From: James Morse <james.morse@arm.com> maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/... --------------------------- Add code to head.S's el2_setup to detect MPAM and disable any EL2 traps. This register resets to an unknown value, setting it to the default parititons/pmg before we enable the MMU is the best thing to do. Kexec/kdump will depend on this if the previous kernel left the CPU configured with a restrictive configuration. If linux is booted at the highest implemented exception level el2_setup will clear the enable bit, disabling MPAM. This code can't be enabled until a subsequent patch adds the Kconfig and cpufeature boiler plate. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- arch/arm64/include/asm/el2_setup.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h index b7afaa026842..1e2181820a0a 100644 --- a/arch/arm64/include/asm/el2_setup.h +++ b/arch/arm64/include/asm/el2_setup.h @@ -208,6 +208,21 @@ msr spsr_el2, x0 .endm +.macro __init_el2_mpam +#ifdef CONFIG_ARM64_MPAM + /* Memory Partioning And Monitoring: disable EL2 traps */ + mrs x1, id_aa64pfr0_el1 + ubfx x0, x1, #ID_AA64PFR0_EL1_MPAM_SHIFT, #4 + cbz x0, .Lskip_mpam_\@ // skip if no MPAM + msr_s SYS_MPAM2_EL2, xzr // use the default partition + // and disable lower traps + mrs_s x0, SYS_MPAMIDR_EL1 + tbz x0, #17, .Lskip_mpam_\@ // skip if no MPAMHCR reg + msr_s SYS_MPAMHCR_EL2, xzr // clear TRAP_MPAMIDR_EL1 -> EL2 +.Lskip_mpam_\@: +#endif /* CONFIG_ARM64_MPAM */ +.endm + /** * Initialize EL2 registers to sane values. This should be called early on all * cores that were booted in EL2. Note that everything gets initialised as @@ -225,6 +240,7 @@ __init_el2_stage2 __init_el2_gicv3 __init_el2_hstr + __init_el2_mpam __init_el2_nvhe_idregs __init_el2_cptr __init_el2_fgt -- 2.25.1