linux/aarch64: make mcontext_t.__reserved pub

jstarks · jstarks · commit a6d12264e8cd · 2025-11-06T05:52:29.000Z
The `mcontext_t.__reserved` field is documented to contain extra
context, such as FP state and the ESR register. This field is 16-byte
aligned, so for simplicity expose it as an array of `u128` elements
(similar to how `musl` defines it as an array of `long double`s in
C).
diff --git a/src/unix/linux_like/android/b64/aarch64/mod.rs b/src/unix/linux_like/android/b64/aarch64/mod.rs
@@ -67,14 +67,13 @@ s! {
         pub uc_mcontext: mcontext_t,
     }
 
-    #[repr(align(16))]
     pub struct mcontext_t {
         pub fault_address: c_ulonglong,
         pub regs: [c_ulonglong; 31],
         pub sp: c_ulonglong,
         pub pc: c_ulonglong,
         pub pstate: c_ulonglong,
-        __reserved: [u64; 512],
+        pub __reserved: [u128; 256],
     }
 
     pub struct user_fpsimd_struct {
diff --git a/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs b/src/unix/linux_like/linux/gnu/b64/aarch64/mod.rs
@@ -212,14 +212,13 @@ s! {
         pub uc_mcontext: mcontext_t,
     }
 
-    #[repr(align(16))]
     pub struct mcontext_t {
         pub fault_address: c_ulonglong,
         pub regs: [c_ulonglong; 31],
         pub sp: c_ulonglong,
         pub pc: c_ulonglong,
         pub pstate: c_ulonglong,
-        __reserved: [u64; 512],
+        pub __reserved: [u128; 256],
     }
 
     pub struct user_fpsimd_struct {
diff --git a/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs b/src/unix/linux_like/linux/musl/b64/aarch64/mod.rs
@@ -96,14 +96,13 @@ s! {
         pub uc_mcontext: mcontext_t,
     }
 
-    #[repr(align(16))]
     pub struct mcontext_t {
         pub fault_address: c_ulong,
         pub regs: [c_ulong; 31],
         pub sp: c_ulong,
         pub pc: c_ulong,
         pub pstate: c_ulong,
-        __reserved: [u64; 512],
+        pub __reserved: [u128; 256],
     }
 
     #[repr(align(8))]

Original file line number	Diff line number	Diff line change
`@@ -67,14 +67,13 @@ s! {`
`67`	`67`	`pub uc_mcontext: mcontext_t,`
`68`	`68`	`}`
`69`	`69`
`70`		`- #[repr(align(16))]`
`71`	`70`	`pub struct mcontext_t {`
`72`	`71`	`pub fault_address: c_ulonglong,`
`73`	`72`	`pub regs: [c_ulonglong; 31],`
`74`	`73`	`pub sp: c_ulonglong,`
`75`	`74`	`pub pc: c_ulonglong,`
`76`	`75`	`pub pstate: c_ulonglong,`
`77`		`- __reserved: [u64; 512],`
	`76`	`+ pub __reserved: [u128; 256],`
`78`	`77`	`}`
`79`	`78`
`80`	`79`	`pub struct user_fpsimd_struct {`
Original file line number	Diff line number	Diff line change
`@@ -212,14 +212,13 @@ s! {`
`212`	`212`	`pub uc_mcontext: mcontext_t,`
`213`	`213`	`}`
`214`	`214`
`215`		`- #[repr(align(16))]`
`216`	`215`	`pub struct mcontext_t {`
`217`	`216`	`pub fault_address: c_ulonglong,`
`218`	`217`	`pub regs: [c_ulonglong; 31],`
`219`	`218`	`pub sp: c_ulonglong,`
`220`	`219`	`pub pc: c_ulonglong,`
`221`	`220`	`pub pstate: c_ulonglong,`
`222`		`- __reserved: [u64; 512],`
	`221`	`+ pub __reserved: [u128; 256],`
`223`	`222`	`}`
`224`	`223`
`225`	`224`	`pub struct user_fpsimd_struct {`
Original file line number	Diff line number	Diff line change
`@@ -96,14 +96,13 @@ s! {`
`96`	`96`	`pub uc_mcontext: mcontext_t,`
`97`	`97`	`}`
`98`	`98`
`99`		`- #[repr(align(16))]`
`100`	`99`	`pub struct mcontext_t {`
`101`	`100`	`pub fault_address: c_ulong,`
`102`	`101`	`pub regs: [c_ulong; 31],`
`103`	`102`	`pub sp: c_ulong,`
`104`	`103`	`pub pc: c_ulong,`
`105`	`104`	`pub pstate: c_ulong,`
`106`		`- __reserved: [u64; 512],`
	`105`	`+ pub __reserved: [u128; 256],`
`107`	`106`	`}`
`108`	`107`
`109`	`108`	`#[repr(align(8))]`