[Xen-devel] [PATCH v2 05/10] x86/traps: Functional prep work

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

* Promote certain actions to earlier in __start_xen().
* Declare double_fault and early_page_fault as standard trap handlers.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Keir Fraser <keir@xxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>

---

It would be nice if the linker could sort the exception tables for us, and the
Xen check could simply assert that it was sorted.  Making this happen is not a
job for now.

v2:
 * Don't introduce an explicitly latent this_cpu() bug before
   percpu_area_init(), and implicit latent bug with subsequent changes.
---
 xen/arch/x86/setup.c            |   14 +++++++-------
 xen/arch/x86/x86_64/traps.c     |    1 -
 xen/include/asm-x86/processor.h |    2 ++
 xen/include/asm-x86/setup.h     |    1 -
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 68f4bcc..82ce344 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -558,8 +558,15 @@ void __init noreturn __start_xen(unsigned long mbi_p)
         .stop_bits = 1
     };
 
+    set_processor_id(0);
+    set_current((struct vcpu *)0xfffff000); /* debug sanity. */
+    idle_vcpu[0] = current;
+
     percpu_init_areas();
 
+    smp_prepare_boot_cpu();
+    sort_exception_tables();
+
     set_intr_gate(TRAP_page_fault, &early_page_fault);
 
     loader = (mbi->flags & MBI_LOADERNAME)
@@ -588,15 +595,10 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 
     parse_video_info();
 
-    set_current((struct vcpu *)0xfffff000); /* debug sanity */
-    idle_vcpu[0] = current;
-    set_processor_id(0); /* needed early, for smp_processor_id() */
     if ( cpu_has_efer )
         rdmsrl(MSR_EFER, this_cpu(efer));
     asm volatile ( "mov %%cr4,%0" : "=r" (this_cpu(cr4)) );
 
-    smp_prepare_boot_cpu();
-
     /* We initialise the serial devices very early so we can get debugging. */
     ns16550.io_base = 0x3f8;
     ns16550.irq     = 4;
@@ -1212,8 +1214,6 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     if ( opt_watchdog ) 
         nmi_watchdog = NMI_LOCAL_APIC;
 
-    sort_exception_tables();
-
     find_smp_config();
 
     dmi_scan_machine();
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index af20e0b..898f9a0 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -223,7 +223,6 @@ void show_page_walk(unsigned long addr)
            l1_table_offset(addr), l1e_get_intpte(l1e), pfn);
 }
 
-void double_fault(void);
 void do_double_fault(struct cpu_user_regs *regs)
 {
     unsigned int cpu;
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index 35b2433..c9051be 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -500,12 +500,14 @@ DECLARE_TRAP_HANDLER(overflow);
 DECLARE_TRAP_HANDLER(bounds);
 DECLARE_TRAP_HANDLER(invalid_op);
 DECLARE_TRAP_HANDLER(device_not_available);
+DECLARE_TRAP_HANDLER(double_fault);
 DECLARE_TRAP_HANDLER(coprocessor_segment_overrun);
 DECLARE_TRAP_HANDLER(invalid_TSS);
 DECLARE_TRAP_HANDLER(segment_not_present);
 DECLARE_TRAP_HANDLER(stack_segment);
 DECLARE_TRAP_HANDLER(general_protection);
 DECLARE_TRAP_HANDLER(page_fault);
+DECLARE_TRAP_HANDLER(early_page_fault);
 DECLARE_TRAP_HANDLER(coprocessor_error);
 DECLARE_TRAP_HANDLER(simd_coprocessor_error);
 DECLARE_TRAP_HANDLER(machine_check);
diff --git a/xen/include/asm-x86/setup.h b/xen/include/asm-x86/setup.h
index 3039e1b..8f8c6f3 100644
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -7,7 +7,6 @@ extern unsigned long xenheap_initial_phys_start;
 
 void early_cpu_init(void);
 void early_time_init(void);
-void early_page_fault(void);
 
 int intel_cpu_init(void);
 int amd_init_cpu(void);
-- 
1.7.10.4


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