gpu: nvgpu: prevent crash during unbind

This change solves crashes during bind that were introduced in the driver
during the OS unification refactoring due to lack of coverage of the remove()
function.

The fixes during remove are:

(1) Prevent NULL dereference on GPUs with secure boot
(2) Prevent NULL dereferences when fecs_trace is not enabled
(3) Added PRAMIN blocker during driver removal if HW is no longer accesible
(4) Prevent double free of debugfs nodes as they are handled on the
debugfs_remove_recursive() call
(5) quiesce() can now be called without checking is HW accesible flag is set
(6) added function to free irq so no IRQ association is left on the driver after
it is removed
(7) prevent NULL dereference on nvgpu_thread_stop() if the thread is already
stopped

JIRA: EVLR-1739

Change-Id: I787d38f202d5267a6b34815f23e1bc88110e8455
Signed-off-by: David Nieto <dmartineznie@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1563005
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/common/pramin.c b/drivers/gpu/nvgpu/common/pramin.c
index ae9c9b1f..7955e6c2 100644
--- a/drivers/gpu/nvgpu/common/pramin.c
+++ b/drivers/gpu/nvgpu/common/pramin.c
@@ -16,6 +16,7 @@
 
 #include <nvgpu/pramin.h>
 #include <nvgpu/page_allocator.h>
+#include <nvgpu/enabled.h>
 
 #include "gk20a/gk20a.h"
 
@@ -88,6 +89,14 @@ void nvgpu_pramin_access_batched(struct gk20a *g, struct nvgpu_mem *mem,
         void *sgl;
         u32 byteoff, start_reg, until_end, n;
 
+        /*
+         * TODO: Vidmem is not accesible through pramin on shutdown path.
+         * driver should be refactored to prevent this from happening, but for
+         * now it is ok just to ignore the writes
+         */
+        if (!g->regs && nvgpu_is_enabled(g, NVGPU_DRIVER_IS_DYING))
+                return;
+
         alloc = get_vidmem_page_alloc(mem->priv.sgt->sgl);
         sgt = &alloc->sgt;
         for (sgl = sgt->sgl; sgl; sgl = nvgpu_sgt_get_next(sgt, sgl)) {