COMBOOT API calls set the carry flag on failure. This was not being propagated because the COMBOOT interrupt handler used iret to return with EFLAGS restored from the stack. This patch uses a far return that discards the stale EFLAGS value from the stack instead.
Reported-by: Geoff Lywood <[email protected]> Signed-off-by: Stefan Hajnoczi <[email protected]> --- This patch has been tested and reviewed in the issue tracker: http://support.etherboot.org/index.php?do=details&task_id=77 src/arch/i386/interface/syslinux/comboot_call.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/src/arch/i386/interface/syslinux/comboot_call.c b/src/arch/i386/interface/syslinux/comboot_call.c index 51a1b6d..2ce39aa 100644 --- a/src/arch/i386/interface/syslinux/comboot_call.c +++ b/src/arch/i386/interface/syslinux/comboot_call.c @@ -669,7 +669,7 @@ void hook_comboot_interrupts ( ) { "pushw %%cs\n\t" "call prot_call\n\t" "addw $4, %%sp\n\t" - "iret\n\t" ) + "lret $2\n\t" ) : : "i" ( int20 ) ); hook_bios_interrupt ( 0x20, ( unsigned int ) int20_wrapper, @@ -681,7 +681,7 @@ void hook_comboot_interrupts ( ) { "pushw %%cs\n\t" "call prot_call\n\t" "addw $4, %%sp\n\t" - "iret\n\t" ) + "lret $2\n\t" ) : : "i" ( int21 ) ); hook_bios_interrupt ( 0x21, ( unsigned int ) int21_wrapper, @@ -693,8 +693,8 @@ void hook_comboot_interrupts ( ) { "pushw %%cs\n\t" "call prot_call\n\t" "addw $4, %%sp\n\t" - "iret\n\t" ) - : : "i" ( int22) ); + "lret $2\n\t" ) + : : "i" ( int22 ) ); hook_bios_interrupt ( 0x22, ( unsigned int ) int22_wrapper, &int22_vector ); -- 1.7.0 _______________________________________________ gPXE-devel mailing list [email protected] http://etherboot.org/mailman/listinfo/gpxe-devel
