c096e7d0b9
There are two types of stacks: the kernel ones and the user ones. The kernel stacks are used by Occlum and managed by Intel SGX SDK itself, while the user stacks are used by the threads created and managed by Occlum. These user stacks are transparent to Intel SGX SDK so far. The problem is that Intel SGX SDK needs to be aware of the user stacks. SGX exception handlers will check whether the rsp value---when the exception happened---is within the stack of the current SGX thread. If the check fails, the registered exception handler will not be triggered. But when exceptions are triggered by the threads running upon Occlum, the rsp value points to the user stacks, which Intel SGX SDK are completely unware of. So the check always fails. Therefore, we extend Intel SGX SDK with two new APIs: int sgx_enable_user_stack(size_t stack_base, size_t stack_limit); void sgx_disable_user_stack(void); And this commit uses the two APIs to inform Intel SGX SDK about the Occlum-managed stacks. And the rsp checks in SGX exception handlers will check whether rsp is within the user stacks.
92 lines
3.4 KiB
C
92 lines
3.4 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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typedef struct t_cpuid {
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unsigned int eax;
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unsigned int ebx;
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unsigned int ecx;
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unsigned int edx;
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} t_cpuid_t;
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static inline void native_cpuid(int leaf, int subleaf, t_cpuid_t *p)
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{
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memset(p, 0, sizeof(*p));
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/* ecx is often an input as well as an output. */
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asm volatile("cpuid"
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: "=a" (p->eax),
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"=b" (p->ebx),
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"=c" (p->ecx),
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"=d" (p->edx)
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: "a" (leaf), "c" (subleaf));
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}
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int main(int argc, char **argv)
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{
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/* Gets CPUID information and tests the SGX support of the CPU */
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t_cpuid_t cpu;
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int leaf = 1;
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int subleaf = 0;
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native_cpuid(leaf, subleaf, &cpu);
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printf("eax: %x ebx: %x ecx: %x edx: %x\n", cpu.eax, cpu.ebx, cpu.ecx, cpu.edx);
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printf("Stepping %d\n", cpu.eax & 0xF); // Bit 3-0
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printf("Model %d\n", (cpu.eax >> 4) & 0xF); // Bit 7-4
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printf("Family %d\n", (cpu.eax >> 8) & 0xF); // Bit 11-8
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printf("Processor Type %d\n", (cpu.eax >> 12) & 0x3); // Bit 13-12
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printf("Extended Model %d\n", (cpu.eax >> 16) & 0xF); // Bit 19-16
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printf("Extended Family %d\n", (cpu.eax >> 20) & 0xFF); // Bit 27-20
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// if smx (Safer Mode Extensions) set - SGX global enable is supported
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printf("smx: %d\n", (cpu.ecx >> 6) & 1); // CPUID.1:ECX.[bit6]
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/* Extended feature bits (EAX=07H, ECX=0H)*/
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printf("\nExtended feature bits (EAX=07H, ECX=0H)\n");
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leaf = 7;
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subleaf = 0;
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native_cpuid(leaf, subleaf, &cpu);
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printf("eax: %x ebx: %x ecx: %x edx: %x\n", cpu.eax, cpu.ebx, cpu.ecx, cpu.edx);
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//CPUID.(EAX=07H, ECX=0H):EBX.SGX = 1,
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// Bit 02: SGX. Supports Intel® Software Guard Extensions (Intel® SGX Extensions) if 1.
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printf("SGX is available: %d\n", (cpu.ebx >> 2) & 0x1);
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/* SGX has to be enabled in MSR.IA32_Feature_Control.SGX_Enable
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check with msr-tools: rdmsr -ax 0x3a
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SGX_Enable is Bit 18
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if SGX_Enable = 0 no leaf information will appear.
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for more information check Intel Docs Architectures-software-developer-system-programming-manual - 35.1 Architectural MSRS
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*/
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/* CPUID Leaf 12H, Sub-Leaf 0 Enumeration of Intel SGX Capabilities (EAX=12H,ECX=0) */
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printf("\nCPUID Leaf 12H, Sub-Leaf 0 of Intel SGX Capabilities (EAX=12H,ECX=0)\n");
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leaf = 0x12;
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subleaf = 0;
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native_cpuid(leaf, subleaf, &cpu);
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printf("eax: %x ebx: %x ecx: %x edx: %x\n", cpu.eax, cpu.ebx, cpu.ecx, cpu.edx);
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printf("Sgx 1 supported: %d\n", cpu.eax & 0x1);
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printf("Sgx 2 supported: %d\n", (cpu.eax >> 1) & 0x1);
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printf("MaxEnclaveSize_Not64: %x\n", cpu.edx & 0xFF);
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printf("MaxEnclaveSize_64: %x\n", (cpu.edx >> 8) & 0xFF);
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/* CPUID Leaf 12H, Sub-Leaf 1 Enumeration of Intel SGX Capabilities (EAX=12H,ECX=1) */
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printf("\nCPUID Leaf 12H, Sub-Leaf 1 of Intel SGX Capabilities (EAX=12H,ECX=1)\n");
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leaf = 0x12;
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subleaf = 1;
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native_cpuid(leaf, subleaf, &cpu);
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printf("eax: %x ebx: %x ecx: %x edx: %x\n", cpu.eax, cpu.ebx, cpu.ecx, cpu.edx);
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int i;
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for (i=2; i<4; i++) {
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/* CPUID Leaf 12H, Sub-Leaf i Enumeration of Intel SGX Capabilities (EAX=12H,ECX=i) */
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printf("\nCPUID Leaf 12H, Sub-Leaf %d of Intel SGX Capabilities (EAX=12H,ECX=%d)\n", i, i);
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leaf = 0x12;
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subleaf = i;
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native_cpuid(leaf, subleaf, &cpu);
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printf("eax: %x ebx: %x ecx: %x edx: %x\n", cpu.eax, cpu.ebx, cpu.ecx, cpu.edx);
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}
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return 0;
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}
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