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x86/entry: Convert Debug exception to IDTENTRY_DB

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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
This commit is contained in:
Thomas Gleixner 2020-02-25 23:33:26 +01:00
parent 9f58fdde95
commit 2bbc68f837
8 changed files with 24 additions and 30 deletions
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10
arch/x86/entry/entry_32.S
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@ -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:
/*

2
arch/x86/entry/entry_64.S
View File

@ -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
/*

4
arch/x86/include/asm/idtentry.h
View File

@ -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

3
arch/x86/include/asm/traps.h
View File

@ -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);

8
arch/x86/kernel/idt.c
View File

@ -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

21
arch/x86/kernel/traps.c
View File

@ -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

2
arch/x86/xen/enlighten_pv.c
View File

@ -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 ),

4
arch/x86/xen/xen-asm_64.S
View File

@ -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