[RISCV][ASAN] implementation for vfork interceptor for riscv64

[EccoTheDolphin]

Summary

[5/11] patch series to port ASAN for riscv64

Depends On D87573

[eugenis]

This looks reasonable, but I'm not very familiar with the ISA.
LGTM

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_riscv64.inc.S

22

why "??" ?

[EccoTheDolphin]

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_riscv64.inc.S

22

This is a remnant from the initial draft. will adjust

[EccoTheDolphin]

comments update

[EccoTheDolphin]

addressing comments/rebasing

[EccoTheDolphin]

addressing comments

[jrtc27]

Can we please just have a riscv version that works for both RV32 and RV64? It should just be a case of changing some ld/sd's to LOAD/STORE macros that are either [ls]w or [ls]d, and the various multiples of 8 to n*__riscv_xlen instead.

compiler-rt/lib/asan/asan_interceptors.h

117

Why is this using SANITIZER_RISCV64 when all the other arches query their compiler-defined macros directly?

[EccoTheDolphin]

In D87574#2288793, @jrtc27 wrote:

Can we please just have a riscv version that works for both RV32 and RV64? It should just be a case of changing some ld/sd's to LOAD/STORE macros that are either [ls]w or [ls]d, and the various multiples of 8 to n*__riscv_xlen instead.

The purpose of this commit series is to make sure sure we have ASAN support functional for RISCV64. I have the setup and a decent passrate. Making sure that some code does work on RV32 requires a dedicated testing environment. I can address RV32 case in a subsequent commit .

[EccoTheDolphin]

compiler-rt/lib/asan/asan_interceptors.h

117

This change was requested as part of https://reviews.llvm.org/D87580 review. The motivation is that we don't have a define for RISCV64 rendering the overall condition as:

defined(__riscv) && (__riscv_xlen == 64)

too complex. It's much simpler this way.

compiler-rt/lib/asan/asan_interceptors.h

 //===-- asan_interceptors.h -------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of AddressSanitizer, an address sanity checker.
 //
 // ASan-private header for asan_interceptors.cpp
 //===----------------------------------------------------------------------===//
 #ifndef ASAN_INTERCEPTORS_H
 #define ASAN_INTERCEPTORS_H
 
-#include "asan_internal.h"
 #include "asan_interceptors_memintrinsics.h"
+#include "asan_internal.h"
 #include "interception/interception.h"
+#include "sanitizer_common/sanitizer_platform.h"
 #include "sanitizer_common/sanitizer_platform_interceptors.h"
 
 namespace __asan {
 
 void InitializeAsanInterceptors();
 void InitializePlatformInterceptors();
 
 #define ENSURE_ASAN_INITED()      \

 #endif
 
 #if SANITIZER_LINUX && !SANITIZER_ANDROID
 # define ASAN_INTERCEPT___STRDUP 1
 #else
 # define ASAN_INTERCEPT___STRDUP 0
 #endif
 
-#if SANITIZER_LINUX && (defined(__arm__) || defined(__aarch64__) || \
-                        defined(__i386__) || defined(__x86_64__))
+#if SANITIZER_LINUX &&                                                \
+    (defined(__arm__) || defined(__aarch64__) || defined(__i386__) || \
+     defined(__x86_64__) || SANITIZER_RISCV64)
 # define ASAN_INTERCEPT_VFORK 1
 #else
 # define ASAN_INTERCEPT_VFORK 0
 #endif
 
 #if SANITIZER_NETBSD
 # define ASAN_INTERCEPT_PTHREAD_ATFORK 1
 #else

compiler-rt/lib/asan/asan_interceptors_vfork.S

 #include "sanitizer_common/sanitizer_asm.h"
 
 #if defined(__linux__)
 #define COMMON_INTERCEPTOR_SPILL_AREA __asan_extra_spill_area
 #define COMMON_INTERCEPTOR_HANDLE_VFORK __asan_handle_vfork
 #include "sanitizer_common/sanitizer_common_interceptors_vfork_aarch64.inc.S"
 #include "sanitizer_common/sanitizer_common_interceptors_vfork_arm.inc.S"
-#include "sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S"
 #include "sanitizer_common/sanitizer_common_interceptors_vfork_i386.inc.S"
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_riscv64.inc.S"
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S"
 #endif
 
 NO_EXEC_STACK_DIRECTIVE

compiler-rt/lib/hwasan/hwasan_interceptors_vfork.S

 #include "sanitizer_common/sanitizer_asm.h"
 
 #if defined(__linux__) && HWASAN_WITH_INTERCEPTORS
 #define COMMON_INTERCEPTOR_SPILL_AREA __hwasan_extra_spill_area
 #define COMMON_INTERCEPTOR_HANDLE_VFORK __hwasan_handle_vfork
 #include "sanitizer_common/sanitizer_common_interceptors_vfork_aarch64.inc.S"
+#include "sanitizer_common/sanitizer_common_interceptors_vfork_riscv64.inc.S"
 #include "sanitizer_common/sanitizer_common_interceptors_vfork_x86_64.inc.S"
 #endif
 
 NO_EXEC_STACK_DIRECTIVE

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors_vfork_riscv64.inc.S

+#if (defined(__riscv) && (__riscv_xlen == 64)) && defined(__linux__)
+
+#include "sanitizer_common/sanitizer_asm.h"
+
+ASM_HIDDEN(COMMON_INTERCEPTOR_SPILL_AREA)
+
+.comm _ZN14__interception10real_vforkE,8,8
+.globl ASM_WRAPPER_NAME(vfork)
+ASM_TYPE_FUNCTION(ASM_WRAPPER_NAME(vfork))
+ASM_WRAPPER_NAME(vfork):
+        // Save ra in the off-stack spill area.
+        // allocate space on stack
+        addi    sp, sp, -16
+        // store ra value 
+        sd      ra, 8(sp)
+        call    COMMON_INTERCEPTOR_SPILL_AREA
+        // restore previous values from stack
+        ld      ra, 8(sp)
+        // adjust stack
+        addi    sp, sp, 16
+        // store ra by x10
+        sd      ra, 0(x10)
+
+        // Call real vfork. This may return twice. User code that runs between the first and the second return
+        // may clobber the stack frame of the interceptor; that's why it does not have a frame.
+        la x10, _ZN14__interception10real_vforkE
+        ld x10, 0(x10)
+        jalr x10
+
+        // adjust stack
+        addi    sp, sp, -16
+        // store x10 by adjusted stack
+        sd      x10, 8(sp)
+        // jump to exit label if x10 is 0
+        beqz    x10, .L_exit
+
+        // x0 != 0 => parent process. Clear stack shadow.
+        // put old sp to x10
+        addi   x10, sp, 16
+        call   COMMON_INTERCEPTOR_HANDLE_VFORK
+
+.L_exit:
+        // Restore ra
+        call   COMMON_INTERCEPTOR_SPILL_AREA
+        ld     ra, 0(x10)
+        // load value by stack
+        ld     x10, 8(sp)
+        // adjust stack
+        addi   sp, sp, 16
+        ret
+ASM_SIZE(vfork)
+
+.weak vfork
+.set vfork, ASM_WRAPPER_NAME(vfork)
+
+#endif