From 744937b0b12a669f298949c4a810794c59fead98 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 3 Mar 2015 07:48:50 +0100 Subject: [PATCH] efi: Clean up the efi_call_phys_[prolog|epilog]() save/restore interaction Currently x86-64 efi_call_phys_prolog() saves into a global variable (save_pgd), and efi_call_phys_epilog() restores the kernel pagetables from that global variable. Change this to a cleaner save/restore pattern where the saving function returns the saved object and the restore function restores that. Apply the same concept to the 32-bit code as well. Plus this approach, as an added bonus, allows us to express the !efi_enabled(EFI_OLD_MEMMAP) situation in a clean fashion as well, via a 'NULL' return value. Cc: Tapasweni Pathak Signed-off-by: Ingo Molnar Signed-off-by: Matt Fleming --- arch/x86/include/asm/efi.h | 6 ++++-- arch/x86/platform/efi/efi.c | 5 +++-- arch/x86/platform/efi/efi_32.c | 11 ++++++++--- arch/x86/platform/efi/efi_64.c | 26 ++++++++++++++++---------- 4 files changed, 31 insertions(+), 17 deletions(-) diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 25bce45c6fc4..3738b138b843 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -2,6 +2,8 @@ #define _ASM_X86_EFI_H #include +#include + /* * We map the EFI regions needed for runtime services non-contiguously, * with preserved alignment on virtual addresses starting from -4G down @@ -89,8 +91,8 @@ extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size, 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 void __init efi_call_phys_prolog(void); -extern void __init efi_call_phys_epilog(void); +extern pgd_t * __init efi_call_phys_prolog(void); +extern void __init efi_call_phys_epilog(pgd_t *save_pgd); extern void __init efi_unmap_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 e7a01e32db95..02744df576d5 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -86,8 +86,9 @@ static efi_status_t __init phys_efi_set_virtual_address_map( { efi_status_t status; unsigned long flags; + pgd_t *save_pgd; - efi_call_phys_prolog(); + save_pgd = efi_call_phys_prolog(); /* Disable interrupts around EFI calls: */ local_irq_save(flags); @@ -96,7 +97,7 @@ static efi_status_t __init phys_efi_set_virtual_address_map( descriptor_version, virtual_map); local_irq_restore(flags); - efi_call_phys_epilog(); + efi_call_phys_epilog(save_pgd); return status; } diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c index abecc6e1dc90..ed5b67338294 100644 --- a/arch/x86/platform/efi/efi_32.c +++ b/arch/x86/platform/efi/efi_32.c @@ -56,19 +56,24 @@ 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) {} -void __init efi_call_phys_prolog(void) +pgd_t * __init efi_call_phys_prolog(void) { struct desc_ptr gdt_descr; + pgd_t *save_pgd; + /* Current pgd is swapper_pg_dir, we'll restore it later: */ + save_pgd = swapper_pg_dir; load_cr3(initial_page_table); __flush_tlb_all(); gdt_descr.address = __pa(get_cpu_gdt_table(0)); gdt_descr.size = GDT_SIZE - 1; load_gdt(&gdt_descr); + + return save_pgd; } -void __init efi_call_phys_epilog(void) +void __init efi_call_phys_epilog(pgd_t *save_pgd) { struct desc_ptr gdt_descr; @@ -76,7 +81,7 @@ void __init efi_call_phys_epilog(void) gdt_descr.size = GDT_SIZE - 1; load_gdt(&gdt_descr); - load_cr3(swapper_pg_dir); + load_cr3(save_pgd); __flush_tlb_all(); } diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 427eb3540e5f..a0ac0f9c307f 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -41,8 +41,6 @@ #include #include -static pgd_t *save_pgd __initdata; - /* * We allocate runtime services regions bottom-up, starting from -4G, i.e. * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G. @@ -77,14 +75,16 @@ static void __init early_code_mapping_set_exec(int executable) } } -void __init efi_call_phys_prolog(void) +pgd_t * __init efi_call_phys_prolog(void) { unsigned long vaddress; + pgd_t *save_pgd; + int pgd; int n_pgds; if (!efi_enabled(EFI_OLD_MEMMAP)) - return; + return NULL; early_code_mapping_set_exec(1); @@ -97,22 +97,28 @@ void __init efi_call_phys_prolog(void) set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress)); } __flush_tlb_all(); + + return save_pgd; } -void __init efi_call_phys_epilog(void) +void __init efi_call_phys_epilog(pgd_t *save_pgd) { /* * After the lock is released, the original page table is restored. */ - int pgd; - int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE); + int pgd_idx; + int nr_pgds; - if (!efi_enabled(EFI_OLD_MEMMAP)) + if (!save_pgd) return; - for (pgd = 0; pgd < n_pgds; pgd++) - set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[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]); + kfree(save_pgd); + __flush_tlb_all(); early_code_mapping_set_exec(0); } -- 2.34.1