x86/entry: Convert Debug exception to IDTENTRY_DB

Convert #DB to IDTENTRY_ERRORCODE:
  - Implement the C entry point with DEFINE_IDTENTRY_DB
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135314.900297476@linutronix.de

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index d4961cac73f64d3ee91fd5e28fe1e2898abab57f..30c6ed3d7c52c73f5af411c66be2f9d1882b2afd 100644 (file)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1488,16 +1488,6 @@ ret_to_user:
        jmp     restore_all_switch_stack
 SYM_CODE_END(handle_exception)
 
-SYM_CODE_START(debug)
-       /*
-        * Entry from sysenter is now handled in common_exception
-        */
-       ASM_CLAC
-       pushl   $0
-       pushl   $do_debug
-       jmp     common_exception
-SYM_CODE_END(debug)
-
 SYM_CODE_START(double_fault)
 1:
        /*

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 3d7f2cc29be3709b419397606625b96cd0cdbf74..f47629a7f8e641c39f9a005db810115ead83eb8d 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1074,12 +1074,10 @@ apicinterrupt IRQ_WORK_VECTOR                   irq_work_interrupt              smp_irq_work_interrupt
 
 idtentry       X86_TRAP_PF             page_fault              do_page_fault                   has_error_code=1
 
-idtentry_mce_db        X86_TRAP_DB             debug                   do_debug
 idtentry_df    X86_TRAP_DF             double_fault            do_double_fault
 
 #ifdef CONFIG_XEN_PV
 idtentry       512 /* dummy */         hypervisor_callback     xen_do_hypervisor_callback      has_error_code=0
-idtentry       X86_TRAP_DB             xendebug                do_debug                        has_error_code=0
 #endif
 
 /*

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 1f067e6c4051adb8a88ed77459f8d768928c42a5..fcd4230a979b6803901fd1f4f7a2f956528486e9 100644 (file)
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -262,4 +262,8 @@ DECLARE_IDTENTRY_MCE(X86_TRAP_MC,   exc_machine_check);
 DECLARE_IDTENTRY_NMI(X86_TRAP_NMI,     exc_nmi);
 DECLARE_IDTENTRY_XEN(X86_TRAP_NMI,     nmi);
 
+/* #DB */
+DECLARE_IDTENTRY_DEBUG(X86_TRAP_DB,    exc_debug);
+DECLARE_IDTENTRY_XEN(X86_TRAP_DB,      debug);
+
 #endif

diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 57b83ae19c15f250f10994f7548a4438d3f4b42e..9bd602d0130d55fc905da82c391b29f08f143a99 100644 (file)
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -11,7 +11,6 @@
 
 #define dotraplinkage __visible
 
-asmlinkage void debug(void);
 #ifdef CONFIG_X86_64
 asmlinkage void double_fault(void);
 #endif
@@ -19,12 +18,10 @@ asmlinkage void page_fault(void);
 asmlinkage void async_page_fault(void);
 
 #if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
-asmlinkage void xen_xendebug(void);
 asmlinkage void xen_double_fault(void);
 asmlinkage void xen_page_fault(void);
 #endif
 
-dotraplinkage void do_debug(struct pt_regs *regs, long error_code);
 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
 dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);
 

diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index d3fecd88677c4653ca98b0f8b0457aaf74345f22..ddf3f3db3235c282ae8eb8ea0cae0f0cc4701545 100644 (file)
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -59,7 +59,7 @@ static bool idt_setup_done __initdata;
  * stacks work only after cpu_init().
  */
 static const __initconst struct idt_data early_idts[] = {
-       INTG(X86_TRAP_DB,               debug),
+       INTG(X86_TRAP_DB,               asm_exc_debug),
        SYSG(X86_TRAP_BP,               asm_exc_int3),
 #ifdef CONFIG_X86_32
        INTG(X86_TRAP_PF,               page_fault),
@@ -93,7 +93,7 @@ static const __initconst struct idt_data def_idts[] = {
 #else
        INTG(X86_TRAP_DF,               double_fault),
 #endif
-       INTG(X86_TRAP_DB,               debug),
+       INTG(X86_TRAP_DB,               asm_exc_debug),
 
