[PATCH] arm64: uapi: Use __u128 instead of __uint128_t in UAPI headers

[Will Deacon <will@kernel.org>]

The arm64 UAPI exposes '__uint128_t' types in the members of
'struct user_fpsimd_state', 'struct user_pac_address_keys' and in the
signal frame via 'struct fpsimd_context'. Since the alignment of such
a type appears to be non-portable (16 bytes on arm64, 8 bytes on s390),
prefer the '__u128' typedef from uapi/linux/types.h, which makes the
alignment explicit and allows the definitions to be reused by other
host architectures.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Steffen Eiden <seiden@linux.ibm.com>
Cc: Andreas Grapentin <gra@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---

This aims to help a little with the s390/arm64 KVM series at:

https://lore.kernel.org/r/20260529155050.2902245-1-seiden@linux.ibm.com

by allowing the relevant parts of the arm64 UAPI to be used directly by
s390 rather than copied and modified.

I think it's a straightforward change, but the only thing that makes me
pause for thought is whether there are toolchains out there which accept
__uint128_t but not __int128. Then again, if that crops up as an issue
we can probably just tweak the typedef we have in uapi/linux/types.h.

 arch/arm64/include/uapi/asm/ptrace.h     | 12 ++++++------
 arch/arm64/include/uapi/asm/sigcontext.h |  6 +++---
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h
index 6fed93fb2536..15649a253a57 100644
--- a/arch/arm64/include/uapi/asm/ptrace.h
+++ b/arch/arm64/include/uapi/asm/ptrace.h
@@ -93,7 +93,7 @@ struct user_pt_regs {
 };
 
 struct user_fpsimd_state {
-	__uint128_t	vregs[32];
+	__u128		vregs[32];
 	__u32		fpsr;
 	__u32		fpcr;
 	__u32		__reserved[2];
@@ -258,14 +258,14 @@ struct user_pac_mask {
 /* pointer authentication keys (NT_ARM_PACA_KEYS, NT_ARM_PACG_KEYS) */
 
 struct user_pac_address_keys {
-	__uint128_t	apiakey;
-	__uint128_t	apibkey;
-	__uint128_t	apdakey;
-	__uint128_t	apdbkey;
+	__u128	apiakey;
+	__u128	apibkey;
+	__u128	apdakey;
+	__u128	apdbkey;
 };
 
 struct user_pac_generic_keys {
-	__uint128_t	apgakey;
+	__u128	apgakey;
 };
 
 /* ZA state (NT_ARM_ZA) */
diff --git a/arch/arm64/include/uapi/asm/sigcontext.h b/arch/arm64/include/uapi/asm/sigcontext.h
index e29bf3e2d0cc..d250ca7a1d46 100644
--- a/arch/arm64/include/uapi/asm/sigcontext.h
+++ b/arch/arm64/include/uapi/asm/sigcontext.h
@@ -78,7 +78,7 @@ struct fpsimd_context {
 	struct _aarch64_ctx head;
 	__u32 fpsr;
 	__u32 fpcr;
-	__uint128_t vregs[32];
+	__u128 vregs[32];
 };
 
 /*
@@ -266,8 +266,8 @@ struct gcs_context {
  *	-	----				-----------
  *	REGS					the entire SVE context
  *
- *	ZREGS	__uint128_t[SVE_NUM_ZREGS][vq]	all Z-registers
- *	ZREG	__uint128_t[vq]			individual Z-register Zn
+ *	ZREGS	__u128[SVE_NUM_ZREGS][vq]	all Z-registers
+ *	ZREG	__u128[vq]			individual Z-register Zn
  *
  *	PREGS	uint16_t[SVE_NUM_PREGS][vq]	all P-registers
  *	PREG	uint16_t[vq]			individual P-register Pn
-- 
2.55.0.rc0.738.g0c8ab3ebcc-goog