From: Ard Biesheuvel ardb@kernel.org

When FEAT_LPA{,2} are not implemented, the ID_AA64MMFR0_EL1.PARange and TCR.IPS values corresponding with 52-bit physical addressing are reserved.

Setting the TCR.IPS field to 0b110 (52-bit physical addressing) has side effects, such as how the TTBRn_ELx.BADDR fields are interpreted, and so it is important that disabling FEAT_LPA2 (by overriding the ID_AA64MMFR0.TGran fields) also presents a PARange field consistent with that.

So limit the field to 48 bits unless LPA2 is enabled, and update existing references to use the override consistently.

Fixes: 352b0395b505 ("arm64: Enable 52-bit virtual addressing for 4k and 16k granule configs") Cc: stable@vger.kernel.org Signed-off-by: Ard Biesheuvel ardb@kernel.org --- arch/arm64/include/asm/assembler.h | 5 +++++ arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/kernel/pi/idreg-override.c | 9 +++++++++ arch/arm64/kernel/pi/map_kernel.c | 6 ++++++ arch/arm64/mm/init.c | 7 ++++++- 5 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 3d8d534a7a77..ad63457a05c5 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -343,6 +343,11 @@ alternative_cb_end // Narrow PARange to fit the PS field in TCR_ELx ubfx \tmp0, \tmp0, #ID_AA64MMFR0_EL1_PARANGE_SHIFT, #3 mov \tmp1, #ID_AA64MMFR0_EL1_PARANGE_MAX +#ifdef CONFIG_ARM64_LPA2 +alternative_if_not ARM64_HAS_VA52 + mov \tmp1, #ID_AA64MMFR0_EL1_PARANGE_48 +alternative_else_nop_endif +#endif cmp \tmp0, \tmp1 csel \tmp0, \tmp1, \tmp0, hi bfi \tcr, \tmp0, \pos, #3 diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 6ce71f444ed8..f8cb8a6ab98a 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -3478,7 +3478,7 @@ static void verify_hyp_capabilities(void) return;

safe_mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); - mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); + mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1); mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);

/* Verify VMID bits */ diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c index 22159251eb3a..c6b185b885f7 100644 --- a/arch/arm64/kernel/pi/idreg-override.c +++ b/arch/arm64/kernel/pi/idreg-override.c @@ -83,6 +83,15 @@ static bool __init mmfr2_varange_filter(u64 val) id_aa64mmfr0_override.val |= (ID_AA64MMFR0_EL1_TGRAN_LPA2 - 1) << ID_AA64MMFR0_EL1_TGRAN_SHIFT; id_aa64mmfr0_override.mask |= 0xfU << ID_AA64MMFR0_EL1_TGRAN_SHIFT; + + /* + * Override PARange to 48 bits - the override will just be + * ignored if the actual PARange is smaller, but this is + * unlikely to be the case for LPA2 capable silicon. + */ + id_aa64mmfr0_override.val |= + ID_AA64MMFR0_EL1_PARANGE_48 << ID_AA64MMFR0_EL1_PARANGE_SHIFT; + id_aa64mmfr0_override.mask |= 0xfU << ID_AA64MMFR0_EL1_PARANGE_SHIFT; } #endif return true; diff --git a/arch/arm64/kernel/pi/map_kernel.c b/arch/arm64/kernel/pi/map_kernel.c index f374a3e5a5fe..e57b043f324b 100644 --- a/arch/arm64/kernel/pi/map_kernel.c +++ b/arch/arm64/kernel/pi/map_kernel.c @@ -136,6 +136,12 @@ static void noinline __section(".idmap.text") set_ttbr0_for_lpa2(u64 ttbr) { u64 sctlr = read_sysreg(sctlr_el1); u64 tcr = read_sysreg(tcr_el1) | TCR_DS; + u64 mmfr0 = read_sysreg(id_aa64mmfr0_el1); + u64 parange = cpuid_feature_extract_unsigned_field(mmfr0, + ID_AA64MMFR0_EL1_PARANGE_SHIFT); + + tcr &= ~TCR_IPS_MASK; + tcr |= parange << TCR_IPS_SHIFT;

asm(" msr sctlr_el1, %0 ;" " isb ;" diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index d21f67d67cf5..2b2289d55eaa 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -280,7 +280,12 @@ void __init arm64_memblock_init(void)

if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { extern u16 memstart_offset_seed; - u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); + + /* + * Use the sanitised version of id_aa64mmfr0_el1 so that linear + * map randomization can be enabled by shrinking the IPA space. + */ + u64 mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1); int parange = cpuid_feature_extract_unsigned_field( mmfr0, ID_AA64MMFR0_EL1_PARANGE_SHIFT); s64 range = linear_region_size -