[GIT PULL] x86 fixes

Ingo Molnar
2023-12-23T14:34:09Z

Linus,

Please pull the latest x86/urgent git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-2023-12-23

# HEAD: d5a10b976ecb77fa49b95f3f1016ca2997c122cb x86/acpi: Handle bogus MADT APIC tables gracefully

Misc fixes:

- Fix a secondary CPUs enumeration regression caused by creative
MADT APIC table entries on certain systems.

- Fix a race in the NOP-patcher that can spuriously trigger crashes
on bootup.

- Fix a bootup failure regression caused by the parallel bringup
code, caused by firmware inconsistency between the APIC
initialization states of the boot and secondary CPUs, on certain
systems.

Thanks,

Ingo

------------------>
Thomas Gleixner (4):
x86/smpboot/64: Handle X2APIC BIOS inconsistency gracefully
x86/alternatives: Sync core before enabling interrupts
x86/alternatives: Disable interrupts and sync when optimizing NOPs in place
x86/acpi: Handle bogus MADT APIC tables gracefully

arch/x86/kernel/acpi/boot.c | 2 +-
arch/x86/kernel/alternative.c | 14 ++++++++++++--
arch/x86/kernel/head_64.S | 16 ++++++++++++++++
3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 1a0dd80d81ac..85a3ce2a3666 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -293,6 +293,7 @@ acpi_parse_lapic(union acpi_subtable_headers * header, const unsigned long end)
processor->processor_id, /* ACPI ID */
processor->lapic_flags & ACPI_MADT_ENABLED);

+ has_lapic_cpus = true;
return 0;
}

@@ -1134,7 +1135,6 @@ static int __init acpi_parse_madt_lapic_entries(void)
if (!count) {
count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_APIC,
acpi_parse_lapic, MAX_LOCAL_APIC);
- has_lapic_cpus = count > 0;
x2count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_X2APIC,
acpi_parse_x2apic, MAX_LOCAL_APIC);
}
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 73be3931e4f0..aae7456ece07 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -255,6 +255,16 @@ static void __init_or_module noinline optimize_nops(u8 *instr, size_t len)
}
}

+static void __init_or_module noinline optimize_nops_inplace(u8 *instr, size_t len)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ optimize_nops(instr, len);
+ sync_core();
+ local_irq_restore(flags);
+}
+
/*
* In this context, "source" is where the instructions are placed in the
* section .altinstr_replacement, for example during kernel build by the
@@ -438,7 +448,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
* patch if feature is *NOT* present.
*/
if (!boot_cpu_has(a->cpuid) == !(a->flags & ALT_FLAG_NOT)) {
- optimize_nops(instr, a->instrlen);
+ optimize_nops_inplace(instr, a->instrlen);
continue;
}

@@ -1685,8 +1695,8 @@ void __init_or_module text_poke_early(void *addr, const void *opcode,
} else {
local_irq_save(flags);
memcpy(addr, opcode, len);
- local_irq_restore(flags);
sync_core();
+ local_irq_restore(flags);

/*
* Could also do a CLFLUSH here to speed up CPU recovery; but
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 086a2c3aaaa0..0f8103240fda 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -255,6 +255,22 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
testl $X2APIC_ENABLE, %eax
jnz .Lread_apicid_msr

+#ifdef CONFIG_X86_X2APIC
+ /*
+ * If system is in X2APIC mode then MMIO base might not be
+ * mapped causing the MMIO read below to fault. Faults can't
+ * be handled at that point.
+ */
+ cmpl $0, x2apic_mode(%rip)
+ jz .Lread_apicid_mmio
+
+ /* Force the AP into X2APIC mode. */
+ orl $X2APIC_ENABLE, %eax
+ wrmsr
+ jmp .Lread_apicid_msr
+#endif
+
+.Lread_apicid_mmio:
/* Read the APIC ID from the fix-mapped MMIO space. */
movq apic_mmio_base(%rip), %rcx
addq $APIC_ID, %rcx