diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-03-12 14:26:00 +0300 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2023-03-16 13:08:39 -0700 |
| commit | 428e106ae1ad4e45d3fd6978a753db475d0d0ec9 (patch) | |
| tree | 4bbc741cbd795dadc9f7543b8aa219cd3759db25 /fs/proc | |
| parent | 82721d8b25d76c5a6f4c6cf4ce4e5b33788820a1 (diff) | |
mm: Introduce untagged_addr_remote()
untagged_addr() removes tags/metadata from the address and brings it to
the canonical form. The helper is implemented on arm64 and sparc. Both of
them do untagging based on global rules.
However, Linear Address Masking (LAM) on x86 introduces per-process
settings for untagging. As a result, untagged_addr() is now only
suitable for untagging addresses for the current proccess.
The new helper untagged_addr_remote() has to be used when the address
targets remote process. It requires the mmap lock for target mm to be
taken.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-6-kirill.shutemov%40linux.intel.com
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/task_mmu.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 6a96e1713fd5..29fd6b1f4058 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1689,8 +1689,13 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, /* watch out for wraparound */ start_vaddr = end_vaddr; - if (svpfn <= (ULONG_MAX >> PAGE_SHIFT)) - start_vaddr = untagged_addr(svpfn << PAGE_SHIFT); + if (svpfn <= (ULONG_MAX >> PAGE_SHIFT)) { + ret = mmap_read_lock_killable(mm); + if (ret) + goto out_free; + start_vaddr = untagged_addr_remote(mm, svpfn << PAGE_SHIFT); + mmap_read_unlock(mm); + } /* Ensure the address is inside the task */ if (start_vaddr > mm->task_size) |