From 287f48e6e5cdabecefc7a88e35b1a7beca88493a Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Tue, 11 Oct 2022 00:01:35 +0000
Subject: [PATCH] riscv64: more <sys/ucontext.h>.

Actually, we don't want to reuse the kernel struct ucontext because its
uc_mcontext has the wrong type, which means the fields within that end
up with the wrong names. Add the call site that made that evident, and
update <sys/ucontext.h> appropriately.

Signed-off-by: Mao Han <han_mao@linux.alibaba.com>
Signed-off-by: Xia Lifang <lifang_xia@linux.alibaba.com>
Signed-off-by: Chen Guoyin <chenguoyin.cgy@linux.alibaba.com>
Signed-off-by: Wang Chen <wangchen20@iscas.ac.cn>
Signed-off-by: Lu Xufan <luxufan@iscas.ac.cn>
Test: treehugger
Change-Id: If1d079afef0d5953aa22d9b0e049cfb0119c7718
---
 libc/bionic/android_profiling_dynamic.cpp |  8 +++++---
 libc/include/sys/ucontext.h               | 14 ++++++++++++--
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/libc/bionic/android_profiling_dynamic.cpp b/libc/bionic/android_profiling_dynamic.cpp
index 3460a6d54..8c9127ecc 100644
--- a/libc/bionic/android_profiling_dynamic.cpp
+++ b/libc/bionic/android_profiling_dynamic.cpp
@@ -204,12 +204,14 @@ static void HandleSigsysSeccompOverride(int /*signal_number*/, siginfo_t* info,
   auto ret = -ENOSYS;
   ucontext_t* ctx = reinterpret_cast<ucontext_t*>(void_context);
 
-#if defined(__arm__)
+#if defined(__aarch64__)
+  ctx->uc_mcontext.regs[0] = ret;
+#elif defined(__arm__)
   ctx->uc_mcontext.arm_r0 = ret;
-#elif defined(__aarch64__)
-  ctx->uc_mcontext.regs[0] = ret;  // x0
 #elif defined(__i386__)
   ctx->uc_mcontext.gregs[REG_EAX] = ret;
+#elif defined(__riscv)
+  ctx->uc_mcontext.__gregs[REG_A0] = ret;
 #elif defined(__x86_64__)
   ctx->uc_mcontext.gregs[REG_RAX] = ret;
 #else
diff --git a/libc/include/sys/ucontext.h b/libc/include/sys/ucontext.h
index b000914ad..68b218ea1 100644
--- a/libc/include/sys/ucontext.h
+++ b/libc/include/sys/ucontext.h
@@ -320,6 +320,7 @@ typedef struct ucontext {
 #define REG_RA 1
 #define REG_SP 2
 #define REG_TP 4
+#define REG_A0 10
 
 typedef unsigned long __riscv_mc_gp_state[NGREG];
 
@@ -358,8 +359,17 @@ typedef struct mcontext_t {
   union __riscv_mc_fp_state __fpregs;
 } mcontext_t;
 
-#include <asm/ucontext.h>
-typedef struct ucontext ucontext_t;
+/* This matches the kernel <asm/ucontext.h> but using mcontext_t. */
+
+typedef struct ucontext_t {
+  unsigned long uc_flags;
+  struct ucontext_t* uc_link;
+  stack_t uc_stack;
+  sigset_t uc_sigmask;
+  /* The kernel adds extra padding here to allow sigset_t to grow. */
+  char __padding[128 - sizeof(sigset_t)];
+  mcontext_t uc_mcontext;
+} ucontext_t;
 
 #endif