@@ -15,10 +15,10 @@
.macro __uaccess_ttbr0_disable, tmp1
mrs \tmp1, ttbr1_el1 // swapper_pg_dir
bic \tmp1, \tmp1, #TTBR_ASID_MASK
- sub \tmp1, \tmp1, #PAGE_SIZE // reserved_pg_dir just before swapper_pg_dir
+ sub \tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET // reserved_pg_dir
msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1
isb
- add \tmp1, \tmp1, #PAGE_SIZE
+ add \tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET
msr ttbr1_el1, \tmp1 // set reserved ASID
isb
.endm
@@ -159,6 +159,12 @@
#define IOREMAP_MAX_ORDER (PMD_SHIFT)
#endif
+/*
+ * Open-coded (swapper_pg_dir - reserved_pg_dir) as this cannot be calculated
+ * until link time.
+ */
+#define RESERVED_SWAPPER_OFFSET (PAGE_SIZE)
+
#ifndef __ASSEMBLY__
#include <linux/bitops.h>
@@ -87,7 +87,7 @@ static inline void __uaccess_ttbr0_disable(void)
ttbr = read_sysreg(ttbr1_el1);
ttbr &= ~TTBR_ASID_MASK;
/* reserved_pg_dir placed before swapper_pg_dir */
- write_sysreg(ttbr - PAGE_SIZE, ttbr0_el1);
+ write_sysreg(ttbr - RESERVED_SWAPPER_OFFSET, ttbr0_el1);
isb();
/* Set reserved ASID */
write_sysreg(ttbr, ttbr1_el1);
@@ -316,3 +316,6 @@ ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE,
* If padding is applied before .head.text, virt<->phys conversions will fail.
*/
ASSERT(_text == KIMAGE_VADDR, "HEAD is misaligned")
+
+ASSERT(swapper_pg_dir - reserved_pg_dir == RESERVED_SWAPPER_OFFSET,
+ "RESERVED_SWAPPER_OFFSET is wrong!")
Add RESERVED_SWAPPER_OFFSET and use that instead of hardcoding the offset between swapper_pg_dir and reserved_pg_dir. Then use RESERVED_SWAPPER_OFFSET to assert that the offset is correct at link time. Signed-off-by: Joey Gouly <joey.gouly@arm.com> --- arch/arm64/include/asm/asm-uaccess.h | 4 ++-- arch/arm64/include/asm/memory.h | 6 ++++++ arch/arm64/include/asm/uaccess.h | 2 +- arch/arm64/kernel/vmlinux.lds.S | 3 +++ 4 files changed, 12 insertions(+), 3 deletions(-)