cef99b311d
**Status**: Box FG V2 + ExternalGuard 実装完了、hak_free_at routing は Phase 14-C に revert **Files Created**: 1. core/box/front_gate_v2.h (98 lines) - Ultra-fast 1-byte header classification (TINY/POOL/MIDCAND/EXTERNAL) - Performance: 2-5 cycles - Same-page guard added (防御的プログラミング) 2. core/box/external_guard_box.h (146 lines) - ENV-controlled mincore safety check - HAKMEM_EXTERNAL_GUARD_MINCORE=0/1 (default: OFF) - Uses __libc_free() to avoid infinite loop **Routing**: - hak_free_at reverted to Phase 14-C (classify_ptr-based, stable) - Phase 15 routing caused SEGV on page-aligned pointers **Performance**: - Phase 14-C (mincore ON): 16.5M ops/s (stable) - mincore: 841 calls/100K iterations - mincore OFF: SEGV (unsafe AllocHeader deref) **Next Steps** (deferred): - Mid/Large/C7 registry consolidation - AllocHeader safety validation - ExternalGuard integration **Recommendation**: Stick with Phase 14-C for now - mincore overhead acceptable (~1.9ms / 100K) - Focus on other bottlenecks (TLS SLL, SuperSlab churn) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
98 lines
3.2 KiB
C
98 lines
3.2 KiB
C
// front_gate_v2.h - Box FG (Front Gate V2): Domain Classification
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// Purpose: Fast domain routing based on 1-byte header ONLY
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// Design: ChatGPT consultation Phase 15 - Box Separation
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//
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// Responsibilities (ONLY):
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// 1. Read 1-byte header (ptr-1)
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// 2. Classify: TINY | POOL | MIDCAND | EXTERNAL
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// 3. Extract class_idx for TINY/POOL
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//
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// Out of scope (delegated to other boxes):
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// - NO mincore (Box ExternalGuard only)
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// - NO AllocHeader (Box ExternalGuard only)
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// - NO registry lookup (Box Tiny/Pool/Mid)
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// - NO free/alloc logic (routing only)
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//
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// Performance: 2-5 cycles (single byte read + bitwise ops)
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#ifndef HAK_BOX_FRONT_GATE_V2_H
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#define HAK_BOX_FRONT_GATE_V2_H
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#include <stdint.h>
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// Domain types (粗い分類のみ)
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typedef enum {
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FG_DOMAIN_TINY, // 0xa0 | class_idx (C0-C7, 8B-1KB)
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FG_DOMAIN_POOL, // 0xb0 | class_idx (Pool TLS, 8-52KB)
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FG_DOMAIN_MIDCAND, // Candidate for Mid/Large (needs registry lookup)
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FG_DOMAIN_EXTERNAL // Not hakmem managed (or NULL/invalid)
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} fg_domain_t;
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// Classification result
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typedef struct {
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fg_domain_t domain;
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int class_idx; // Valid for TINY/POOL (-1 otherwise)
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} fg_classification_t;
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// Ultra-fast domain classification (1-byte header only)
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// Contract:
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// - Input: ptr (USER pointer, can be NULL)
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// - Output: {domain, class_idx}
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// - Safety: NULL-safe, no crashes on invalid pointers
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// - Performance: 2-5 cycles
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static inline fg_classification_t fg_classify_domain(void* ptr) {
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fg_classification_t result = {.domain = FG_DOMAIN_EXTERNAL, .class_idx = -1};
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// NULL check
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if (!ptr) return result;
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// Guard against low addresses (avoid segfault on ptr-1)
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if ((uintptr_t)ptr < 4096) return result;
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// CRITICAL: Same-page guard (header must be in same page as ptr)
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// If ptr is page-aligned (offset_in_page == 0), header would be on previous page (unsafe)
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uintptr_t offset_in_page = (uintptr_t)ptr & 0xFFF;
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if (offset_in_page == 0) {
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// Page-aligned pointer → no header in same page → must be MIDCAND or EXTERNAL
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result.domain = FG_DOMAIN_MIDCAND;
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return result;
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}
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// Safe to read header (same page guaranteed)
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uint8_t header = *((uint8_t*)ptr - 1);
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// Tiny: 0xa0 | class_idx (class_idx = 0-7)
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if ((header & 0xf0) == 0xa0) {
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result.domain = FG_DOMAIN_TINY;
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result.class_idx = (int)(header & 0x0f);
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return result;
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}
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// Pool TLS: 0xb0 | class_idx
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if ((header & 0xf0) == 0xb0) {
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result.domain = FG_DOMAIN_POOL;
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result.class_idx = (int)(header & 0x0f);
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return result;
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}
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// Mid/Large candidate (no 1-byte header, needs registry lookup)
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// Note: Could be Mid/Large, or could be External (libc/mmap)
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// Delegated to Box MidRouter for registry lookup
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result.domain = FG_DOMAIN_MIDCAND;
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result.class_idx = -1;
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return result;
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}
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// Domain name (debug/logging)
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static inline const char* fg_domain_name(fg_domain_t domain) {
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switch (domain) {
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case FG_DOMAIN_TINY: return "TINY";
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case FG_DOMAIN_POOL: return "POOL";
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case FG_DOMAIN_MIDCAND: return "MIDCAND";
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case FG_DOMAIN_EXTERNAL: return "EXTERNAL";
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default: return "UNKNOWN";
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}
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}
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#endif // HAK_BOX_FRONT_GATE_V2_H
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