[Xen-devel] [PATCH 2/2] x86/mce: Sanitise the #MC entry path

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

The 'error_code' function parameters are not used at all; drop it from the
call chain.  If it is needed at some point in the future, it is available via
cpu_user_regs.

Having do_machine_check() call the non-inlineable machine_check_vector() just
to get at the static function pointer '_machine_check_vector' is silly.  Move
do_machine_check() from traps.c to mce.c and do away with
machine_check_vector() entirely.

Both {intel,amd}_init_mce() register their own local function as the #MC
handler, each of which call mcheck_cmn_handler() in an identical way.  Fix
this craziness by actually turning mcheck_cmn_handler() into a valid #MC
handler (as its comments already state), and have {intel,amd}_init_mce()
register it instead of their own private handlers.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Christoph Egger <chegger@xxxxxxxxx>
CC: Liu Jinsong <jinsong.liu@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/cpu/mcheck/mce.c       |   11 ++++++-----
 xen/arch/x86/cpu/mcheck/mce.h       |    5 ++---
 xen/arch/x86/cpu/mcheck/mce_amd.c   |    9 +--------
 xen/arch/x86/cpu/mcheck/mce_intel.c |    8 +-------
 xen/arch/x86/traps.c                |    5 -----
 xen/include/asm-x86/traps.h         |    2 --
 6 files changed, 10 insertions(+), 30 deletions(-)

diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
index 13e5547..812daf6 100644
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -70,7 +70,7 @@ static void __init mce_set_verbosity(char *str)
 custom_param("mce_verbosity", mce_set_verbosity);
 
 /* Handle unconfigured int18 (should never happen) */
-static void unexpected_machine_check(const struct cpu_user_regs *regs, long 
error_code)
+static void unexpected_machine_check(const struct cpu_user_regs *regs)
 {
     console_force_unlock();
     printk("Unexpected Machine Check Exception\n");
@@ -88,9 +88,9 @@ void x86_mce_vector_register(x86_mce_vector_t hdlr)
 
 /* Call the installed machine check handler for this CPU setup. */
 
-void machine_check_vector(const struct cpu_user_regs *regs, long error_code)
+void do_machine_check(const struct cpu_user_regs *regs)
 {
-    _machine_check_vector(regs, error_code);
+    _machine_check_vector(regs);
 }
 
 /* Init machine check callback handler
@@ -459,9 +459,10 @@ static int mce_urgent_action(const struct cpu_user_regs 
*regs,
 }
 
 /* Shared #MC handler. */
-void mcheck_cmn_handler(const struct cpu_user_regs *regs, long error_code,
-    struct mca_banks *bankmask, struct mca_banks *clear_bank)
+void mcheck_cmn_handler(const struct cpu_user_regs *regs)
 {
+    struct mca_banks *bankmask = mca_allbanks;
+    struct mca_banks *clear_bank = __get_cpu_var(mce_clear_banks);
     uint64_t gstatus;
     mctelem_cookie_t mctc = NULL;
     struct mca_summary bs;
diff --git a/xen/arch/x86/cpu/mcheck/mce.h b/xen/arch/x86/cpu/mcheck/mce.h
index 0397f80..e83d431 100644
--- a/xen/arch/x86/cpu/mcheck/mce.h
+++ b/xen/arch/x86/cpu/mcheck/mce.h
@@ -62,13 +62,12 @@ void x86_mc_get_cpu_info(unsigned, uint32_t *, uint16_t *, 
uint16_t *,
                         uint32_t *, uint32_t *, uint32_t *, uint32_t *);
 
 /* Register a handler for machine check exceptions. */
-typedef void (*x86_mce_vector_t)(const struct cpu_user_regs *, long);
+typedef void (*x86_mce_vector_t)(const struct cpu_user_regs *regs);
 extern void x86_mce_vector_register(x86_mce_vector_t);
 
 /* Common generic MCE handler that implementations may nominate
  * via x86_mce_vector_register. */
-extern void mcheck_cmn_handler(const struct cpu_user_regs *, long,
-    struct mca_banks *, struct mca_banks *);
+extern void mcheck_cmn_handler(const struct cpu_user_regs *regs);
 
