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author | Frans Kaashoek <[email protected]> | 2019-07-19 08:38:51 -0400 |
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committer | Frans Kaashoek <[email protected]> | 2019-07-19 08:38:51 -0400 |
commit | 91566327012cad2ca99df47f9321dfc012d8a7ff (patch) | |
tree | e9cb082d502a9f56857270264bea254149a3318d /mkfs | |
parent | b924e44f06c9c0882a2cffe6c9215b12c5aee2e6 (diff) | |
download | xv6-labs-91566327012cad2ca99df47f9321dfc012d8a7ff.tar.gz xv6-labs-91566327012cad2ca99df47f9321dfc012d8a7ff.tar.bz2 xv6-labs-91566327012cad2ca99df47f9321dfc012d8a7ff.zip |
One way of supporting a guard page below kstack: allocate kstacks in
procinit() and map them high up (below TRAMPOLNE) with an empty
mapping below each stack. Never free a kernel stack.
Another way would be to allocate and map them dynamically, but then we
need to reload page table when switching processes in scheduler()
and/or have a kernel pagetable per proc (if we want k->stack to be the
same virtual address in each process).
One gotcha: kernel addresses are not equal to physical addresses for
stack addresses. A stack address must be translated if we need its
physical address (e.g., virtio passes a stack address to the disk).
Diffstat (limited to 'mkfs')
0 files changed, 0 insertions, 0 deletions