[PATCH v3 4/4] xen/x86: switch x86 to use generic implemetation of bug.h

[Oleksii Kurochko <oleksii.kurochko@gmail.com>]

The following changes were made:
* Make GENERIC_BUG_FRAME mandatory for X86
* Update asm/bug.h using generic implementation in <xen/bug.h>
* Change prototype of debugger_trap_fatal() in asm/debugger.h
  to align it with generic prototype in <xen/debugger.h>.
* Update do_invalid_op using generic do_bug_frame()

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
---
Changes in V3:
 * As prototype and what do_bug_frame() returns was changed so patch 3 and 4
   was updated to use a new version of do_bug_frame
 * MODIFIER was change to BUG_ASM_CONST to align with generic implementation
---
Changes in V2:
  * Remove all unnecessary things from <asm/bug.h> as they were introduced in
    <xen/bug.h>.
  * Define BUG_INSTR = 'ud2' and MODIFIER = 'c' ( it is needed to skip '$'
    when use an imidiate in x86 assembly )
  * Update do_invalid_op() to re-use handle_bug_frame() and find_bug_frame()
    from generic implemetation of CONFIG_GENERIC_BUG_FRAME
  * Code style fixes.
---
 xen/arch/x86/Kconfig                |  1 +
 xen/arch/x86/include/asm/bug.h      | 73 ++------------------------
 xen/arch/x86/include/asm/debugger.h |  4 +-
 xen/arch/x86/traps.c                | 81 +++--------------------------
 4 files changed, 14 insertions(+), 145 deletions(-)

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 6a7825f4ba..b0ff1f3ee6 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -11,6 +11,7 @@ config X86
 	select ARCH_MAP_DOMAIN_PAGE
 	select ARCH_SUPPORTS_INT128
 	select CORE_PARKING
+	select GENERIC_BUG_FRAME
 	select HAS_ALTERNATIVE
 	select HAS_COMPAT
 	select HAS_CPUFREQ
diff --git a/xen/arch/x86/include/asm/bug.h b/xen/arch/x86/include/asm/bug.h
index 4b3e7b019d..d7eb41baf3 100644
--- a/xen/arch/x86/include/asm/bug.h
+++ b/xen/arch/x86/include/asm/bug.h
@@ -3,75 +3,10 @@
 
 #ifndef __ASSEMBLY__
 
-#define BUG_FRAME_STRUCT
+#define BUG_INSTR       "ud2"
+#define BUG_ASM_CONST   "c"
 
-struct bug_frame {
-    signed int loc_disp:BUG_DISP_WIDTH;
-    unsigned int line_hi:BUG_LINE_HI_WIDTH;
-    signed int ptr_disp:BUG_DISP_WIDTH;
-    unsigned int line_lo:BUG_LINE_LO_WIDTH;
-    signed int msg_disp[];
-};
-
-#define bug_loc(b) ((const void *)(b) + (b)->loc_disp)
-#define bug_ptr(b) ((const void *)(b) + (b)->ptr_disp)
-#define bug_line(b) (((((b)->line_hi + ((b)->loc_disp < 0)) &                \
-                       ((1 << BUG_LINE_HI_WIDTH) - 1)) <<                    \
-                      BUG_LINE_LO_WIDTH) +                                   \
-                     (((b)->line_lo + ((b)->ptr_disp < 0)) &                 \
-                      ((1 << BUG_LINE_LO_WIDTH) - 1)))
-#define bug_msg(b) ((const char *)(b) + (b)->msg_disp[1])
-
-#define _ASM_BUGFRAME_TEXT(second_frame)                                     \
-    ".Lbug%=: ud2\n"                                                         \
-    ".pushsection .bug_frames.%c[bf_type], \"a\", @progbits\n"               \
-    ".p2align 2\n"                                                           \
-    ".Lfrm%=:\n"                                                             \
-    ".long (.Lbug%= - .Lfrm%=) + %c[bf_line_hi]\n"                           \
-    ".long (%c[bf_ptr] - .Lfrm%=) + %c[bf_line_lo]\n"                        \
-    ".if " #second_frame "\n"                                                \
-    ".long 0, %c[bf_msg] - .Lfrm%=\n"                                        \
-    ".endif\n"                                                               \
-    ".popsection\n"                                                          \
-
-#define _ASM_BUGFRAME_INFO(type, line, ptr, msg)                             \
-    [bf_type]    "i" (type),                                                 \
-    [bf_ptr]     "i" (ptr),                                                  \
-    [bf_msg]     "i" (msg),                                                  \
-    [bf_line_lo] "i" ((line & ((1 << BUG_LINE_LO_WIDTH) - 1))                \
-                      << BUG_DISP_WIDTH),                                    \
-    [bf_line_hi] "i" (((line) >> BUG_LINE_LO_WIDTH) << BUG_DISP_WIDTH)
-
-#define BUG_FRAME(type, line, ptr, second_frame, msg) do {                   \
-    BUILD_BUG_ON((line) >> (BUG_LINE_LO_WIDTH + BUG_LINE_HI_WIDTH));         \
-    BUILD_BUG_ON((type) >= BUGFRAME_NR);                                     \
-    asm volatile ( _ASM_BUGFRAME_TEXT(second_frame)                          \
-                   :: _ASM_BUGFRAME_INFO(type, line, ptr, msg) );            \
-} while (0)
-
-
-#define WARN() BUG_FRAME(BUGFRAME_warn, __LINE__, __FILE__, 0, NULL)
-#define BUG() do {                                              \
-    BUG_FRAME(BUGFRAME_bug,  __LINE__, __FILE__, 0, NULL);      \
-    unreachable();                                              \
-} while (0)
-
-/*
- * TODO: untangle header dependences, break BUILD_BUG_ON() out of xen/lib.h,
- * and use a real static inline here to get proper type checking of fn().
- */
-#define run_in_exception_handler(fn)                            \
-    do {                                                        \
-        (void)((fn) == (void (*)(struct cpu_user_regs *))NULL); \
-        BUG_FRAME(BUGFRAME_run_fn, 0, fn, 0, NULL);             \
-    } while ( 0 )
-
-#define assert_failed(msg) do {                                 \
-    BUG_FRAME(BUGFRAME_assert, __LINE__, __FILE__, 1, msg);     \
-    unreachable();                                              \
-} while (0)
-
-#else  /* !__ASSEMBLY__ */
+#else
 
