4.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Will Deacon <will.deacon@xxxxxxx>
Commit 7655abb95386 upstream.
In preparation for mapping kernelspace and userspace with different
ASIDs, move the ASID to TTBR1 and update switch_mm to context-switch
TTBR0 via an invalid mapping (the zero page).
Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: Laura Abbott <labbott@xxxxxxxxxx>
Tested-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/mmu_context.h | 7 +++++++
arch/arm64/include/asm/pgtable-hwdef.h | 1 +
arch/arm64/include/asm/proc-fns.h | 6 ------
arch/arm64/mm/proc.S | 9 ++++++---
4 files changed, 14 insertions(+), 9 deletions(-)
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -57,6 +57,13 @@ static inline void cpu_set_reserved_ttbr
isb();
}
+static inline void cpu_switch_mm(pgd_t *pgd, struct mm_struct *mm)
+{
+ BUG_ON(pgd == swapper_pg_dir);
+ cpu_set_reserved_ttbr0();
+ cpu_do_switch_mm(virt_to_phys(pgd),mm);
+}
+
/*
* TCR.T0SZ value to use when the ID map is active. Usually equals
* TCR_T0SZ(VA_BITS), unless system RAM is positioned very high in
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -272,6 +272,7 @@
#define TCR_TG1_4K (UL(2) << TCR_TG1_SHIFT)
#define TCR_TG1_64K (UL(3) << TCR_TG1_SHIFT)
+#define TCR_A1 (UL(1) << 22)
#define TCR_ASID16 (UL(1) << 36)
#define TCR_TBI0 (UL(1) << 37)
#define TCR_HA (UL(1) << 39)
--- a/arch/arm64/include/asm/proc-fns.h
+++ b/arch/arm64/include/asm/proc-fns.h
@@ -35,12 +35,6 @@ extern u64 cpu_do_resume(phys_addr_t ptr
#include <asm/memory.h>
-#define cpu_switch_mm(pgd,mm) \
-do { \
- BUG_ON(pgd == swapper_pg_dir); \
- cpu_do_switch_mm(virt_to_phys(pgd),mm); \
-} while (0)
-
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* __ASM_PROCFNS_H */
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -139,9 +139,12 @@ ENDPROC(cpu_do_resume)
*/
ENTRY(cpu_do_switch_mm)
pre_ttbr0_update_workaround x0, x2, x3
+ mrs x2, ttbr1_el1
mmid x1, x1 // get mm->context.id
- bfi x0, x1, #48, #16 // set the ASID
- msr ttbr0_el1, x0 // set TTBR0
+ bfi x2, x1, #48, #16 // set the ASID
+ msr ttbr1_el1, x2 // in TTBR1 (since TCR.A1 is set)
+ isb
+ msr ttbr0_el1, x0 // now update TTBR0
isb
post_ttbr0_update_workaround
ret
@@ -224,7 +227,7 @@ ENTRY(__cpu_setup)
* both user and kernel.
*/
ldr x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
- TCR_TG_FLAGS | TCR_ASID16 | TCR_TBI0
+ TCR_TG_FLAGS | TCR_ASID16 | TCR_TBI0 | TCR_A1
tcr_set_idmap_t0sz x10, x9
/*