Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 "A sizeable pile of arm64 updates for 5.8.

  Summary below, but the big two features are support for Branch Target
  Identification and Clang's Shadow Call stack. The latter is currently
  arm64-only, but the high-level parts are all in core code so it could
  easily be adopted by other architectures pending toolchain support

  Branch Target Identification (BTI):

   - Support for ARMv8.5-BTI in both user- and kernel-space. This allows
     branch targets to limit the types of branch from which they can be
     called and additionally prevents branching to arbitrary code,
     although kernel support requires a very recent toolchain.

   - Function annotation via SYM_FUNC_START() so that assembly functions
     are wrapped with the relevant "landing pad" instructions.

   - BPF and vDSO updates to use the new instructions.

   - Addition of a new HWCAP and exposure of BTI capability to userspace
     via ID register emulation, along with ELF loader support for the
     BTI feature in .note.gnu.property.

   - Non-critical fixes to CFI unwind annotations in the sigreturn
     trampoline.

  Shadow Call Stack (SCS):

   - Support for Clang's Shadow Call Stack feature, which reserves
     platform register x18 to point at a separate stack for each task
     that holds only return addresses. This protects function return
     control flow from buffer overruns on the main stack.

   - Save/restore of x18 across problematic boundaries (user-mode,
     hypervisor, EFI, suspend, etc).

   - Core support for SCS, should other architectures want to use it
     too.

   - SCS overflow checking on context-switch as part of the existing
     stack limit check if CONFIG_SCHED_STACK_END_CHECK=y.

  CPU feature detection:

   - Removed numerous "SANITY CHECK" errors when running on a system
     with mismatched AArch32 support at EL1. This is primarily a concern
     for KVM, which disabled support for 32-bit guests on such a system.

   - Addition of new ID registers and fields as the architecture has
     been extended.

  Perf and PMU drivers:

   - Minor fixes and cleanups to system PMU drivers.

  Hardware errata:

   - Unify KVM workarounds for VHE and nVHE configurations.

   - Sort vendor errata entries in Kconfig.

  Secure Monitor Call Calling Convention (SMCCC):

   - Update to the latest specification from Arm (v1.2).

   - Allow PSCI code to query the SMCCC version.

  Software Delegated Exception Interface (SDEI):

   - Unexport a bunch of unused symbols.

   - Minor fixes to handling of firmware data.

  Pointer authentication:

   - Add support for dumping the kernel PAC mask in vmcoreinfo so that
     the stack can be unwound by tools such as kdump.

   - Simplification of key initialisation during CPU bringup.

  BPF backend:

   - Improve immediate generation for logical and add/sub instructions.

  vDSO:

   - Minor fixes to the linker flags for consistency with other
     architectures and support for LLVM's unwinder.

   - Clean up logic to initialise and map the vDSO into userspace.

  ACPI:

   - Work around for an ambiguity in the IORT specification relating to
     the "num_ids" field.

   - Support _DMA method for all named components rather than only PCIe
     root complexes.

   - Minor other IORT-related fixes.

  Miscellaneous:

   - Initialise debug traps early for KGDB and fix KDB cacheflushing
     deadlock.

   - Minor tweaks to early boot state (documentation update, set
     TEXT_OFFSET to 0x0, increase alignment of PE/COFF sections).

   - Refactoring and cleanup"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits)
  KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h
  KVM: arm64: Check advertised Stage-2 page size capability
  arm64/cpufeature: Add get_arm64_ftr_reg_nowarn()
  ACPI/IORT: Remove the unused __get_pci_rid()
  arm64/cpuinfo: Add ID_MMFR4_EL1 into the cpuinfo_arm64 context
  arm64/cpufeature: Add remaining feature bits in ID_AA64PFR1 register
  arm64/cpufeature: Add remaining feature bits in ID_AA64PFR0 register
  arm64/cpufeature: Add remaining feature bits in ID_AA64ISAR0 register
  arm64/cpufeature: Add remaining feature bits in ID_MMFR4 register
  arm64/cpufeature: Add remaining feature bits in ID_PFR0 register
  arm64/cpufeature: Introduce ID_MMFR5 CPU register
  arm64/cpufeature: Introduce ID_DFR1 CPU register
  arm64/cpufeature: Introduce ID_PFR2 CPU register
  arm64/cpufeature: Make doublelock a signed feature in ID_AA64DFR0
  arm64/cpufeature: Drop TraceFilt feature exposure from ID_DFR0 register
  arm64/cpufeature: Add explicit ftr_id_isar0[] for ID_ISAR0 register
  arm64: mm: Add asid_gen_match() helper
  firmware: smccc: Fix missing prototype warning for arm_smccc_version_init
  arm64: vdso: Fix CFI directives in sigreturn trampoline
  arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
  ...

