Commit-ID: 4c2b4058ab32581931c2caf760b689fd4b019a87 Gitweb: https://git.kernel.org/tip/4c2b4058ab32581931c2caf760b689fd4b019a87 Author: Kirill A. Shutemov <kirill.shute...@linux.intel.com> AuthorDate: Wed, 14 Feb 2018 21:25:34 +0300 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 16 Feb 2018 10:48:46 +0100
x86/mm: Initialize 'pgtable_l5_enabled' at boot-time 'pgtable_l5_enabled' indicates which paging mode we are using. We need to initialize it at boot-time according to machine capability. Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com> Cc: Andy Lutomirski <l...@kernel.org> Cc: Arjan van de Ven <ar...@linux.intel.com> Cc: Borislav Petkov <b...@suse.de> Cc: Dan Williams <dan.j.willi...@intel.com> Cc: Dave Hansen <dave.han...@linux.intel.com> Cc: David Woodhouse <dw...@infradead.org> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: linux...@kvack.org Link: http://lkml.kernel.org/r/20180214182542.69302-2-kirill.shute...@linux.intel.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/boot/compressed/kaslr.c | 8 +++++++- arch/x86/kernel/head64.c | 24 +++++++++++++++++++++++- 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index b18e8f9..d02a838 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -47,7 +47,7 @@ #include <linux/decompress/mm.h> #ifdef CONFIG_X86_5LEVEL -unsigned int pgtable_l5_enabled __ro_after_init = 1; +unsigned int pgtable_l5_enabled __ro_after_init; unsigned int pgdir_shift __ro_after_init = 48; unsigned int ptrs_per_p4d __ro_after_init = 512; #endif @@ -729,6 +729,12 @@ void choose_random_location(unsigned long input, return; } +#ifdef CONFIG_X86_5LEVEL + if (__read_cr4() & X86_CR4_LA57) { + pgtable_l5_enabled = 1; + } +#endif + boot_params->hdr.loadflags |= KASLR_FLAG; /* Prepare to add new identity pagetables on demand. */ diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 98b0ff4..ffb31c5 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -40,7 +40,7 @@ static unsigned int __initdata next_early_pgt; pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); #ifdef CONFIG_X86_5LEVEL -unsigned int pgtable_l5_enabled __ro_after_init = 1; +unsigned int pgtable_l5_enabled __ro_after_init; EXPORT_SYMBOL(pgtable_l5_enabled); unsigned int pgdir_shift __ro_after_init = 48; EXPORT_SYMBOL(pgdir_shift); @@ -64,6 +64,26 @@ static void __head *fixup_pointer(void *ptr, unsigned long physaddr) return ptr - (void *)_text + (void *)physaddr; } +#ifdef CONFIG_X86_5LEVEL +static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr) +{ + return fixup_pointer(ptr, physaddr); +} + +static void __head check_la57_support(unsigned long physaddr) +{ + if (native_cpuid_eax(0) < 7) + return; + + if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) + return; + + *fixup_int(&pgtable_l5_enabled, physaddr) = 1; +} +#else +static void __head check_la57_support(unsigned long physaddr) {} +#endif + unsigned long __head __startup_64(unsigned long physaddr, struct boot_params *bp) { @@ -76,6 +96,8 @@ unsigned long __head __startup_64(unsigned long physaddr, int i; unsigned int *next_pgt_ptr; + check_la57_support(physaddr); + /* Is the address too large? */ if (physaddr >> MAX_PHYSMEM_BITS) for (;;);
