Commit 396e0b8e authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86/orc: Make it callthunk aware 



Callthunks addresses on the stack would confuse the ORC unwinder. Handle
them correctly and tell ORC to proceed further down the stack.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
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/20220915111148.511637628@infradead.org
parent f1389181

arch/x86/include/asm/alternative.h

+5 −0
Original line number Original line Diff line number Diff line
@@ -92,6 +92,7 @@ extern void callthunks_patch_builtin_calls(void); 
extern void callthunks_patch_module_calls(struct callthunk_sites *sites,

extern void callthunks_patch_module_calls(struct callthunk_sites *sites,

					  struct module *mod);

					  struct module *mod);

extern void *callthunks_translate_call_dest(void *dest);

extern void *callthunks_translate_call_dest(void *dest);

extern bool is_callthunk(void *addr);

#else

#else

static __always_inline void callthunks_patch_builtin_calls(void) {}

static __always_inline void callthunks_patch_builtin_calls(void) {}

static __always_inline void

static __always_inline void
@@ -101,6 +102,10 @@ static __always_inline void *callthunks_translate_call_dest(void *dest) 
{

{

	return dest;

	return dest;

}

}

static __always_inline bool is_callthunk(void *addr)

{

	return false;

}

#endif

#endif





#ifdef CONFIG_SMP

#ifdef CONFIG_SMP

arch/x86/kernel/callthunks.c

+13 −0
Original line number Original line Diff line number Diff line
@@ -293,6 +293,19 @@ void *callthunks_translate_call_dest(void *dest) 
	return target ? : dest;

	return target ? : dest;

}

}





bool is_callthunk(void *addr)

{

	unsigned int tmpl_size = SKL_TMPL_SIZE;

	void *tmpl = skl_call_thunk_template;

	unsigned long dest;



	dest = roundup((unsigned long)addr, CONFIG_FUNCTION_ALIGNMENT);

	if (!thunks_initialized || skip_addr((void *)dest))

		return false;



	return !bcmp((void *)(dest - tmpl_size), tmpl, tmpl_size);

}



#ifdef CONFIG_MODULES

#ifdef CONFIG_MODULES

void noinline callthunks_patch_module_calls(struct callthunk_sites *cs,

void noinline callthunks_patch_module_calls(struct callthunk_sites *cs,

					    struct module *mod)

					    struct module *mod)

arch/x86/kernel/unwind_orc.c

+20 −1
Original line number Original line Diff line number Diff line
@@ -136,6 +136,21 @@ static struct orc_entry null_orc_entry = { 
	.type = UNWIND_HINT_TYPE_CALL

	.type = UNWIND_HINT_TYPE_CALL

};

};





#ifdef CONFIG_CALL_THUNKS

static struct orc_entry *orc_callthunk_find(unsigned long ip)

{

	if (!is_callthunk((void *)ip))

		return NULL;



	return &null_orc_entry;

}

#else

static struct orc_entry *orc_callthunk_find(unsigned long ip)

{

	return NULL;

}

#endif



/* Fake frame pointer entry -- used as a fallback for generated code */

/* Fake frame pointer entry -- used as a fallback for generated code */

static struct orc_entry orc_fp_entry = {

static struct orc_entry orc_fp_entry = {

	.type		= UNWIND_HINT_TYPE_CALL,

	.type		= UNWIND_HINT_TYPE_CALL,
@@ -189,7 +204,11 @@ static struct orc_entry *orc_find(unsigned long ip) 
	if (orc)

	if (orc)

		return orc;

		return orc;





	return orc_ftrace_find(ip);

	orc =  orc_ftrace_find(ip);

	if (orc)

		return orc;



	return orc_callthunk_find(ip);

}

}





#ifdef CONFIG_MODULES

#ifdef CONFIG_MODULES