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Subject[PATCH v13 08/13] x86/sgx: Add wrappers for ENCLS leaf functions
Date
Add wrappers for Intel(R) SGX ENCLS opcode leaf functions except
ENCLS(EINIT). ENCLS invokes privileged functions for managing (creation,
initialization and swapping) and debugging enclaves.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/asm/sgx.h | 261 +++++++++++++++++++++++++++++++++++++
1 file changed, 261 insertions(+)

diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
index 17b7b3aa66bf..f8e419378f30 100644
--- a/arch/x86/include/asm/sgx.h
+++ b/arch/x86/include/asm/sgx.h
@@ -69,4 +69,265 @@ static inline void *sgx_epc_addr(struct sgx_epc_page *page)
return (void *)(bank->va + (page->desc & PAGE_MASK) - bank->pa);
}

+/**
+ * ENCLS_FAULT_FLAG - flag signifying an ENCLS return code is a trapnr
+ *
+ * ENCLS has its own (positive value) error codes and also generates
+ * ENCLS specific #GP and #PF faults. And the ENCLS values get munged
+ * with system error codes as everything percolates back up the stack.
+ * Unfortunately (for us), we need to precisely identify each unique
+ * error code, e.g. the action taken if EWB fails varies based on the
+ * type of fault and on the exact SGX error code, i.e. we can't simply
+ * convert all faults to -EFAULT.
+ *
+ * To make all three error types coexist, we set bit 30 to identify an
+ * ENCLS fault. Bit 31 (technically bits N:31) is used to differentiate
+ * between positive (faults and SGX error codes) and negative (system
+ * error codes) values.
+ */
+#define ENCLS_FAULT_FLAG 0x40000000UL
+#define ENCLS_FAULT_FLAG_ASM "$0x40000000"
+
+/**
+ * IS_ENCLS_FAULT - check if a return code indicates an ENCLS fault
+ *
+ * Check for a fault by looking for a postive value with the fault
+ * flag set. The postive value check is needed to filter out system
+ * error codes since negative values will have all higher order bits
+ * set, including ENCLS_FAULT_FLAG.
+ */
+#define IS_ENCLS_FAULT(r) ((int)(r) > 0 && ((r) & ENCLS_FAULT_FLAG))
+
+/**
+ * ENCLS_TRAPNR - retrieve the trapnr exactly as passed via _ASM_EXTABLE_FAULT
+ *
+ * Retrieve the encoded trapnr from the specified return code, keeping
+ * any error code bits that were included in trapnr when it was supplied
+ * to the _ASM_EXTABLE_FAULT handler.
+ */
+#define ENCLS_TRAPNR(r) ((r) & ~ENCLS_FAULT_FLAG)
+
+/**
+ * ENCLS_FAULT_VECTOR - retrieve the fault vector from a return code
+ *
+ * Retrieve the encoded fault vector, e.g. #GP or #PF, from the specified
+ * return code, dropping any potential error code bits in trapnr.
+ */
+#define ENCLS_FAULT_VECTOR(r) (ENCLS_TRAPNR(r) & 0x1f)
+
+/**
+ * encls_to_err - translate an ENCLS fault or SGX code into a system error code
+ * @ret: positive value return code
+ *
+ * Returns:
+ * -EFAULT for faults
+ * -EINTR for unmasked events
+ * -EINVAL for SGX_INVALID_* error codes
+ * -EBUSY for non-fatal resource contention errors
+ * -EIO for all other errors
+ *
+ * Translate a postive return code, e.g. from ENCLS, into a system error
+ * code. Primarily used by functions that cannot return a non-negative
+ * error code, e.g. kernel callbacks.
+ */
+static inline int encls_to_err(int ret)
+{
+ if (IS_ENCLS_FAULT(ret))
+ return -EFAULT;
+
+ switch (ret) {
+ case SGX_UNMASKED_EVENT:
+ return -EINTR;
+ case SGX_INVALID_SIG_STRUCT:
+ case SGX_INVALID_ATTRIBUTE:
+ case SGX_INVALID_MEASUREMENT:
+ case SGX_INVALID_EINITTOKEN:
+ case SGX_INVALID_CPUSVN:
+ case SGX_INVALID_ISVSVN:
+ case SGX_INVALID_KEYNAME:
+ return -EINVAL;
+ case SGX_ENCLAVE_ACT:
+ case SGX_CHILD_PRESENT:
+ case SGX_ENTRYEPOCH_LOCKED:
+ case SGX_PREV_TRK_INCMPL:
+ case SGX_PAGE_NOT_MODIFIABLE:
+ case SGX_PAGE_NOT_DEBUGGABLE:
+ return -EBUSY;
+ default:
+ return -EIO;
+ };
+}
+
+/**
+ * __encls_ret_N - encode an ENCLS leaf that returns an error code in EAX
+ * @rax: leaf number
+ * @inputs: asm inputs for the leaf
+ *
+ * Returns:
+ * 0 on success
+ * SGX error code on failure
+ * trapnr with ENCLS_FAULT_FLAG set on fault
+ *
+ * Emit assembly for an ENCLS leaf that returns an error code, e.g. EREMOVE.
