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authorLancelot SIX <lancelot.six@amd.com>2025-01-28 19:16:49 +0000
committerAlex Deucher <alexander.deucher@amd.com>2025-02-12 19:47:15 -0500
commitd584198a6fe4c51f4aa88ad72f258f8961a0f11c (patch)
tree653ba967937093d338ed8beee6ead9425b5610cd
parenta0a455b4bc7483ad60e8b8a50330c1e05bb7bfcf (diff)
drm/amdkfd: Ensure consistent barrier state saved in gfx12 trap handler
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
-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 984f0e705078..651660958e5b 100644
--- a/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h
+++ b/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h
@@ -4121,7 +4121,8 @@ 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