[RFC PATCH 2/6] arm64: vdso: avoid virt_to_page() translations on kernel symbols

[Ard Biesheuvel]

The translation performed by virt_to_page() is only valid for linear
addresses, and kernel symbols are no longer in the linear mapping.
So perform the __pa() translation explicitly, which does the right
thing in either case, and only then translate to a struct page offset.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
 arch/arm64/kernel/vdso.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 97bc68f4c689..fb3c17f031aa 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -131,11 +131,12 @@ static int __init vdso_init(void)
 		return -ENOMEM;
 
 	/* Grab the vDSO data page. */
-	vdso_pagelist[0] = virt_to_page(vdso_data);
+	vdso_pagelist[0] = pfn_to_page(__pa(vdso_data) >> PAGE_SHIFT);
 
 	/* Grab the vDSO code pages. */
-	for (i = 0; i < vdso_pages; i++)
-		vdso_pagelist[i + 1] = virt_to_page(&vdso_start + i * PAGE_SIZE);
+	vdso_pagelist[1] = pfn_to_page(__pa(&vdso_start) >> PAGE_SHIFT);
+	for (i = 1; i < vdso_pages; i++)
+		vdso_pagelist[i + 1] = vdso_pagelist[1] + i;
 
 	/* Populate the special mapping structures */
 	vdso_spec[0] = (struct vm_special_mapping) {
-- 
2.5.0