mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-10-09 10:09:11 +00:00
Code Issues Releases Wiki Activity

arm64: ssbd: Restore mitigation status on CPU resume

Browse source 
commit 647d0519b5 upstream.

On a system where firmware can dynamically change the state of the
mitigation, the CPU will always come up with the mitigation enabled,
including when coming back from suspend.

If the user has requested "no mitigation" via a command line option,
let's enforce it by calling into the firmware again to disable it.

Similarily, for a resume from hibernate, the mitigation could have
been disabled by the boot kernel. Let's ensure that it is set
back on in that case.

Acked-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marc Zyngier 2018-07-20 10:53:06 +01:00 committed by Greg Kroah-Hartman
parent 02e26bd9ad
commit c5c89bb4de
4 changed files with 26 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
arch/arm64/include/asm/cpufeature.h
View file

@ -278,6 +278,12 @@ static inline int arm64_get_ssbd_state(void)
#endif
}
#ifdef CONFIG_ARM64_SSBD
void arm64_set_ssbd_mitigation(bool state);
#else
static inline void arm64_set_ssbd_mitigation(bool state) {}
#endif
#endif /* __ASSEMBLY__ */
#endif

2
arch/arm64/kernel/cpu_errata.c
View file

@ -299,7 +299,7 @@ void __init arm64_enable_wa2_handling(struct alt_instr *alt,
*updptr = cpu_to_le32(aarch64_insn_gen_nop());
}
static void arm64_set_ssbd_mitigation(bool state)
void arm64_set_ssbd_mitigation(bool state)
{
switch (psci_ops.conduit) {
case PSCI_CONDUIT_HVC:

11
arch/arm64/kernel/hibernate.c
View file

@ -313,6 +313,17 @@ int swsusp_arch_suspend(void)
sleep_cpu = -EINVAL;
__cpu_suspend_exit();
/*
* Just in case the boot kernel did turn the SSBD
* mitigation off behind our back, let's set the state
* to what we expect it to be.
*/
switch (arm64_get_ssbd_state()) {
case ARM64_SSBD_FORCE_ENABLE:
case ARM64_SSBD_KERNEL:
arm64_set_ssbd_mitigation(true);
}
}
local_dbg_restore(flags);

8
arch/arm64/kernel/suspend.c
View file

@ -62,6 +62,14 @@ void notrace __cpu_suspend_exit(void)
*/
if (hw_breakpoint_restore)
hw_breakpoint_restore(cpu);
/*
* On resume, firmware implementing dynamic mitigation will
* have turned the mitigation on. If the user has forcefully
* disabled it, make sure their wishes are obeyed.
*/
if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE)
arm64_set_ssbd_mitigation(false);
}
/*