From b07984a249555dc0c3dca60d6a28d1832cf4a0f2 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 25 Jan 2016 11:45:00 +0000 Subject: [PATCH] arm64: add function to install the idmap In some cases (e.g. when making invasive changes to the kernel page tables) we will need to execute code from the idmap. Add a new helper which may be used to install the idmap, complementing the existing cpu_uninstall_idmap. Signed-off-by: Mark Rutland Reviewed-by: Catalin Marinas Tested-by: Ard Biesheuvel Reviewed-by: Ard Biesheuvel Tested-by: Jeremy Linton Cc: Laura Abbott Cc: Will Deacon Signed-off-by: Catalin Marinas (cherry picked from commit 609116d202a8c5fd3fe393eb85373cbee906df68) Signed-off-by: Alex Shi --- arch/arm64/include/asm/mmu_context.h | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index b1b2514d8883..944f2730a940 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -74,7 +74,7 @@ static inline bool __cpu_uses_extended_idmap(void) /* * Set TCR.T0SZ to its default value (based on VA_BITS) */ -static inline void cpu_set_default_tcr_t0sz(void) +static inline void __cpu_set_tcr_t0sz(unsigned long t0sz) { unsigned long tcr; @@ -87,9 +87,12 @@ static inline void cpu_set_default_tcr_t0sz(void) " msr tcr_el1, %0 ;" " isb" : "=&r" (tcr) - : "r"(TCR_T0SZ(VA_BITS)), "I"(TCR_T0SZ_OFFSET), "I"(TCR_TxSZ_WIDTH)); + : "r"(t0sz), "I"(TCR_T0SZ_OFFSET), "I"(TCR_TxSZ_WIDTH)); } +#define cpu_set_default_tcr_t0sz() __cpu_set_tcr_t0sz(TCR_T0SZ(VA_BITS)) +#define cpu_set_idmap_tcr_t0sz() __cpu_set_tcr_t0sz(idmap_t0sz) + /* * Remove the idmap from TTBR0_EL1 and install the pgd of the active mm. * @@ -114,6 +117,15 @@ static inline void cpu_uninstall_idmap(void) cpu_switch_mm(mm->pgd, mm); } +static inline void cpu_install_idmap(void) +{ + cpu_set_reserved_ttbr0(); + local_flush_tlb_all(); + cpu_set_idmap_tcr_t0sz(); + + cpu_switch_mm(idmap_pg_dir, &init_mm); +} + /* * It would be nice to return ASIDs back to the allocator, but unfortunately * that introduces a race with a generation rollover where we could erroneously -- 2.34.1