Merge tag 'v5.0-rc7' into patchwork

Linux 5.0-rc7

* tag 'v5.0-rc7': (1667 commits)
  Linux 5.0-rc7
  Input: elan_i2c - add ACPI ID for touchpad in Lenovo V330-15ISK
  Input: st-keyscan - fix potential zalloc NULL dereference
  Input: apanel - switch to using brightness_set_blocking()
  powerpc/64s: Fix possible corruption on big endian due to pgd/pud_present()
  efi/arm: Revert "Defer persistent reservations until after paging_init()"
  arm64, mm, efi: Account for GICv3 LPI tables in static memblock reserve table
  sunrpc: fix 4 more call sites that were using stack memory with a scatterlist
  include/linux/module.h: copy __init/__exit attrs to init/cleanup_module
  Compiler Attributes: add support for __copy (gcc >= 9)
  lib/crc32.c: mark crc32_le_base/__crc32c_le_base aliases as __pure
  auxdisplay: ht16k33: fix potential user-after-free on module unload
  x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls
  i2c: bcm2835: Clear current buffer pointers and counts after a transfer
  i2c: cadence: Fix the hold bit setting
  drm: Use array_size() when creating lease
  dm thin: fix bug where bio that overwrites thin block ignores FUA
  Revert "exec: load_script: don't blindly truncate shebang string"
  Revert "gfs2: read journal in large chunks to locate the head"
  net: ethernet: freescale: set FEC ethtool regs version
  ...

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 7689c7aa1d77..3e8063f4f9d3 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -16,6 +16,8 @@
 #ifndef __ASM_MMU_H
 #define __ASM_MMU_H
 
+#include <asm/cputype.h>
+
 #define MMCF_AARCH32	0x1	/* mm context flag for AArch32 executables */
 #define USER_ASID_BIT	48
 #define USER_ASID_FLAG	(UL(1) << USER_ASID_BIT)
@@ -44,6 +46,48 @@ static inline bool arm64_kernel_unmapped_at_el0(void)
 	       cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0);
 }
 
+static inline bool arm64_kernel_use_ng_mappings(void)
+{
+	bool tx1_bug;
+
+	/* What's a kpti? Use global mappings if we don't know. */
+	if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0))
+		return false;
+
+	/*
+	 * Note: this function is called before the CPU capabilities have
+	 * been configured, so our early mappings will be global. If we
+	 * later determine that kpti is required, then
+	 * kpti_install_ng_mappings() will make them non-global.
+	 */
+	if (arm64_kernel_unmapped_at_el0())
+		return true;
+
+	if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
+		return false;
+
+	/*
+	 * KASLR is enabled so we're going to be enabling kpti on non-broken
+	 * CPUs regardless of their susceptibility to Meltdown. Rather
+	 * than force everybody to go through the G -> nG dance later on,
+	 * just put down non-global mappings from the beginning.
+	 */
+	if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
+		tx1_bug = false;
+#ifndef MODULE
+	} else if (!static_branch_likely(&arm64_const_caps_ready)) {
+		extern const struct midr_range cavium_erratum_27456_cpus[];
+
+		tx1_bug = is_midr_in_range_list(read_cpuid_id(),
+						cavium_erratum_27456_cpus);
+#endif
+	} else {
+		tx1_bug = __cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456);
+	}
+
+	return !tx1_bug && kaslr_offset() > 0;
+}
+
 typedef void (*bp_hardening_cb_t)(void);
 
 struct bp_hardening_data {