On Wed, 2006-05-24 at 18:56 -0400, Vivek Goyal wrote: > On Wed, May 24, 2006 at 01:40:31PM +0900, Magnus Damm wrote: > > kexec: Avoid overwriting the current pgd (V2) > > > > This patch updates the kexec code for i386 and x86_64 to avoid overwriting > > the current pgd. For most people is overwriting the current pgd is not a big > > problem. When kexec:ing into a new kernel that reinitializes and makes use > > of > > all memory we don't care about saving state. > > > > But overwriting the current pgd is not a good solution in the case of kdump > > (CONFIG_CRASH_DUMP) where we want to preserve as much state as possible > > when > > a crash occurs. This patch solves the overwriting issue. > > > > 20060524: V2 > > > > - Broke out architecture-specific data structures into asm/kexec.h > > - Fixed a i386/PAE page table problem only triggering on real hardware. > > - Moved segment handling code into the assembly routines. > > What's the advantage of moving segment handling code into assembly > routines? It will only add to the fear of control code page size growing > beyond 4K.
I have two main reasons: - Why wrap assembler instructions in C code if you just can move them into an already existing assembly file? Much cleaner IMO. - I'm currently working on making kexec to work under xen/dom0. And by moving the segment handling code into the assembly file we reduce the amount of duplicated code. I was concerned about the size of the assembly code too and I just re-checked with my patches applied: i386: 300 / 4096 bytes used x86_64: 364 / 4096 bytes used I'd say we have more than enough space! Thanks, / magnus _______________________________________________ fastboot mailing list [email protected] https://lists.osdl.org/mailman/listinfo/fastboot
