From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Mark Rutland , Laura Abbott , Ard Biesheuvel , James Morse , Will Deacon , Catalin Marinas , Marc Zyngier Subject: [PATCH 4.9 43/66] arm64: assembler: introduce ldr_this_cpu Date: Fri, 20 Jul 2018 14:14:00 +0200 Message-Id: <20180720121409.713670182@linuxfoundation.org> In-Reply-To: <20180720121407.228772286@linuxfoundation.org> References: <20180720121407.228772286@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Rutland 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 Tested-by: Laura Abbott Cc: Ard Biesheuvel Cc: James Morse Cc: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/assembler.h | 19 +++++++++++++++---- arch/arm64/kernel/entry.S | 2 +- 2 files changed, 16 insertions(+), 5 deletions(-) --- 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 \reg, \reg, \tmp + 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 + ldr \dst, [\dst, \tmp] .endm /* --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -243,7 +243,7 @@ alternative_insn eret, nop, ARM64_UNMAP_ 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