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x86: make get_cpu_vendor() accessible from Xen code

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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>
This commit is contained in:
Juergen Gross 2024-10-17 08:29:48 +02:00
parent f9244fb55f
commit efbcd61d9b
2 changed files with 24 additions and 16 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/include/asm/processor.h
View file

@ -230,6 +230,8 @@ 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_secondary_cpu(struct cpuinfo_x86 *);
extern void print_cpu_info(struct cpuinfo_x86 *);

32
arch/x86/kernel/cpu/common.c
View file

@ -867,7 +867,7 @@ static void cpu_detect_tlb(struct cpuinfo_x86 *c)
tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]);
}
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;
@ -1649,15 +1649,11 @@ 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;
@ -1665,20 +1661,30 @@ 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 (i = 0; i < X86_VENDOR_NUM && cpu_devs[i]; i++) {
for (j = 0; j < 2; j++) {
if (!cpudev->c_ident[j])
if (!cpu_devs[i]->c_ident[j])
continue;
pr_info(" %s %s\n", cpudev->c_vendor,
cpudev->c_ident[j]);
pr_info(" %s %s\n", cpu_devs[i]->c_vendor,
cpu_devs[i]->c_ident[j]);
}
}
#endif
}
early_identify_cpu(&boot_cpu_data);
}