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author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2018-02-09 17:22:26 +0300 |
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committer | Ingo Molnar <mingo@kernel.org> | 2018-02-11 12:36:18 +0100 |
commit | 4440977be1347d43503f381716e4918413b5a6f0 (patch) | |
tree | 2acb2738b14afa7887d4df31774fdc5c2efe6d25 /arch/x86/boot/compressed | |
parent | 7cc4eb1bdd8b082f3d889daccd9412aa10e56165 (diff) | |
download | op-kernel-dev-4440977be1347d43503f381716e4918413b5a6f0.zip op-kernel-dev-4440977be1347d43503f381716e4918413b5a6f0.tar.gz |
x86/boot/compressed/64: Introduce paging_prepare()
Rename l5_paging_required() to paging_prepare() and change the
interface of the function.
This is a preparation for the next patch, which would make the function
also allocate memory for the 32-bit trampoline.
The function now returns a 128-bit structure. RAX would return
trampoline memory address (zero for now) and RDX would indicate if we
need to enable 5-level paging.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
[ Typo fixes and general clarification. ]
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180209142228.21231-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/boot/compressed')
-rw-r--r-- | arch/x86/boot/compressed/head_64.S | 41 | ||||
-rw-r--r-- | arch/x86/boot/compressed/pgtable_64.c | 25 |
2 files changed, 31 insertions, 35 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index fc313e2..d598d65 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -304,20 +304,6 @@ ENTRY(startup_64) /* Set up the stack */ leaq boot_stack_end(%rbx), %rsp -#ifdef CONFIG_X86_5LEVEL - /* - * Check if we need to enable 5-level paging. - * RSI holds real mode data and need to be preserved across - * a function call. - */ - pushq %rsi - call l5_paging_required - popq %rsi - - /* If l5_paging_required() returned zero, we're done here. */ - cmpq $0, %rax - je lvl5 - /* * At this point we are in long mode with 4-level paging enabled, * but we want to enable 5-level paging. @@ -325,12 +311,28 @@ ENTRY(startup_64) * The problem is that we cannot do it directly. Setting LA57 in * long mode would trigger #GP. So we need to switch off long mode * first. + */ + + /* + * paging_prepare() sets up the trampoline and checks if we need to + * enable 5-level paging. * - * NOTE: This is not going to work if bootloader put us above 4G - * limit. + * Address of the trampoline is returned in RAX. + * Non zero RDX on return means we need to enable 5-level paging. * - * The first step is go into compatibility mode. + * RSI holds real mode data and needs to be preserved across + * this function call. */ + pushq %rsi + call paging_prepare + popq %rsi + + /* Save the trampoline address in RCX */ + movq %rax, %rcx + + /* Check if we need to enable 5-level paging */ + cmpq $0, %rdx + jz lvl5 /* Clear additional page table */ leaq lvl5_pgtable(%rbx), %rdi @@ -352,7 +354,6 @@ ENTRY(startup_64) pushq %rax lretq lvl5: -#endif /* Zero EFLAGS */ pushq $0 @@ -490,7 +491,6 @@ relocated: jmp *%rax .code32 -#ifdef CONFIG_X86_5LEVEL compatible_mode: /* Setup data and stack segments */ movl $__KERNEL_DS, %eax @@ -526,7 +526,6 @@ compatible_mode: movl %eax, %cr0 lret -#endif no_longmode: /* This isn't an x86-64 CPU so hang */ @@ -585,7 +584,5 @@ boot_stack_end: .balign 4096 pgtable: .fill BOOT_PGT_SIZE, 1, 0 -#ifdef CONFIG_X86_5LEVEL lvl5_pgtable: .fill PAGE_SIZE, 1, 0 -#endif diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c index b4469a3..3f1697f 100644 --- a/arch/x86/boot/compressed/pgtable_64.c +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -9,20 +9,19 @@ */ unsigned long __force_order; -int l5_paging_required(void) -{ - /* Check if leaf 7 is supported. */ - - if (native_cpuid_eax(0) < 7) - return 0; +struct paging_config { + unsigned long trampoline_start; + unsigned long l5_required; +}; - /* Check if la57 is supported. */ - if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) - return 0; +struct paging_config paging_prepare(void) +{ + struct paging_config paging_config = {}; - /* Check if 5-level paging has already been enabled. */ - if (native_read_cr4() & X86_CR4_LA57) - return 0; + /* Check if LA57 is desired and supported */ + if (IS_ENABLED(CONFIG_X86_5LEVEL) && native_cpuid_eax(0) >= 7 && + (native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) + paging_config.l5_required = 1; - return 1; + return paging_config; } |