From 2bbc68f8373c0631ebf137f376fbea00e8086be7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 25 Feb 2020 23:33:26 +0100 Subject: [PATCH] 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 Reviewed-by: Alexandre Chartre Acked-by: Peter Zijlstra Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505135314.900297476@linutronix.de --- arch/x86/entry/entry_32.S | 10 ---------- arch/x86/entry/entry_64.S | 2 -- arch/x86/include/asm/idtentry.h | 4 ++++ arch/x86/include/asm/traps.h | 3 --- arch/x86/kernel/idt.c | 8 ++++---- arch/x86/kernel/traps.c | 21 +++++++++++++-------- arch/x86/xen/enlighten_pv.c | 2 +- arch/x86/xen/xen-asm_64.S | 4 ++-- 8 files changed, 24 insertions(+), 30 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index d4961ca..30c6ed3 100644 --- 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 3d7f2cc..f47629a 100644 --- 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 1f067e6..fcd4230a 100644 --- 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 57b83ae..9bd602d 100644 --- 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 d3fecd8..ddf3f3d 100644 --- 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 de5120e..569408a 100644 --- 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 0d6c278..376851d 100644 --- 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 04fa01b..9999ea3 100644 --- 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 -- 2.7.4