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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Copyright (C) 2026 Richard Qin */
/*
* RISC-V Kernel Linker Script Template
*
* This is a C-preprocessed linker script (.lds.S). The build system
* runs it through CPP to produce the final vmlinux.lds which is
* passed to the linker.
*
* Architecture-specific definitions:
* - OUTPUT_ARCH, ENTRY
* - PAGE_OFFSET, BASE_ADDRESS, PHYS_BASE
* - .head.text placement
* - GP anchor (__global_pointer$ for RISC-V medany)
* - early_pgdir and boot stacks in .bss
*
* Common section macros come from include/lume/vmlinux.lds.h
*
* Reference: docs/specs/linker_and_entry.md
*/
#include <lume/lumeos.lds.h>
/* ===== RISC-V Architecture Constants ===== */
OUTPUT_ARCH(riscv)
PAGE_OFFSET = 0xFFFFFFC000000000;
BASE_ADDRESS = 0xFFFFFFC080200000;
PHYS_BASE = 0x80200000;
ENTRY(_start)
/* ===== RISC-V: GP anchor in .data (medany model) ===== */
#define ARCH_DATA_EXTRA \
. = ALIGN(16); \
PROVIDE(__global_pointer$ = . + 0x800); \
*(.sdata .sdata.*)
/* ===== RISC-V: page-table storage + per-CPU boot stacks in .bss =====
*
* Linux RISC-V layout (arch/riscv/kernel/vmlinux.lds.S):
* early_pg_dir — first early page table built by setup_vm,
* used for the rest of boot after MMU enable
* trampoline_pg_dir — single-page table used only during the SATP
* switch from physical to higher-half VA; its
* identity + virt mappings of _start must both
* be valid in the same instruction window
* fixmap_pg_dir — covers the FIXADDR_START range used by the
* early console (UART MMIO before kernel page
* table proper is built)
*
* All three are allocated here so head.S can take their addresses without
* a C definition; their PA == VA mapping covers them during setup_vm.
*/
#define ARCH_BSS_EXTRA \
. = ALIGN(4096); \
early_pg_dir = .; \
. += 4096; \
trampoline_pg_dir = .; \
. += 4096; \
fixmap_pg_dir = .; \
. += 4096; \
/* Legacy name retained for any caller still referencing it; */ \
/* points at the same first 4 KiB as early_pg_dir. */ \
early_pgdir = early_pg_dir; \
/* Per-CPU boot stacks: 8KB per CPU, max 8 CPUs */ \
. = ALIGN(4096); \
boot_stack = .; \
. += 8192 * 8; \
boot_stack_top = .;
/* ===== Layout ===== */
SECTIONS {
. = BASE_ADDRESS;
/* .head.text: Image Header (must be at byte 0 of the kernel image) */
.head.text : AT(PHYS_BASE) {
_start = .;
KEEP(*(.head.text))
}
TEXT_SECTION
. = ALIGN(4096);
/* .rela.dyn lives between .text and .rodata so it ends up in the
* read-only PT_LOAD segment. Mirrors Linux vmlinux.lds.S where
* .rela.dyn sits at the tail of init data, just before RO_DATA. */
RELA_DYN_SECTION
. = ALIGN(4096);
RODATA_SECTION
. = ALIGN(4096);
DATA_SECTION
. = ALIGN(8);
/* .got lives right after .data in the RW PT_LOAD. All other
* dynamic-linker artefacts (.plt, .dynamic, .dynsym, .dynstr,
* .hash, .gnu.hash, .interp, .dynbss) are discarded by the
* DISCARDS macro — mirrors Linux arch/riscv/kernel/vmlinux.lds.S. */
GOT_SECTION
. = ALIGN(4096);
/* End of file-backed image (BSS follows as NOBITS) */
__lume_image_end = .;
BSS_SECTION
KERNEL_END
DISCARDS
}
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