diff options
| author | Marc Zyngier <maz@kernel.org> | 2024-10-21 19:14:34 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2024-10-23 11:57:46 +0100 |
| commit | 358dd4a9bdac63a0a8fb13773bfce6f599e25433 (patch) | |
| tree | 3dd5229752b305be2d2718bf55bf68081ef7cc01 | |
| parent | 0f612c6eb13ad85a60e00c751c83e24f4a32cd0a (diff) | |
arm64: Add command-line override for ID_AA64MMFR0_EL1.ECV
It appears that relatively popular hardware out there implements
the CNTPOFF_EL2 variant of FEAT_ECV, advertises it via ID_AA64MMFR0_EL1,
but cannot be bothered to set SCR_EL3.ECVEn to 1.
You would probably think that "this is fine, EL3 will take the
trap on access to CNTPOFF_EL2 and flip the ECVEn bit", as that's
what a semi-decent firmware implementation would do.
But no. None of that. This particular implementation takes the trap,
considers its purpose in life, decides that it has none, and *RESETS*
the system.
Yes, x1e001de, I'm talking about you.
In order to allow this machine to be promoted slightly above the
level of a glorified door-stop, add a new "id_aa64mmfr0.ecv" override.
allowing the kernel to pretend this option was never there.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241021181434.1052974-1-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/kernel/pi/idreg-override.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c index 29d4b6244a6f..fbc37b2733e2 100644 --- a/arch/arm64/kernel/pi/idreg-override.c +++ b/arch/arm64/kernel/pi/idreg-override.c @@ -38,6 +38,15 @@ struct ftr_set_desc { #define FIELD(n, s, f) { .name = n, .shift = s, .width = 4, .filter = f } +static const struct ftr_set_desc mmfr0 __prel64_initconst = { + .name = "id_aa64mmfr0", + .override = &id_aa64mmfr0_override, + .fields = { + FIELD("ecv", ID_AA64MMFR0_EL1_ECV_SHIFT, NULL), + {} + }, +}; + static bool __init mmfr1_vh_filter(u64 val) { /* @@ -196,6 +205,7 @@ static const struct ftr_set_desc sw_features __prel64_initconst = { static const PREL64(const struct ftr_set_desc, reg) regs[] __prel64_initconst = { + { &mmfr0 }, { &mmfr1 }, { &mmfr2 }, { &pfr0 }, |