+ * And because SGX isn't complex enough as it is, leafs that return an error
+ * code also modify flags.
+ */
+#define __encls_ret_N(rax, inputs...) \
+ ({ \
+ int ret; \
+ asm volatile( \
+ "1: .byte 0x0f, 0x01, 0xcf;\n\t" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: orl "ENCLS_FAULT_FLAG_ASM",%%eax\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE_FAULT(1b, 3b) \
+ : "=a"(ret) \
+ : "a"(rax), inputs \
+ : "memory", "cc"); \
+ ret; \
+ })
+
+#define __encls_ret_1(rax, rcx) \
+ ({ \
+ __encls_ret_N(rax, "c"(rcx)); \
+ })
+
+#define __encls_ret_2(rax, rbx, rcx) \
+ ({ \
+ __encls_ret_N(rax, "b"(rbx), "c"(rcx)); \
+ })
+
+#define __encls_ret_3(rax, rbx, rcx, rdx) \
+ ({ \
+ __encls_ret_N(rax, "b"(rbx), "c"(rcx), "d"(rdx)); \
+ })
+
+/**
+ * __encls_N - encode an ENCLS leaf that doesn't return an error code
+ * @rax: leaf number
+ * @rbx_out: optional output variable
+ * @inputs: asm inputs for the leaf
+ *
+ * Returns:
+ * 0 on success
+ * trapnr with ENCLS_FAULT_FLAG set on fault
+ *
+ * Emit assembly for an ENCLS leaf that does not return an error code,
+ * e.g. ECREATE. Leaves without error codes either succeed or fault.
+ * @rbx_out is an optional parameter for use by EDGBRD, which returns
+ * the the requested value in RBX.
+ */
+#define __encls_N(rax, rbx_out, inputs...) \
+ ({ \
+ int ret; \
+ asm volatile( \
+ "1: .byte 0x0f, 0x01, 0xcf;\n\t" \
+ " xor %%eax,%%eax;\n" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: orl "ENCLS_FAULT_FLAG_ASM",%%eax\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE_FAULT(1b, 3b) \
+ : "=a"(ret), "=b"(rbx_out) \
+ : "a"(rax), inputs \
+ : "memory"); \
+ ret; \
+ })
+
+#define __encls_2(rax, rbx, rcx) \
+ ({ \
+ unsigned long ign_rbx_out; \
+ __encls_N(rax, ign_rbx_out, "b"(rbx), "c"(rcx)); \
+ })
+
+#define __encls_1_1(rax, data, rcx) \
+ ({ \
+ unsigned long rbx_out; \
+ int ret = __encls_N(rax, rbx_out, "c"(rcx)); \
+ if (!ret) \
+ data = rbx_out; \
+ ret; \
+ })
+
+static inline int __ecreate(struct sgx_pageinfo *pginfo, void *secs)
+{
+ return __encls_2(ECREATE, pginfo, secs);
+}
+
+static inline int __eextend(void *secs, void *epc)
+{
+ return __encls_2(EEXTEND, secs, epc);
+}
+
+static inline int __eadd(struct sgx_pageinfo *pginfo, void *epc)
+{
+ return __encls_2(EADD, pginfo, epc);
+}
+
+static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
+ void *secs)
+{
+ return __encls_ret_3(EINIT, sigstruct, secs, einittoken);
+}
+
+static inline int __eremove(void *epc)
+{
+ return __encls_ret_1(EREMOVE, epc);
+}
+
+static inline int __edbgwr(void *addr, unsigned long *data)
+{
+ return __encls_2(EDGBWR, *data, addr);
+}
+
+static inline int __edbgrd(void *addr, unsigned long *data)
+{
+ return __encls_1_1(EDGBRD, *data, addr);
+}
+
+static inline int __etrack(void *epc)
+{
+ return __encls_ret_1(ETRACK, epc);
+}
+
+static inline int __eldu(struct sgx_pageinfo *pginfo, void *epc, void *va)
+{
+ return __encls_ret_3(ELDU, pginfo, epc, va);
+}
+
+static inline int __eblock(void *epc)
+{
+ return __encls_ret_1(EBLOCK, epc);
+}
+
+static inline int __epa(void *epc)
+{
+ unsigned long rbx = SGX_PAGE_TYPE_VA;
+
+ return __encls_2(EPA, rbx, epc);
+}
+
+static inline int __ewb(struct sgx_pageinfo *pginfo, void *epc, void *va)
+{
+ return __encls_ret_3(EWB, pginfo, epc, va);
+}
+
+static inline int __eaug(struct sgx_pageinfo *pginfo, void *epc)
+{
+ return __encls_2(EAUG, pginfo, epc);
+}
+
+static inline int __emodpr(struct sgx_secinfo *secinfo, void *epc)
+{
+ return __encls_ret_2(EMODPR, secinfo, epc);
+}
+
+static inline int __emodt(struct sgx_secinfo *secinfo, void *epc)
+{
+ return __encls_ret_2(EMODT, secinfo, epc);
+}
+
#endif /* _ASM_X86_SGX_H */
--
2.17.1
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