[RFC PATCH v4 24/28] x86: Access the setup data through debugfs decrypted

Tom Lendacky
2017-02-16T15:47:34Z

Use memremap() to map the setup data. This simplifies the code and will
make the appropriate decision as to whether a RAM remapping can be done
or if a fallback to ioremap_cache() is needed (which includes checking
PageHighMem).

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/kernel/kdebugfs.c | 30 +++++++++++-------------------
1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kernel/kdebugfs.c b/arch/x86/kernel/kdebugfs.c
index bdb83e4..c3d354d 100644
--- a/arch/x86/kernel/kdebugfs.c
+++ b/arch/x86/kernel/kdebugfs.c
@@ -48,17 +48,13 @@ static ssize_t setup_data_read(struct file *file, char __user *user_buf,

pa = node->paddr + sizeof(struct setup_data) + pos;
pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
- if (PageHighMem(pg)) {
- p = ioremap_cache(pa, count);
- if (!p)
- return -ENXIO;
- } else
- p = __va(pa);
+ p = memremap(pa, count, MEMREMAP_WB);
+ if (!p)
+ return -ENXIO;

remain = copy_to_user(user_buf, p, count);

- if (PageHighMem(pg))
- iounmap(p);
+ memunmap(p);

if (remain)
return -EFAULT;
@@ -127,15 +123,12 @@ static int __init create_setup_data_nodes(struct dentry *parent)
}

pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
- if (PageHighMem(pg)) {
- data = ioremap_cache(pa_data, sizeof(*data));
- if (!data) {
- kfree(node);
- error = -ENXIO;
- goto err_dir;
- }
- } else
- data = __va(pa_data);
+ data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
+ if (!data) {
+ kfree(node);
+ error = -ENXIO;
+ goto err_dir;
+ }

node->paddr = pa_data;
node->type = data->type;
@@ -143,8 +136,7 @@ static int __init create_setup_data_nodes(struct dentry *parent)
error = create_setup_data_node(d, no, node);
pa_data = data->next;

- if (PageHighMem(pg))
- iounmap(data);
+ memunmap(data);
if (error)
goto err_dir;
no++;