`EIP-7823` and `EIP-7883` implementation --- Osaka `MODEXP` changes #2477

OlivierBBB · 2025-11-12T17:58:23Z

Note

Introduces fork-aware MODEXP (London/Osaka) with new metadata, pricing, and OOB flows; refactors Blake/MODEXP modules; updates MMU/Hub/Counter/RPC to pass fork; and extends tests accordingly.

Fork-aware tracing and limits:
- Pass Fork into ZkCounter, Hub (MMU), and RPC creators; compute MODEXP/BLAKE rows and sizes per fork (London vs Osaka).
MODEXP (EIP-7823/7883) implementation:
- New fork-specific classes: London/OsakaModexpSubsection, London/OsakaModexpMetadata, London/OsakaModexpPricingOobCall, London/OsakaModexpXbsOobCall.
- Adjust success criteria, pricing, input bounds, lead-log multiplier (8→16 in Osaka), and max input size; update OOB/XBS flows and result handling.
Blake/MODEXP refactor:
- Replace BlakeModexpData with abstract BlakeModexp and BlakeModexpOperation plus London/Osaka variants; compute row counts dynamically; use fork-specific indices.
- Update BLAKE2f handling to use new ops and counts (numberOfRowsBlake).
MMU updates:
- Make Mmu, MmuInstructions, ModexpData, ModexpZero fork-aware; adjust micro-row counts and component sizes per fork.
Hub/Call flow:
- CallSection selects London/Osaka MODEXP subsection; PrecompileSubsection sets return data using fork max sizes.
RPC & Tests:
- RPC counters instantiate ZkCounter with fork; numerous tests updated/added to cover Osaka behavior and gas/pricing changes.

^{Written by Cursor Bugbot for commit cfa8e8e. This will update automatically on new commits. Configure here.}

...ensys/linea/zktracer/module/hub/section/call/precompileSubsection/OsakaModexpSubsection.java

...ktracer/module/hub/fragment/imc/oob/precompiles/modexp/xbsOobCall/OsakaModexpXbsOobCall.java

...sensys/linea/zktracer/module/hub/section/call/precompileSubsection/PrecompileSubsection.java

letypequividelespoubelles · 2025-11-13T02:58:00Z

...tization/src/main/java/net/consensys/linea/zktracer/module/hub/fragment/imc/mmu/MmuCall.java

-  public static MmuCall forModexpExtractMbs(
-      final Hub hub, final ModexpSubsection subsection, final ModexpMetadata metaData) {
+  public static MmuCall extractMbsForModexp(
+      final Hub hub, final LondonModexpSubsection subsection, final ModexpMetadata metaData) {


Is it normal ? What's happening for OsakaModexpSection ?

letypequividelespoubelles · 2025-11-13T03:00:07Z

...net/consensys/linea/zktracer/module/hub/precompiles/modexpMetadata/LondonModexpMetadata.java

+  }
+
+  public int getMaxInputSize() {
+    return 512;


this constant has a name somewhere ...

It doesn't in the HUB constraints.

...n/java/net/consensys/linea/zktracer/module/blake2fmodexpdata/LondonBlakeModexpOperation.java

With Lorenzo and François

arithmetization/src/main/java/net/consensys/linea/zktracer/ZkCounter.java

One failing test (MODEXP limits)

the old tests were overwriting mbs in memory !

...ensys/linea/zktracer/module/hub/section/call/precompileSubsection/OsakaModexpSubsection.java

...module/hub/fragment/imc/oob/precompiles/modexp/pricingOobCall/OsakaModexpPricingOobCall.java

...ensys/linea/zktracer/module/hub/section/call/precompileSubsection/OsakaModexpSubsection.java

...nsys/linea/zktracer/module/hub/section/call/precompileSubsection/LondonModexpSubsection.java

cursor · 2025-11-17T20:21:40Z

...ensys/linea/zktracer/module/hub/section/call/precompileSubsection/OsakaModexpSubsection.java

