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From: Marc Zyngier <marc.zyngier@arm.com>
To: stable@vger.kernel.org
Cc: Will Deacon <will.deacon@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>
Subject: [PATCH 01/23] arm64: assembler: introduce ldr_this_cpu
Date: Fri, 20 Jul 2018 10:56:12 +0100	[thread overview]
Message-ID: <20180720095634.2173-2-marc.zyngier@arm.com> (raw)
In-Reply-To: <20180720095634.2173-1-marc.zyngier@arm.com>

From: Mark Rutland <mark.rutland@arm.com>

Commit 1b7e2296a822dfd2349960addc42a139360ce769 upstream.

Shortly we will want to load a percpu variable in the return from
userspace path. We can save an instruction by folding the addition of
the percpu offset into the load instruction, and this patch adds a new
helper to do so.

At the same time, we clean up this_cpu_ptr for consistency. As with
{adr,ldr,str}_l, we change the template to take the destination register
first, and name this dst. Secondly, we rename the macro to adr_this_cpu,
following the scheme of adr_l, and matching the newly added
ldr_this_cpu.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/assembler.h | 19 +++++++++++++++----
 arch/arm64/kernel/entry.S          |  2 +-
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index bfcfec3590f6..a4f227f6a400 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -239,14 +239,25 @@ lr	.req	x30		// link register
 	.endm
 
 	/*
+	 * @dst: Result of per_cpu(sym, smp_processor_id())
 	 * @sym: The name of the per-cpu variable
-	 * @reg: Result of per_cpu(sym, smp_processor_id())
 	 * @tmp: scratch register
 	 */
-	.macro this_cpu_ptr, sym, reg, tmp
-	adr_l	\reg, \sym
+	.macro adr_this_cpu, dst, sym, tmp
+	adr_l	\dst, \sym
+	mrs	\tmp, tpidr_el1
+	add	\dst, \dst, \tmp
+	.endm
+
+	/*
+	 * @dst: Result of READ_ONCE(per_cpu(sym, smp_processor_id()))
+	 * @sym: The name of the per-cpu variable
+	 * @tmp: scratch register
+	 */
+	.macro ldr_this_cpu dst, sym, tmp
+	adr_l	\dst, \sym
 	mrs	\tmp, tpidr_el1
-	add	\reg, \reg, \tmp
+	ldr	\dst, [\dst, \tmp]
 	.endm
 
 /*
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index b79e302d2a3e..7fed00b47692 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -243,7 +243,7 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 	cmp	x25, tsk
 	b.ne	9998f
 
-	this_cpu_ptr irq_stack, x25, x26
+	adr_this_cpu x25, irq_stack, x26
 	mov	x26, #IRQ_STACK_START_SP
 	add	x26, x25, x26
 
-- 
2.18.0

  reply	other threads:[~2018-07-20 10:44 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-20  9:56 [PATCH 00/23] arm64: 4.9 backport of the SSBD mitigation patches Marc Zyngier
2018-07-20  9:56 ` Marc Zyngier [this message]
2018-07-20  9:56 ` [PATCH 02/23] KVM: arm64: Store vcpu on the stack during __guest_enter() Marc Zyngier
2018-07-20  9:56 ` [PATCH 03/23] KVM: arm/arm64: Convert kvm_host_cpu_state to a static per-cpu allocation Marc Zyngier
2018-07-20  9:56 ` [PATCH 04/23] KVM: arm64: Change hyp_panic()s dependency on tpidr_el2 Marc Zyngier
2018-07-20  9:56 ` [PATCH 05/23] arm64: alternatives: use tpidr_el2 on VHE hosts Marc Zyngier
2018-07-20  9:56 ` [PATCH 06/23] KVM: arm64: Stop save/restoring host tpidr_el1 on VHE Marc Zyngier
2018-07-20  9:56 ` [PATCH 07/23] arm64: alternatives: Add dynamic patching feature Marc Zyngier
2018-07-20  9:56 ` [PATCH 08/23] KVM: arm/arm64: Do not use kern_hyp_va() with kvm_vgic_global_state Marc Zyngier
2018-07-20  9:56 ` [PATCH 09/23] KVM: arm64: Avoid storing the vcpu pointer on the stack Marc Zyngier
2018-07-20  9:56 ` [PATCH 10/23] arm/arm64: smccc: Add SMCCC-specific return codes Marc Zyngier
2018-07-20  9:56 ` [PATCH 11/23] arm64: Call ARCH_WORKAROUND_2 on transitions between EL0 and EL1 Marc Zyngier
2018-07-20  9:56 ` [PATCH 12/23] arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2 Marc Zyngier
2018-07-20  9:56 ` [PATCH 13/23] arm64: Add ARCH_WORKAROUND_2 probing Marc Zyngier
2018-07-20  9:56 ` [PATCH 14/23] arm64: Add 'ssbd' command-line option Marc Zyngier
2018-07-20  9:56 ` [PATCH 15/23] arm64: ssbd: Add global mitigation state accessor Marc Zyngier
2018-07-20  9:56 ` [PATCH 16/23] arm64: ssbd: Skip apply_ssbd if not using dynamic mitigation Marc Zyngier
2018-07-20  9:56 ` [PATCH 17/23] arm64: ssbd: Restore mitigation status on CPU resume Marc Zyngier
2018-07-20  9:56 ` [PATCH 18/23] arm64: ssbd: Introduce thread flag to control userspace mitigation Marc Zyngier
2018-07-20  9:56 ` [PATCH 19/23] arm64: ssbd: Add prctl interface for per-thread mitigation Marc Zyngier
2018-07-20  9:56 ` [PATCH 20/23] arm64: KVM: Add HYP per-cpu accessors Marc Zyngier
2018-07-20  9:56 ` [PATCH 21/23] arm64: KVM: Add ARCH_WORKAROUND_2 support for guests Marc Zyngier
2018-07-20  9:56 ` [PATCH 22/23] arm64: KVM: Handle guest's ARCH_WORKAROUND_2 requests Marc Zyngier
2018-07-20  9:56 ` [PATCH 23/23] arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID Marc Zyngier
2018-07-20 10:43 ` [PATCH 00/23] arm64: 4.9 backport of the SSBD mitigation patches Greg KH

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