consequence, the state captured by the group leader is invalid, and is eventually incorrectly restored. This patch proposes to have all waves in a workgroup wait for each other at the end of their save sequence (just before calling s_endpgm_saved). Signed-off-by: Lancelot SIX <lancelot.six@amd.com> Reviewed-by: Jay Cornwall <jay.cornwall@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org # 6.12.x Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h3
-rw-r--r--drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm4
2 files changed, 6 insertions, 1 deletions
diff --git a/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h b/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h
index 02f7ba8c93cd..7062f12b5b75 100644
--- a/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h
+++ b/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h
@@ -4117,7 +4117,8 @@ static const uint32_t cwsr_trap_gfx12_hex[] = {
0x0000ffff, 0x8bfe7e7e,
0x8bea6a6a, 0xb97af804,
0xbe804ec2, 0xbf94fffe,
- 0xbe804a6c, 0xbfb10000,
+ 0xbe804a6c, 0xbe804ec2,
+ 0xbf94fffe, 0xbfb10000,
0xbf9f0000, 0xbf9f0000,
0xbf9f0000, 0xbf9f0000,
0xbf9f0000, 0x00000000,
diff --git a/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm b/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm
index 1740e98c6719..7b9d36e5fa43 100644
--- a/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm
+++ b/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm
@@ -1049,6 +1049,10 @@ L_SKIP_BARRIER_RESTORE:
s_rfe_b64 s_restore_pc_lo //Return to the main shader program and resume execution
L_END_PGM:
+ // Make sure that no wave of the workgroup can exit the trap handler
+ // before the workgroup barrier state is saved.
+ s_barrier_signal -2
+ s_barrier_wait -2
s_endpgm_saved
end