[patch 05/24] x86/entry/32: Provide macro to emit IDT entry stubs

Thomas Gleixner
2020-02-25T23:26:10Z

32 and 64 bit have unnecessary different ways to populate the exception
entry code. Provide a idtentry macro which allows to consolidate all of
that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/entry/entry_32.S | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)

--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -44,6 +44,7 @@
#include <asm/asm.h>
#include <asm/smap.h>
#include <asm/frame.h>
+#include <asm/trapnr.h>
#include <asm/nospec-branch.h>

#include "calling.h"
@@ -726,6 +727,47 @@

.Lend_\@:
.endm
+
+#ifdef CONFIG_X86_INVD_BUG
+.macro idtentry_push_func vector cfunc
+ .if \vector == X86_TRAP_XF
+ /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
+ ALTERNATIVE "pushl $do_general_protection", \
+ "pushl $do_simd_coprocessor_error", \
+ X86_FEATURE_XMM
+ .else
+ pushl $\cfunc
+ .endif
+.endm
+#else
+.macro idtentry_push_func vector cfunc
+ pushl $\cfunc
+.endm
+#endif
+
+/**
+ * idtentry - Macro to generate entry stubs for simple IDT entries
+ * @vector: Vector number
+ * @asmsym: ASM symbol for the entry point
+ * @cfunc: C function to be called
+ * @has_error_code: Hardware pushed error code on stack
+ */
+.macro idtentry vector asmsym cfunc has_error_code:req
+SYM_CODE_START(\asmsym)
+ ASM_CLAC
+ cld
+
+ .if \has_error_code == 0
+ pushl $0 /* Clear the error code */
+ .endif
+
+ /* Push the C-function address into the GS slot */
+ idtentry_push_func \vector \cfunc
+ /* Invoke the common exception entry */
+ jmp common_exception
+SYM_CODE_END(\asmsym)
+.endm
+
/*
* %eax: prev task
* %edx: next task