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| author |   Steve Capper <steve.capper@arm.com> | 2019-08-07 16:55:19 +0100 |
|---|---|---|
| committer |   Will Deacon <will@kernel.org> | 2019-08-09 11:17:24 +0100 |
| commit | c812026c54cfaec23fa1d78cdbfd0e56e787470a (patch) | |
| tree | 21c649aa4bd867a2d871e7c2ad9192824999874f /arch/arm64/kernel | |
| parent | arm64: mm: Introduce vabits_actual (diff) | |
| download | linux-dev-c812026c54cfaec23fa1d78cdbfd0e56e787470a.tar.xz linux-dev-c812026c54cfaec23fa1d78cdbfd0e56e787470a.zip | |
arm64: mm: Logic to make offset_ttbr1 conditional
When running with a 52-bit userspace VA and a 48-bit kernel VA we offset
ttbr1_el1 to allow the kernel pagetables with a 52-bit PTRS_PER_PGD to
be used for both userspace and kernel.
Moving on to a 52-bit kernel VA we no longer require this offset to
ttbr1_el1 should we be running on a system with HW support for 52-bit
VAs.
This patch introduces conditional logic to offset_ttbr1 to query
SYS_ID_AA64MMFR2_EL1 whenever 52-bit VAs are selected. If there is HW
support for 52-bit VAs then the ttbr1 offset is skipped.
We choose to read a system register rather than vabits_actual because
offset_ttbr1 can be called in places where the kernel data is not
actually mapped.
Calls to offset_ttbr1 appear to be made from rarely called code paths so
this extra logic is not expected to adversely affect performance.
Signed-off-by: Steve Capper <steve.capper@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/head.S | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/hibernate-asm.S | 8 |
2 files changed, 5 insertions, 5 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 6dc7349868d9..a96dc4386c7c 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -777,7 +777,7 @@ ENTRY(__enable_mmu) phys_to_ttbr x1, x1 phys_to_ttbr x2, x2 msr ttbr0_el1, x2 // load TTBR0 - offset_ttbr1 x1 + offset_ttbr1 x1, x3 msr ttbr1_el1, x1 // load TTBR1 isb msr sctlr_el1, x0 diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S index 2f4a2ce7264b..38bcd4d4e43b 100644 --- a/arch/arm64/kernel/hibernate-asm.S +++ b/arch/arm64/kernel/hibernate-asm.S @@ -22,14 +22,14 @@ * Even switching to our copied tables will cause a changed output address at * each stage of the walk. */ -.macro break_before_make_ttbr_switch zero_page, page_table, tmp +.macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2 phys_to_ttbr \tmp, \zero_page msr ttbr1_el1, \tmp isb tlbi vmalle1 dsb nsh phys_to_ttbr \tmp, \page_table - offset_ttbr1 \tmp + offset_ttbr1 \tmp, \tmp2 msr ttbr1_el1, \tmp isb .endm @@ -70,7 +70,7 @@ ENTRY(swsusp_arch_suspend_exit) * We execute from ttbr0, change ttbr1 to our copied linear map tables * with a break-before-make via the zero page */ - break_before_make_ttbr_switch x5, x0, x6 + break_before_make_ttbr_switch x5, x0, x6, x8 mov x21, x1 mov x30, x2 @@ -101,7 +101,7 @@ ENTRY(swsusp_arch_suspend_exit) dsb ish /* wait for PoU cleaning to finish */ /* switch to the restored kernels page tables */ - break_before_make_ttbr_switch x25, x21, x6 + break_before_make_ttbr_switch x25, x21, x6, x8 ic ialluis dsb ish |