diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-17 14:06:53 -0600 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-17 14:06:53 -0600 |
commit | 4f292c4de4f6fb83776c0ff22674121eb6ddfa2f (patch) | |
tree | 7625005ed153dbc8341867bfc0076aae5adf93f9 /arch/x86/mm/cpu_entry_area.c | |
parent | 03d84bd6d43269df2dc63b2945dfed6610fac526 (diff) | |
parent | 3e844d842d49cdbe61a4b338bdd512654179488a (diff) | |
download | linux-4f292c4de4f6fb83776c0ff22674121eb6ddfa2f.tar.gz linux-4f292c4de4f6fb83776c0ff22674121eb6ddfa2f.tar.bz2 linux-4f292c4de4f6fb83776c0ff22674121eb6ddfa2f.zip |
Merge tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Dave Hansen:
"New Feature:
- Randomize the per-cpu entry areas
Cleanups:
- Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open coding it
- Move to "native" set_memory_rox() helper
- Clean up pmd_get_atomic() and i386-PAE
- Remove some unused page table size macros"
* tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
x86/mm: Ensure forced page table splitting
x86/kasan: Populate shadow for shared chunk of the CPU entry area
x86/kasan: Add helpers to align shadow addresses up and down
x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names
x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area
x86/mm: Recompute physical address for every page of per-CPU CEA mapping
x86/mm: Rename __change_page_attr_set_clr(.checkalias)
x86/mm: Inhibit _PAGE_NX changes from cpa_process_alias()
x86/mm: Untangle __change_page_attr_set_clr(.checkalias)
x86/mm: Add a few comments
x86/mm: Fix CR3_ADDR_MASK
x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros
mm: Convert __HAVE_ARCH_P..P_GET to the new style
mm: Remove pointless barrier() after pmdp_get_lockless()
x86/mm/pae: Get rid of set_64bit()
x86_64: Remove pointless set_64bit() usage
x86/mm/pae: Be consistent with pXXp_get_and_clear()
x86/mm/pae: Use WRITE_ONCE()
x86/mm/pae: Don't (ab)use atomic64
mm/gup: Fix the lockless PMD access
...
Diffstat (limited to 'arch/x86/mm/cpu_entry_area.c')
-rw-r--r-- | arch/x86/mm/cpu_entry_area.c | 50 |
1 files changed, 46 insertions, 4 deletions
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 42cd96e7d733..8bb1aa6a7aa3 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -9,22 +9,60 @@ #include <asm/cpu_entry_area.h> #include <asm/fixmap.h> #include <asm/desc.h> +#include <asm/kasan.h> static DEFINE_PER_CPU_PAGE_ALIGNED(struct entry_stack_page, entry_stack_storage); #ifdef CONFIG_X86_64 static DEFINE_PER_CPU_PAGE_ALIGNED(struct exception_stacks, exception_stacks); DEFINE_PER_CPU(struct cea_exception_stacks*, cea_exception_stacks); -#endif -#ifdef CONFIG_X86_32 +static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, _cea_offset); + +static __always_inline unsigned int cea_offset(unsigned int cpu) +{ + return per_cpu(_cea_offset, cpu); +} + +static __init void init_cea_offsets(void) +{ + unsigned int max_cea; + unsigned int i, j; + + max_cea = (CPU_ENTRY_AREA_MAP_SIZE - PAGE_SIZE) / CPU_ENTRY_AREA_SIZE; + + /* O(sodding terrible) */ + for_each_possible_cpu(i) { + unsigned int cea; + +again: + cea = prandom_u32_max(max_cea); + + for_each_possible_cpu(j) { + if (cea_offset(j) == cea) + goto again; + + if (i == j) + break; + } + + per_cpu(_cea_offset, i) = cea; + } +} +#else /* !X86_64 */ DECLARE_PER_CPU_PAGE_ALIGNED(struct doublefault_stack, doublefault_stack); + +static __always_inline unsigned int cea_offset(unsigned int cpu) +{ + return cpu; +} +static inline void init_cea_offsets(void) { } #endif /* Is called from entry code, so must be noinstr */ noinstr struct cpu_entry_area *get_cpu_entry_area(int cpu) { - unsigned long va = CPU_ENTRY_AREA_PER_CPU + cpu * CPU_ENTRY_AREA_SIZE; + unsigned long va = CPU_ENTRY_AREA_PER_CPU + cea_offset(cpu) * CPU_ENTRY_AREA_SIZE; BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0); return (struct cpu_entry_area *) va; @@ -148,6 +186,9 @@ static void __init setup_cpu_entry_area(unsigned int cpu) pgprot_t tss_prot = PAGE_KERNEL; #endif + kasan_populate_shadow_for_vaddr(cea, CPU_ENTRY_AREA_SIZE, + early_cpu_to_node(cpu)); + cea_set_pte(&cea->gdt, get_cpu_gdt_paddr(cpu), gdt_prot); cea_map_percpu_pages(&cea->entry_stack_page, @@ -201,7 +242,6 @@ static __init void setup_cpu_entry_area_ptes(void) /* The +1 is for the readonly IDT: */ BUILD_BUG_ON((CPU_ENTRY_AREA_PAGES+1)*PAGE_SIZE != CPU_ENTRY_AREA_MAP_SIZE); - BUILD_BUG_ON(CPU_ENTRY_AREA_TOTAL_SIZE != CPU_ENTRY_AREA_MAP_SIZE); BUG_ON(CPU_ENTRY_AREA_BASE & ~PMD_MASK); start = CPU_ENTRY_AREA_BASE; @@ -217,6 +257,8 @@ void __init setup_cpu_entry_areas(void) { unsigned int cpu; + init_cea_offsets(); + setup_cpu_entry_area_ptes(); for_each_possible_cpu(cpu) |