On Fri, 10 Feb, at 02:30:39PM, Andy Lutomirski wrote:
> efi_call_phys_prolog() used to return a "pgd_t *" that meant one of
> three different things depending on kernel and system configuration.
> Clean it up so it uses a union and is more explicit about what's
> going on.
>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
>
> Matt, this is at best a minor cleanup, and I don't really need it for
> anything. I wrote it while trying to udnerstand this code for my
> PCID series, and I think it's a bit cleaner.
I'm fairly sure Ingo was the last sucker^Wdeveloper to touch this
code, so I'd like to give him a chance to respond.
But it seems like a fair change to me. If no one complains I'll apply
it for v4.12.
> arch/x86/include/asm/efi.h | 17 +++++++++++++++--
> arch/x86/platform/efi/efi.c | 6 +++---
> arch/x86/platform/efi/efi_32.c | 12 ++++++------
> arch/x86/platform/efi/efi_64.c | 22 ++++++++++++----------
> 4 files changed, 36 insertions(+), 21 deletions(-)
>
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index e99675b9c861..ada9d49f7874 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -111,11 +111,24 @@ extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size,
>
> #endif /* CONFIG_X86_32 */
>
> +union efi_saved_pgd {
> + /*
> + * If !EFI_OLD_MEMMAP or we're 32-bit, this is a verbatim saved CR3
> + * value.
> + */
> + unsigned long cr3;
> +
> +#ifdef CONFIG_X86_64
> + /* If EFI_OLD_MEMMAP, this is a kmalloced copy of the pgd. */
> + pgd_t *pgd;
> +#endif
> +};
> +
> extern struct efi_scratch efi_scratch;
> extern void __init efi_set_executable(efi_memory_desc_t *md, bool executable);
> extern int __init efi_memblock_x86_reserve_range(void);
> -extern pgd_t * __init efi_call_phys_prolog(void);
> -extern void __init efi_call_phys_epilog(pgd_t *save_pgd);
> +extern union efi_saved_pgd __init efi_call_phys_prolog(void);
> +extern void __init efi_call_phys_epilog(union efi_saved_pgd saved_pgd);
> extern void __init efi_print_memmap(void);
> extern void __init efi_memory_uc(u64 addr, unsigned long size);
> extern void __init efi_map_region(efi_memory_desc_t *md);
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 274dfc481849..c25795066ec2 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -81,9 +81,9 @@ static efi_status_t __init phys_efi_set_virtual_address_map(
> {
> efi_status_t status;
> unsigned long flags;
> - pgd_t *save_pgd;
> + union efi_saved_pgd saved_pgd;
>
> - save_pgd = efi_call_phys_prolog();
> + saved_pgd = efi_call_phys_prolog();
>
> /* Disable interrupts around EFI calls: */
> local_irq_save(flags);
> @@ -92,7 +92,7 @@ static efi_status_t __init phys_efi_set_virtual_address_map(
> descriptor_version, virtual_map);
> local_irq_restore(flags);
>
> - efi_call_phys_epilog(save_pgd);
> + efi_call_phys_epilog(saved_pgd);
>
> return status;
> }
> diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
> index cef39b097649..9b1abcf6e7bb 100644
> --- a/arch/x86/platform/efi/efi_32.c
> +++ b/arch/x86/platform/efi/efi_32.c
> @@ -58,13 +58,13 @@ void __init efi_map_region(efi_memory_desc_t *md)
> void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
> void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
>
> -pgd_t * __init efi_call_phys_prolog(void)
> +union efi_saved_pgd __init efi_call_phys_prolog(void)
> {
> struct desc_ptr gdt_descr;
> - pgd_t *save_pgd;
> + union efi_saved_pgd saved_pgd;
>
> /* Current pgd is swapper_pg_dir, we'll restore it later: */
> - save_pgd = swapper_pg_dir;
> + saved_pgd.cr3 = __pa(swapper_pg_dir);
> load_cr3(initial_page_table);
> __flush_tlb_all();
>
> @@ -72,10 +72,10 @@ pgd_t * __init efi_call_phys_prolog(void)
> gdt_descr.size = GDT_SIZE - 1;
> load_gdt(&gdt_descr);
>
> - return save_pgd;
> + return saved_pgd;
> }
>
> -void __init efi_call_phys_epilog(pgd_t *save_pgd)
> +void __init efi_call_phys_epilog(union efi_saved_pgd saved_pgd)
> {
> struct desc_ptr gdt_descr;
>
> @@ -83,7 +83,7 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
> gdt_descr.size = GDT_SIZE - 1;
> load_gdt(&gdt_descr);
>
> - load_cr3(save_pgd);
> + write_cr3(saved_pgd.cr3);
> __flush_tlb_all();
> }
>
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 2f25a363068c..95318822b99f 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -69,16 +69,16 @@ static void __init early_code_mapping_set_exec(int executable)
> }
> }
>
> -pgd_t * __init efi_call_phys_prolog(void)
> +union efi_saved_pgd __init efi_call_phys_prolog(void)
> {
> unsigned long vaddress;
> - pgd_t *save_pgd;
> + union efi_saved_pgd saved_pgd;
>
> int pgd;
> int n_pgds;
>
> if (!efi_enabled(EFI_OLD_MEMMAP)) {
> - save_pgd = (pgd_t *)read_cr3();
> + saved_pgd.cr3 = read_cr3();
> write_cr3((unsigned long)efi_scratch.efi_pgt);
> goto out;
> }
> @@ -86,20 +86,21 @@ pgd_t * __init efi_call_phys_prolog(void)
> early_code_mapping_set_exec(1);
>
> n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
> - save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL);
> + saved_pgd.pgd = kmalloc_array(n_pgds, sizeof(*saved_pgd.pgd),
> + GFP_KERNEL);
>
> for (pgd = 0; pgd < n_pgds; pgd++) {
> - save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
> + saved_pgd.pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
> vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
> set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
> }
> out:
> __flush_tlb_all();
>
> - return save_pgd;
> + return saved_pgd;
> }
>
> -void __init efi_call_phys_epilog(pgd_t *save_pgd)
> +void __init efi_call_phys_epilog(union efi_saved_pgd saved_pgd)
> {
> /*
> * After the lock is released, the original page table is restored.
> @@ -108,7 +109,7 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
> int nr_pgds;
>
> if (!efi_enabled(EFI_OLD_MEMMAP)) {
> - write_cr3((unsigned long)save_pgd);
> + write_cr3(saved_pgd.cr3);
> __flush_tlb_all();
> return;
> }
> @@ -116,9 +117,10 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
> nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
>
> for (pgd_idx = 0; pgd_idx < nr_pgds; pgd_idx++)
> - set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE), save_pgd[pgd_idx]);
> + set_pgd(pgd_offset_k(pgd_idx * PGDIR_SIZE),
> + saved_pgd.pgd[pgd_idx]);
>
> - kfree(save_pgd);
> + kfree(saved_pgd.pgd);
>
> __flush_tlb_all();
> early_code_mapping_set_exec(0);
> --
> 2.9.3
>
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