x86: make get_cpu_vendor() accessible from Xen code

commit efbcd61d9b upstream.

In order to be able to differentiate between AMD and Intel based
systems for very early hypercalls without having to rely on the Xen
hypercall page, make get_cpu_vendor() non-static.

Refactor early_cpu_init() for the same reason by splitting out the
loop initializing cpu_devs() into an externally callable function.

This is part of XSA-466 / CVE-2024-53241.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Juergen Gross 2024-10-17 08:29:48 +02:00 committed by Greg Kroah-Hartman
parent 1d5354a918
commit e74011db51
2 changed files with 24 additions and 16 deletions

View File

@ -194,6 +194,8 @@ static inline unsigned long long l1tf_pfn_limit(void)
return BIT_ULL(boot_cpu_data.x86_cache_bits - 1 - PAGE_SHIFT);
}
void init_cpu_devs(void);
void get_cpu_vendor(struct cpuinfo_x86 *c);
extern void early_cpu_init(void);
extern void identify_boot_cpu(void);
extern void identify_secondary_cpu(struct cpuinfo_x86 *);

View File

@ -792,7 +792,7 @@ void detect_ht(struct cpuinfo_x86 *c)
#endif
}
static void get_cpu_vendor(struct cpuinfo_x86 *c)
void get_cpu_vendor(struct cpuinfo_x86 *c)
{
char *v = c->x86_vendor_id;
int i;
@ -1505,15 +1505,11 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
detect_nopl();
}
void __init early_cpu_init(void)
void __init init_cpu_devs(void)
{
const struct cpu_dev *const *cdev;
int count = 0;
#ifdef CONFIG_PROCESSOR_SELECT
pr_info("KERNEL supported cpus:\n");
#endif
for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) {
const struct cpu_dev *cpudev = *cdev;
@ -1521,20 +1517,30 @@ void __init early_cpu_init(void)
break;
cpu_devs[count] = cpudev;
count++;
}
}
void __init early_cpu_init(void)
{
#ifdef CONFIG_PROCESSOR_SELECT
unsigned int i, j;
pr_info("KERNEL supported cpus:\n");
#endif
init_cpu_devs();
#ifdef CONFIG_PROCESSOR_SELECT
{
unsigned int j;
for (j = 0; j < 2; j++) {
if (!cpudev->c_ident[j])
continue;
pr_info(" %s %s\n", cpudev->c_vendor,
cpudev->c_ident[j]);
}
for (i = 0; i < X86_VENDOR_NUM && cpu_devs[i]; i++) {
for (j = 0; j < 2; j++) {
if (!cpu_devs[i]->c_ident[j])
continue;
pr_info(" %s %s\n", cpu_devs[i]->c_vendor,
cpu_devs[i]->c_ident[j]);
}
#endif
}
#endif
early_identify_cpu(&boot_cpu_data);
}