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HELLO: Zero out HULK bss section

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This commit is contained in:
Josh Holtrop 2022-03-25 11:53:01 -04:00
parent 37d5621e41
commit 0568a813f2
1 changed files with 45 additions and 6 deletions
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51
src/hello/hello.d
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@ -16,6 +16,7 @@ __gshared EFI_SYSTEM_TABLE * st;
private __gshared BootInfo bootinfo; private __gshared BootInfo bootinfo;
private __gshared UINTN memory_map_key; private __gshared UINTN memory_map_key;
extern extern(C) __gshared ubyte hulk_bin_start; extern extern(C) __gshared ubyte hulk_bin_start;
extern extern(C) __gshared ubyte hulk_bin_end;
/** /**
* Detect if we're running in QEMU. * Detect if we're running in QEMU.
@ -229,6 +230,31 @@ private void map2m(ulong source_page, ulong dest_page, PageTableEntry * pt_base)
} }
} }
/**
* Allocate a memory region for the HULK bss section.
*
* @param bss_size Size of the HULK bss section.
*
* @return Physical memory address.
*/
private ulong alloc_hulk_bss(size_t bss_size)
{
for (size_t i = 0u; i < bootinfo.memory_map_count; i++)
{
if ((bootinfo.memory_map[i].type == EfiConventionalMemory) &&
(bootinfo.memory_map[i].size >= bss_size))
{
memset64(cast(void *)bootinfo.memory_map[i].base, 0u, bss_size / 8u);
return bootinfo.memory_map[i].base;
}
}
/* We failed to find free memory. */
for (;;)
{
}
}
/** /**
* Map HULK virtual addresses to physical kernel location. * Map HULK virtual addresses to physical kernel location.
* *
@ -237,14 +263,27 @@ private void map2m(ulong source_page, ulong dest_page, PageTableEntry * pt_base)
private void map_hulk(PageTableEntry * pt_base) private void map_hulk(PageTableEntry * pt_base)
{ {
ulong virt = HULK_VIRTUAL_START; ulong virt = HULK_VIRTUAL_START;
ulong phys = cast(ulong)&hulk_bin_start; ulong hulk_bin_phys_start = cast(ulong)&hulk_bin_start;
HulkHeader * hulk_header = cast(HulkHeader *)&hulk_bin_start; ulong hulk_bin_phys_end = cast(ulong)&hulk_bin_end;
size_t end_phys = phys + cast(size_t)hulk_header.total_size; ulong phys_iter = hulk_bin_phys_start;
while (phys < end_phys) while (phys_iter < hulk_bin_phys_end)
{ {
map4k(virt, phys, pt_base); map4k(virt, phys_iter, pt_base);
virt += 4096u; virt += 4096u;
phys += 4096u; phys_iter += 4096u;
}
/* Now the binary has been mapped, but the bss section still needs to be
* allocated, zeroed and mapped. */
HulkHeader * hulk_header = cast(HulkHeader *)&hulk_bin_start;
size_t hulk_bin_phys_size = hulk_bin_phys_end - hulk_bin_phys_end;
size_t bss_size = cast(size_t)hulk_header.total_size - hulk_bin_phys_size;
ulong bss_phys = alloc_hulk_bss(bss_size);
ulong bss_phys_end = bss_phys + bss_size;
while (bss_phys < bss_phys_end)
{
map4k(virt, bss_phys, pt_base);
virt += 4096u;
bss_phys += 4096u;
} }
} }