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[pxe] Set %ax to zero on entry to PXE NBP 

This is not strictly an entry requirement, but it does mean that a PXE
NBP returning without setting %ax will appear to have returned
success.
pull/1/head
Michael Brown 2009-02-23 08:43:27 +00:00
parent 6a3f5d6db7
commit 784d3f336e
1 changed files with 10 additions and 9 deletions
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19
src/arch/i386/interface/pxe/pxe_call.c
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@ -433,23 +433,24 @@ void pxe_init_structures ( void ) {
* @ret rc Return status code * @ret rc Return status code
*/ */
int pxe_start_nbp ( void ) { int pxe_start_nbp ( void ) {
int discard_b, discard_c, discard_d; int discard_b, discard_c, discard_d, discard_D;
uint16_t rc; uint16_t rc;
/* Far call to PXE NBP */ /* Far call to PXE NBP */
__asm__ __volatile__ ( REAL_CODE ( "pushw %%cx\n\t" __asm__ __volatile__ ( REAL_CODE ( "movw %%cx, %%es\n\t"
"pushw %%ax\n\t" "pushw %%es\n\t"
"movw %%cx, %%es\n\t" "pushw %%di\n\t"
"sti\n\t" "sti\n\t"
"lcall $0, $0x7c00\n\t" "lcall $0, $0x7c00\n\t"
"addw $4, %%sp\n\t" ) "addw $4, %%sp\n\t" )
: "=a" ( rc ), "=b" ( discard_b ), : "=a" ( rc ), "=b" ( discard_b ),
"=c" ( discard_c ), "=d" ( discard_d ) "=c" ( discard_c ), "=d" ( discard_d ),
: "a" ( __from_text16 ( &ppxe ) ), "=D" ( discard_D )
"b" ( __from_text16 ( &pxenv ) ), : "a" ( 0 ), "b" ( __from_text16 ( &pxenv ) ),
"c" ( rm_cs ), "c" ( rm_cs ),
"d" ( virt_to_phys ( &pxenv ) ) "d" ( virt_to_phys ( &pxenv ) ),
: "esi", "edi", "ebp", "memory" ); "D" ( __from_text16 ( &ppxe ) )
: "esi", "ebp", "memory" );
return rc; return rc;
} }