Commit bbaceb18 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Peter Zijlstra
Browse files

x86/retbleed: Add SKL call thunk 



Add the actual SKL call thunk for call depth accounting.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.101125588@infradead.org
parent 3b6c1747

arch/x86/kernel/callthunks.c

+20 −5
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/moduleloader.h>



#include <asm/alternative.h>

#include <asm/asm-offsets.h>

#include <asm/cpu.h>

#include <asm/ftrace.h>

#include <asm/insn.h>
@@ -55,7 +56,21 @@ static const struct core_text builtin_coretext = { 
	.name = "builtin",

};



static struct thunk_desc callthunk_desc __ro_after_init;

asm (

	".pushsection .rodata				\n"

	".global skl_call_thunk_template		\n"

	"skl_call_thunk_template:			\n"

		__stringify(INCREMENT_CALL_DEPTH)"	\n"

	".global skl_call_thunk_tail			\n"

	"skl_call_thunk_tail:				\n"

	".popsection					\n"

);



extern u8 skl_call_thunk_template[];

extern u8 skl_call_thunk_tail[];



#define SKL_TMPL_SIZE \

	((unsigned int)(skl_call_thunk_tail - skl_call_thunk_template))



extern void error_entry(void);

extern void xen_error_entry(void);
@@ -157,11 +172,11 @@ static const u8 nops[] = { 


static __init_or_module void *patch_dest(void *dest, bool direct)

{

	unsigned int tsize = callthunk_desc.template_size;

	unsigned int tsize = SKL_TMPL_SIZE;

	u8 *pad = dest - tsize;



	/* Already patched? */

	if (!bcmp(pad, callthunk_desc.template, tsize))

	if (!bcmp(pad, skl_call_thunk_template, tsize))

		return pad;



	/* Ensure there are nops */
@@ -171,9 +186,9 @@ static __init_or_module void *patch_dest(void *dest, bool direct) 
	}



	if (direct)

		memcpy(pad, callthunk_desc.template, tsize);

		memcpy(pad, skl_call_thunk_template, tsize);

	else

		text_poke_copy_locked(pad, callthunk_desc.template, tsize, true);

		text_poke_copy_locked(pad, skl_call_thunk_template, tsize, true);

	return pad;

}