On Thu, 15 Dec 2022 at 13:40, Evgeniy Baskov <baskov@xxxxxxxxx> wrote:
>
> 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.
>
> Tested-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> Tested-by: Peter Jones <pjones@xxxxxxxxxx>
> Signed-off-by: Evgeniy Baskov <baskov@xxxxxxxxx>
> ---
> 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,
Please use a more discriminating name here - the trailing _ is rather
hard to spot.
> + 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,
This function is never called, it only has its address taken, so the
'inline' makes no sense here.
> + 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,
initialization
> + * 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
>