 /*
  * Construct a bugframe, suitable for using in assembly code.  Should always
@@ -113,6 +48,6 @@ struct bug_frame {
 #define ASSERT_FAILED(msg)                                      \
      BUG_FRAME BUGFRAME_assert, __LINE__, __FILE__, 1, msg
 
-#endif /* !__ASSEMBLY__ */
+#endif /* __ASSEMBLY__ */
 
 #endif /* __X86_BUG_H__ */
diff --git a/xen/arch/x86/include/asm/debugger.h b/xen/arch/x86/include/asm/debugger.h
index a5c299c6c3..1873dc5779 100644
--- a/xen/arch/x86/include/asm/debugger.h
+++ b/xen/arch/x86/include/asm/debugger.h
@@ -14,9 +14,9 @@
 
 /* Returns true if GDB handled the trap, or it is surviveable. */
 static inline bool debugger_trap_fatal(
-    unsigned int vector, struct cpu_user_regs *regs)
+    unsigned int vector, const struct cpu_user_regs *regs)
 {
-    int rc = __trap_to_gdb(regs, vector);
+    int rc = __trap_to_gdb((struct cpu_user_regs *)regs, vector);
 
     if ( rc == 0 )
         return true;
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index cade9e12f8..7c33ebceff 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -24,6 +24,7 @@
  * Gareth Hughes <gareth@valinux.com>, May 2000
  */
 
+#include <xen/bug.h>
 #include <xen/init.h>
 #include <xen/sched.h>
 #include <xen/lib.h>
@@ -1166,12 +1167,9 @@ void cpuid_hypervisor_leaves(const struct vcpu *v, uint32_t leaf,
 
 void do_invalid_op(struct cpu_user_regs *regs)
 {
-    const struct bug_frame *bug = NULL;
     u8 bug_insn[2];
-    const char *prefix = "", *filename, *predicate, *eip = (char *)regs->rip;
-    unsigned long fixup;
-    int id = -1, lineno;
-    const struct virtual_region *region;
+    const char *eip = (char *)regs->rip;
+    int id;
 
     if ( likely(guest_mode(regs)) )
     {
@@ -1185,83 +1183,18 @@ void do_invalid_op(struct cpu_user_regs *regs)
          memcmp(bug_insn, "\xf\xb", sizeof(bug_insn)) )
         goto die;
 
-    region = find_text_region(regs->rip);
-    if ( region )
-    {
-        for ( id = 0; id < BUGFRAME_NR; id++ )
-        {
-            const struct bug_frame *b;
-            unsigned int i;
-
-            for ( i = 0, b = region->frame[id].bugs;
-                  i < region->frame[id].n_bugs; b++, i++ )
-            {
-                if ( bug_loc(b) == eip )
-                {
-                    bug = b;
-                    goto found;
-                }
-            }
-        }
-    }
-
- found:
-    if ( !bug )
+    id = do_bug_frame(regs, regs->rip);
+    if ( id < 0 )
         goto die;
-    eip += sizeof(bug_insn);
-    if ( id == BUGFRAME_run_fn )
-    {
-        void (*fn)(struct cpu_user_regs *) = bug_ptr(bug);
-
-        fn(regs);
-        fixup_exception_return(regs, (unsigned long)eip);
-        return;
-    }
 
-    /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
-    filename = bug_ptr(bug);
-    if ( !is_kernel(filename) && !is_patch(filename) )
-        goto die;
-    fixup = strlen(filename);
-    if ( fixup > 50 )
-    {
-        filename += fixup - 47;
-        prefix = "...";
-    }
-    lineno = bug_line(bug);
+    eip += sizeof(bug_insn);
 
     switch ( id )
     {
+    case BUGFRAME_run_fn:
     case BUGFRAME_warn:
-        printk("Xen WARN at %s%s:%d\n", prefix, filename, lineno);
-        show_execution_state(regs);
         fixup_exception_return(regs, (unsigned long)eip);
         return;
-
-    case BUGFRAME_bug:
-        printk("Xen BUG at %s%s:%d\n", prefix, filename, lineno);
-
-        if ( debugger_trap_fatal(TRAP_invalid_op, regs) )
-            return;
-
-        show_execution_state(regs);
-        panic("Xen BUG at %s%s:%d\n", prefix, filename, lineno);
-
-    case BUGFRAME_assert:
-        /* ASSERT: decode the predicate string pointer. */
-        predicate = bug_msg(bug);
-        if ( !is_kernel(predicate) && !is_patch(predicate) )
-            predicate = "<unknown>";
-
-        printk("Assertion '%s' failed at %s%s:%d\n",
-               predicate, prefix, filename, lineno);
-
-        if ( debugger_trap_fatal(TRAP_invalid_op, regs) )
-            return;
-
-        show_execution_state(regs);
-        panic("Assertion '%s' failed at %s%s:%d\n",
-              predicate, prefix, filename, lineno);
     }
 
  die:
-- 
2.39.0