1 // SPDX-License-Identifier: GPL-2.0-only
6  * This test case simulates a tracer redirecting tracee execution to
7  * a function and then restoring tracee state using PTRACE_GETREGS and
10  * modify a segment register.  This makes sure that ptrace correctly
11  * restores segment state when using PTRACE_SETREGS.
13  * This is not part of fsgsbase.c, because that test is 64-bit only.
53 		MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);  in init_seg()
55 		err(1, "mmap");  in init_seg()
64 		.limit           = sizeof(unsigned int) - 1,  in init_seg()
65 		.seg_32bit       = 1,  in init_seg()
66 		.contents        = 0, /* Data, grow-up */  in init_seg()
72 	if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) == 0) {  in init_seg()
81 			MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);  in init_seg()
84 		low_desc->entry_number = -1;  in init_seg()
86 		/* 32-bit set_thread_area */  in init_seg()
89 			      : "=a" (ret), "+m" (*low_desc)  in init_seg()
90 			      : "a" (243), "b" (low_desc)  in init_seg()
99 			printf("[NOTE]\tcould not create a segment -- can't test anything\n");  in init_seg()
114 	 * we modify a segment register in order to make sure that ptrace  in tracee_zap_segment()
115 	 * can correctly restore segment registers.  in tracee_zap_segment()
120 	 * Write a nonzero selector with base zero to the segment register.  in tracee_zap_segment()
121 	 * Using a null selector would defeat the test on AMD pre-Zen2  in tracee_zap_segment()
122 	 * CPUs, as such CPUs don't clear the base when loading a null  in tracee_zap_segment()
144 	printf("\tSetting up a segment\n");  in main()
150 		return 1;  in main()
152 	printf("[OK]\tThe segment points to the right place.\n");  in main()
156 		err(1, "fork");  in main()
162 			err(1, "PTRACE_TRACEME");  in main()
166 		printf("\tTracee will take a nap until signaled\n");  in main()
169 		printf("\tTracee was resumed.  Will re-check segment.\n");  in main()
174 			exit(1);  in main()
177 		printf("[OK]\tThe segment points to the right place.\n");  in main()
185 		err(1, "waitpid");  in main()
190 		err(1, "PTRACE_GETREGS");  in main()
201 	regs2.rsp -= 128;	/* Don't clobber the redzone. */  in main()
208 		err(1, "PTRACE_GETREGS");  in main()
210 		err(1, "PTRACE_GETREGS");  in main()
214 		err(1, "waitpid");  in main()
218 		err(1, "PTRACE_GETREGS");  in main()
220 		err(1, "PTRACE_GETREGS");  in main()
224 		err(1, "waitpid");  in main()
228 		return 1;  in main()
233 		return 1;  in main()
239 		return 1;  in main()