[04/29] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper

Message ID	1519790211-16582-5-git-send-email-alex.shi@linaro.org
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Headers	show Delivered-To: patch@linaro.org Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; From: Alex Shi <alex.shi@linaro.org> To: Marc Zyngier <marc.zyngier@arm.com>, Will Deacon <will.deacon@arm.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Catalin Marinas <catalin.marinas@arm.com>, stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alex Shi <alex.shi@linaro.org> Subject: [PATCH 04/29] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper Date: Wed, 28 Feb 2018 11:56:26 +0800 Message-Id: <1519790211-16582-5-git-send-email-alex.shi@linaro.org> In-Reply-To: <1519790211-16582-1-git-send-email-alex.shi@linaro.org> References: <1519790211-16582-1-git-send-email-alex.shi@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk
Series	arm meltdown fix backporting review for lts 4.9 \| expand [0/29] arm meltdown fix backporting review for lts 4.9 [02/29] arm64: mm: Move ASID from TTBR0 to TTBR1 [03/29] arm64: mm: Allocate ASIDs in pairs [04/29] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper [05/29] arm64: mm: Invalidate both kernel and user ASIDs when performing TLBI [06/29] arm64: factor out entry stack manipulation [07/29] arm64: entry.S: move SError handling into a C function for future expansion [08/29] module: extend 'rodata=off' boot cmdline parameter to module mappings [09/29] arm64: entry: Add exception trampoline page for exceptions from EL0 [10/29] arm64: mm: Map entry trampoline into trampoline and kernel page tables [12/29] arm64: entry: Hook up entry trampoline to exception vectors [14/29] arm64: entry: Add fake CPU feature for unmapping the kernel at EL0 [15/29] arm64: kaslr: Put kernel vectors address in separate data page [16/29] arm64: use RET instruction for exiting the trampoline [17/29] arm64: Kconfig: Add CONFIG_UNMAP_KERNEL_AT_EL0 [18/29] arm64: Kconfig: Reword UNMAP_KERNEL_AT_EL0 kconfig entry [19/29] arm64: Take into account ID_AA64PFR0_EL1.CSV3 [20/29] arm64: Allow checking of a CPU-local erratum [21/29] arm64: capabilities: Handle duplicate entries for a capability [22/29] arm64: cputype: Add missing MIDR values for Cortex-A72 and Cortex-A75 [23/29] arm64: cputype: Add MIDR values for Cavium ThunderX2 CPUs [24/29] arm64: Turn on KPTI only on CPUs that need it [26/29] arm64: kpti: Add ->enable callback to remap swapper using nG mappings [27/29] arm64: Force KPTI to be disabled on Cavium ThunderX [28/29] arm64: entry: Reword comment about post_ttbr_update_workaround [29/29] arm64: idmap: Use "awx" flags for .idmap.text .pushsection directives

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1519790211-16582-5-git-send-email-alex.shi@linaro.org

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Received-SPF: pass (google.com: best guess record for domain of
	linux-kernel-owner@vger.kernel.org designates 209.132.180.67
	as permitted sender) client-ip=209.132.180.67; 
From: Alex Shi <alex.shi@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>, Will Deacon <will.deacon@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
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Cc: Alex Shi <alex.shi@linaro.org>
Subject: [PATCH 04/29] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper
Date: Wed, 28 Feb 2018 11:56:26 +0800
Message-Id: <1519790211-16582-5-git-send-email-alex.shi@linaro.org>
In-Reply-To: <1519790211-16582-1-git-send-email-alex.shi@linaro.org>
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Sender: linux-kernel-owner@vger.kernel.org
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Series

arm meltdown fix backporting review for lts 4.9 | expand

Commit Message

Alex Shi Feb. 28, 2018, 3:56 a.m. UTC

From: Will Deacon <will.deacon@arm.com>


commit fc0e1299da54 upstream.

In order for code such as TLB invalidation to operate efficiently when
the decision to map the kernel at EL0 is determined at runtime, this
patch introduces a helper function, arm64_kernel_unmapped_at_el0, to
determine whether or not the kernel is mapped whilst running in userspace.

Currently, this just reports the value of CONFIG_UNMAP_KERNEL_AT_EL0,
but will later be hooked up to a fake CPU capability using a static key.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Tested-by: Laura Abbott <labbott@redhat.com>

Tested-by: Shanker Donthineni <shankerd@codeaurora.org>

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

Signed-off-by: Alex Shi <alex.shi@linaro.org>

---
 arch/arm64/include/asm/mmu.h | 8 ++++++++
 1 file changed, 8 insertions(+)

-- 
2.7.4

diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 49924e5..279e75b 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -18,6 +18,8 @@ 
 
 #define USER_ASID_FLAG	(UL(1) << 48)
 
+#ifndef __ASSEMBLY__
+
 typedef struct {
 	atomic64_t	id;
 	void		*vdso;
@@ -30,6 +32,11 @@  typedef struct {
  */
 #define ASID(mm)	((mm)->context.id.counter & 0xffff)
 
+static inline bool arm64_kernel_unmapped_at_el0(void)
+{
+	return IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0);
+}
+
 extern void paging_init(void);
 extern void bootmem_init(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
@@ -39,4 +46,5 @@  extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 			       pgprot_t prot, bool allow_block_mappings);
 extern void *fixmap_remap_fdt(phys_addr_t dt_phys);
 
+#endif	/* !__ASSEMBLY__ */
 #endif

[04/29] arm64: mm: Add arm64_kernel_unmapped_at_el0 helper

Commit Message

Patch