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    Subject[tip:x86/apic] x86, irq: Refine mp_register_ioapic() to prepare for IOAPIC hotplug
    Commit-ID:  36f3a2a6cec30b332035ccad32d749b2216a2168
    Gitweb: http://git.kernel.org/tip/36f3a2a6cec30b332035ccad32d749b2216a2168
    Author: Jiang Liu <jiang.liu@linux.intel.com>
    AuthorDate: Mon, 27 Oct 2014 13:21:43 +0800
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Mon, 3 Nov 2014 11:56:08 +0100

    x86, irq: Refine mp_register_ioapic() to prepare for IOAPIC hotplug

    Refine mp_register_ioapic() to prepare for IOAPIC hotplug by:
    1) change return value from void to int.
    2) check for gsi range conflicts
    3) check for IOAPIC physical address conflicts
    4) enhance the way to allocate IOAPIC index

    Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
    Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: Joerg Roedel <joro@8bytes.org>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
    Cc: Bjorn Helgaas <bhelgaas@google.com>
    Cc: Randy Dunlap <rdunlap@infradead.org>
    Cc: Yinghai Lu <yinghai@kernel.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Grant Likely <grant.likely@linaro.org>
    Cc: Prarit Bhargava <prarit@redhat.com>
    Link: http://lkml.kernel.org/r/1414387308-27148-14-git-send-email-jiang.liu@linux.intel.com
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    arch/x86/include/asm/io_apic.h | 4 +-
    arch/x86/kernel/apic/io_apic.c | 87 +++++++++++++++++++++++++++---------------
    2 files changed, 58 insertions(+), 33 deletions(-)

    diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
    index a666dcd..8741c1e 100644
    --- a/arch/x86/include/asm/io_apic.h
    +++ b/arch/x86/include/asm/io_apic.h
    @@ -188,8 +188,8 @@ extern int mp_find_ioapic_pin(int ioapic, u32 gsi);
    extern u32 mp_pin_to_gsi(int ioapic, int pin);
    extern int mp_map_gsi_to_irq(u32 gsi, unsigned int flags);
    extern void mp_unmap_irq(int irq);
    -extern void mp_register_ioapic(int id, u32 address, u32 gsi_base,
    - struct ioapic_domain_cfg *cfg);
    +extern int mp_register_ioapic(int id, u32 address, u32 gsi_base,
    + struct ioapic_domain_cfg *cfg);
    extern int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
    irq_hw_number_t hwirq);
    extern void mp_irqdomain_unmap(struct irq_domain *domain, unsigned int virq);
    diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
    index 19501ab..090d3fe 100644
    --- a/arch/x86/kernel/apic/io_apic.c
    +++ b/arch/x86/kernel/apic/io_apic.c
    @@ -3840,20 +3840,6 @@ int mp_find_ioapic_pin(int ioapic, u32 gsi)
    return gsi - gsi_cfg->gsi_base;
    }

    -static int bad_ioapic(unsigned long address)
    -{
    - if (nr_ioapics >= MAX_IO_APICS) {
    - pr_warn("WARNING: Max # of I/O APICs (%d) exceeded (found %d), skipping\n",
    - MAX_IO_APICS, nr_ioapics);
    - return 1;
    - }
    - if (!address) {
    - pr_warn("WARNING: Bogus (zero) I/O APIC address found in table, skipping!\n");
    - return 1;
    - }
    - return 0;
    -}
    -
    static int bad_ioapic_register(int idx)
    {
    union IO_APIC_reg_00 reg_00;
    @@ -3873,29 +3859,51 @@ static int bad_ioapic_register(int idx)
    return 0;
    }