+    super(hub, callSection, modexpMetadata);
+    checkState(
+        modexpMetadata instanceof OsakaModexpMetadata,
+        "modexpMetadata must be LondonModexpMetadata");


Bug: Error Message Confuses Metadata Types

The error message in the checkState validation says "modexpMetadata must be LondonModexpMetadata" but the check validates that modexpMetadata instanceof OsakaModexpMetadata. The error message is incorrect and misleading - it should say "modexpMetadata must be OsakaModexpMetadata" to match the actual validation being performed.

leadLog is essentially defined as log_2(exponent_leading_word) + multiplier * (ebs - 32) with multiplier = 8 pre-Osaka, and 16 post-Osaka

letypequividelespoubelles · 2025-11-19T12:54:02Z

...ion/src/main/java/net/consensys/linea/zktracer/module/blake2fmodexpdata/BlakeComponents.java


-import static net.consensys.linea.zktracer.module.blake2fmodexpdata.BlakeModexpDataOperation.BLAKE2f_HASH_INPUT_OFFSET;
-import static net.consensys.linea.zktracer.module.blake2fmodexpdata.BlakeModexpDataOperation.BLAKE2f_HASH_INPUT_SIZE;
+import static net.consensys.linea.zktracer.module.blake2fmodexpdata.BlakeModexpOperation.BLAKE2f_HASH_INPUT_OFFSET;


why rm the data ? We have it for other modules (EcData, etc ...)

letypequividelespoubelles · 2025-11-19T12:55:10Z

...ization/src/main/java/net/consensys/linea/zktracer/module/blake2fmodexpdata/BlakeModexp.java

  }

-  private void callWcpForIdCheck(final int operationID) {
+  private void callWcpForIdCheck(final long operationID) {


operation is from hubStamp, whicj is a i32, so int is enough no ?

letypequividelespoubelles · 2025-11-19T12:57:49Z

...rc/main/java/net/consensys/linea/zktracer/module/blake2fmodexpdata/BlakeModexpOperation.java

+    return blake2fComponents.isPresent();
+  }
+
+  public static int legalModexpComponentByteSize(Fork fork) {


should add a commet to say that legal is accepted by linea in Prague vs non exceptionnal in Osaka

letypequividelespoubelles · 2025-11-19T13:00:30Z

...n/src/main/java/net/consensys/linea/zktracer/module/blake2fmodexpdata/LondonBlakeModexp.java

LondonBlakeModexp == OsakaBmakeModexp as it's the underlying operation which is different depeding on the Fork. So Imho, it seems no need to have an abstract BlakeModexpData and two extends. Only keep a non abstract BlakeModexppData seems enough.

letypequividelespoubelles · 2025-11-19T13:02:17Z

...tization/src/main/java/net/consensys/linea/zktracer/module/hub/fragment/imc/mmu/MmuCall.java

-  public static MmuCall forModexpExtractBbs(
-      final Hub hub, final ModexpSubsection subsection, final ModexpMetadata metaData) {
+  public static MmuCall extractBbsForModexp(
+      final Hub hub, final LondonModexpSubsection subsection, final ModexpMetadata metaData) {


why sopecialized a LondonModexpSection, and not only an abstract ModexpSubsection ?
As it is, it seems we only accept London (but as Osaka extends London it works), so it's strange.

letypequividelespoubelles · 2025-11-19T13:13:43Z

arithmetization/src/main/java/net/consensys/linea/zktracer/module/hub/Hub.java

    rlpAddr = new RlpAddr(this, trm, keccak);
    blockdata = setBlockData(this, wcp, euc, chain);
-    mmu = new Mmu(euc, wcp);
+    mmu = new Mmu(euc, wcp, fork);


we should refactor the mmuCall to give as an input only the ModexMetaData ...

