Focal update: v5.4.184 upstream stable release

SRU Justification

    Impact:
       The upstream process for stable tree updates is quite similar
       in scope to the Ubuntu SRU process, e.g., each patch has to
       demonstrably fix a bug, and each patch is vetted by upstream
       by originating either directly from a mainline/stable Linux tree or
       a minimally backported form of that patch. The following upstream
       stable patches should be included in the Ubuntu kernel:

       v5.4.184 upstream stable release
       from git://git.kernel.org/

arm/arm64: Provide a wrapper for SMCCC 1.1 calls
arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit()
ARM: report Spectre v2 status through sysfs
ARM: early traps initialisation
ARM: use LOADADDR() to get load address of sections
UBUNTU: [Config] updateconfigs for HARDEN_BRANCH_HISTORY
ARM: Spectre-BHB workaround
ARM: include unprivileged BPF status in Spectre V2 reporting
ARM: fix build error when BPF_SYSCALL is disabled
ARM: fix co-processor register typo
ARM: Do not use NOCROSSREFS directive with ld.lld
ARM: fix build warning in proc-v7-bugs.c
xen/xenbus: don't let xenbus_grant_ring() remove grants in error case
xen/grant-table: add gnttab_try_end_foreign_access()
xen/blkfront: don't use gnttab_query_foreign_access() for mapped status
xen/netfront: don't use gnttab_query_foreign_access() for mapped status
xen/scsifront: don't use gnttab_query_foreign_access() for mapped status
xen/gntalloc: don't use gnttab_query_foreign_access()
xen: remove gnttab_query_foreign_access()
xen/9p: use alloc/free_pages_exact()
xen/pvcalls: use alloc/free_pages_exact()
xen/gnttab: fix gnttab_end_foreign_access() without page specified
xen/netfront: react properly to failing gnttab_end_foreign_access_ref()
Linux 5.4.184
UBUNTU: upstream stable to v5.4.184