diff --git a/libc-test/build.rs b/libc-test/build.rs
index b42402f08a229..fd61758bdc4e7 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -2836,6 +2836,7 @@ fn test_linux(target: &str) {
         "linux/vm_sockets.h",
         "linux/wait.h",
         "sys/fanotify.h",
+        [musl]: "asm/sigcontext.h",
         // <sys/auxv.h> is not present on uclibc
         [!uclibc]: "sys/auxv.h",
     }
diff --git a/src/unix/linux_like/linux/musl/b32/x86/mod.rs b/src/unix/linux_like/linux/musl/b32/x86/mod.rs
index a6efea13b9d1d..60af5d2510cc2 100644
--- a/src/unix/linux_like/linux/musl/b32/x86/mod.rs
+++ b/src/unix/linux_like/linux/musl/b32/x86/mod.rs
@@ -1,5 +1,6 @@
 pub type c_char = i8;
 pub type wchar_t = i32;
+pub type greg_t = i32;
 
 s! {
     pub struct stat {
@@ -49,7 +50,7 @@ s! {
     pub struct stack_t {
         pub ss_sp: *mut ::c_void,
         pub ss_flags: ::c_int,
-        pub ss_size: ::size_t
+        pub ss_size: ::size_t,
     }
 
     pub struct ipc_perm {
@@ -61,7 +62,7 @@ s! {
         pub mode: ::mode_t,
         pub __seq: ::c_int,
         __unused1: ::c_long,
-        __unused2: ::c_long
+        __unused2: ::c_long,
     }
 
     pub struct shmid_ds {
@@ -112,8 +113,28 @@ s! {
         pub f_spare: [::c_ulong; 4],
     }
 
+    pub struct _fpreg {
+        pub significand: [u16; 4],
+        pub exponent: u16,
+    }
+
+    pub struct _fpstate {
+        pub cw: ::c_ulong,
+        pub sw: ::c_ulong,
+        pub tag: ::c_ulong,
+        pub ipoff: ::c_ulong,
+        pub cssel: ::c_ulong,
+        pub dataoff: ::c_ulong,
+        pub datasel: ::c_ulong,
+        pub _st: [_fpreg; 8],
+        pub status: ::c_ulong,
+    }
+
     pub struct mcontext_t {
-        __private: [u32; 22]
+        pub gregs: [greg_t; 19],
+        pub fpregs: *mut _fpstate,
+        pub oldmask: ::c_ulong,
+        pub cr2: ::c_ulong,
     }
 
     pub struct siginfo_t {
@@ -124,6 +145,10 @@ s! {
         _align: [usize; 0],
     }
 
+    pub struct sigset_t {
+        pub sig: [::c_ulong; if cfg!(target_arch = "x86_64") { 1 } else { 2 };]
+    }
+
     pub struct statfs64 {
         pub f_type: ::c_ulong,
         pub f_bsize: ::c_ulong,
@@ -163,7 +188,7 @@ s_no_extra_traits! {
         pub uc_stack: ::stack_t,
         pub uc_mcontext: mcontext_t,
         pub uc_sigmask: ::sigset_t,
-        __private: [u8; 112],
+        pub __fpregs_mem: [::c_ulong; 28],
     }
 }
 
@@ -876,6 +901,27 @@ pub const EFL: ::c_int = 14;
 pub const UESP: ::c_int = 15;
 pub const SS: ::c_int = 16;
 
+// offsets in mcontext_t.gregs from sys/ucontext.h
+pub const REG_GS: ::c_int = 0;
+pub const REG_FS: ::c_int = 1;
+pub const REG_ES: ::c_int = 2;
+pub const REG_DS: ::c_int = 3;
+pub const REG_EDI: ::c_int = 4;
+pub const REG_ESI: ::c_int = 5;
+pub const REG_EBP: ::c_int = 6;
+pub const REG_ESP: ::c_int = 7;
+pub const REG_EBX: ::c_int = 8;
+pub const REG_EDX: ::c_int = 9;
+pub const REG_ECX: ::c_int = 10;
+pub const REG_EAX: ::c_int = 11;
+pub const REG_TRAPNO: ::c_int = 12;
+pub const REG_ERR: ::c_int = 13;
+pub const REG_EIP: ::c_int = 14;
+pub const REG_CS: ::c_int = 15;
+pub const REG_EFL: ::c_int = 16;
+pub const REG_UESP: ::c_int = 17;
+pub const REG_SS: ::c_int = 18;
+
 extern "C" {
     pub fn getrandom(buf: *mut ::c_void, buflen: ::size_t, flags: ::c_uint) -> ::ssize_t;
 }