 /* Register a handler for judging whether mce is recoverable. */
 typedef int (*mce_recoverable_t)(uint64_t status);
diff --git a/xen/arch/x86/cpu/mcheck/mce_amd.c 
b/xen/arch/x86/cpu/mcheck/mce_amd.c
index 9daa461..4e8ad38 100644
--- a/xen/arch/x86/cpu/mcheck/mce_amd.c
+++ b/xen/arch/x86/cpu/mcheck/mce_amd.c
@@ -241,13 +241,6 @@ amd_f10_handler(struct mc_info *mi, uint16_t bank, 
uint64_t status)
     return mc_ext;
 }
 
-/* Common AMD Machine Check Handler for AMD K8 and higher */
-static void amd_cmn_machine_check(const struct cpu_user_regs *regs, long 
error_code)
-{
-    mcheck_cmn_handler(regs, error_code, mca_allbanks,
-                       __get_cpu_var(mce_clear_banks));
-}
-
 static int amd_need_clearbank_scan(enum mca_source who, uint64_t status)
 {
     if ( who != MCA_MCE_SCAN )
@@ -287,7 +280,7 @@ amd_mcheck_init(struct cpuinfo_x86 *ci)
     /* Assume that machine check support is available.
      * The minimum provided support is at least the K8. */
     mce_handler_init();
-    x86_mce_vector_register(amd_cmn_machine_check);
+    x86_mce_vector_register(mcheck_cmn_handler);
     mce_need_clearbank_register(amd_need_clearbank_scan);
 
     for ( i = 0; i < nr_mce_banks; i++ )
diff --git a/xen/arch/x86/cpu/mcheck/mce_intel.c 
b/xen/arch/x86/cpu/mcheck/mce_intel.c
index ad06efc..48e797e 100644
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c
@@ -384,12 +384,6 @@ static const struct mca_error_handler 
intel_mce_uhandlers[] = {
     {intel_default_check, intel_default_mce_uhandler}
 };
 
-static void intel_machine_check(const struct cpu_user_regs * regs, long 
error_code)
-{
-    mcheck_cmn_handler(regs, error_code, mca_allbanks,
-        __get_cpu_var(mce_clear_banks));
-}
-
 /* According to MCA OS writer guide, CMCI handler need to clear bank when
  * 1) CE (UC = 0)
  * 2) ser_support = 1, Superious error, OVER = 0, EN = 0, [UC = 1]
@@ -772,7 +766,7 @@ static void intel_init_mce(void)
     if (firstbank) /* if cmci enabled, firstbank = 0 */
         wrmsrl(MSR_IA32_MC0_STATUS, 0x0ULL);
 
-    x86_mce_vector_register(intel_machine_check);
+    x86_mce_vector_register(mcheck_cmn_handler);
     mce_recoverable_register(intel_recoverable_scan);
     mce_need_clearbank_register(intel_need_clearbank_scan);
     mce_register_addrcheck(intel_checkaddr);
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 44ac014..8e38c5a 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -1086,11 +1086,6 @@ void do_int3(struct cpu_user_regs *regs)
     do_guest_trap(TRAP_int3, regs, 0);
 }
 
-void do_machine_check(const struct cpu_user_regs *regs)
-{
-    machine_check_vector(regs, regs->error_code);
-}
-
 static void reserved_bit_page_fault(
     unsigned long addr, struct cpu_user_regs *regs)
 {
diff --git a/xen/include/asm-x86/traps.h b/xen/include/asm-x86/traps.h
index 47b7ab9..ebb6378 100644
--- a/xen/include/asm-x86/traps.h
+++ b/xen/include/asm-x86/traps.h
@@ -28,8 +28,6 @@ struct softirq_trap {
 
 struct cpu_user_regs;
 
-extern void machine_check_vector(const struct cpu_user_regs *regs, long 
error_code);
-
 void async_exception_cleanup(struct vcpu *);
  
 /**
-- 
1.7.10.4


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