| Message ID | 1512059986-21325-4-git-send-email-will.deacon@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: Unmap the kernel whilst running in userspace (KAISER) | expand |
Hi Will, On Thu, Nov 30, 2017 at 04:39:31PM +0000, Will Deacon wrote: > 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> [...] > +#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) A minor thing, but could we please fix the spacing for the cpu_do_switch_mm() arguments while we move this? AFAICT, there's no reason this needs to be a macro, and the following works with v4.15-rc1 defconfig: 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); } Otherwise, the patch looks good to me. Thanks, Mark.
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 95233dfc4c39..a8a64898a2aa 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 @@ -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 /*
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(-) -- 2.1.4