Commit be45e63f authored by Mark Rutland's avatar Mark Rutland Committed by Will Deacon
Browse files

kselftest/arm64: tpidr2: Adjust to new clone() behaviour 



In order to fix an ABI problem, we recently changed the way that a
clone() syscall manipulates TPIDR2 and PSTATE.ZA. Historically the child
would inherit the parent's TPIDR2 value unless CLONE_SETTLS was set, and
now the child will inherit the parent's TPIDR2 value unless CLONE_VM is
set.

Update the tpidr2 test for the new behaviour.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Kiss <daniel.kiss@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Richard Sandiford <richard.sandiford@arm.com>
Cc: Sander De Smalen <sander.desmalen@arm.com>
Cc: Tamas Petz <tamas.petz@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yury Khrustalev <yury.khrustalev@arm.com>
Link: https://lore.kernel.org/r/20250508132644.1395904-23-mark.rutland@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 78b23877

tools/testing/selftests/arm64/abi/tpidr2.c

+12 −2
Original line number Diff line number Diff line
@@ -169,8 +169,10 @@ static int sys_clone(unsigned long clone_flags, unsigned long newsp, 
			   child_tidptr);

}



#define __STACK_SIZE (8 * 1024 * 1024)



/*

 * If we clone with CLONE_SETTLS then the value in the parent should

 * If we clone with CLONE_VM then the value in the parent should

 * be unchanged and the child should start with zero and be able to

 * set its own value.

 */
@@ -179,11 +181,19 @@ static int write_clone_read(void) 
	int parent_tid, child_tid;

	pid_t parent, waiting;

	int ret, status;

	void *stack;



	parent = getpid();

	set_tpidr2(parent);



	ret = sys_clone(CLONE_SETTLS, 0, &parent_tid, 0, &child_tid);

	stack = malloc(__STACK_SIZE);

	if (!stack) {

		putstr("# malloc() failed\n");

		return 0;

	}



	ret = sys_clone(CLONE_VM, (unsigned long)stack + __STACK_SIZE,

			&parent_tid, 0, &child_tid);

	if (ret == -1) {

		putstr("# clone() failed\n");

		putnum(errno);