    -void mp_register_ioapic(int id, u32 address, u32 gsi_base,
    - struct ioapic_domain_cfg *cfg)
    +static int find_free_ioapic_entry(void)
    +{
    + return nr_ioapics;
    +}
    +
    +/**
    + * mp_register_ioapic - Register an IOAPIC device
    + * @id: hardware IOAPIC ID
    + * @address: physical address of IOAPIC register area
    + * @gsi_base: base of GSI associated with the IOAPIC
    + * @cfg: configuration information for the IOAPIC
    + */
    +int mp_register_ioapic(int id, u32 address, u32 gsi_base,
    + struct ioapic_domain_cfg *cfg)
    {
    - int idx = 0;
    - int entries;
    struct mp_ioapic_gsi *gsi_cfg;
    + int idx, ioapic, entries;
    + u32 gsi_end;

    - if (bad_ioapic(address))
    - return;
    + if (!address) {
    + pr_warn("Bogus (zero) I/O APIC address found, skipping!\n");
    + return -EINVAL;
    + }
    + for_each_ioapic(ioapic)
    + if (ioapics[ioapic].mp_config.apicaddr == address) {
    + pr_warn("address 0x%x conflicts with IOAPIC%d\n",
    + address, ioapic);
    + return -EEXIST;
    + }

    - idx = nr_ioapics;
    + idx = find_free_ioapic_entry();
    + if (idx >= MAX_IO_APICS) {
    + pr_warn("Max # of I/O APICs (%d) exceeded (found %d), skipping\n",
    + MAX_IO_APICS, idx);
    + return -ENOSPC;
    + }

    ioapics[idx].mp_config.type = MP_IOAPIC;
    ioapics[idx].mp_config.flags = MPC_APIC_USABLE;
    ioapics[idx].mp_config.apicaddr = address;
    - ioapics[idx].irqdomain = NULL;
    - ioapics[idx].irqdomain_cfg = *cfg;

    set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
    -
    if (bad_ioapic_register(idx)) {
    clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
    - return;
    + return -ENODEV;
    }

    ioapics[idx].mp_config.apicid = io_apic_unique_id(idx, id);
    @@ -3906,24 +3914,41 @@ void mp_register_ioapic(int id, u32 address, u32 gsi_base,
    * and to prevent reprogramming of IOAPIC pins (PCI GSIs).
    */
    entries = io_apic_get_redir_entries(idx);
    + gsi_end = gsi_base + entries - 1;
    + for_each_ioapic(ioapic) {
    + gsi_cfg = mp_ioapic_gsi_routing(ioapic);
    + if ((gsi_base >= gsi_cfg->gsi_base &&
    + gsi_base <= gsi_cfg->gsi_end) ||
    + (gsi_end >= gsi_cfg->gsi_base &&
    + gsi_end <= gsi_cfg->gsi_end)) {
    + pr_warn("GSI range [%u-%u] for new IOAPIC conflicts with GSI[%u-%u]\n",
    + gsi_base, gsi_end,
    + gsi_cfg->gsi_base, gsi_cfg->gsi_end);
    + clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
    + return -ENOSPC;
    + }
    + }
    gsi_cfg = mp_ioapic_gsi_routing(idx);
    gsi_cfg->gsi_base = gsi_base;
    - gsi_cfg->gsi_end = gsi_base + entries - 1;
    + gsi_cfg->gsi_end = gsi_end;

    - /*
    - * The number of IO-APIC IRQ registers (== #pins):
    - */
    - ioapics[idx].nr_registers = entries;
    + ioapics[idx].irqdomain = NULL;
    + ioapics[idx].irqdomain_cfg = *cfg;

    if (gsi_cfg->gsi_end >= gsi_top)
    gsi_top = gsi_cfg->gsi_end + 1;
    + if (nr_ioapics <= idx)
    + nr_ioapics = idx + 1;
    +
    + /* Set nr_registers to mark entry present */
    + ioapics[idx].nr_registers = entries;

    pr_info("IOAPIC[%d]: apic_id %d, version %d, address 0x%x, GSI %d-%d\n",
    idx, mpc_ioapic_id(idx),
    mpc_ioapic_ver(idx), mpc_ioapic_addr(idx),
    gsi_cfg->gsi_base, gsi_cfg->gsi_end);

    - nr_ioapics++;
    + return 0;
    }

    int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,

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