| Message ID | 20210225032108.1458352-1-jniethe5@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [1/3] powernv/memtrace: Allow mmaping trace buffers | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (626a6c3d2e20da80aaa710104f34ea6037b28b33) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 34 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Thu, 25 Feb 2021 14:21:06 +1100, Jordan Niethe wrote: > Let the memory removed from the linear mapping to be used for the trace > buffers be mmaped. This is a useful way of providing cache-inhibited > memory for the alignment_handler selftest. Patches 1 & 2 applied to powerpc/next. [1/3] powernv/memtrace: Allow mmaping trace buffers https://git.kernel.org/powerpc/c/08a022ad3dfafc7e33d4529015e14bb75179cacc [2/3] selftests/powerpc: Suggest memtrace instead of /dev/mem for ci memory https://git.kernel.org/powerpc/c/812aa68ef7d4d71bed996468ead665092a3f8de9 cheers
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c index 5fc9408bb0b3..8a1df39305e9 100644 --- a/arch/powerpc/platforms/powernv/memtrace.c +++ b/arch/powerpc/platforms/powernv/memtrace.c @@ -45,10 +45,26 @@ static ssize_t memtrace_read(struct file *filp, char __user *ubuf, return simple_read_from_buffer(ubuf, count, ppos, ent->mem, ent->size); } +int memtrace_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct memtrace_entry *ent = filp->private_data; + + if (ent->size < vma->vm_end - vma->vm_start) + return -EINVAL; + + if (vma->vm_pgoff << PAGE_SHIFT >= ent->size) + return -EINVAL; + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + return remap_pfn_range(vma, vma->vm_start, PHYS_PFN(ent->start) + vma->vm_pgoff, + vma->vm_end - vma->vm_start, vma->vm_page_prot); +} + static const struct file_operations memtrace_fops = { .llseek = default_llseek, .read = memtrace_read, .open = simple_open, + .mmap = memtrace_mmap, }; static void memtrace_clear_range(unsigned long start_pfn, @@ -158,7 +174,7 @@ static int memtrace_init_debugfs(void) dir = debugfs_create_dir(ent->name, memtrace_debugfs_dir); ent->dir = dir; - debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops); + debugfs_create_file_unsafe("trace", 0600, dir, ent, &memtrace_fops); debugfs_create_x64("start", 0400, dir, &ent->start); debugfs_create_x64("size", 0400, dir, &ent->size); }
Let the memory removed from the linear mapping to be used for the trace buffers be mmaped. This is a useful way of providing cache-inhibited memory for the alignment_handler selftest. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> --- arch/powerpc/platforms/powernv/memtrace.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)