efi/capsule-loader: Use page addresses rather than struct page pointers

To give some leeway to code that handles non-standard capsule headers,
let's keep an array of page addresses rather than struct page pointers.

This gives special implementations of efi_capsule_setup_info() the
opportunity to mangle the payload a bit before it is presented to the
firmware, without putting any knowledge of the nature of such quirks
into the generic code.

Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170602135207.21708-10-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
index cbc3526953d5..ec8ac5c4dd84 100644
--- a/drivers/firmware/efi/capsule-loader.c
+++ b/drivers/firmware/efi/capsule-loader.c
@@ -20,6 +20,10 @@
 
 #define NO_FURTHER_WRITE_ACTION -1
 
+#ifndef phys_to_page
+#define phys_to_page(x)		pfn_to_page((x) >> PAGE_SHIFT)
+#endif
+
 /**
  * efi_free_all_buff_pages - free all previous allocated buffer pages
  * @cap_info: pointer to current instance of capsule_info structure
@@ -31,7 +35,7 @@
 static void efi_free_all_buff_pages(struct capsule_info *cap_info)
 {
 	while (cap_info->index > 0)
-		__free_page(cap_info->pages[--cap_info->index]);
+		__free_page(phys_to_page(cap_info->pages[--cap_info->index]));
 
 	cap_info->index = NO_FURTHER_WRITE_ACTION;
 }
@@ -161,12 +165,12 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
 			goto failed;
 		}
 
-		cap_info->pages[cap_info->index++] = page;
+		cap_info->pages[cap_info->index++] = page_to_phys(page);
 		cap_info->page_bytes_remain = PAGE_SIZE;
+	} else {
+		page = phys_to_page(cap_info->pages[cap_info->index - 1]);
 	}
 
-	page = cap_info->pages[cap_info->index - 1];
-
 	kbuff = kmap(page);
 	kbuff += PAGE_SIZE - cap_info->page_bytes_remain;