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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2018-02-14 21:25:42 +0300
committerIngo Molnar <mingo@kernel.org>2018-02-16 12:48:49 +0300
commit6657fca06e3ffab8d0b3f9d8b397f5ee498952d7 (patch)
tree974d247b3c7459a2d595cc837d69ab84f57913a5 /arch/x86/boot/compressed/misc.c
parent91f606a8fa68264224cbc76888fa8649cdbe9990 (diff)
downloadlinux-6657fca06e3ffab8d0b3f9d8b397f5ee498952d7.tar.xz
x86/mm: Allow to boot without LA57 if CONFIG_X86_5LEVEL=y
All pieces of the puzzle are in place and we can now allow to boot with CONFIG_X86_5LEVEL=y on a machine without LA57 support. Kernel will detect that LA57 is missing and fold p4d at runtime. Update the documentation and the Kconfig option description to reflect the change. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180214182542.69302-10-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/boot/compressed/misc.c')
-rw-r--r--arch/x86/boot/compressed/misc.c16
1 files changed, 0 insertions, 16 deletions
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 98761a1576ce..b50c42455e25 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -169,16 +169,6 @@ void __puthex(unsigned long value)
}
}
-static bool l5_supported(void)
-{
- /* Check if leaf 7 is supported. */
- if (native_cpuid_eax(0) < 7)
- return 0;
-
- /* Check if la57 is supported. */
- return native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31));
-}
-
#if CONFIG_X86_NEED_RELOCS
static void handle_relocations(void *output, unsigned long output_len,
unsigned long virt_addr)
@@ -372,12 +362,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
console_init();
debug_putstr("early console in extract_kernel\n");
- if (IS_ENABLED(CONFIG_X86_5LEVEL) && !l5_supported()) {
- error("This linux kernel as configured requires 5-level paging\n"
- "This CPU does not support the required 'cr4.la57' feature\n"
- "Unable to boot - please use a kernel appropriate for your CPU\n");
- }
-
free_mem_ptr = heap; /* Heap */
free_mem_end_ptr = heap + BOOT_HEAP_SIZE;