From: James Morse <james.morse@arm.com> To: Jun Yao <yaojun8558363@gmail.com> Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v4 2/6] arm64/mm: Pass ttbr1 as a parameter to __enable_mmu(). Date: Fri, 7 Sep 2018 10:57:17 +0100 [thread overview] Message-ID: <4279135f-393c-d3c1-91dd-cc77159a6062@arm.com> (raw) In-Reply-To: <20180822095432.12125-3-yaojun8558363@gmail.com> Hi Jun, On 22/08/18 10:54, Jun Yao wrote: > The kernel sets up the initial page table in the init_pg_dir. (Nit: 'will set up', it doesn't until patch 3.) > However, it will create the final page table in the swapper_pg_dir > during the initialization process. We need to let __enable_mmu() > know which page table to use. > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index 2c83a8c47e3f..c3e4b1886cde 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -756,6 +757,7 @@ ENDPROC(__secondary_switched) > * Enable the MMU. > * > * x0 = SCTLR_EL1 value for turning on the MMU. > + * x1 = TTBR1_EL1 value for turning on the MMU. > * > * Returns to the caller via x30/lr. This requires the caller to be covered > * by the .idmap.text section. > @@ -764,15 +766,15 @@ ENDPROC(__secondary_switched) > * If it isn't, park the CPU > */ > ENTRY(__enable_mmu) > - mrs x1, ID_AA64MMFR0_EL1 > - ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4 > - cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED > + mrs x5, ID_AA64MMFR0_EL1 > + ubfx x6, x5, #ID_AA64MMFR0_TGRAN_SHIFT, 4 > + cmp x6, #ID_AA64MMFR0_TGRAN_SUPPORTED > b.ne __no_granule_support > - update_early_cpu_boot_status 0, x1, x2 > - adrp x1, idmap_pg_dir > - adrp x2, swapper_pg_dir > - phys_to_ttbr x3, x1 > - phys_to_ttbr x4, x2 > + update_early_cpu_boot_status 0, x5, x6 > + adrp x5, idmap_pg_dir > + mov x6, x1 > + phys_to_ttbr x3, x5 > + phys_to_ttbr x4, x6 > msr ttbr0_el1, x3 // load TTBR0 > msr ttbr1_el1, x4 // load TTBR1 > isb > @@ -791,7 +793,7 @@ ENDPROC(__enable_mmu) > > __no_granule_support: > /* Indicate that this CPU can't boot and is stuck in the kernel */ > - update_early_cpu_boot_status CPU_STUCK_IN_KERNEL, x1, x2 > + update_early_cpu_boot_status CPU_STUCK_IN_KERNEL, x5, x6 (You don't need to change these as they are both temporary registers.) Reviewed-by: James Morse <james.morse@arm.com> Thanks, James
WARNING: multiple messages have this Message-ID (diff)
From: james.morse@arm.com (James Morse) To: linux-arm-kernel@lists.infradead.org Subject: [RESEND PATCH v4 2/6] arm64/mm: Pass ttbr1 as a parameter to __enable_mmu(). Date: Fri, 7 Sep 2018 10:57:17 +0100 [thread overview] Message-ID: <4279135f-393c-d3c1-91dd-cc77159a6062@arm.com> (raw) In-Reply-To: <20180822095432.12125-3-yaojun8558363@gmail.com> Hi Jun, On 22/08/18 10:54, Jun Yao wrote: > The kernel sets up the initial page table in the init_pg_dir. (Nit: 'will set up', it doesn't until patch 3.) > However, it will create the final page table in the swapper_pg_dir > during the initialization process. We need to let __enable_mmu() > know which page table to use. > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index 2c83a8c47e3f..c3e4b1886cde 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -756,6 +757,7 @@ ENDPROC(__secondary_switched) > * Enable the MMU. > * > * x0 = SCTLR_EL1 value for turning on the MMU. > + * x1 = TTBR1_EL1 value for turning on the MMU. > * > * Returns to the caller via x30/lr. This requires the caller to be covered > * by the .idmap.text section. > @@ -764,15 +766,15 @@ ENDPROC(__secondary_switched) > * If it isn't, park the CPU > */ > ENTRY(__enable_mmu) > - mrs x1, ID_AA64MMFR0_EL1 > - ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4 > - cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED > + mrs x5, ID_AA64MMFR0_EL1 > + ubfx x6, x5, #ID_AA64MMFR0_TGRAN_SHIFT, 4 > + cmp x6, #ID_AA64MMFR0_TGRAN_SUPPORTED > b.ne __no_granule_support > - update_early_cpu_boot_status 0, x1, x2 > - adrp x1, idmap_pg_dir > - adrp x2, swapper_pg_dir > - phys_to_ttbr x3, x1 > - phys_to_ttbr x4, x2 > + update_early_cpu_boot_status 0, x5, x6 > + adrp x5, idmap_pg_dir > + mov x6, x1 > + phys_to_ttbr x3, x5 > + phys_to_ttbr x4, x6 > msr ttbr0_el1, x3 // load TTBR0 > msr ttbr1_el1, x4 // load TTBR1 > isb > @@ -791,7 +793,7 @@ ENDPROC(__enable_mmu) > > __no_granule_support: > /* Indicate that this CPU can't boot and is stuck in the kernel */ > - update_early_cpu_boot_status CPU_STUCK_IN_KERNEL, x1, x2 > + update_early_cpu_boot_status CPU_STUCK_IN_KERNEL, x5, x6 (You don't need to change these as they are both temporary registers.) Reviewed-by: James Morse <james.morse@arm.com> Thanks, James
next prev parent reply other threads:[~2018-09-07 9:57 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-08-22 9:54 [RESEND PATCH v4 0/6] arm64/mm: Move swapper_pg_dir to rodata Jun Yao 2018-08-22 9:54 ` Jun Yao 2018-08-22 9:54 ` [RESEND PATCH v4 1/6] arm64/mm: Introduce the init_pg_dir Jun Yao 2018-08-22 9:54 ` Jun Yao 2018-09-07 9:57 ` James Morse 2018-09-07 9:57 ` James Morse 2018-08-22 9:54 ` [RESEND PATCH v4 2/6] arm64/mm: Pass ttbr1 as a parameter to __enable_mmu() Jun Yao 2018-08-22 9:54 ` Jun Yao 2018-09-07 9:57 ` James Morse [this message] 2018-09-07 9:57 ` James Morse 2018-08-22 9:54 ` [RESEND PATCH v4 3/6] arm64/mm: Create the initial page table in the init_pg_dir Jun Yao 2018-08-22 9:54 ` Jun Yao 2018-09-07 9:57 ` James Morse 2018-09-07 9:57 ` James Morse 2018-08-22 9:54 ` [RESEND PATCH v4 4/6] arm64/mm: Create the final page table directly in swapper_pg_dir Jun Yao 2018-08-22 9:54 ` Jun Yao 2018-09-07 9:57 ` James Morse 2018-09-07 9:57 ` James Morse 2018-08-22 9:54 ` [RESEND PATCH v4 5/6] arm64/mm: Populate the swapper_pg_dir by fixmap Jun Yao 2018-08-22 9:54 ` Jun Yao 2018-09-07 9:58 ` James Morse 2018-09-07 9:58 ` James Morse 2018-09-10 11:41 ` Jun Yao 2018-09-10 11:41 ` Jun Yao 2018-09-14 8:44 ` James Morse 2018-09-14 8:44 ` James Morse 2018-09-13 10:50 ` Jun Yao 2018-09-13 10:50 ` Jun Yao 2018-09-14 8:38 ` James Morse 2018-09-14 8:38 ` James Morse 2018-08-22 9:54 ` [RESEND PATCH v4 6/6] arm64/mm: Move {idmap_pg_dir .. swapper_pg_dir} to rodata section Jun Yao 2018-08-22 9:54 ` Jun Yao 2018-09-07 9:57 ` [RESEND PATCH v4 0/6] arm64/mm: Move swapper_pg_dir to rodata James Morse 2018-09-07 9:57 ` James Morse
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