fix(libkernel): report guest unwind tables in sceKernelGetModuleInfoForUnwind on Linux

A title that ships its own libc.prx unwinds C++ exceptions with that
libc's libunwind, which asks sceKernelGetModuleInfoForUnwind where each
frame's eh_frame is. On Linux the call always reported no tables, so
no C++ exception thrown in guest code could be caught. For the main
executable and .guest.prx images, report the PT_GNU_EH_FRAME tables
that sceKernelGetModuleInfoFromAddr finds, as Windows does from
.ehmeta. Other host images still report none.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HeC9bA3n74TzJRYv9AgBE8

core/libs/tests/GuestUnwindModuleInfoLinux.cpp

@@ -0,0 +1,76 @@
+#include "SceTypes.hpp"
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <link.h>
+
+extern "C" {
+int APS5_VABI sceKernelGetModuleInfoForUnwind(uint64_t addr, int flags, ModuleInfoForUnwind* info);
+void* APS5_VABI dlopen_nid_postfix(const char* path, int flags);
+void* APS5_VABI dlsym_nid_postfix(void* handle, const char* name);
+int APS5_VABI dlclose_nid_postfix(void* handle);
+}
+
+static void Require(bool value) { if (!value) std::abort(); }
+
+struct TableSearch {
+    std::uintptr_t address;
+    std::uintptr_t header;
+    bool found;
+};
+
+static int FindTables(dl_phdr_info* image, std::size_t, void* data) {
+    auto& search = *static_cast<TableSearch*>(data);
+    bool contains = false;
+    std::uintptr_t header = 0;
+    for (std::uint16_t i = 0; i < image->dlpi_phnum; ++i) {
+        const auto& segment = image->dlpi_phdr[i];
+        const std::uintptr_t start = image->dlpi_addr + segment.p_vaddr;
+        if (segment.p_type == PT_LOAD && search.address >= start && search.address - start < segment.p_memsz) contains = true;
+        if (segment.p_type == PT_GNU_EH_FRAME) header = start;
+    }
+    if (!contains) return 0;
+    search.header = header;
+    search.found = true;
+    return 1;
+}
+
+static ModuleInfoForUnwind Query(const void* address) {
+    ModuleInfoForUnwind info{};
+    Require(sceKernelGetModuleInfoForUnwind(reinterpret_cast<std::uint64_t>(address), 1, &info) == 0);
+    Require(info.st_size == sizeof(ModuleInfoForUnwind));
+    Require(reinterpret_cast<std::uint64_t>(address) - info.seg0_addr < info.seg0_size);
+    return info;
+}
+
+static void RequireTables(const void* address) {
+    TableSearch search{reinterpret_cast<std::uintptr_t>(address), 0, false};
+    dl_iterate_phdr(FindTables, &search);
+    Require(search.found && search.header != 0);
+    const auto* header = reinterpret_cast<const std::uint8_t*>(search.header);
+    Require(header[0] == 1 && header[1] == 0x1b);
+    std::int32_t offset = 0;
+    std::memcpy(&offset, header + 4, sizeof(offset));
+    const auto info = Query(address);
+    Require(info.eh_frame_hdr_addr == search.header);
+    Require(info.eh_frame_addr == search.header + 4 + static_cast<std::intptr_t>(offset));
+    Require(info.eh_frame_size != 0);
+}
+
+static void RequireNoTables(const void* address) {
+    const auto info = Query(address);
+    Require(info.eh_frame_hdr_addr == 0 && info.eh_frame_addr == 0 && info.eh_frame_size == 0);
+}
+
+int main(int argc, char** argv) {
+    Require(argc == 2);
+    RequireTables(reinterpret_cast<const void*>(&Query));
+    void* module = dlopen_nid_postfix(argv[1], 2);
+    Require(module != nullptr);
+    const void* add = dlsym_nid_postfix(module, "GuestModuleAdd_nid_postfix");
+    Require(add != nullptr);
+    RequireTables(add);
+    RequireNoTables(reinterpret_cast<const void*>(&dl_iterate_phdr));
+    RequireNoTables(reinterpret_cast<const void*>(&sceKernelGetModuleInfoForUnwind));
+    Require(dlclose_nid_postfix(module) == 0);
+}