diff options
| -rw-r--r-- | tools/testing/selftests/arm64/gcs/.gitignore | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/arm64/gcs/Makefile | 8 | ||||
| -rw-r--r-- | tools/testing/selftests/arm64/gcs/gcspushm.S | 96 | ||||
| -rw-r--r-- | tools/testing/selftests/arm64/gcs/gcsstr.S | 99 |
4 files changed, 204 insertions, 1 deletions
diff --git a/tools/testing/selftests/arm64/gcs/.gitignore b/tools/testing/selftests/arm64/gcs/.gitignore index 1e8d1f6b27f2..bbb8e40a7e52 100644 --- a/tools/testing/selftests/arm64/gcs/.gitignore +++ b/tools/testing/selftests/arm64/gcs/.gitignore @@ -3,3 +3,5 @@ libc-gcs gcs-locking gcs-stress gcs-stress-thread +gcspushm +gcsstr diff --git a/tools/testing/selftests/arm64/gcs/Makefile b/tools/testing/selftests/arm64/gcs/Makefile index d8b06ca51e22..d2f3497a9103 100644 --- a/tools/testing/selftests/arm64/gcs/Makefile +++ b/tools/testing/selftests/arm64/gcs/Makefile @@ -6,7 +6,7 @@ # nolibc. # -TEST_GEN_PROGS := basic-gcs libc-gcs gcs-locking gcs-stress +TEST_GEN_PROGS := basic-gcs libc-gcs gcs-locking gcs-stress gcspushm gcsstr TEST_GEN_PROGS_EXTENDED := gcs-stress-thread LDLIBS+=-lpthread @@ -22,3 +22,9 @@ $(OUTPUT)/basic-gcs: basic-gcs.c $(OUTPUT)/gcs-stress-thread: gcs-stress-thread.S $(CC) -nostdlib $^ -o $@ + +$(OUTPUT)/gcspushm: gcspushm.S + $(CC) -nostdlib $^ -o $@ + +$(OUTPUT)/gcsstr: gcsstr.S + $(CC) -nostdlib $^ -o $@ diff --git a/tools/testing/selftests/arm64/gcs/gcspushm.S b/tools/testing/selftests/arm64/gcs/gcspushm.S new file mode 100644 index 000000000000..bbe17c1325ac --- /dev/null +++ b/tools/testing/selftests/arm64/gcs/gcspushm.S @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0-only +// +// Copyright 2024 Arm Limited +// +// Give ourselves GCS push permissions then use them + +#include <asm/unistd.h> + +/* Shadow Stack/Guarded Control Stack interface */ +#define PR_GET_SHADOW_STACK_STATUS 74 +#define PR_SET_SHADOW_STACK_STATUS 75 +#define PR_LOCK_SHADOW_STACK_STATUS 76 + +# define PR_SHADOW_STACK_ENABLE (1UL << 0) +# define PR_SHADOW_STACK_WRITE (1UL << 1) +# define PR_SHADOW_STACK_PUSH (1UL << 2) + +#define KSFT_SKIP 4 + +.macro function name + .macro endfunction + .type \name, @function + .purgem endfunction + .endm +\name: +.endm + +// Print a single character x0 to stdout +// Clobbers x0-x2,x8 +function putc + str x0, [sp, #-16]! + + mov x0, #1 // STDOUT_FILENO + mov x1, sp + mov x2, #1 + mov x8, #__NR_write + svc #0 + + add sp, sp, #16 + ret +endfunction +.globl putc + +// Print a NUL-terminated string starting at address x0 to stdout +// Clobbers x0-x3,x8 +function puts + mov x1, x0 + + mov x2, #0 +0: ldrb w3, [x0], #1 + cbz w3, 1f + add x2, x2, #1 + b 0b + +1: mov w0, #1 // STDOUT_FILENO + mov x8, #__NR_write + svc #0 + + ret +endfunction +.globl puts + +// Utility macro