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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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f60fe78f13
We allocate our IRQ stacks using a percpu array. This allows us to generate our IRQ stack pointers with adr_this_cpu, but bloats the kernel Image with the boot CPU's IRQ stack. Additionally, these are packed with other percpu variables, and aren't guaranteed to have guard pages. When we enable VMAP_STACK we'll want to vmap our IRQ stacks also, in order to provide guard pages and to permit more stringent alignment requirements. Doing so will require that we use a percpu pointer to each IRQ stack, rather than allocating a percpu IRQ stack in the kernel image. This patch updates our IRQ stack code to use a percpu pointer to the base of each IRQ stack. This will allow us to change the way the stack is allocated with minimal changes elsewhere. In some cases we may try to backtrace before the IRQ stack pointers are initialised, so on_irq_stack() is updated to account for this. In testing with cyclictest, there was no measureable difference between using adr_this_cpu (for irq_stack) and ldr_this_cpu (for irq_stack_ptr) in the IRQ entry path. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Tested-by: Laura Abbott <labbott@redhat.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com>
69 lines
1.9 KiB
C
69 lines
1.9 KiB
C
/*
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* Based on arch/arm/kernel/irq.c
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*
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* Copyright (C) 1992 Linus Torvalds
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* Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
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* Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
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* Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
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* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kernel_stat.h>
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#include <linux/irq.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/irqchip.h>
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#include <linux/seq_file.h>
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unsigned long irq_err_count;
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/* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
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DEFINE_PER_CPU(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack) __aligned(16);
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DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
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int arch_show_interrupts(struct seq_file *p, int prec)
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{
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show_ipi_list(p, prec);
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seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
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return 0;
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}
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void (*handle_arch_irq)(struct pt_regs *) = NULL;
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void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
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{
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if (handle_arch_irq)
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return;
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handle_arch_irq = handle_irq;
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}
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static void init_irq_stacks(void)
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{
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int cpu;
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for_each_possible_cpu(cpu)
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per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
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}
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void __init init_IRQ(void)
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{
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init_irq_stacks();
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irqchip_init();
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if (!handle_arch_irq)
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panic("No interrupt controller found.");
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}
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