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| author | Richard Qin <richard.qin.x@gmail.com> | 2026-04-21 23:05:54 +0800 |
|---|---|---|
| committer | Richard Qin <richard.qin.x@gmail.com> | 2026-04-21 23:05:54 +0800 |
| commit | b0ccdda4bc3af04e54677cd910ed04c5ba1b1a63 (patch) | |
| tree | 2e5e065ea30abf6e07fc3f8ebf5a653dd5c2849e /na/arch/riscv/boot | |
| parent | df1af31b90d904fddc45c6da6da5ee36d905a0ca (diff) | |
| download | lume-b0ccdda4bc3af04e54677cd910ed04c5ba1b1a63.tar.gz lume-b0ccdda4bc3af04e54677cd910ed04c5ba1b1a63.tar.xz | |
feat: add RISC-V architecture configuration header with memory layout constants
Diffstat (limited to 'na/arch/riscv/boot')
| -rw-r--r-- | na/arch/riscv/boot/entry.S | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/na/arch/riscv/boot/entry.S b/na/arch/riscv/boot/entry.S index 895c778..f53a4c8 100644 --- a/na/arch/riscv/boot/entry.S +++ b/na/arch/riscv/boot/entry.S @@ -20,9 +20,10 @@ * Reference: docs/specs/linker_and_entry.md */ +#include <lume/config.h> + #define PAGE_OFFSET 0xFFFFFFC000000000 #define BOOT_STACK_SIZE 8192 -#define NCPU_MAX 8 /* SV39 PTE flags */ #define PTE_V (1 << 0) /* Valid */ @@ -192,18 +193,24 @@ real_start: /* ---- 6.3: Jump to higher-half virtual address ---- */ /* Now we are executing via the identity map (PA == VA for 0x8...). - * Load the VA of the next instruction and jump there, - * so PC switches from physical to virtual address space. */ + * `la` is PC-relative (medany), so it yields a PHYSICAL address. + * We must add PAGE_OFFSET to convert to the higher-half VA. */ la t0, .Lhigher_half + li t1, PAGE_OFFSET + add t0, t0, t1 jr t0 .Lhigher_half: /* We are now running at virtual addresses (0xFFFFFFC0...) ! * The identity map is still active but will be removed by vmm_init(). */ - /* ---- 6.4: Reload sp with virtual address ---- */ - /* Boot stack was set up using physical-linked VA already (linker placed - * boot_stack in higher-half), so sp is valid. Reload gp just in case. */ + /* ---- 6.4: Fix sp and gp to virtual addresses ---- */ + /* sp was set up before MMU using PC-relative `la`, so it holds a + * physical address. Add PAGE_OFFSET to convert to higher-half VA. + * gp is similarly reloaded — now that PC is at VA, `la` resolves + * correctly via PC-relative addressing. */ + li t0, PAGE_OFFSET + add sp, sp, t0 .option push .option norelax la gp, __global_pointer$ |