Merge remote-tracking branch 'origin/master' into perf/core

Further perf/core patches will depend on:

  d3f7b1bb2040 ("mm/gup: fix gup_fast with dynamic page table folding")

which is already in Linus' tree.

1 files changed, 17 insertions, 10 deletions

diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c
index c8862696a47b..2a78746f5a4c 100644
--- a/arch/x86/boot/compressed/pgtable_64.c
+++ b/arch/x86/boot/compressed/pgtable_64.c
@@ -5,18 +5,16 @@
 #include "pgtable.h"
 #include "../string.h"
 
-/*
- * __force_order is used by special_insns.h asm code to force instruction
- * serialization.
- *
- * It is not referenced from the code, but GCC < 5 with -fPIE would fail
- * due to an undefined symbol. Define it to make these ancient GCCs work.
- */
-unsigned long __force_order;
-
 #define BIOS_START_MIN		0x20000U	/* 128K, less than this is insane */
 #define BIOS_START_MAX		0x9f000U	/* 640K, absolute maximum */
 
+#ifdef CONFIG_X86_5LEVEL
+/* __pgtable_l5_enabled needs to be in .data to avoid being cleared along with .bss */
+unsigned int __section(".data") __pgtable_l5_enabled;
+unsigned int __section(".data") pgdir_shift = 39;
+unsigned int __section(".data") ptrs_per_p4d = 1;
+#endif
+
 struct paging_config {
 	unsigned long trampoline_start;
 	unsigned long l5_required;
@@ -32,7 +30,7 @@ static char trampoline_save[TRAMPOLINE_32BIT_SIZE];
  * Avoid putting the pointer into .bss as it will be cleared between
  * paging_prepare() and extract_kernel().
  */
-unsigned long *trampoline_32bit __section(.data);
+unsigned long *trampoline_32bit __section(".data");
 
 extern struct boot_params *boot_params;
 int cmdline_find_option_bool(const char *option);
@@ -207,4 +205,13 @@ void cleanup_trampoline(void *pgtable)
 
 	/* Restore trampoline memory */
 	memcpy(trampoline_32bit, trampoline_save, TRAMPOLINE_32BIT_SIZE);
+
+	/* Initialize variables for 5-level paging */
+#ifdef CONFIG_X86_5LEVEL
+	if (__read_cr4() & X86_CR4_LA57) {
+		__pgtable_l5_enabled = 1;
+		pgdir_shift = 48;
+		ptrs_per_p4d = 512;
+	}
+#endif
 }