gpu: nvgpu: add linux REMAP support

Add REMAP ioctl and accompanying support to the linux nvgpu driver.

REMAP support provides per-page control over sparse VM areas using the
concept of a virtual memory pool.

The REMAP ioctl accepts a list of operations (each a map or unmap) that
modify the VM area pages tracked by the virtual mmemory pool.

Inclusion of REMAP support in the nvgpu build is controlled by the new
CONFIG_NVGPU_REMAP flag.  This flag is enabled by default for linux builds.
A new NVGPU_GPU_FLAGS_SUPPORT_REMAP characteristics flag is added for use
in detecting when REMAP support is available.

When a VM allocation tagged with NVGPU_VM_AREA_ALLOC_SPARSE is made the
base virtual memory pool resources are allocated.  Per-page resources are
later allocated when the NVGPU_AS_IOCTL_REMAP ioctl is issued.  All REMAP
resources are released when the corresponding VM area is freed.

Jira NVGPU-6804

Change-Id: I1f2cdc0c06c1698a62640c1c6fbcb2f9db24a0bc
Signed-off-by: scottl <scottl@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2542178
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>

arch/nvgpu-common.yaml

@@ -675,6 +675,12 @@ mm:
                  include/nvgpu/vm_area.h ]
       deps: [ ]
       tags: unit-testable
+    vm_remap:
+      safe: no
+      sources: [ common/mm/vm_remap.c,
+                 include/nvgpu/vm_remap.h ]
+      deps: [ ]
+      tags: unit-testable
     vm:
       safe: yes
       sources: [ common/mm/vm.c,

arch/nvgpu-linux.yaml

@@ -228,7 +228,8 @@ vgpu:
              os/linux/vgpu/vgpu_linux.h ]
 
 vm:
-  sources: [ os/linux/vm.c ]
+  sources: [ os/linux/vm.c,
+             os/linux/vm_remap.c ]
 
 cic:
   sources: [ os/linux/cic/cic_stub.c ]
@@ -252,7 +253,8 @@ headers:
              include/nvgpu/linux/thread.h,
              include/nvgpu/linux/log.h,
              include/nvgpu/linux/utils.h,
-             include/nvgpu/linux/vm.h ]
+             include/nvgpu/linux/vm.h,
+             include/nvgpu/linux/vm_remap.h ]
 
 # An extra unit to lump all the unclassified Linux files.
 extra:

arch/nvgpu-posix.yaml

@@ -22,6 +22,7 @@ all:
              os/posix/posix-nvgpu_mem.c,
              os/posix/posix-tsg.c,
              os/posix/posix-vm.c,
+             os/posix/posix-vm_remap.c,
              os/posix/soc.c,
              os/posix/bsearch.c,
              os/posix/posix-clk_arb.c,
@@ -51,6 +52,7 @@ headers:
              include/nvgpu/posix/probe.h,
              include/nvgpu/posix/soc_fuse.h,
              include/nvgpu/posix/vm.h,
+             include/nvgpu/posix/posix-vm_remap.h,
              include/nvgpu/posix/posix_vidmem.h,
              include/nvgpu/posix/posix-nvhost.h,
              include/nvgpu/posix/trace_gk20a.h ]