arm64 fixes for -rc3

- Fix broken kpti page-table rewrite in bizarre KASLR configuration
 
 - Fix module loading with KASLR
 
 - Remove redundant definition of ARCH_SLAB_MINALIGN
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Will Deacon:
 "Three arm64 fixes for -rc3.

  We've plugged a couple of nasty issues involving KASLR-enabled
  kernels, and removed a redundant #define that was introduced as part
  of the KHWASAN fixes from akpm at -rc2.

   - Fix broken kpti page-table rewrite in bizarre KASLR configuration

   - Fix module loading with KASLR

   - Remove redundant definition of ARCH_SLAB_MINALIGN"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  kasan, arm64: remove redundant ARCH_SLAB_MINALIGN define
  arm64: kaslr: ensure randomized quantities are clean to the PoC
  arm64: kpti: Update arm64_kernel_use_ng_mappings() when forced on

arch/arm64/include/asm/cache.h

@@ -60,8 +60,6 @@
 
 #ifdef CONFIG_KASAN_SW_TAGS
 #define ARCH_SLAB_MINALIGN	(1ULL << KASAN_SHADOW_SCALE_SHIFT)
-#else
-#define ARCH_SLAB_MINALIGN	__alignof__(unsigned long long)
 #endif
 
 #ifndef __ASSEMBLY__

arch/arm64/include/asm/mmu.h

@@ -60,8 +60,11 @@ static inline bool arm64_kernel_use_ng_mappings(void)
 	 * 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 arm64_kernel_unmapped_at_el0();
+		return false;
 
 	/*
 	 * KASLR is enabled so we're going to be enabling kpti on non-broken

arch/arm64/kernel/kaslr.c

@@ -14,6 +14,7 @@
 #include <linux/sched.h>
 #include <linux/types.h>
 
+#include <asm/cacheflush.h>
 #include <asm/fixmap.h>
 #include <asm/kernel-pgtable.h>
 #include <asm/memory.h>
@@ -43,7 +44,7 @@ static __init u64 get_kaslr_seed(void *fdt)
 	return ret;
 }
 
-static __init const u8 *get_cmdline(void *fdt)
+static __init const u8 *kaslr_get_cmdline(void *fdt)
 {
 	static __initconst const u8 default_cmdline[] = CONFIG_CMDLINE;
 
@@ -109,7 +110,7 @@ u64 __init kaslr_early_init(u64 dt_phys)
 	 * Check if 'nokaslr' appears on the command line, and
 	 * return 0 if that is the case.
 	 */
-	cmdline = get_cmdline(fdt);
+	cmdline = kaslr_get_cmdline(fdt);
 	str = strstr(cmdline, "nokaslr");
 	if (str == cmdline || (str > cmdline && *(str - 1) == ' '))
 		return 0;
@@ -169,5 +170,8 @@ u64 __init kaslr_early_init(u64 dt_phys)
 	module_alloc_base += (module_range * (seed & ((1 << 21) - 1))) >> 21;
 	module_alloc_base &= PAGE_MASK;
 
+	__flush_dcache_area(&module_alloc_base, sizeof(module_alloc_base));
+	__flush_dcache_area(&memstart_offset_seed, sizeof(memstart_offset_seed));
+
 	return offset;
 }