drm/nouveau/gsp: Allocate fwsec-sb at boot

drm/nouveau/gsp: Allocate fwsec-sb at boot

At the moment - the memory allocation for fwsec-sb is created as-needed and
is released after being used. Typically this is at some point well after
driver load, which can cause runtime suspend/resume to initially work on
driver load but then later fail on a machine that has been running for long
enough with sufficiently high enough memory pressure:

  kworker/7:1: page allocation failure: order:5, mode:0xcc0(GFP_KERNEL),
  nodemask=(null),cpuset=/,mems_allowed=0
  CPU: 7 UID: 0 PID: 875159 Comm: kworker/7:1 Not tainted
  6.17.8-300.fc43.x86_64 #1 PREEMPT(lazy)
  Hardware name: SLIMBOOK Executive/Executive, BIOS N.1.10GRU06 02/02/2024
  Workqueue: pm pm_runtime_work
  Call Trace:
   <TASK>
   dump_stack_lvl+0x5d/0x80
   warn_alloc+0x163/0x190
   ? __alloc_pages_direct_compact+0x1b3/0x220
   __alloc_pages_slowpath.constprop.0+0x57a/0xb10
   __alloc_frozen_pages_noprof+0x334/0x350
   __alloc_pages_noprof+0xe/0x20
   __dma_direct_alloc_pages.isra.0+0x1eb/0x330
   dma_direct_alloc_pages+0x3c/0x190
   dma_alloc_pages+0x29/0x130
   nvkm_firmware_ctor+0x1ae/0x280 [nouveau]
   nvkm_falcon_fw_ctor+0x3e/0x60 [nouveau]
   nvkm_gsp_fwsec+0x10e/0x2c0 [nouveau]
   ? sysvec_apic_timer_interrupt+0xe/0x90
   nvkm_gsp_fwsec_sb+0x27/0x70 [nouveau]
   tu102_gsp_fini+0x65/0x110 [nouveau]
   ? ktime_get+0x3c/0xf0
   nvkm_subdev_fini+0x67/0xc0 [nouveau]
   nvkm_device_fini+0x94/0x140 [nouveau]
   nvkm_udevice_fini+0x50/0x70 [nouveau]
   nvkm_object_fini+0xb1/0x140 [nouveau]
   nvkm_object_fini+0x70/0x140 [nouveau]
   ? __pfx_pci_pm_runtime_suspend+0x10/0x10
   nouveau_do_suspend+0xe4/0x170 [nouveau]
   nouveau_pmops_runtime_suspend+0x3e/0xb0 [nouveau]
   pci_pm_runtime_suspend+0x67/0x1a0
   ? __pfx_pci_pm_runtime_suspend+0x10/0x10
   __rpm_callback+0x45/0x1f0
   ? __pfx_pci_pm_runtime_suspend+0x10/0x10
   rpm_callback+0x6d/0x80
   rpm_suspend+0xe5/0x5e0
   ? finish_task_switch.isra.0+0x99/0x2c0
   pm_runtime_work+0x98/0xb0
   process_one_work+0x18f/0x350
   worker_thread+0x25a/0x3a0
   ? __pfx_worker_thread+0x10/0x10
   kthread+0xf9/0x240
   ? __pfx_kthread+0x10/0x10
   ? __pfx_kthread+0x10/0x10
   ret_from_fork+0xf1/0x110
   ? __pfx_kthread+0x10/0x10
   ret_from_fork_asm+0x1a/0x30
   </TASK>

The reason this happens is because the fwsec-sb firmware image only
supports being booted from a contiguous coherent sysmem allocation. If a
system runs into enough memory fragmentation from memory pressure, such as
what can happen on systems with low amounts of memory, this can lead to a
situation where it later becomes impossible to find space for a large
enough contiguous allocation to hold fwsec-sb. This causes us to fail to
boot the firmware image, causing the GPU to fail booting and causing the
driver to fail.

Since this firmware can't use non-contiguous allocations, the best solution
to avoid this issue is to simply allocate the memory for fwsec-sb during
initial driver-load, and reuse the memory allocation when fwsec-sb needs to
be used. We then release the memory allocations on driver unload.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 594766ca3e53 ("drm/nouveau/gsp: move booter handling to GPU-specific code")
Cc: <stable@vger.kernel.org> # v6.16+
Reviewed-by: Timur Tabi <ttabi@nvidia.com>
Link: https://patch.msgid.link/20251202175918.63533-1-lyude@redhat.com