[PATCH] x86/boot/64/clang: Use fixup_pointer() to access '__supported_pte_mask'

Alexander Potapenko
2018-05-08T12:16:51Z

Similarly to commit 187e91fe5e91
("x86/boot/64/clang: Use fixup_pointer() to access 'next_early_pgt'"),
'__supported_pte_mask' must be also accessed using fixup_pointer() to
avoid position-dependent relocations.

Signed-off-by: Alexander Potapenko <glider@google.com>
Fixes: fb43d6cb91ef ("x86/mm: Do not auto-massage page protections")
---
arch/x86/kernel/head64.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 0c408f8c4ed4..1b36ae4d0035 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -113,6 +113,7 @@ unsigned long __head __startup_64(unsigned long physaddr,
p4dval_t *p4d;
pudval_t *pud;
pmdval_t *pmd, pmd_entry;
+ pteval_t *mask_ptr;
bool la57;
int i;
unsigned int *next_pgt_ptr;
@@ -196,7 +197,8 @@ unsigned long __head __startup_64(unsigned long physaddr,

pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
/* Filter out unsupported __PAGE_KERNEL_* bits: */
- pmd_entry &= __supported_pte_mask;
+ mask_ptr = (pteval_t *)fixup_pointer(&__supported_pte_mask, physaddr);
+ pmd_entry &= *mask_ptr;
pmd_entry += sme_get_me_mask();
pmd_entry += physaddr;

--
2.17.0.441.gb46fe60e1d-goog