1 files changed, 69 insertions, 0 deletions
diff --git a/arch/riscv64/kernel/csr.h b/arch/riscv64/kernel/csr.h
new file mode 100644
index 0000000..ade397c
--- /dev/null
+++ b/arch/riscv64/kernel/csr.h
@@ -0,0 +1,69 @@
+#ifndef APOS_CSR_H
+#define APOS_CSR_H
+
+/**
+ * @file csr.h
+ * riscv64-specific header for CSR handling
+ */
+
+#define SATP_MODE_Sv32       0x80000000
+#define SATP_MODE_Sv39       0x8000000000000000
+#define SATP_MODE_Sv48       0x9000000000000000
+
+/* unprivileged CSR registers */
+#define CSR_TIME             0xc01
+#define CSR_TIMEH            0xc81
+
+/* supervisor CSR registers */
+#define CSR_SSTATUS          0x100
+#define CSR_SIE              0x104
+#define CSR_STVEC            0x105
+#define CSR_SCOUNTEREN       0x106
+
+#define CSR_SENVCFG          0x10A
+
+#define CSR_SSCRATCH         0x140
+#define CSR_SEPC             0x141
+#define CSR_SCAUSE           0x142
+#define CSR_STVAL            0x143
+#define CSR_SIP              0x144
+
+#define CSR_SATP             0x180
+
+#define CSR_SCONTEXT         0x5A8
+
+/* Exception causes */
+#define EXC_INST_MISALIGNED  0
+#define EXC_INST_ACCESS      1
+#define EXC_BREAKPOINT       3
+#define EXC_LOAD_ACCESS      5
+#define EXC_STORE_ACCESS     7
+#define EXC_SYSCALL          8
+#define EXC_INST_PAGE_FAULT  12
+#define EXC_LOAD_PAGE_FAULT  13
+#define EXC_STORE_PAGE_FAULT 15
+
+/* status CSR bits */
+#define SSTATUS_SUM          (1 << 18)
+#define SSTATUS_SPP          (1 << 8)
+
+/* directly lifted from Linux:/arch/riscv/include/asm/asm.h:9-13 */
+#if defined(__ASSEMBLY__)
+#define __ASM_STR(x) x
+#else
+#define __ASM_STR(x) #x
+#endif
+
+#define csr_read(csr, res)                                                     \
+	__asm__ volatile ("csrr %0, " __ASM_STR(csr) : "=r" (res) : : "memory")
+
+#define csr_write(csr, val)                                                    \
+	__asm__ volatile ("csrw " __ASM_STR(csr) ", %0" : : "r" (val) : "memory")
+
+#define csr_set(csr, val)                                                      \
+	__asm__ volatile ("csrs " __ASM_STR(csr) ", %0" : : "r" (val) : "memory")
+
+#define csr_clear(csr, val)                                                    \
+	__asm__ volatile ("csrc " __ASM_STR(csr) ", %0" : : "r" (val) : "memory")
+
+#endif /* APOS_CSR_H */