arm64: Expose DC CVAP to userspace

The ARMv8.2-DCPoP feature introduces persistent memory support to the
architecture, by defining a point of persistence in the memory
hierarchy, and a corresponding cache maintenance operation, DC CVAP.
Expose the support via HWCAP and MRS emulation.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/Documentation/arm64/cpu-feature-registers.txt b/Documentation/arm64/cpu-feature-registers.txt
index d1c97f9f51cc3bd3fd21ad181253bb354e7771b1..dad411d635d88c09c6965f506e9ff27b5cfbc38b 100644 (file)
--- a/Documentation/arm64/cpu-feature-registers.txt
+++ b/Documentation/arm64/cpu-feature-registers.txt
@@ -179,6 +179,8 @@ infrastructure:
      | FCMA                         | [19-16] |    y    |
      |--------------------------------------------------|
      | JSCVT                        | [15-12] |    y    |
+     |--------------------------------------------------|
+     | DPB                          | [3-0]   |    y    |
      x--------------------------------------------------x
 
 Appendix I: Example

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 248339e4aaf5a7a0b6bc09bc2184654bbda72845..f707fed5886f011bce5fd4723d5ab2c739d997b7 100644 (file)
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -329,6 +329,7 @@
 #define ID_AA64ISAR1_LRCPC_SHIFT       20
 #define ID_AA64ISAR1_FCMA_SHIFT                16
 #define ID_AA64ISAR1_JSCVT_SHIFT       12
+#define ID_AA64ISAR1_DPB_SHIFT         0
 
 /* id_aa64pfr0 */
 #define ID_AA64PFR0_GIC_SHIFT          24

diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 4e187ce2a8113472b6c94ffb4feb934a45d4e254..4b9344cba83ae30256af652ad56aa9d6cd9e8ac1 100644 (file)
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -35,5 +35,6 @@
 #define HWCAP_JSCVT            (1 << 13)
 #define HWCAP_FCMA             (1 << 14)
 #define HWCAP_LRCPC            (1 << 15)
+#define HWCAP_DCPOP            (1 << 16)
 
 #endif /* _UAPI__ASM_HWCAP_H */

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9f9e0064c8c151c95b2995cc14c69b2d6902878f..a2542ef3ff25c59140dcbc063cd6fa1be2a257ff 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -120,6 +120,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
+       ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_DPB_SHIFT, 4, 0),
        ARM64_FTR_END,
 };
 
@@ -916,6 +917,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_FP_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_FPHP),
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 0, CAP_HWCAP, HWCAP_ASIMD),
        HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_ASIMD_SHIFT, FTR_SIGNED, 1, CAP_HWCAP, HWCAP_ASIMDHP),
+       HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_DPB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_DCPOP),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_JSCVT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_JSCVT),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_FCMA),
        HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_LRCPC),

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index f495ee5049fd767c3a1bd1f555599167f9a1a1f1..311885962830bd058f6555b95dbdbe266dbef2e7 100644 (file)
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -68,6 +68,7 @@ static const char *const hwcap_str[] = {
        "jscvt",
        "fcma",
        "lrcpc",
+       "dcpop",
        NULL
 };