On Sat, 2 Aug 2003, David Xu wrote: > On Saturday 02 August 2003 06:24, Munish Chopra wrote: > > On 2003-08-02 00:20 +0200, Thorsten Greiner wrote: > > > * Daniel Eischen <eischen_at_vigrid.com> [2003-08-02 00:06]: > > > > I think the bug was in the old code allowing this to > > > > happen... > > > > > > Well, than someone should tell that to NVidia. Their driver is > > > closed source and comes without "user servicable parts". > > > > > > Regards > > > -Thorsten > > > > That's going to be a lot easier to get through if someone can confirm > > whether 0-16 are reserved, or whether (like julian says), 6-15 are > > actually safe and something else is being clobbered. > > #define LSYS5CALLS_SEL 0 /* forced by intel BCS */ > #define LSYS5SIGR_SEL 1 > #define L43BSDCALLS_SEL 2 /* notyet */ > #define LUCODE_SEL 3 > #define LSOL26CALLS_SEL 4 /* Solaris >= 2.6 system call gate */ > #define LUDATA_SEL 5 > /* separate stack, es,fs,gs sels ? */ > /* #define LPOSIXCALLS_SEL 5*/ /* notyet */ > #define LBSDICALLS_SEL 16 /* BSDI system call gate */ > #define NLDT (LBSDICALLS_SEL + 1) > > LUCODE_SEL is used by kernel to load _ucodesel to user %cs > LUDATA_SEL is used by kernel to load _udatasel to user %ds, %es, %fs, %gs. > I didn't check other ABIs, but setting to a fixed location of LDT in userland > is also a bad idea, I think it will conflict with thread library soon, > it is better to use dynamic allocating facility newly added in i386_set_ldt. Perhaps we need to rethink the interface and disallow specification of any ldt; only allow dynamic. We would need a different method of setting an array of them, though. -- Dan EischenReceived on Fri Aug 01 2003 - 13:51:36 UTC
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