lkml.org 
[lkml]   [2017]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 03/18] arm64: mm: Move ASID from TTBR0 to TTBR1
Date
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).

Signed-off-by: Will Deacon <will.deacon@arm.com>
---
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(-)

diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index 3257895a9b5e..56723bcbfaaa 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -37,6 +37,13 @@
#include <asm/sysreg.h>
#include <asm/tlbflush.h>

+#define cpu_switch_mm(pgd,mm) \
+do { \
+ BUG_ON(pgd == swapper_pg_dir); \
+ cpu_set_reserved_ttbr0(); \
+ cpu_do_switch_mm(virt_to_phys(pgd),mm); \
+} while (0)
+
static inline void contextidr_thread_switch(struct task_struct *next)
{
if (!IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR))
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index eb0c2bd90de9..8df4cb6ac6f7 100644
--- 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)
diff --git a/arch/arm64/include/asm/proc-fns.h b/arch/arm64/include/asm/proc-fns.h
index 14ad6e4e87d1..16cef2e8449e 100644
--- 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, u64 idmap_ttbr);

#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 */
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 877d42fb0df6..0bd7550b7230 100644
--- 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
@@ -225,7 +228,7 @@ 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

/*
--
2.1.4
\
 
 \ /
  Last update: 2017-11-17 19:26    [W:0.314 / U:1.456 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site