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X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Jan 2026 22:20:29.8780 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: ce8c0296-f646-484d-b963-08de57a8f468 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: DB1PEPF000509EE.eurprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM8PR08MB5809 Hi Will, > On Sun, Dec 14, 2025 at 11:22:44AM +0000, Yeoreum Yun wrote: > > Refactor futex atomic operations using ll/sc method with > > clearing PSTATE.PAN to prepare to apply FEAT_LSUI on them. > > > > Signed-off-by: Yeoreum Yun > > Reviewed-by: Catalin Marinas > > --- > > arch/arm64/include/asm/futex.h | 128 +++++++++++++++++++++------------ > > 1 file changed, 82 insertions(+), 46 deletions(-) > > > > diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h > > index bc06691d2062..f8cb674bdb3f 100644 > > --- a/arch/arm64/include/asm/futex.h > > +++ b/arch/arm64/include/asm/futex.h > > @@ -7,17 +7,21 @@ > > > > #include > > #include > > +#include > > > > #include > > > > #define FUTEX_MAX_LOOPS 128 /* What's the largest number you can think of? */ > > > > -#define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \ > > -do { \ > > +#define LLSC_FUTEX_ATOMIC_OP(op, insn) \ > > +static __always_inline int \ > > +__llsc_futex_atomic_##op(int oparg, u32 __user *uaddr, int *oval) \ > > +{ \ > > unsigned int loops = FUTEX_MAX_LOOPS; \ > > + int ret, oldval, tmp; \ > > \ > > uaccess_enable_privileged(); \ > > - asm volatile( \ > > + asm volatile("// __llsc_futex_atomic_" #op "\n" \ > > " prfm pstl1strm, %2\n" \ > > "1: ldxr %w1, %2\n" \ > > insn "\n" \ > > @@ -35,45 +39,103 @@ do { \ > > : "r" (oparg), "Ir" (-EAGAIN) \ > > : "memory"); \ > > uaccess_disable_privileged(); \ > > -} while (0) > > + \ > > + if (!ret) \ > > + *oval = oldval; \ > > + \ > > + return ret; \ > > +} > > + > > +LLSC_FUTEX_ATOMIC_OP(add, "add %w3, %w1, %w5") > > +LLSC_FUTEX_ATOMIC_OP(or, "orr %w3, %w1, %w5") > > +LLSC_FUTEX_ATOMIC_OP(and, "and %w3, %w1, %w5") > > +LLSC_FUTEX_ATOMIC_OP(eor, "eor %w3, %w1, %w5") > > +LLSC_FUTEX_ATOMIC_OP(set, "mov %w3, %w5") > > Since you're reworking this code, how about we take the opportunity to > use named arguments instead of the numbers? Okay. Let me try this. -- Sincerely, Yeoreum Yun