Messages in this thread | | | Subject | Re: [patch 08/24] x86/entry: Convert Divide Error to IDTENTRY | From | Alexandre Chartre <> | Date | Fri, 28 Feb 2020 15:58:03 +0100 |
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On 2/25/20 11:16 PM, Thomas Gleixner wrote: > Convert #DE to IDTENTRY: > - Implement the C entry point with DEFINE_IDTENTRY > - 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 > > No functional change. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > arch/x86/entry/entry_32.S | 7 ------- > arch/x86/entry/entry_64.S | 1 - > arch/x86/include/asm/idtentry.h | 3 +++ > arch/x86/include/asm/traps.h | 3 --- > arch/x86/kernel/idt.c | 2 +- > arch/x86/kernel/traps.c | 7 ++++++- > arch/x86/xen/enlighten_pv.c | 7 ++++++- > arch/x86/xen/xen-asm_64.S | 2 +- > 8 files changed, 17 insertions(+), 15 deletions(-) > > --- a/arch/x86/entry/entry_32.S > +++ b/arch/x86/entry/entry_32.S > @@ -1386,13 +1386,6 @@ SYM_CODE_START(alignment_check) > jmp common_exception > SYM_CODE_END(alignment_check) > > -SYM_CODE_START(divide_error) > - ASM_CLAC > - pushl $0 # no error code > - pushl $do_divide_error > - jmp common_exception > -SYM_CODE_END(divide_error) > - > #ifdef CONFIG_X86_MCE > SYM_CODE_START(machine_check) > ASM_CLAC > --- a/arch/x86/entry/entry_64.S > +++ b/arch/x86/entry/entry_64.S > @@ -1061,7 +1061,6 @@ apicinterrupt IRQ_WORK_VECTOR irq_work > * Exception entry points. > */ > > -idtentry X86_TRAP_DE divide_error do_divide_error has_error_code=0 > idtentry X86_TRAP_OF overflow do_overflow has_error_code=0 > idtentry X86_TRAP_BP int3 do_int3 has_error_code=0 > idtentry X86_TRAP_BR bounds do_bounds has_error_code=0 > --- a/arch/x86/include/asm/idtentry.h > +++ b/arch/x86/include/asm/idtentry.h > @@ -76,4 +76,7 @@ static __always_inline void __##func(str > > #endif /* __ASSEMBLY__ */ > > +/* Simple exception entries: */ > +DECLARE_IDTENTRY(X86_TRAP_DE, exc_divide_error); > +
I think this macro has a tricky behavior because it will declare C functions when included in a C file, and define assembly idtentry when included in an assembly file.
I see your point which is to have a single statement which provides both C and assembly functions, but this dual behavior is not obvious when reading the code. Maybe add a comment to explain this behavior?
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
alex.
> #endif > --- a/arch/x86/include/asm/traps.h > +++ b/arch/x86/include/asm/traps.h > @@ -11,7 +11,6 @@ > > #define dotraplinkage __visible > > -asmlinkage void divide_error(void); > asmlinkage void debug(void); > asmlinkage void nmi(void); > asmlinkage void int3(void); > @@ -38,7 +37,6 @@ asmlinkage void machine_check(void); > asmlinkage void simd_coprocessor_error(void); > > #if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV) > -asmlinkage void xen_divide_error(void); > asmlinkage void xen_xennmi(void); > asmlinkage void xen_xendebug(void); > asmlinkage void xen_int3(void); > @@ -62,7 +60,6 @@ asmlinkage void xen_machine_check(void); > asmlinkage void xen_simd_coprocessor_error(void); > #endif > > -dotraplinkage void do_divide_error(struct pt_regs *regs, long error_code); > dotraplinkage void do_debug(struct pt_regs *regs, long error_code); > dotraplinkage void do_nmi(struct pt_regs *regs, long error_code); > dotraplinkage void do_int3(struct pt_regs *regs, long error_code); > --- a/arch/x86/kernel/idt.c > +++ b/arch/x86/kernel/idt.c > @@ -70,7 +70,7 @@ static const __initconst struct idt_data > * set up TSS. > */ > static const __initconst struct idt_data def_idts[] = { > - INTG(X86_TRAP_DE, divide_error), > + INTG(X86_TRAP_DE, asm_exc_divide_error), > INTG(X86_TRAP_NMI, nmi), > INTG(X86_TRAP_BR, bounds), > INTG(X86_TRAP_UD, invalid_op), > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -279,6 +279,12 @@ static inline void __user *error_get_tra > return (void __user *)uprobe_get_trap_addr(regs); > } > > +DEFINE_IDTENTRY(exc_divide_error) > +{ > + do_error_trap(regs, 0, "divide_error", X86_TRAP_DE, SIGFPE, > + FPE_INTDIV, error_get_trap_addr(regs)); > +} > + > #define IP ((void __user *)uprobe_get_trap_addr(regs)) > #define DO_ERROR(trapnr, signr, sicode, addr, str, name) \ > dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ > @@ -286,7 +292,6 @@ dotraplinkage void do_##name(struct pt_r > do_error_trap(regs, error_code, str, trapnr, signr, sicode, addr); \ > } > > -DO_ERROR(X86_TRAP_DE, SIGFPE, FPE_INTDIV, IP, "divide error", divide_error) > DO_ERROR(X86_TRAP_OF, SIGSEGV, 0, NULL, "overflow", overflow) > DO_ERROR(X86_TRAP_UD, SIGILL, ILL_ILLOPN, IP, "invalid opcode", invalid_op) > DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, 0, NULL, "coprocessor segment overrun", coprocessor_segment_overrun) > --- a/arch/x86/xen/enlighten_pv.c > +++ b/arch/x86/xen/enlighten_pv.c > @@ -602,6 +602,11 @@ struct trap_array_entry { > bool ist_okay; > }; > > +#define TRAP_ENTRY(func, ist_ok) { \ > + .orig = asm_##func, \ > + .xen = xen_asm_##func, \ > + .ist_okay = ist_ok } > + > static struct trap_array_entry trap_array[] = { > { debug, xen_xendebug, true }, > { double_fault, xen_double_fault, true }, > @@ -615,7 +620,7 @@ static struct trap_array_entry trap_arra > { entry_INT80_compat, xen_entry_INT80_compat, false }, > #endif > { page_fault, xen_page_fault, false }, > - { divide_error, xen_divide_error, false }, > + TRAP_ENTRY(exc_divide_error, false ), > { bounds, xen_bounds, false }, > { invalid_op, xen_invalid_op, false }, > { device_not_available, xen_device_not_available, false }, > --- a/arch/x86/xen/xen-asm_64.S > +++ b/arch/x86/xen/xen-asm_64.S > @@ -28,7 +28,7 @@ SYM_CODE_END(xen_\name) > _ASM_NOKPROBE(xen_\name) > .endm > > -xen_pv_trap divide_error > +xen_pv_trap asm_exc_divide_error > xen_pv_trap debug > xen_pv_trap xendebug > xen_pv_trap int3 > >
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