In a next cleaning PR

letypequividelespoubelles · 2025-11-19T13:15:21Z

...test/java/net/consensys/linea/zktracer/module/limits/precompileLimits/ModexpLimitsTests.java

      }
    }
+
+    // arguments.clear();


letypequividelespoubelles · 2025-11-19T13:15:52Z

arithmetization/src/test/resources/junit-platform.properties

-# junit.jupiter.execution.parallel.enabled = true
-# junit.jupiter.execution.parallel.mode.default = concurrent
-# junit.jupiter.execution.parallel.config.strategy = dynamic
+junit.jupiter.execution.parallel.enabled = true


letypequividelespoubelles · 2025-11-19T13:16:12Z

testing/src/main/java/net/consensys/linea/reporting/TracerTestBase.java

    // Configure chain information and fork before any tests are run, including any methods used as
    // MethodSource.
-    TracerTestBase.chainConfig = ChainConfig.MAINNET_TESTCONFIG(getForkOrDefault(OSAKA));
+    TracerTestBase.chainConfig = ChainConfig.MAINNET_TESTCONFIG(getForkOrDefault(PRAGUE));


back to osaka, the release will be for Osaka

letypequividelespoubelles · 2025-11-19T13:17:01Z

plan.md

cursor · 2025-11-19T17:36:12Z

...nsys/linea/zktracer/module/hub/section/call/precompileSubsection/LondonModexpSubsection.java

+  }
+
+  protected boolean allXbsesAreInBounds() {
+    return true;


Bug: Missing maxNumberOfLines override in LondonModexpSubsection

The LondonModexpSubsection class doesn't override the maxNumberOfLines() method that was present in the original ModexpSubsection class. This causes it to inherit the default implementation from PrecompileSubsection which returns 0, instead of the correct value NB_ROWS_HUB_PRC_MODEXP (13). This affects line counting for MODEXP precompile operations and could lead to incorrect trace sizing calculations.

…tyThreeSixtyFourthsPrecompileTests

cursor · 2025-11-19T19:53:07Z

...nsys/linea/zktracer/module/hub/section/call/precompileSubsection/LondonModexpSubsection.java

+  }
+
+  protected boolean allXbsesAreInBounds() {
+    return true;


Bug: Missing maxNumberOfLines override in LondonModexpSubsection

The LondonModexpSubsection class was refactored from ModexpSubsection but the maxNumberOfLines() method override was removed. The diff shows the old ModexpSubsection had this method returning NB_ROWS_HUB_PRC_MODEXP (value 13), but the new LondonModexpSubsection doesn't override it, causing it to inherit the default return value of 0 from PrecompileSubsection. This breaks the precompile subsection initialization in the constructor which calls new ArrayList<>(maxNumberOfLines()), potentially causing incorrect memory allocation and fragment list sizing for MODEXP operations.

OlivierBBB added 3 commits November 7, 2025 15:49

feat: constraints update

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constraints update

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first commit

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OlivierBBB self-assigned this Nov 12, 2025

OlivierBBB added hardfork Osaka modexp labels Nov 12, 2025

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letypequividelespoubelles reviewed Nov 13, 2025

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various ...

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...n/java/net/consensys/linea/zktracer/module/blake2fmodexpdata/LondonBlakeModexpOperation.java Outdated Show resolved Hide resolved

OlivierBBB added 2 commits November 14, 2025 09:07

stuff ...

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arithmetization/src/main/java/net/consensys/linea/zktracer/ZkCounter.java Outdated Show resolved Hide resolved

OlivierBBB added 3 commits November 14, 2025 20:01

fix: 99% up to par + @EqualsAndHash(callSuper = true)

5be004c

One failing test (MODEXP limits)

fix: ModexpTests

de62eed

the old tests were overwriting mbs in memory !

feat: fix ZkCounter event detection

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...ensys/linea/zktracer/module/hub/section/call/precompileSubsection/OsakaModexpSubsection.java Show resolved Hide resolved

spotless ... again ?

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...ensys/linea/zktracer/module/hub/section/call/precompileSubsection/OsakaModexpSubsection.java Show resolved Hide resolved

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OlivierBBB added 3 commits November 16, 2025 20:06

feat: Osaka MODEXP pricing OOB call

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