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-rw-r--r--bootmain.c29
1 files changed, 14 insertions, 15 deletions
diff --git a/bootmain.c b/bootmain.c
index 8ba4bd4..14f4ff3 100644
--- a/bootmain.c
+++ b/bootmain.c
@@ -11,7 +11,7 @@
#define SECTSIZE 512
-void readseg(uint, uint, uint);
+void readseg(uchar*, uint, uint);
void
bootmain(void)
@@ -19,32 +19,31 @@ bootmain(void)
struct elfhdr *elf;
struct proghdr *ph, *eph;
void (*entry)(void);
+ uchar* va;
elf = (struct elfhdr*)0x10000; // scratch space
// Read 1st page off disk
- readseg((uint)elf, SECTSIZE*8, 0);
+ readseg((uchar*)elf, 4096, 0);
// Is this an ELF executable?
if(elf->magic != ELF_MAGIC)
- goto bad;
+ return; // let bootasm.S handle error
// Load each program segment (ignores ph flags).
ph = (struct proghdr*)((uchar*)elf + elf->phoff);
eph = ph + elf->phnum;
- for(; ph < eph; ph++)
- readseg(ph->va & 0xFFFFFF, ph->memsz, ph->offset);
+ for(; ph < eph; ph++) {
+ va = (uchar*)(ph->va & 0xFFFFFF);
+ readseg(va, ph->filesz, ph->offset);
+ if(ph->memsz > ph->filesz)
+ stosb(va + ph->filesz, 0, ph->memsz - ph->filesz);
+ }
// Call the entry point from the ELF header.
// Does not return!
entry = (void(*)(void))(elf->entry & 0xFFFFFF);
entry();
-
-bad:
- outw(0x8A00, 0x8A00);
- outw(0x8A00, 0x8E00);
- for(;;)
- ;
}
void
@@ -76,14 +75,14 @@ readsect(void *dst, uint offset)
// Read 'count' bytes at 'offset' from kernel into virtual address 'va'.
// Might copy more than asked.
void
-readseg(uint va, uint count, uint offset)
+readseg(uchar* va, uint count, uint offset)
{
- uint eva;
+ uchar* eva;
eva = va + count;
// Round down to sector boundary.
- va &= ~(SECTSIZE - 1);
+ va -= offset % SECTSIZE;
// Translate from bytes to sectors; kernel starts at sector 1.
offset = (offset / SECTSIZE) + 1;
@@ -92,5 +91,5 @@ readseg(uint va, uint count, uint offset)
// We'd write more to memory than asked, but it doesn't matter --
// we load in increasing order.
for(; va < eva; va += SECTSIZE, offset++)
- readsect((uchar*)va, offset);
+ readsect(va, offset);
}