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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-09 09:54:46 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-09 09:54:46 -0700 |
commit | a5ad5742f671de906adbf29fbedf0a04705cebad (patch) | |
tree | 88d1a4c18e2025a5a8335dbbc9dea8bebeba5789 /arch/x86/mm/init.c | |
parent | 013b2deba9a6b80ca02f4fafd7dedf875e9b4450 (diff) | |
parent | 4fa7252338a56fbc90220e6330f136a379175a7a (diff) | |
download | linux-a5ad5742f671de906adbf29fbedf0a04705cebad.tar.gz linux-a5ad5742f671de906adbf29fbedf0a04705cebad.tar.bz2 linux-a5ad5742f671de906adbf29fbedf0a04705cebad.zip |
Merge branch 'akpm' (patches from Andrew)
Merge even more updates from Andrew Morton:
- a kernel-wide sweep of show_stack()
- pagetable cleanups
- abstract out accesses to mmap_sem - prep for mmap_sem scalability work
- hch's user acess work
Subsystems affected by this patch series: debug, mm/pagemap, mm/maccess,
mm/documentation.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (93 commits)
include/linux/cache.h: expand documentation over __read_mostly
maccess: return -ERANGE when probe_kernel_read() fails
x86: use non-set_fs based maccess routines
maccess: allow architectures to provide kernel probing directly
maccess: move user access routines together
maccess: always use strict semantics for probe_kernel_read
maccess: remove strncpy_from_unsafe
tracing/kprobes: handle mixed kernel/userspace probes better
bpf: rework the compat kernel probe handling
bpf:bpf_seq_printf(): handle potentially unsafe format string better
bpf: handle the compat string in bpf_trace_copy_string better
bpf: factor out a bpf_trace_copy_string helper
maccess: unify the probe kernel arch hooks
maccess: remove probe_read_common and probe_write_common
maccess: rename strnlen_unsafe_user to strnlen_user_nofault
maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault
maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault
maccess: update the top of file comment
maccess: clarify kerneldoc comments
maccess: remove duplicate kerneldoc comments
...
Diffstat (limited to 'arch/x86/mm/init.c')
-rw-r--r-- | arch/x86/mm/init.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 112d3b98a3b6..001dd7dc829f 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -680,6 +680,28 @@ static void __init memory_map_bottom_up(unsigned long map_start, } } +/* + * The real mode trampoline, which is required for bootstrapping CPUs + * occupies only a small area under the low 1MB. See reserve_real_mode() + * for details. + * + * If KASLR is disabled the first PGD entry of the direct mapping is copied + * to map the real mode trampoline. + * + * If KASLR is enabled, copy only the PUD which covers the low 1MB + * area. This limits the randomization granularity to 1GB for both 4-level + * and 5-level paging. + */ +static void __init init_trampoline(void) +{ +#ifdef CONFIG_X86_64 + if (!kaslr_memory_enabled()) + trampoline_pgd_entry = init_top_pgt[pgd_index(__PAGE_OFFSET)]; + else + init_trampoline_kaslr(); +#endif +} + void __init init_mem_mapping(void) { unsigned long end; |