With ARMv8.2-LVA and LPA architecture extensions, arm64 hardware which
supports these extensions can support upto 52-bit virtual and 52-bit
physical addresses respectively.
Since at the moment we enable the support of these extensions via CONFIG
flags, e.g.
- LPA via CONFIG_ARM64_PA_BITS_52, and
- LVA via CONFIG_ARM64_FORCE_52BIT
The easiest way a user can determine the physical/virtual
addresses supported on the hardware, is via the '/proc/cpuinfo'
interface.
This patches enables the same.
Signed-off-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx>
---
arch/arm64/include/asm/cpufeature.h | 59 ++++++++++++++++++++++++-------------
arch/arm64/include/asm/sysreg.h | 19 ++++++++++++
arch/arm64/kernel/cpuinfo.c | 4 ++-
3 files changed, 61 insertions(+), 21 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index dfcfba725d72..2f1270ddc277 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -522,6 +522,45 @@ static inline bool system_supports_32bit_el0(void)
return cpus_have_const_cap(ARM64_HAS_32BIT_EL0);
}
+static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange)
+{
+ switch (parange) {
+ case ID_AA64MMFR0_PARANGE_32: return PARANGE_32;
+ case ID_AA64MMFR0_PARANGE_36: return PARANGE_36;
+ case ID_AA64MMFR0_PARANGE_40: return PARANGE_40;
+ case ID_AA64MMFR0_PARANGE_44: return PARANGE_44;
+ case ID_AA64MMFR0_PARANGE_48: return PARANGE_48;
+ case ID_AA64MMFR0_PARANGE_52: return PARANGE_52;
+ /*
+ * A future PE could use a value unknown to the kernel.
+ * However, by the "D10.1.4 Principles of the ID scheme
+ * for fields in ID registers", ARM DDI 0487C.a, any new
+ * value is guaranteed to be higher than what we know already.
+ * As a safe limit, we return the limit supported by the kernel.
+ */
+ default: return CONFIG_ARM64_PA_BITS;
+ }
+}
+
+static inline u32 id_aa64mmfr0_pa_range_bits(void)
+{
+ u64 mmfr0;
+
+ mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
+ return id_aa64mmfr0_parange_to_phys_shift(mmfr0 & 0x7);
+}
+
+static inline u32 id_aa64mmfr2_va_range_bits(void)
+{
+ u64 mmfr2;
+ u32 val;
+
+ mmfr2 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR2_EL1);
+ val = cpuid_feature_extract_unsigned_field(mmfr2,
+ ID_AA64MMFR2_LVA_SHIFT);
+ return ((val == ID_AA64MMFR2_VARANGE_52) ? VARANGE_52 : VARANGE_48);
+}
+
static inline bool system_supports_4kb_granule(void)
{
u64 mmfr0;
@@ -636,26 +675,6 @@ static inline void arm64_set_ssbd_mitigation(bool state) {}
extern int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt);
-static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange)
-{
- switch (parange) {
- case 0: return 32;
- case 1: return 36;
- case 2: return 40;
- case 3: return 42;
- case 4: return 44;
- case 5: return 48;
- case 6: return 52;
- /*
- * A future PE could use a value unknown to the kernel.
- * However, by the "D10.1.4 Principles of the ID scheme
- * for fields in ID registers", ARM DDI 0487C.a, any new
- * value is guaranteed to be higher than what we know already.
- * As a safe limit, we return the limit supported by the kernel.
- */
- default: return CONFIG_ARM64_PA_BITS;
- }
-}
#endif /* __ASSEMBLY__ */
#endif
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 72dc4c011014..70910b14b2f3 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -617,9 +617,22 @@
#define ID_AA64MMFR0_TGRAN64_SUPPORTED 0x0
#define ID_AA64MMFR0_TGRAN16_NI 0x0
#define ID_AA64MMFR0_TGRAN16_SUPPORTED 0x1
+#define ID_AA64MMFR0_PARANGE_32 0x0
+#define ID_AA64MMFR0_PARANGE_36 0x1
+#define ID_AA64MMFR0_PARANGE_40 0x2
+#define ID_AA64MMFR0_PARANGE_42 0x3
+#define ID_AA64MMFR0_PARANGE_44 0x4
#define ID_AA64MMFR0_PARANGE_48 0x5
#define ID_AA64MMFR0_PARANGE_52 0x6
+#define PARANGE_32 32
+#define PARANGE_36 36
+#define PARANGE_40 40
+#define PARANGE_42 42
+#define PARANGE_44 44
+#define PARANGE_48 48
+#define PARANGE_52 52
+
#ifdef CONFIG_ARM64_PA_BITS_52
#define ID_AA64MMFR0_PARANGE_MAX ID_AA64MMFR0_PARANGE_52
#else
@@ -646,6 +659,12 @@
#define ID_AA64MMFR2_UAO_SHIFT 4
#define ID_AA64MMFR2_CNP_SHIFT 0
+#define ID_AA64MMFR2_VARANGE_48 0x0
+#define ID_AA64MMFR2_VARANGE_52 0x1
+
+#define VARANGE_48 48
+#define VARANGE_52 52
+
/* id_aa64dfr0 */
#define ID_AA64DFR0_PMSVER_SHIFT 32
#define ID_AA64DFR0_CTX_CMPS_SHIFT 28
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index ca0685f33900..66583ac3be19 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -177,7 +177,9 @@ static int c_show(struct seq_file *m, void *v)
seq_printf(m, "CPU architecture: 8\n");
seq_printf(m, "CPU variant\t: 0x%x\n", MIDR_VARIANT(midr));
seq_printf(m, "CPU part\t: 0x%03x\n", MIDR_PARTNUM(midr));
- seq_printf(m, "CPU revision\t: %d\n\n", MIDR_REVISION(midr));
+ seq_printf(m, "CPU revision\t: %d\n", MIDR_REVISION(midr));
+ seq_printf(m, "address sizes\t: %d bits physical, %d bits virtual\n\n",
+ id_aa64mmfr0_pa_range_bits(), id_aa64mmfr2_va_range_bits());
}
return 0;
--
2.7.4
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