[PATCHv7 10/19] x86/mm: Make __PHYSICAL_MASK_SHIFT and __VIRTUAL_MASK_SHIFT dynamic
From: Kirill A. Shutemov <hidden>
Date: 2017-09-18 10:59:17
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 entry code, x86 mm · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
For boot-time switching between paging modes, we need to be able to adjust physical and virtual mask shifts. It has significant effect on kernel image size: text data bss dec hex filename 10710666 4880000 860160 16450826 fb050a vmlinux.before 10735996 4880000 860160 16476156 fb67fc vmlinux.after The change is mostly due to __PHYSICAL_MASK_SHIFT change: the value is used in pte_pfn() and many other page table manipulation routines (directly or indirectly). Signed-off-by: Kirill A. Shutemov <redacted> --- arch/x86/entry/entry_64.S | 12 ++++++++++++ arch/x86/include/asm/page_64_types.h | 4 ++-- arch/x86/mm/dump_pagetables.c | 8 ++++++-- arch/x86/mm/kaslr.c | 4 +++- 4 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 49167258d587..eec0ca064c67 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S@@ -268,8 +268,20 @@ return_from_SYSCALL_64: * Change top bits to match most significant bit (47th or 56th bit * depending on paging mode) in the address. */ +#ifdef CONFIG_X86_5LEVEL + testl $1, pgtable_l5_enabled(%rip) + jz 1f + shl $(64 - 57), %rcx + sar $(64 - 57), %rcx + jmp 2f +1: + shl $(64 - 48), %rcx + sar $(64 - 48), %rcx +2: +#else shl $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx sar $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx +#endif /* If this changed %rcx, it was not canonical */ cmpq %rcx, %r11
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 0126d6bc2eb1..79d2180ffdec 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h@@ -52,8 +52,8 @@ /* See Documentation/x86/x86_64/mm.txt for a description of the memory map. */ #ifdef CONFIG_X86_5LEVEL -#define __PHYSICAL_MASK_SHIFT 52 -#define __VIRTUAL_MASK_SHIFT 56 +#define __PHYSICAL_MASK_SHIFT (pgtable_l5_enabled ? 52 : 46) +#define __VIRTUAL_MASK_SHIFT (pgtable_l5_enabled ? 56 : 47) #else #define __PHYSICAL_MASK_SHIFT 46 #define __VIRTUAL_MASK_SHIFT 47
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 2eabd07ae2d2..a1d983a45ab0 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c@@ -82,8 +82,8 @@ static struct addr_marker address_markers[] = { { 0/* VMALLOC_START */, "vmalloc() Area" }, { 0/* VMEMMAP_START */, "Vmemmap" }, #ifdef CONFIG_KASAN - { KASAN_SHADOW_START, "KASAN shadow" }, - { KASAN_SHADOW_END, "KASAN shadow end" }, + { 0/* KASAN_SHADOW_START */, "KASAN shadow" }, + { 0/* KASAN_SHADOW_END */, "KASAN shadow end" }, #endif # ifdef CONFIG_X86_ESPFIX64 { ESPFIX_BASE_ADDR, "ESPfix Area", 16 },
@@ -515,6 +515,10 @@ static int __init pt_dump_init(void) address_markers[LOW_KERNEL_NR].start_address = PAGE_OFFSET; address_markers[VMALLOC_START_NR].start_address = VMALLOC_START; address_markers[VMEMMAP_START_NR].start_address = VMEMMAP_START; +#ifdef CONFIG_KASAN + address_markers[KASAN_SHADOW_START_NR].start_address = KASAN_SHADOW_START; + address_markers[KASAN_SHADOW_END_NR].start_address = KASAN_SHADOW_END; +#endif #endif #ifdef CONFIG_X86_32 address_markers[VMALLOC_START_NR].start_address = VMALLOC_START;
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index e6420b18f6e0..5597dd0635dd 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c@@ -62,7 +62,7 @@ static __initdata struct kaslr_memory_region { unsigned long *base; unsigned long size_tb; } kaslr_regions[] = { - { &page_offset_base, 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT) /* Maximum */ }, + { &page_offset_base, 0 }, { &vmalloc_base, VMALLOC_SIZE_TB }, { &vmemmap_base, 1 }, };
@@ -106,6 +106,8 @@ void __init kernel_randomize_memory(void) if (!kaslr_memory_enabled()) return; + kaslr_regions[0].size_tb = 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT); + /* * Update Physical memory mapping to available and * add padding if needed (especially for memory hotplug support).
--
2.14.1
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