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x86/orc: Make it callthunk aware

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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: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.511637628@infradead.org
This commit is contained in:
Peter Zijlstra 2022-09-15 13:11:33 +02:00
parent f138918162
commit 396e0b8e09
3 changed files with 38 additions and 1 deletions
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5
arch/x86/include/asm/alternative.h
View File

@ -92,6 +92,7 @@ extern void callthunks_patch_builtin_calls(void);
extern void callthunks_patch_module_calls(struct callthunk_sites *sites,
struct module *mod);
extern void *callthunks_translate_call_dest(void *dest);
extern bool is_callthunk(void *addr);
#else
static __always_inline void callthunks_patch_builtin_calls(void) {}
static __always_inline void
@ -101,6 +102,10 @@ static __always_inline void *callthunks_translate_call_dest(void *dest)
{
return dest;
}
static __always_inline bool is_callthunk(void *addr)
{
return false;
}
#endif
#ifdef CONFIG_SMP

13
arch/x86/kernel/callthunks.c
View File

@ -293,6 +293,19 @@ void *callthunks_translate_call_dest(void *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
void noinline callthunks_patch_module_calls(struct callthunk_sites *cs,
struct module *mod)

21
arch/x86/kernel/unwind_orc.c
View File

@ -136,6 +136,21 @@ static struct orc_entry null_orc_entry = {
.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 */
static struct orc_entry orc_fp_entry = {
.type = UNWIND_HINT_TYPE_CALL,
@ -189,7 +204,11 @@ static struct orc_entry *orc_find(unsigned long ip)
if (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