Merge 4.9.306 into android-4.9-q

Changes in 4.9.306
	x86/speculation: Add RETPOLINE_AMD support to the inline asm CALL_NOSPEC variant
	x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support
	x86/retpoline: Remove minimal retpoline support
	Documentation: Add section about CPU vulnerabilities for Spectre
	Documentation: Add swapgs description to the Spectre v1 documentation
	Documentation: refer to config RANDOMIZE_BASE for kernel address-space randomization
	x86/speculation: Merge one test in spectre_v2_user_select_mitigation()
	x86,bugs: Unconditionally allow spectre_v2=retpoline,amd
	x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE
	x86/speculation: Add eIBRS + Retpoline options
	Documentation/hw-vuln: Update spectre doc
	x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting
	x86/speculation: Use generic retpoline by default on AMD
	x86/speculation: Update link to AMD speculation whitepaper
	x86/speculation: Warn about Spectre v2 LFENCE mitigation
	x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT
	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
	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
	x86/build: Fix compiler support check for CONFIG_RETPOLINE
	x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE
	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/gnttab: fix gnttab_end_foreign_access() without page specified
	xen/netfront: react properly to failing gnttab_end_foreign_access_ref()
	Linux 4.9.306

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I8083a622bda3bf4418f266a34c96d8175bc5e933