@@ -271,6 +271,10 @@ __iowrite64_copy(void __iomem *to, const void *from, size_t count)
* I/O memory mapping functions.
*/
+typedef int (*ioremap_prot_hook_t)(phys_addr_t phys_addr, size_t size,
+ pgprot_t *prot);
+int arm64_ioremap_prot_hook_register(const ioremap_prot_hook_t hook);
+
#define ioremap_prot ioremap_prot
#define _PAGE_IOREMAP PROT_DEVICE_nGnRE
@@ -3,10 +3,22 @@
#include <linux/mm.h>
#include <linux/io.h>
+static ioremap_prot_hook_t ioremap_prot_hook;
+
+int arm64_ioremap_prot_hook_register(ioremap_prot_hook_t hook)
+{
+ if (WARN_ON(ioremap_prot_hook))
+ return -EBUSY;
+
+ ioremap_prot_hook = hook;
+ return 0;
+}
+
void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
unsigned long prot)
{
unsigned long last_addr = phys_addr + size - 1;
+ pgprot_t pgprot = __pgprot(prot);
/* Don't allow outside PHYS_MASK */
if (last_addr & ~PHYS_MASK)
@@ -16,7 +28,16 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr))))
return NULL;
- return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
+ /*
+ * If a hook is registered (e.g. for confidential computing
+ * purposes), call that now and barf if it fails.
+ */
+ if (unlikely(ioremap_prot_hook) &&
+ WARN_ON(ioremap_prot_hook(phys_addr, size, &pgprot))) {
+ return NULL;
+ }
+
+ return generic_ioremap_prot(phys_addr, size, pgprot);
}
EXPORT_SYMBOL(ioremap_prot);
Confidential Computing environments such as pKVM and Arm's CCA distinguish between shared (i.e. emulated) and private (i.e. assigned) MMIO regions. Introduce a hook into our implementation of ioremap_prot() so that MMIO regions can be shared if necessary. Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/io.h | 4 ++++ arch/arm64/mm/ioremap.c | 23 ++++++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-)