FAILED: patch "[PATCH] drm/amdkfd: Ensure consistent barrier state saved in gfx12" failed to apply to 6.13-stable tree

[email protected]

author maintainer

2025-02-18 11:26 UTC #0 lore raw

The patch below does not apply to the 6.13-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.13.y
git checkout FETCH_HEAD
git cherry-pick -x d584198a6fe4c51f4aa88ad72f258f8961a0f11c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025021802-scrimmage-oppressor-8e61@gregkh' --subject-prefix 'PATCH 6.13.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d584198a6fe4c51f4aa88ad72f258f8961a0f11c Mon Sep 17 00:00:00 2001
From: Lancelot SIX <[email protected]>
Date: Tue, 28 Jan 2025 19:16:49 +0000
Subject: [PATCH] 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 <[email protected]>

Reviewed-by Jay Cornwall <[email protected]>

Signed-off-by Alex Deucher <[email protected]>

Cc [email protected] # 6.12.x

drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h +2 -1

index 984f0e705078..651660958e5b 100644
@@ -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,

drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm +4 -0

index 1740e98c6719..7b9d36e5fa43 100644
@@ -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

Lancelot SIX

2025-02-21 18:09 UTC #1 lore raw

PATCH 1/1 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).

This is a cherry-pick. The cwsr_trap_handler.h part of the original part was valid and applied cleanly. The part of the patch that applied to cwsr_trap_handler_gfx12.asm did not apply cleanly since 80ae55e6115ef "drm/amdkfd: Move gfx12 trap handler to separate file" is not part of this branch. Instead, I ported the change to cwsr_trap_handler_gfx10.asm, and guarded it with "ASIC_FAMILY >= CHIP_GFX12".

Signed-off-by Lancelot SIX <[email protected]>

Reviewed-by Jay Cornwall <[email protected]>

Signed-off-by Alex Deucher <[email protected]>

Cc [email protected] # 6.12.x

(cherry picked from commit d584198a6fe4c51f4aa88ad72f258f8961a0f11c)

Signed-off-by Lancelot SIX <[email protected]>

---
 drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h         | 3 ++-
 drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx10.asm | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h +2 -1

index 02f7ba8c93cd4..7062f12b5b751 100644
@@ -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,

drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx10.asm +6 -0

index 44772eec9ef4d..8fd7f17df494c 100644
@@ -1463,6 +1463,12 @@ L_RETURN_WITHOUT_PRIV:
 	s_rfe_b64	s_restore_pc_lo						//Return to the main shader program and resume execution
 
 L_END_PGM:
+#if ASIC_FAMILY >= CHIP_GFX12
+	// 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
+#endif
 	s_endpgm_saved
 end

base-commit: 4e3ac4150cbd02585dc5cd1b4a25b8519a57c6a2

Signature · 1 line

2.43.0

Sasha Levin

maintainer Reviewed-by Jay Cornwall on v1 1/1

2025-02-22 15:53 UTC #2 lore raw

Re: [PATCH] drm/amdkfd: Ensure consistent barrier state saved in gfx12 trap handler

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
❌ Build failures detected
⚠️ Found matching upstream commit but patch is missing proper reference to it

Found matching upstream commit: d584198a6fe4c51f4aa88ad72f258f8961a0f11c

Status in newer kernel trees:
6.6.y | Not found

Note: The patch differs from the upstream commit:
---
1: d584198a6fe4c ! 1: 4d030c400adf7 drm/amdkfd: Ensure consistent barrier state saved in gfx12 trap handler
@@ Commit message
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).

+ This is a cherry-pick. The cwsr_trap_handler.h part of the original
+ part was valid and applied cleanly. The part of the patch that applied
+ to cwsr_trap_handler_gfx12.asm did not apply cleanly since
+ 80ae55e6115ef "drm/amdkfd: Move gfx12 trap handler to separate file" is
+ not part of this branch. Instead, I ported the change to
+ cwsr_trap_handler_gfx10.asm, and guarded it with "ASIC_FAMILY >=
+ CHIP_GFX12".
+

Signed-off-by Lancelot SIX <[email protected]>

Reviewed-by Jay Cornwall <[email protected]>

Signed-off-by Alex Deucher <[email protected]>

Cc [email protected] # 6.12.x

+ (cherry picked from commit d584198a6fe4c51f4aa88ad72f258f8961a0f11c)
+ Signed-off-by: Lancelot SIX <[email protected]>

## drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h ##
@@ drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h: static const uint32_t cwsr_trap_gfx12_hex[] = {
@@ drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h: static const uint32_t cwsr_trap_
0xbf9f0000, 0xbf9f0000,
0xbf9f0000, 0x00000000,

- ## drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm ##
-@@ drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx12.asm: L_SKIP_BARRIER_RESTORE:
+ ## drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx10.asm ##
+@@ drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx10.asm: L_RETURN_WITHOUT_PRIV:
s_rfe_b64 s_restore_pc_lo //Return to the main shader program and resume execution

L_END_PGM:
++#if ASIC_FAMILY >= CHIP_GFX12
+ // 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
++#endif
s_endpgm_saved
end

---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.13.y       |  Success    |  Success   |
| stable/linux-6.12.y       |  Success    |  Success   |
| stable/linux-6.6.y        |  Failed     |  N/A       |
| stable/linux-6.1.y        |  Failed     |  N/A       |
| stable/linux-5.15.y       |  Failed     |  N/A       |
| stable/linux-5.10.y       |  Failed     |  N/A       |
| stable/linux-5.4.y        |  Failed     |  N/A       |

Build Errors:
Patch failed to apply on stable/linux-6.6.y. Reject:

diff a/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h b/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler.h (rejected hunks)
@@ -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 a/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx10.asm b/drivers/gpu/drm/amd/amdkfd/cwsr_trap_handler_gfx10.asm (rejected hunks)
@@ -1463,6 +1463,12 @@ L_RETURN_WITHOUT_PRIV:
s_rfe_b64 s_restore_pc_lo //Return to the main shader program and resume execution