| 1 | /* |
| 2 | * aarch64 linux replacement vdso. |
| 3 | * |
| 4 | * Copyright 2023 Linaro, Ltd. |
| 5 | * |
| 6 | * SPDX-License-Identifier: GPL-2.0-or-later |
| 7 | */ |
| 8 | |
| 9 | #include <asm/unistd.h> |
| 10 | |
| 11 | /* ??? These are in include/elf.h, which is not ready for inclusion in asm. */ |
| 12 | #define NT_GNU_PROPERTY_TYPE_0 5 |
| 13 | #define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 |
| 14 | #define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) |
| 15 | #define GNU_PROPERTY_AARCH64_FEATURE_1_PAC (1U << 1) |
| 16 | |
| 17 | #define GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT \ |
| 18 | (GNU_PROPERTY_AARCH64_FEATURE_1_BTI | GNU_PROPERTY_AARCH64_FEATURE_1_PAC) |
| 19 | |
| 20 | .section .note.gnu.property |
| 21 | .align 3 |
| 22 | .long 2f - 1f |
| 23 | .long 6f - 3f |
| 24 | .long NT_GNU_PROPERTY_TYPE_0 |
| 25 | 1: .string "GNU" |
| 26 | 2: .align 3 |
| 27 | 3: .long GNU_PROPERTY_AARCH64_FEATURE_1_AND |
| 28 | .long 5f - 4f |
| 29 | 4: .long GNU_PROPERTY_AARCH64_FEATURE_1_DEFAULT |
| 30 | 5: .align 3 |
| 31 | 6: |
| 32 | |
| 33 | .text |
| 34 | |
| 35 | .macro endf name |
| 36 | .globl \name |
| 37 | .type \name, @function |
| 38 | .size \name, . - \name |
| 39 | .endm |
| 40 | |
| 41 | .macro vdso_syscall name, nr |
| 42 | \name: |
| 43 | bti c |
| 44 | mov x8, #\nr |
| 45 | svc #0 |
| 46 | ret |
| 47 | endf \name |
| 48 | .endm |
| 49 | |
| 50 | .cfi_startproc |
| 51 | |
| 52 | vdso_syscall __kernel_gettimeofday, __NR_gettimeofday |
| 53 | vdso_syscall __kernel_clock_gettime, __NR_clock_gettime |
| 54 | vdso_syscall __kernel_clock_getres, __NR_clock_getres |
| 55 | |
| 56 | .cfi_endproc |
| 57 | |
| 58 | |
| 59 | /* |
| 60 | * TODO: The kernel makes a big deal of turning off the .cfi directives, |
| 61 | * because they cause libgcc to crash, but that's because they're wrong. |
| 62 | * |
| 63 | * For now, elide the unwind info for __kernel_rt_sigreturn and rely on |
| 64 | * the libgcc fallback routine as we have always done. This requires |
| 65 | * that the code sequence used be exact. |
| 66 | * |
| 67 | * Add a nop as a spacer to ensure that unwind does not pick up the |
| 68 | * unwind info from the preceding syscall. |
| 69 | */ |
| 70 | nop |
| 71 | __kernel_rt_sigreturn: |
| 72 | /* No BTI C insn here -- we arrive via RET. */ |
| 73 | mov x8, #__NR_rt_sigreturn |
| 74 | sigreturn_region_start: |
| 75 | svc #0 |
| 76 | sigreturn_region_end: |
| 77 | endf __kernel_rt_sigreturn |