[Xen-changelog] [xen master] xen/arm: Add some useful debug in coprocessor trapping

[patchbot@xxxxxxx]

commit 42642dbd8511a8a3c2e70792a31d725b780a7744
Author:     Julien Grall <julien.grall@xxxxxxxxxx>
AuthorDate: Thu Jun 19 15:09:49 2014 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Fri Jun 27 14:13:22 2014 +0100

    xen/arm: Add some useful debug in coprocessor trapping
    
    XSA-93 adds a couple of new functions to trap coprocessor registers. They
    unconditionally inject an undefined instruction to guest.
    
    When debugging an OS at early stage, it may be hard to know why the guest
    received an UNDEFINED. Add some debug message to help the developer when Xen
    is built in debug mode.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/arch/arm/traps.c            |   20 ++++++++++++++++++++
 xen/include/asm-arm/processor.h |   11 +++++++++++
 2 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 994b654..2fde0dd 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1546,23 +1546,43 @@ bad_cp:
 
 static void do_cp14_dbg(struct cpu_user_regs *regs, union hsr hsr)
 {
+#ifndef NDEBUG
+    struct hsr_cp64 cp64 = hsr.cp64;
+#endif
+
     if ( !check_conditional_instr(regs, hsr) )
     {
         advance_pc(regs, hsr);
         return;
     }
 
+#ifndef NDEBUG
+    gdprintk(XENLOG_ERR,
+             "%s p14, %d, r%d, r%d, cr%d @ 0x%"PRIregister"\n",
+             cp64.read ? "mrrc" : "mcrr",
+             cp64.op1, cp64.reg1, cp64.reg2, cp64.crm, regs->pc);
+    gdprintk(XENLOG_ERR, "unhandled 64-bit CP14 access %#x\n",
+             hsr.bits & HSR_CP64_REGS_MASK);
+#endif
     inject_undef32_exception(regs);
 }
 
 static void do_cp(struct cpu_user_regs *regs, union hsr hsr)
 {
+#ifndef NDEBUG
+    struct hsr_cp cp = hsr.cp;
+#endif
+
     if ( !check_conditional_instr(regs, hsr) )
     {
         advance_pc(regs, hsr);
         return;
     }
 
+#ifndef NDEBUG
+    ASSERT(!cp.tas); /* We don't trap SIMD instruction */
+    gdprintk(XENLOG_ERR, "unhandled CP%d access\n", cp.coproc);
+#endif
     inject_undef32_exception(regs);
 }
 
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index ebc683d..3be86f1 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -295,6 +295,17 @@ union hsr {
         unsigned long ec:6;     /* Exception Class */
     } cp64; /* HSR_EC_CP15_64, HSR_EC_CP14_64 */
 
+     struct hsr_cp {
+        unsigned long coproc:4; /* Number of coproc accessed */
+        unsigned long sbz0p:1;
+        unsigned long tas:1;    /* Trapped Advanced SIMD */
+        unsigned long res0:14;
+        unsigned long cc:4;     /* Condition Code */
+        unsigned long ccvalid:1;/* CC Valid */
+        unsigned long len:1;    /* Instruction length */
+        unsigned long ec:6;     /* Exception Class */
+    } cp; /* HSR_EC_CP */
+
 #ifdef CONFIG_ARM_64
     struct hsr_sysreg {
         unsigned long read:1;   /* Direction */
--
generated by git-patchbot for /home/xen/git/xen.git#master

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