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b611303811
Resume from hibernate needs to clean any text executed by the kernel with the MMU off to the PoC. Collect these functions together into the .idmap.text section as all this code is tightly coupled and also needs the same cleaning after resume. Data is more complicated, secondary_holding_pen_release is written with the MMU on, clean and invalidated, then read with the MMU off. In contrast __boot_cpu_mode is written with the MMU off, the corresponding cache line is invalidated, so when we read it with the MMU on we don't get stale data. These cache maintenance operations conflict with each other if the values are within a Cache Writeback Granule (CWG) of each other. Collect the data into two sections .mmuoff.data.read and .mmuoff.data.write, the linker script ensures mmuoff.data.write section is aligned to the architectural maximum CWG of 2KB. Signed-off-by: James Morse <james.morse@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
135 lines
3.4 KiB
C
135 lines
3.4 KiB
C
/*
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* Spin Table SMP initialisation
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*
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* Copyright (C) 2013 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/delay.h>
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#include <linux/init.h>
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#include <linux/of.h>
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#include <linux/smp.h>
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#include <linux/types.h>
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#include <asm/cacheflush.h>
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#include <asm/cpu_ops.h>
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#include <asm/cputype.h>
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#include <asm/io.h>
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#include <asm/smp_plat.h>
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extern void secondary_holding_pen(void);
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volatile unsigned long __section(".mmuoff.data.read")
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secondary_holding_pen_release = INVALID_HWID;
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static phys_addr_t cpu_release_addr[NR_CPUS];
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/*
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* Write secondary_holding_pen_release in a way that is guaranteed to be
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* visible to all observers, irrespective of whether they're taking part
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* in coherency or not. This is necessary for the hotplug code to work
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* reliably.
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*/
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static void write_pen_release(u64 val)
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{
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void *start = (void *)&secondary_holding_pen_release;
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unsigned long size = sizeof(secondary_holding_pen_release);
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secondary_holding_pen_release = val;
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__flush_dcache_area(start, size);
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}
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static int smp_spin_table_cpu_init(unsigned int cpu)
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{
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struct device_node *dn;
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int ret;
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dn = of_get_cpu_node(cpu, NULL);
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if (!dn)
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return -ENODEV;
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/*
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* Determine the address from which the CPU is polling.
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*/
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ret = of_property_read_u64(dn, "cpu-release-addr",
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&cpu_release_addr[cpu]);
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if (ret)
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pr_err("CPU %d: missing or invalid cpu-release-addr property\n",
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cpu);
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of_node_put(dn);
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return ret;
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}
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static int smp_spin_table_cpu_prepare(unsigned int cpu)
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{
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__le64 __iomem *release_addr;
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if (!cpu_release_addr[cpu])
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return -ENODEV;
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/*
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* The cpu-release-addr may or may not be inside the linear mapping.
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* As ioremap_cache will either give us a new mapping or reuse the
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* existing linear mapping, we can use it to cover both cases. In
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* either case the memory will be MT_NORMAL.
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*/
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release_addr = ioremap_cache(cpu_release_addr[cpu],
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sizeof(*release_addr));
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if (!release_addr)
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return -ENOMEM;
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/*
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* We write the release address as LE regardless of the native
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* endianess of the kernel. Therefore, any boot-loaders that
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* read this address need to convert this address to the
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* boot-loader's endianess before jumping. This is mandated by
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* the boot protocol.
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*/
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writeq_relaxed(__pa(secondary_holding_pen), release_addr);
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__flush_dcache_area((__force void *)release_addr,
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sizeof(*release_addr));
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/*
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* Send an event to wake up the secondary CPU.
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*/
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sev();
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iounmap(release_addr);
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return 0;
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}
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static int smp_spin_table_cpu_boot(unsigned int cpu)
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{
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/*
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* Update the pen release flag.
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*/
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write_pen_release(cpu_logical_map(cpu));
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/*
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* Send an event, causing the secondaries to read pen_release.
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*/
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sev();
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return 0;
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}
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const struct cpu_operations smp_spin_table_ops = {
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.name = "spin-table",
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.cpu_init = smp_spin_table_cpu_init,
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.cpu_prepare = smp_spin_table_cpu_prepare,
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.cpu_boot = smp_spin_table_cpu_boot,
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};
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