x86/paravirt: Replace the paravirt patch asm magic

The magic macro DEF_NATIVE() in the paravirt patching code uses inline
assembly to generate a data table for patching in the native instructions.

While clever this is falling apart with LTO and even aside of LTO the
construct is just working by chance according to GCC folks.

Aside of that the tables are constant data and not some form of magic
text.

As these constructs are not subject to frequent changes it is not a
maintenance issue to convert them to regular data tables which are
initialized with hex bytes.

Create a new set of macros and data structures to store the instruction
sequences and convert the code over.

Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20190424134223.690835713@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner
2019-04-24 15:41:18 +02:00
committed by Ingo Molnar
parent fb2af0712f
commit 0b9d2fc1d0
2 changed files with 82 additions and 66 deletions

View File

@@ -370,10 +370,6 @@ extern struct paravirt_patch_template pv_ops;
/* Simple instruction patching code. */
#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
#define DEF_NATIVE(ops, name, code) \
__visible extern const char start_##ops##_##name[], end_##ops##_##name[]; \
asm(NATIVE_LABEL("start_", ops, name) code NATIVE_LABEL("end_", ops, name))
unsigned paravirt_patch_ident_64(void *insnbuf, unsigned len);
unsigned paravirt_patch_default(u8 type, void *insnbuf,
unsigned long addr, unsigned len);