8 files changed, 83 insertions, 49 deletions

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 8007d4aa76dc..4843e94713a4 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -295,15 +295,13 @@ config TURRIS_MOX_RWTM
 	  other manufacturing data and also utilize the Entropy Bit Generator
 	  for hardware random number generation.
 
-config HAVE_ARM_SMCCC
-	bool
-
-source "drivers/firmware/psci/Kconfig"
 source "drivers/firmware/broadcom/Kconfig"
 source "drivers/firmware/google/Kconfig"
 source "drivers/firmware/efi/Kconfig"
 source "drivers/firmware/imx/Kconfig"
 source "drivers/firmware/meson/Kconfig"
+source "drivers/firmware/psci/Kconfig"
+source "drivers/firmware/smccc/Kconfig"
 source "drivers/firmware/tegra/Kconfig"
 source "drivers/firmware/xilinx/Kconfig"
 
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index e9fb838af4df..99510be9f5ed 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -23,12 +23,13 @@ obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
 obj-$(CONFIG_TURRIS_MOX_RWTM)	+= turris-mox-rwtm.o
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL)	+= arm_scmi/
-obj-y				+= psci/
 obj-y				+= broadcom/
 obj-y				+= meson/
 obj-$(CONFIG_GOOGLE_FIRMWARE)	+= google/
 obj-$(CONFIG_EFI)		+= efi/
 obj-$(CONFIG_UEFI_CPER)		+= efi/
 obj-y				+= imx/
+obj-y				+= psci/
+obj-y				+= smccc/
 obj-y				+= tegra/
 obj-y				+= xilinx/
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index 334c8be0c11f..e7e36aab2386 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -429,7 +429,6 @@ int sdei_event_enable(u32 event_num)
 
 	return err;
 }
-EXPORT_SYMBOL(sdei_event_enable);
 
 static int sdei_api_event_disable(u32 event_num)
 {
@@ -471,7 +470,6 @@ int sdei_event_disable(u32 event_num)
 
 	return err;
 }
-EXPORT_SYMBOL(sdei_event_disable);
 
 static int sdei_api_event_unregister(u32 event_num)
 {
@@ -533,7 +531,6 @@ int sdei_event_unregister(u32 event_num)
 
 	return err;
 }
-EXPORT_SYMBOL(sdei_event_unregister);
 
 /*
  * unregister events, but don't destroy them as they are re-registered by
@@ -643,7 +640,6 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
 
 	return err;
 }
-EXPORT_SYMBOL(sdei_event_register);
 
 static int sdei_reregister_event_llocked(struct sdei_event *event)
 {
@@ -1079,26 +1075,9 @@ static struct platform_driver sdei_driver = {
 	.probe		= sdei_probe,
 };
 
-static bool __init sdei_present_dt(void)
-{
-	struct device_node *np, *fw_np;
-
-	fw_np = of_find_node_by_name(NULL, "firmware");
-	if (!fw_np)
-		return false;
-
-	np = of_find_matching_node(fw_np, sdei_of_match);
-	if (!np)
-		return false;
-	of_node_put(np);
-
-	return true;
-}
-
 static bool __init sdei_present_acpi(void)
 {
 	acpi_status status;
-	struct platform_device *pdev;
 	struct acpi_table_header *sdei_table_header;
 
 	if (acpi_disabled)
@@ -1113,20 +1092,26 @@ static bool __init sdei_present_acpi(void)
 	if (ACPI_FAILURE(status))
 		return false;
 
-	pdev = platform_device_register_simple(sdei_driver.driver.name, 0, NULL,
-					       0);
-	if (IS_ERR(pdev))
-		return false;
+	acpi_put_table(sdei_table_header);
 
 	return true;
 }
 
 static int __init sdei_init(void)
 {
-	if (sdei_present_dt() || sdei_present_acpi())
-		platform_driver_register(&sdei_driver);
+	int ret = platform_driver_register(&sdei_driver);
 
-	return 0;
+	if (!ret && sdei_present_acpi()) {
+		struct platform_device *pdev;
+
+		pdev = platform_device_register_simple(sdei_driver.driver.name,
+						       0, NULL, 0);
+		if (IS_ERR(pdev))
+			pr_info("Failed to register ACPI:SDEI platform device %ld\n",
+				PTR_ERR(pdev));
+	}
+
+	return ret;
 }
 
