I've been working through these changes in BBL and the elfloader. The BBL as
mentioned seems to be easy (though I'm not ruling out issues here). The
elfloader is a little more problematic. I have made some modifications there,
but they result in a lot of page table entries that seems erroneous. At the
point where the virtual memory translations are committed (writing to satp
register) it hangs and cannot access memory at the next instruction's address.
Here is what I've done to map_kernel_window in boot.c of the elfloader:
#define NEW_PT_LEVEL_2_BITS = 17 //instead of 21
65 void map_kernel_window(struct image_info *kernel_info)
66 {
67 uint32_t index;
68 unsigned long *lpt;
69
70 /* Map the elfloader into the new address space */
71 printf("_text: %x\n", (uintptr_t)_text);
72 index = GET_PT_INDEX((uintptr_t)_text, PT_LEVEL_1);
73 printf("73 index: %x\n", index);
74
75 #if __riscv_xlen == 32
76 lpt = l1pt;
77 #else
78 lpt = l2pt_elf;
79 l1pt[index] = PTE_CREATE_NEXT((uintptr_t)l2pt_elf);
80 index = GET_PT_INDEX((uintptr_t)_text, PT_LEVEL_2);
81 printf("81 index: %x\n", index);
82 #endif
83
84 if (IS_ALIGNED((uintptr_t)_text, NEW_PT_LEVEL_2_BITS)) {
85 for (int page = 0; index < PTES_PER_PT; index++, page++) {
86 lpt[index] = PTE_CREATE_LEAF((uintptr_t)_text +
87 (page << NEW_PT_LEVEL_2_BITS));
88 printf("_text: %x\n", (uintptr_t)_text);
89 printf("lpt[index]: %x\n", lpt[index]);
90 printf("page: %x\n", page);
91 printf("index: %x\n", index);
92 }
93 } else {
94 printf("Elfloader not properly aligned\n");
95 abort();
96 }
97
98 /* Map the kernel into the new address space */
99 printf("kernel_info->virt_region_start: %x\n",
kernel_info->virt_region_start);
100 index = GET_PT_INDEX(kernel_info->virt_region_start, PT_LEVEL_1);
101 printf("101 index: %x\n", index);
102
103 #if __riscv_xlen == 64
104 lpt = l2pt;
105 l1pt[index] = PTE_CREATE_NEXT((uintptr_t)l2pt);
106 index = GET_PT_INDEX(kernel_info->virt_region_start, PT_LEVEL_2);
107 printf("107 index: %x\n", index);
108 #endif
109 if (VIRT_PHYS_ALIGNED(kernel_info->virt_region_start,
110 kernel_info->phys_region_start,
NEW_PT_LEVEL_2_BITS)) {
111 for (int page = 0; index < PTES_PER_PT; index++, page++) {
112 lpt[index] = PTE_CREATE_LEAF(kernel_info->phys_region_start +
113 (page << NEW_PT_LEVEL_2_BITS));
114 printf("kernel_info->virt_region_start: %x\n",
kernel_info->virt_region_start);
115 printf("lpt[index]: %x\n", lpt[index]);
116 printf("page: %x\n", page);
117 printf("117 index: %x\n", index);
118 }
119 } else {
120 printf("Kernel not properly aligned\n");
121 abort();
122 }
123 printf("l1pt: %x\n", l1pt);
124 }
Can anyone see what I've done wrong here?
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