diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2020-02-25 23:16:12 +0100 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2020-05-05 11:27:54 +0200 |
commit | 004c09e7b8acb423a558af455fadfb100af83126 (patch) | |
tree | 90352567910504aee5b71e2a53aad5196e6daca1 | |
parent | 321f2a353158a34d9e243d7410a6412d8e59e6af (diff) |
x86/idtentry: Provide macros to define/declare IDT entry points
Provide DECLARE/DEFINE_IDTENTRY() macros.
DEFINE_IDTENTRY() provides a wrapper which acts as the function
definition. The exception handler body is just appended to it with curly
brackets. The entry point is marked notrace/noprobe so that irq tracing and
the enter_from_user_mode() can be moved into the C-entry point. As all
C-entries use the same macro (or a later variant) the necessary entry
handling can be implemented at one central place.
DECLARE_IDTENTRY() provides the function prototypes:
- The C entry point cfunc
- The ASM entry point asm_cfunc
- The XEN/PV entry point xen_asm_cfunc
They all follow the same naming convention.
When included from ASM code DECLARE_IDTENTRY() is a macro which emits the
low level entry point in assembly by instantiating idtentry.
IDTENTRY is the simplest variant which just has a pt_regs argument. It's
going to be used for all exceptions which have no error code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
-rw-r--r-- | arch/x86/entry/entry_32.S | 6 | ||||
-rw-r--r-- | arch/x86/entry/entry_64.S | 6 | ||||
-rw-r--r-- | arch/x86/include/asm/idtentry.h | 67 | ||||
-rw-r--r-- | arch/x86/include/asm/traps.h | 2 |
4 files changed, 80 insertions, 1 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 6d4d759be47d..29deda40e299 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -753,6 +753,12 @@ SYM_CODE_END(\asmsym) .endm /* + * Include the defines which emit the idt entries which are shared + * shared between 32 and 64 bit. + */ +#include <asm/idtentry.h> + +/* * %eax: prev task * %edx: next task */ diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index b88f6f6a5508..cd4600867c31 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -700,6 +700,12 @@ SYM_CODE_END(\asmsym) .endm /* + * Include the defines which emit the idt entries which are shared + * shared between 32 and 64 bit. + */ +#include <asm/idtentry.h> + +/* * Interrupt entry helper function. * * Entry runs with interrupts off. Stack layout at entry: diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h new file mode 100644 index 000000000000..5bced430eaf5 --- /dev/null +++ b/arch/x86/include/asm/idtentry.h @@ -0,0 +1,67 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_IDTENTRY_H +#define _ASM_X86_IDTENTRY_H + +/* Interrupts/Exceptions */ +#include <asm/trapnr.h> + +#ifndef __ASSEMBLY__ + +/** + * DECLARE_IDTENTRY - Declare functions for simple IDT entry points + * No error code pushed by hardware + * @vector: Vector number (ignored for C) + * @func: Function name of the entry point + * + * Declares three functions: + * - The ASM entry point: asm_##func + * - The XEN PV trap entry point: xen_##func (maybe unused) + * - The C handler called from the ASM entry point + * + * Note: This is the C variant of DECLARE_IDTENTRY(). As the name says it + * declares the entry points for usage in C code. There is an ASM variant + * as well which is used to emit the entry stubs in entry_32/64.S. + */ +#define DECLARE_IDTENTRY(vector, func) \ + asmlinkage void asm_##func(void); \ + asmlinkage void xen_asm_##func(void); \ + __visible void func(struct pt_regs *regs) + +/** + * DEFINE_IDTENTRY - Emit code for simple IDT entry points + * @func: Function name of the entry point + * + * @func is called from ASM entry code with interrupts disabled. + * + * The macro is written so it acts as function definition. Append the + * body with a pair of curly brackets. + * + * idtentry_enter() contains common code which has to be invoked before + * arbitrary code in the body. idtentry_exit() contains common code + * which has to run before returning to the low level assembly code. + */ +#define DEFINE_IDTENTRY(func) \ +static __always_inline void __##func(struct pt_regs *regs); \ + \ +__visible noinstr void func(struct pt_regs *regs) \ +{ \ + idtentry_enter(regs); \ + instr_begin(); \ + __##func (regs); \ + instr_end(); \ + idtentry_exit(regs); \ +} \ + \ +static __always_inline void __##func(struct pt_regs *regs) + +#else /* !__ASSEMBLY__ */ + +/* + * The ASM variants for DECLARE_IDTENTRY*() which emit the ASM entry stubs. + */ +#define DECLARE_IDTENTRY(vector, func) \ + idtentry vector asm_##func func has_error_code=0 sane=1 + +#endif /* __ASSEMBLY__ */ + +#endif diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 8a0281ffe3f0..725a1a0407cb 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -6,8 +6,8 @@ #include <linux/kprobes.h> #include <asm/debugreg.h> +#include <asm/idtentry.h> #include <asm/siginfo.h> /* TRAP_TRACE, ... */ -#include <asm/trapnr.h> #define dotraplinkage __visible |