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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2019-05-15 07:38:18 +0200 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-05-26 05:04:42 +0200 |
| commit | 3d7081822f7f9eab867d9bcc8fd635208ec438e0 (patch) | |
| tree | 8afb5e61c1f23305996d4a8e03dedd7c048de01d /mm/page_idle.c | |
| parent | x86/uaccess: Allow access_ok() in irq context if pagefault_disabled (diff) | |
| download | linux-3d7081822f7f9eab867d9bcc8fd635208ec438e0.tar.xz linux-3d7081822f7f9eab867d9bcc8fd635208ec438e0.zip | |
uaccess: Add non-pagefault user-space read functions
Add probe_user_read(), strncpy_from_unsafe_user() and
strnlen_unsafe_user() which allows caller to access user-space
in IRQ context.
Current probe_kernel_read() and strncpy_from_unsafe() are
not available for user-space memory, because it sets
KERNEL_DS while accessing data. On some arch, user address
space and kernel address space can be co-exist, but others
can not. In that case, setting KERNEL_DS means given
address is treated as a kernel address space.
Also strnlen_user() is only available from user context since
it can sleep if pagefault is enabled.
To access user-space memory without pagefault, we need
these new functions which sets USER_DS while accessing
the data.
Link: http://lkml.kernel.org/r/155789869802.26965.4940338412595759063.stgit@devnote2
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'mm/page_idle.c')
0 files changed, 0 insertions, 0 deletions