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Commit b1311900 authored by Peter Oskolkov's avatar Peter Oskolkov Committed by Greg Kroah-Hartman
Browse files

rseq/selftests,x86_64: Add rseq_offset_deref_addv() 



commit ea366dd79c05fcd4cf5e225d2de8a3a7c293160c upstream.

This patch adds rseq_offset_deref_addv() function to
tools/testing/selftests/rseq/rseq-x86.h, to be used in a selftest in
the next patch in the patchset.

Once an architecture adds support for this function they should define
"RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV".

Signed-off-by: default avatarPeter Oskolkov <posk@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lkml.kernel.org/r/20200923233618.2572849-2-posk@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7b6bffcf

tools/testing/selftests/rseq/rseq-x86.h

+57 −0
Original line number Diff line number Diff line
@@ -279,6 +279,63 @@ int rseq_addv(intptr_t *v, intptr_t count, int cpu) 
#endif

}



#define RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV



/*

 *   pval = *(ptr+off)

 *  *pval += inc;

 */

static inline __attribute__((always_inline))

int rseq_offset_deref_addv(intptr_t *ptr, off_t off, intptr_t inc, int cpu)

{

	RSEQ_INJECT_C(9)



	__asm__ __volatile__ goto (

		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */

#ifdef RSEQ_COMPARE_TWICE

		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])

#endif

		/* Start rseq by storing table entry pointer into rseq_cs. */

		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))

		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)

		RSEQ_INJECT_ASM(3)

#ifdef RSEQ_COMPARE_TWICE

		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])

#endif

		/* get p+v */

		"movq %[ptr], %%rbx\n\t"

		"addq %[off], %%rbx\n\t"

		/* get pv */

		"movq (%%rbx), %%rcx\n\t"

		/* *pv += inc */

		"addq %[inc], (%%rcx)\n\t"

		"2:\n\t"

		RSEQ_INJECT_ASM(4)

		RSEQ_ASM_DEFINE_ABORT(4, "", abort)

		: /* gcc asm goto does not allow outputs */

		: [cpu_id]		"r" (cpu),

		  [rseq_abi]		"r" (&__rseq_abi),

		  /* final store input */

		  [ptr]			"m" (*ptr),

		  [off]			"er" (off),

		  [inc]			"er" (inc)

		: "memory", "cc", "rax", "rbx", "rcx"

		  RSEQ_INJECT_CLOBBER

		: abort

#ifdef RSEQ_COMPARE_TWICE

		  , error1

#endif

	);

	return 0;

abort:

	RSEQ_INJECT_FAILED

	return -1;

#ifdef RSEQ_COMPARE_TWICE

error1:

	rseq_bug("cpu_id comparison failed");

#endif

}



static inline __attribute__((always_inline))

int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,

				 intptr_t *v2, intptr_t newv2,