 #ifdef CONFIG_X86_MCE
        INTG(X86_TRAP_MC,               asm_exc_machine_check),
@@ -164,7 +164,7 @@ static const __initconst struct idt_data early_pf_idts[] = {
  * stack set to DEFAULT_STACK (0). Required for NMI trap handling.
  */
 static const __initconst struct idt_data dbg_idts[] = {
-       INTG(X86_TRAP_DB,       debug),
+       INTG(X86_TRAP_DB,               asm_exc_debug),
 };
 #endif
 
@@ -185,7 +185,7 @@ gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss;
  * cpu_init() when the TSS has been initialized.
  */
 static const __initconst struct idt_data ist_idts[] = {
-       ISTG(X86_TRAP_DB,       debug,                  IST_INDEX_DB),
+       ISTG(X86_TRAP_DB,       asm_exc_debug,          IST_INDEX_DB),
        ISTG(X86_TRAP_NMI,      asm_exc_nmi,            IST_INDEX_NMI),
        ISTG(X86_TRAP_DF,       double_fault,           IST_INDEX_DF),
 #ifdef CONFIG_X86_MCE

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index de5120e2fbe12664dba98978fd3de0549af6d82c..569408a681b6a591642993918e93ce9bb5a5f390 100644 (file)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -775,7 +775,7 @@ static __always_inline void debug_exit(unsigned long dr7)
  *
  * May run on IST stack.
  */
-dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
+DEFINE_IDTENTRY_DEBUG(exc_debug)
 {
        struct task_struct *tsk = current;
        unsigned long dr6, dr7;
@@ -784,7 +784,10 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 
        debug_enter(&dr6, &dr7);
 
-       nmi_enter();
+       if (user_mode(regs))
+               idtentry_enter(regs);
+       else
+               nmi_enter();
 
        /*
         * The SDM says "The processor clears the BTF flag when it
@@ -821,7 +824,7 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
                goto exit;
 #endif
 
-       if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
+       if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, 0,
                       SIGTRAP) == NOTIFY_STOP)
                goto exit;
 
@@ -835,8 +838,8 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
        cond_local_irq_enable(regs);
 
        if (v8086_mode(regs)) {
-               handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
-                                       X86_TRAP_DB);
+               handle_vm86_trap((struct kernel_vm86_regs *) regs, 0,
+                                X86_TRAP_DB);
                cond_local_irq_disable(regs);
                debug_stack_usage_dec();
                goto exit;
@@ -855,15 +858,17 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
        }
        si_code = get_si_code(tsk->thread.debugreg6);
        if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
-               send_sigtrap(regs, error_code, si_code);
+               send_sigtrap(regs, 0, si_code);
        cond_local_irq_disable(regs);
        debug_stack_usage_dec();
 
 exit:
-       nmi_exit();
+       if (user_mode(regs))
+               idtentry_exit(regs);
+       else
+               nmi_exit();
        debug_exit(dr7);
 }
-NOKPROBE_SYMBOL(do_debug);
 
 /*
  * Note that we play around with the 'TS' bit in an attempt to get

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 0d6c2789e6768ca6410fb09390d6b0c329da5542..376851d1039a2905529828a0822b714d227de6be 100644 (file)
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -615,7 +615,7 @@ struct trap_array_entry {
        .ist_okay       = ist_ok }
 
 static struct trap_array_entry trap_array[] = {
-       { debug,                       xen_xendebug,                    true },
+       TRAP_ENTRY_REDIR(exc_debug, exc_xendebug,       true  ),
        { double_fault,                xen_double_fault,                true },
 #ifdef CONFIG_X86_MCE
        TRAP_ENTRY(exc_machine_check,                   true  ),

diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 04fa01b096ee3aeff0c9112a567cdb6e50288c12..9999ea3774762e3e9d0d5a5f3cf06754e023987d 100644 (file)
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -29,8 +29,8 @@ _ASM_NOKPROBE(xen_\name)
 .endm
 
 xen_pv_trap asm_exc_divide_error
-xen_pv_trap debug
-xen_pv_trap xendebug
+xen_pv_trap asm_exc_debug
+xen_pv_trap asm_exc_xendebug
 xen_pv_trap asm_exc_int3
 xen_pv_trap asm_exc_xennmi
 xen_pv_trap asm_exc_overflow