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x86/microcode/AMD: Check patch level only on the BSP

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Check final patch levels for AMD only on the BSP. This way, we decide
early and only once whether to continue loading or to leave the loader
disabled on such systems.

Simplify a lot.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-13-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Borislav Petkov 2017-01-20 21:29:51 +01:00 committed by Thomas Gleixner
parent 7a93a40be2
commit f3ad136d6e
3 changed files with 52 additions and 69 deletions
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2
arch/x86/include/asm/microcode_amd.h
View File

@ -54,6 +54,4 @@ static inline int __init
save_microcode_in_initrd_amd(unsigned int family) { return -EINVAL; }
void reload_ucode_amd(void) {}
#endif
extern bool check_current_patch_level(u32 *rev, bool early);
#endif /* _ASM_X86_MICROCODE_AMD_H */

78
arch/x86/kernel/cpu/microcode/amd.c
View File

@ -207,7 +207,7 @@ apply_microcode_early_amd(u32 cpuid_1_eax, void *ucode, size_t size,
struct cont_desc desc = { 0 };
u8 (*patch)[PATCH_MAX_SIZE];
struct microcode_amd *mc;
u32 rev, *new_rev;
u32 rev, dummy, *new_rev;
bool ret = false;
#ifdef CONFIG_X86_32
@ -218,9 +218,6 @@ apply_microcode_early_amd(u32 cpuid_1_eax, void *ucode, size_t size,
patch = &amd_ucode_patch;
#endif
if (check_current_patch_level(&rev, true))
return false;
desc.cpuid_1_eax = cpuid_1_eax;
scan_containers(ucode, size, &desc);
@ -231,6 +228,7 @@ apply_microcode_early_amd(u32 cpuid_1_eax, void *ucode, size_t size,
if (!mc)
return ret;
native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
if (rev >= mc->hdr.patch_id)
return ret;
@ -328,13 +326,8 @@ void load_ucode_amd_ap(unsigned int cpuid_1_eax)
{
struct equiv_cpu_entry *eq;
struct microcode_amd *mc;
u32 rev;
u16 eq_id;
/* 64-bit runs with paging enabled, thus early==false. */
if (check_current_patch_level(&rev, false))
return;
/* First AP hasn't cached it yet, go through the blob. */
if (!cont.data) {
struct cpio_data cp;
@ -371,6 +364,10 @@ reget:
return;
if (eq_id == cont.eq_id) {
u32 rev, dummy;
native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
mc = (struct microcode_amd *)amd_ucode_patch;
if (mc && rev < mc->hdr.patch_id) {
@ -436,19 +433,14 @@ int __init save_microcode_in_initrd_amd(unsigned int cpuid_1_eax)
void reload_ucode_amd(void)
{
struct microcode_amd *mc;
u32 rev;
/*
* early==false because this is a syscore ->resume path and by
* that time paging is long enabled.
*/
if (check_current_patch_level(&rev, false))
return;
u32 rev, dummy;
mc = (struct microcode_amd *)amd_ucode_patch;
if (!mc)
return;
rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
if (rev < mc->hdr.patch_id) {
if (!__apply_microcode_amd(mc)) {
ucode_new_rev = mc->hdr.patch_id;
@ -586,60 +578,13 @@ static unsigned int verify_patch_size(u8 family, u32 patch_size,
return patch_size;
}
/*
* Those patch levels cannot be updated to newer ones and thus should be final.
*/
static u32 final_levels[] = {
0x01000098,
0x0100009f,
0x010000af,
0, /* T-101 terminator */
};
/*
* Check the current patch level on this CPU.
*
* @rev: Use it to return the patch level. It is set to 0 in the case of
* error.
*
* Returns:
* - true: if update should stop
* - false: otherwise
*/
bool check_current_patch_level(u32 *rev, bool early)
{
u32 lvl, dummy, i;
bool ret = false;
u32 *levels;
native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
if (IS_ENABLED(CONFIG_X86_32) && early)
levels = (u32 *)__pa_nodebug(&final_levels);
else
levels = final_levels;
for (i = 0; levels[i]; i++) {
if (lvl == levels[i]) {
lvl = 0;
ret = true;
break;
}
}
if (rev)
*rev = lvl;
return ret;
}
static int apply_microcode_amd(int cpu)
{
struct cpuinfo_x86 *c = &cpu_data(cpu);
struct microcode_amd *mc_amd;
struct ucode_cpu_info *uci;
struct ucode_patch *p;
u32 rev;
u32 rev, dummy;
BUG_ON(raw_smp_processor_id() != cpu);
@ -652,8 +597,7 @@ static int apply_microcode_amd(int cpu)
mc_amd = p->data;
uci->mc = p->data;
if (check_current_patch_level(&rev, false))
return -1;
rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
/* need to apply patch? */
if (rev >= mc_amd->hdr.patch_id) {

41
arch/x86/kernel/cpu/microcode/core.c
View File

@ -69,6 +69,42 @@ struct cpu_info_ctx {
int err;
};
/*
* Those patch levels cannot be updated to newer ones and thus should be final.
*/
static u32 final_levels[] = {
0x01000098,
0x0100009f,
0x010000af,
0, /* T-101 terminator */
};
/*
* Check the current patch level on this CPU.
*
* Returns:
* - true: if update should stop
* - false: otherwise
*/
static bool amd_check_current_patch_level(void)
{
u32 lvl, dummy, i;
u32 *levels;
native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
if (IS_ENABLED(CONFIG_X86_32))
levels = (u32 *)__pa_nodebug(&final_levels);
else
levels = final_levels;
for (i = 0; levels[i]; i++) {
if (lvl == levels[i])
return true;
}
return false;
}
static bool __init check_loader_disabled_bsp(void)
{
static const char *__dis_opt_str = "dis_ucode_ldr";
@ -95,6 +131,11 @@ static bool __init check_loader_disabled_bsp(void)
if (native_cpuid_ecx(1) & BIT(31))
return *res;
if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
if (amd_check_current_patch_level())
return *res;
}
if (cmdline_find_option_bool(cmdline, option) <= 0)
*res = false;