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| author | Heiko Carstens <hca@linux.ibm.com> | 2020-09-18 10:26:19 +0200 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2020-10-09 23:45:30 +0200 |
| commit | b61e1f3281c5a53f24f47849873463514f58c1b8 (patch) | |
| tree | 73623ca152797153f08cddc9bca78cb8f619869f /arch/s390/kernel/kprobes.c | |
| parent | eefc69a09ca5b441ee136f9fb68ab5970cfc2d51 (diff) | |
| download | linux-b61e1f3281c5a53f24f47849873463514f58c1b8.tar.bz2 | |
s390/kprobes: move insn_page to text segment
Move the in-kernel kprobes insn page to text segment. Rationale:
having that page in rw data segment is suboptimal, since as soon as a
kprobe is set, this will split the 1:1 kernel mapping for a single
page which get new permissions.
Note: there is always at least one kprobe present for the kretprobe
trampoline; so the mapping will always be split into smaller 4k
mappings because of this.
Moving the kprobes insn page into text segment makes sure that the
page is mapped RO/X in any case, and avoids that the 1:1 mapping is
split.
The kprobe insn_page is defined as a dummy function which is filled
with "br %r14" instructions.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel/kprobes.c')
| -rw-r--r-- | arch/s390/kernel/kprobes.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index b34fa4eef742..6574774d404e 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -22,6 +22,7 @@ #include <asm/set_memory.h> #include <asm/sections.h> #include <asm/dis.h> +#include "entry.h" DEFINE_PER_CPU(struct kprobe *, current_kprobe); DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); @@ -31,7 +32,6 @@ struct kretprobe_blackpoint kretprobe_blacklist[] = { }; DEFINE_INSN_CACHE_OPS(s390_insn); static int insn_page_in_use; -static char insn_page[PAGE_SIZE] __aligned(PAGE_SIZE); void *alloc_insn_page(void) { @@ -53,13 +53,11 @@ static void *alloc_s390_insn_page(void) { if (xchg(&insn_page_in_use, 1) == 1) return NULL; - __set_memory((unsigned long) &insn_page, 1, SET_MEMORY_RO | SET_MEMORY_X); - return &insn_page; + return &kprobes_insn_page; } static void free_s390_insn_page(void *page) { - __set_memory((unsigned long) page, 1, SET_MEMORY_RW | SET_MEMORY_NX); xchg(&insn_page_in_use, 0); } |