[tip:x86/apic] x86, irq: Refine mp_register_ioapic() to prepare for IOAPIC hotplug

tip-bot for Jiang Liu
2014-11-03T11:03:19Z

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,