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Make the ELF entry point a physical address

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This way, the bootloader doesn't have to translate the entry point.
This also makes xv6 multiboot-compliant and follows the convention
used by Linux.
This commit is contained in:
Austin Clements 2011-09-04 15:51:46 -04:00
parent 68b5872716
commit 2fc6c35b2f
2 changed files with 8 additions and 7 deletions
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2
bootmain.c
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@ -43,7 +43,7 @@ bootmain(void)
// Call the entry point from the ELF header. // Call the entry point from the ELF header.
// Does not return! // Does not return!
entry = (void(*)(void))(elf->entry - KERNBASE); entry = (void(*)(void))(elf->entry);
entry(); entry();
} }

13
entry.S
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@ -25,15 +25,16 @@
.globl multiboot_header .globl multiboot_header
multiboot_header: multiboot_header:
#define magic 0x1badb002 #define magic 0x1badb002
#define flags (1<<16 | 1<<0) #define flags 0
.long magic .long magic
.long flags .long flags
.long (-magic-flags) .long (-magic-flags)
.long multiboot_header # beginning of image
.long multiboot_header # By convention, the _start symbol specifies the ELF entry point.
.long edata # Since we haven't set up virtual memory yet, our entry point is
.long end # the physical address of 'entry'.
.long entry .globl _start
_start = V2P_WO(entry)
# Entering xv6 on boot processor. Machine is mostly set up. # Entering xv6 on boot processor. Machine is mostly set up.
.globl entry .globl entry