to print a literal string +// Clobbers x0-x4,x8 +.macro puts string + .pushsection .rodata.str1.1, "aMS", @progbits, 1 +.L__puts_literal\@: .string "\string" + .popsection + + ldr x0, =.L__puts_literal\@ + bl puts +.endm + +.globl _start +function _start + // Run with GCS + mov x0, PR_SET_SHADOW_STACK_STATUS + mov x1, PR_SHADOW_STACK_ENABLE | PR_SHADOW_STACK_PUSH + mov x2, xzr + mov x3, xzr + mov x4, xzr + mov x5, xzr + mov x8, #__NR_prctl + svc #0 + cbz x0, 1f + puts "Failed to enable GCS with push permission\n" + mov x0, #KSFT_SKIP + b 2f +1: + sys #3, c7, c7, #0, x0 // GCSPUSHM + sysl x0, #3, c7, c7, #1 // GCSPOPM + + mov x0, #0 +2: + mov x8, #__NR_exit + svc #0 diff --git a/tools/testing/selftests/arm64/gcs/gcsstr.S b/tools/testing/selftests/arm64/gcs/gcsstr.S new file mode 100644 index 000000000000..a42bba6e30b1 --- /dev/null +++ b/tools/testing/selftests/arm64/gcs/gcsstr.S @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0-only +// +// Copyright 2024 Arm Limited +// +// Give ourselves GCS write permissions then use them + +#include <asm/unistd.h> + +/* Shadow Stack/Guarded Control Stack interface */ +#define PR_GET_SHADOW_STACK_STATUS 74 +#define PR_SET_SHADOW_STACK_STATUS 75 +#define PR_LOCK_SHADOW_STACK_STATUS 76 + +# define PR_SHADOW_STACK_ENABLE (1UL << 0) +# define PR_SHADOW_STACK_WRITE (1UL << 1) +# define PR_SHADOW_STACK_PUSH (1UL << 2) + +#define GCSPR_EL0 S3_3_C2_C5_1 + +#define KSFT_SKIP 4 + +.macro function name + .macro endfunction + .type \name, @function + .purgem endfunction + .endm +\name: +.endm + +// Print a single character x0 to stdout +// Clobbers x0-x2,x8 +function putc + str x0, [sp, #-16]! + + mov x0, #1 // STDOUT_FILENO + mov x1, sp + mov x2, #1 + mov x8, #__NR_write + svc #0 + + add sp, sp, #16 + ret +endfunction +.globl putc + +// Print a NUL-terminated string starting at address x0 to stdout +// Clobbers x0-x3,x8 +function puts + mov x1, x0 + + mov x2, #0 +0: ldrb w3, [x0], #1 + cbz w3, 1f + add x2, x2, #1 + b 0b + +1: mov w0, #1 // STDOUT_FILENO + mov x8, #__NR_write + svc #0 + + ret +endfunction +.globl puts + +// Utility macro to print a literal string +// Clobbers x0-x4,x8 +.macro puts string + .pushsection .rodata.str1.1, "aMS", @progbits, 1 +.L__puts_literal\@: .string "\string" + .popsection + + ldr x0, =.L__puts_literal\@ + bl puts +.endm + +.globl _start +function _start + // Run with GCS + mov x0, PR_SET_SHADOW_STACK_STATUS + mov x1, PR_SHADOW_STACK_ENABLE | PR_SHADOW_STACK_WRITE + mov x2, xzr + mov x3, xzr + mov x4, xzr + mov x5, xzr + mov x8, #__NR_prctl + svc #0 + cbz x0, 1f + puts "Failed to enable GCS with write permission\n" + mov x0, #KSFT_SKIP + b 2f +1: + mrs x0, GCSPR_EL0 + sub x0, x0, #8 + .inst 0xd91f1c01 // GCSSTR x1, x0 + + mov x0, #0 +2: + mov x8, #__NR_exit + svc #0 |