maxv c4cd7f0720 There is an issue in the way the direct map is set up on amd64. ... When allocating memory, the kernel allocates physical pages and virtual addresses for these pages. In order to optimize allocations smaller than PAGE_SIZE, uvm_km_kmem_alloc can allocate a single physical page and take its virtual address in the direct map in high virtual memory. This direct map is set up at boot time, its PTEs do not change, and therefore they don't need to be kentered. These high virtual PTEs being constant, the permissions of the areas they point to are fixed at boot time and cannot change. The problem is that at boot time, they are created with RWX permissions. Therefore, allocations smaller than PAGE_SIZE in the kernel heap are all executable: mbufs, pnbufs, small kmem allocations, etc. Fix this by setting the NOX bit in the direct map pages at boot time. We also set the NOX bit in the temporary tmpva, since it does not need to be executable either. This also makes the U-area non executable on amd64.		2016-05-21 07:15:56 +00:00
..
acpi	Fix build break.	2016-01-28 23:50:04 +00:00
conf	Add cpu_rng, a framework for simple on-CPU random number generators.	2016-02-27 00:09:44 +00:00
include	Add some bit definitions mainly taken from the latest Intel SDM:	2016-04-27 08:51:32 +00:00
isa	add intr_handle_t and let pci_intr_handle_t use it.	2015-04-27 06:51:40 +00:00
pci	Introduce softint-based if_input	2016-02-09 08:32:07 +00:00
x86	There is an issue in the way the direct map is set up on amd64.	2016-05-21 07:15:56 +00:00