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Date: Tue, 25 Oct 2022 17:12:50 +0300 From: Evgeniy Baskov <baskov@...ras.ru> To: Ard Biesheuvel <ardb@...nel.org> Cc: Evgeniy Baskov <baskov@...ras.ru>, Borislav Petkov <bp@...en8.de>, Andy Lutomirski <luto@...nel.org>, Dave Hansen <dave.hansen@...ux.intel.com>, Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de>, Alexey Khoroshilov <khoroshilov@...ras.ru>, Peter Jones <pjones@...hat.com>, lvc-project@...uxtesting.org, x86@...nel.org, linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org Subject: [PATCH v2 12/23] x86/boot: Make kernel_add_identity_map() a pointer Convert kernel_add_identity_map() into a function pointer to be able to provide alternative implementations of this function. Required to enable calling the code using this function from EFI environment. Signed-off-by: Evgeniy Baskov <baskov@...ras.ru> --- arch/x86/boot/compressed/ident_map_64.c | 7 ++++--- arch/x86/boot/compressed/misc.c | 24 ++++++++++++++++++++++++ arch/x86/boot/compressed/misc.h | 15 +++------------ 3 files changed, 31 insertions(+), 15 deletions(-) diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c index ba5108c58a4e..1aee524d3c2b 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -92,9 +92,9 @@ bool has_nx; /* set in head_64.S */ /* * Adds the specified range to the identity mappings. */ -unsigned long kernel_add_identity_map(unsigned long start, - unsigned long end, - unsigned int flags) +unsigned long kernel_add_identity_map_(unsigned long start, + unsigned long end, + unsigned int flags) { int ret; @@ -142,6 +142,7 @@ void initialize_identity_maps(void *rmode) struct setup_data *sd; boot_params = rmode; + kernel_add_identity_map = kernel_add_identity_map_; /* Exclude the encryption mask from __PHYSICAL_MASK */ physical_mask &= ~sme_me_mask; diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index aa4a22bc9cf9..c9c235d65d16 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -275,6 +275,22 @@ static void parse_elf(void *output, unsigned long output_len, free(phdrs); } +/* + * This points to actual implementation of mapping function + * for current environment: either EFI API wrapper, + * own implementation or dummy implementation below. + */ +unsigned long (*kernel_add_identity_map)(unsigned long start, + unsigned long end, + unsigned int flags); + +static inline unsigned long kernel_add_identity_map_dummy(unsigned long start, + unsigned long end, + unsigned int flags) +{ + return start; +} + /* * The compressed kernel image (ZO), has been moved so that its position * is against the end of the buffer used to hold the uncompressed kernel @@ -312,6 +328,14 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, init_default_io_ops(); + /* + * On 64-bit this pointer is set during page table uninitialization, + * but on 32-bit it remains uninitialized, since paging is disabled. + */ + if (IS_ENABLED(CONFIG_X86_32)) + kernel_add_identity_map = kernel_add_identity_map_dummy; + + /* * Detect TDX guest environment. * diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 38d31bec062d..0076b2845b4b 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -180,18 +180,9 @@ static inline int count_immovable_mem_regions(void) { return 0; } #ifdef CONFIG_X86_5LEVEL extern unsigned int __pgtable_l5_enabled, pgdir_shift, ptrs_per_p4d; #endif -#ifdef CONFIG_X86_64 -extern unsigned long kernel_add_identity_map(unsigned long start, - unsigned long end, - unsigned int flags); -#else -static inline unsigned long kernel_add_identity_map(unsigned long start, - unsigned long end, - unsigned int flags) -{ - return start; -} -#endif +extern unsigned long (*kernel_add_identity_map)(unsigned long start, + unsigned long end, + unsigned int flags); /* Used by PAGE_KERN* macros: */ extern pteval_t __default_kernel_pte_mask; -- 2.37.4
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