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| author | Zhiquan Li <zhiquan1.li@intel.com> | 2024-08-05 13:35:31 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-08-07 21:04:38 +0300 |
| commit | ab84ba647f2c94ac4d0c3fc6951c49f08aa1fcf7 (patch) | |
| tree | b09a5e518749b20fddef4edd187fc4f11fcb8a0d /arch | |
| parent | c48b5a4cf3125adb679e28ef093f66ff81368d05 (diff) | |
| download | linux-ab84ba647f2c94ac4d0c3fc6951c49f08aa1fcf7.tar.xz | |
x86/acpi: Remove __ro_after_init from acpi_mp_wake_mailbox
On a platform using the "Multiprocessor Wakeup Structure"[1] to startup
secondary CPUs the control processor needs to memremap() the physical
address of the MP Wakeup Structure mailbox to the variable
acpi_mp_wake_mailbox, which holds the virtual address of mailbox.
To wake up the AP the control processor writes the APIC ID of AP, the
wakeup vector and the ACPI_MP_WAKE_COMMAND_WAKEUP command into the mailbox.
Current implementation doesn't consider the case which restricts boot time
CPU bringup to 1 with the kernel parameter "maxcpus=1" and brings other
CPUs online later from user space as it sets acpi_mp_wake_mailbox to
read-only after init. So when the first AP is tried to brought online
after init, the attempt to update the variable results in a kernel panic.
The memremap() call that initializes the variable cannot be moved into
acpi_parse_mp_wake() because memremap() is not functional at that point in
the boot process. Also as the APs might never be brought up, keep the
memremap() call in acpi_wakeup_cpu() so that the operation only takes place
when needed.
Fixes: 24dd05da8c79 ("x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init")
Signed-off-by: Zhiquan Li <zhiquan1.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/all/20240805103531.1230635-1-zhiquan1.li@intel.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/acpi/madt_wakeup.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/acpi/madt_wakeup.c b/arch/x86/kernel/acpi/madt_wakeup.c index 6cfe762be28b..d5ef6215583b 100644 --- a/arch/x86/kernel/acpi/madt_wakeup.c +++ b/arch/x86/kernel/acpi/madt_wakeup.c @@ -19,7 +19,7 @@ static u64 acpi_mp_wake_mailbox_paddr __ro_after_init; /* Virtual address of the Multiprocessor Wakeup Structure mailbox */ -static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox __ro_after_init; +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox; static u64 acpi_mp_pgd __ro_after_init; static u64 acpi_mp_reset_vector_paddr __ro_after_init; |