 /*
@@ -1143,6 +1128,14 @@ int sdei_event_handler(struct pt_regs *regs,
 	mm_segment_t orig_addr_limit;
 	u32 event_num = arg->event_num;
 
+	/*
+	 * Save restore 'fs'.
+	 * The architecture's entry code save/restores 'fs' when taking an
+	 * exception from the kernel. This ensures addr_limit isn't inherited
+	 * if you interrupted something that allowed the uaccess routines to
+	 * access kernel memory.
+	 * Do the same here because this doesn't come via the same entry code.
+	*/
 	orig_addr_limit = get_fs();
 	set_fs(USER_DS);
 
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 034d71663b1e..cce4a7436052 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -33,6 +33,9 @@ KBUILD_CFLAGS			:= $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \
 				   $(call cc-option,-fno-addrsig) \
 				   -D__DISABLE_EXPORTS
 
+# remove SCS flags from all objects in this directory
+KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
+
 GCOV_PROFILE			:= n
 KASAN_SANITIZE			:= n
 UBSAN_SANITIZE			:= n
diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 2937d44b5df4..92013ecc2d9e 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -46,25 +46,14 @@
  * require cooperation with a Trusted OS driver.
  */
 static int resident_cpu = -1;
+struct psci_operations psci_ops;
+static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE;
 
 bool psci_tos_resident_on(int cpu)
 {
 	return cpu == resident_cpu;
 }
 
-struct psci_operations psci_ops = {
-	.conduit = SMCCC_CONDUIT_NONE,
-	.smccc_version = SMCCC_VERSION_1_0,
-};
-
-enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
-{
-	if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
-		return SMCCC_CONDUIT_NONE;
-
-	return psci_ops.conduit;
-}
-
 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
 				unsigned long, unsigned long);
 static psci_fn *invoke_psci_fn;
@@ -242,7 +231,7 @@ static void set_conduit(enum arm_smccc_conduit conduit)
 		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
 	}
 
-	psci_ops.conduit = conduit;
+	psci_conduit = conduit;
 }
 
 static int get_set_conduit_method(struct device_node *np)
@@ -411,8 +400,8 @@ static void __init psci_init_smccc(void)
 	if (feature != PSCI_RET_NOT_SUPPORTED) {
 		u32 ret;
 		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
-		if (ret == ARM_SMCCC_VERSION_1_1) {
-			psci_ops.smccc_version = SMCCC_VERSION_1_1;
+		if (ret >= ARM_SMCCC_VERSION_1_1) {
+			arm_smccc_version_init(ret, psci_conduit);
 			ver = ret;
 		}
 	}
diff --git a/drivers/firmware/smccc/Kconfig b/drivers/firmware/smccc/Kconfig
new file mode 100644
index 000000000000..27b675d76235
--- /dev/null
+++ b/drivers/firmware/smccc/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config HAVE_ARM_SMCCC
+	bool
+	help
+	  Include support for the Secure Monitor Call (SMC) and Hypervisor
+	  Call (HVC) instructions on Armv7 and above architectures.
+
+config HAVE_ARM_SMCCC_DISCOVERY
+	bool
+	depends on ARM_PSCI_FW
+	default y
+	help
+	 SMCCC v1.0 lacked discoverability and hence PSCI v1.0 was updated
+	 to add SMCCC discovery mechanism though the PSCI firmware
+	 implementation of PSCI_FEATURES(SMCCC_VERSION) which returns
+	 success on firmware compliant to SMCCC v1.1 and above.
diff --git a/drivers/firmware/smccc/Makefile b/drivers/firmware/smccc/Makefile
new file mode 100644
index 000000000000..6f369fe3f0b9
--- /dev/null
+++ b/drivers/firmware/smccc/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+obj-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY)	+= smccc.o
diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c
new file mode 100644
index 000000000000..4e80921ee212
--- /dev/null
+++ b/drivers/firmware/smccc/smccc.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Arm Limited
+ */
+
+#define pr_fmt(fmt) "smccc: " fmt
+
+#include <linux/init.h>
+#include <linux/arm-smccc.h>
+
+static u32 smccc_version = ARM_SMCCC_VERSION_1_0;
+static enum arm_smccc_conduit smccc_conduit = SMCCC_CONDUIT_NONE;
+
+void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit)
+{
+	smccc_version = version;
+	smccc_conduit = conduit;
+}
+
+enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
+{
+	if (smccc_version < ARM_SMCCC_VERSION_1_1)
+		return SMCCC_CONDUIT_NONE;
+
+	return smccc_conduit;
+}
+
+u32 arm_smccc_get_version(void)
+{
+	return smccc_version;
+}