diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2024-02-27 16:19:10 +0100 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-03-04 18:12:06 +0100 |
| commit | 63bed96604205fa0b23c91d268df5f1f1b26faf6 (patch) | |
| tree | f4b4bd2f7a30c419b63c2d8f775876516d3b2680 /arch/x86/kernel/head64.c | |
| parent | dada8587068c820ba5e5d09b9c32d8bc28c4dbe6 (diff) | |
x86/startup_64: Defer assignment of 5-level paging global variables
Assigning the 5-level paging related global variables from the earliest
C code using explicit references that use the 1:1 translation of memory
is unnecessary, as the startup code itself does not rely on them to
create the initial page tables, and this is all it should be doing. So
defer these assignments to the primary C entry code that executes via
the ordinary kernel virtual mapping.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20240227151907.387873-13-ardb+git@google.com
Diffstat (limited to 'arch/x86/kernel/head64.c')
| -rw-r--r-- | arch/x86/kernel/head64.c | 44 |
1 files changed, 14 insertions, 30 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index fd77a266f29d..212e8e06aeba 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -23,6 +23,7 @@ #include <linux/pgtable.h> #include <asm/asm.h> +#include <asm/page_64.h> #include <asm/processor.h> #include <asm/proto.h> #include <asm/smp.h> @@ -68,24 +69,11 @@ unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4; EXPORT_SYMBOL(vmemmap_base); #endif -#ifdef CONFIG_X86_5LEVEL -static void __head *fixup_pointer(void *ptr, unsigned long physaddr) -{ - return ptr - (void *)_text + (void *)physaddr; -} - -static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr) +static inline bool check_la57_support(void) { - return fixup_pointer(ptr, physaddr); -} - -static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr) -{ - return fixup_pointer(ptr, physaddr); -} + if (!IS_ENABLED(CONFIG_X86_5LEVEL)) + return false; -static bool __head check_la57_support(unsigned long physaddr) -{ /* * 5-level paging is detected and enabled at kernel decompression * stage. Only check if it has been enabled there. @@ -93,21 +81,8 @@ static bool __head check_la57_support(unsigned long physaddr) if (!(native_read_cr4() & X86_CR4_LA57)) return false; - *fixup_int(&__pgtable_l5_enabled, physaddr) = 1; - *fixup_int(&pgdir_shift, physaddr) = 48; - *fixup_int(&ptrs_per_p4d, physaddr) = 512; - *fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5; - *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5; - *fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5; - return true; } -#else -static bool __head check_la57_support(unsigned long physaddr) -{ - return false; -} -#endif static unsigned long __head sme_postprocess_startup(struct boot_params *bp, pmdval_t *pmd) { @@ -171,7 +146,7 @@ unsigned long __head __startup_64(unsigned long physaddr, bool la57; int i; - la57 = check_la57_support(physaddr); + la57 = check_la57_support(); /* Is the address too large? */ if (physaddr >> MAX_PHYSMEM_BITS) @@ -456,6 +431,15 @@ asmlinkage __visible void __init __noreturn x86_64_start_kernel(char * real_mode (__START_KERNEL & PGDIR_MASK))); BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); + if (check_la57_support()) { + __pgtable_l5_enabled = 1; + pgdir_shift = 48; + ptrs_per_p4d = 512; + page_offset_base = __PAGE_OFFSET_BASE_L5; + vmalloc_base = __VMALLOC_BASE_L5; + vmemmap_base = __VMEMMAP_BASE_L5; + } + cr4_init_shadow(); /* Kill off the identity-map trampoline */ |