Commit 2465bb83 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 's390-bpf-add-s390-jit-support-for-timed-may_goto' 

Ilya Leoshkevich says:

====================
s390/bpf: Add s390 JIT support for timed may_goto

v1: https://lore.kernel.org/bpf/20250821103256.291412-1-iii@linux.ibm.com/
v1 -> v2: Fix test_stream_errors (caught by CI).

This series adds timed may_goto implementation to the s390x JIT.
Patch 1 is the implementation itself, patches 2-5 are the associated
test changes.
====================

Link: https://patch.msgid.link/20250821113339.292434-1-iii@linux.ibm.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents d0f27ff2 21bce569

arch/s390/net/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,5 +2,5 @@ 
#

# Arch-specific network modules

#

obj-$(CONFIG_BPF_JIT) += bpf_jit_comp.o

obj-$(CONFIG_BPF_JIT) += bpf_jit_comp.o bpf_timed_may_goto.o

obj-$(CONFIG_HAVE_PNETID) += pnet.o

arch/s390/net/bpf_jit_comp.c

+21 −4
Original line number Diff line number Diff line
@@ -1806,10 +1806,22 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, 
			}

		}



		if ((void *)func == arch_bpf_timed_may_goto) {

			/*

			 * arch_bpf_timed_may_goto() has a special ABI: the

			 * parameters are in BPF_REG_AX and BPF_REG_10; the

			 * return value is in BPF_REG_AX; and all GPRs except

			 * REG_W0, REG_W1, and BPF_REG_AX are callee-saved.

			 */



			/* brasl %r0,func */

			EMIT6_PCREL_RILB_PTR(0xc0050000, REG_0, (void *)func);

		} else {

			/* brasl %r14,func */

			EMIT6_PCREL_RILB_PTR(0xc0050000, REG_14, (void *)func);

			/* lgr %b0,%r2: load return value into %b0 */

			EMIT4(0xb9040000, BPF_REG_0, REG_2);

		}



		/*

		 * Copy the potentially updated tail call counter back.
@@ -2993,3 +3005,8 @@ void arch_bpf_stack_walk(bool (*consume_fn)(void *, u64, u64, u64), 
		prev_addr = addr;

	}

}



bool bpf_jit_supports_timed_may_goto(void)

{

	return true;

}

arch/s390/net/bpf_timed_may_goto.S

0 → 100644
+45 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#include <linux/export.h>

#include <linux/linkage.h>

#include <asm/asm-offsets.h>

#include <asm/nospec-insn.h>



#define R2_OFF 0

#define R5_OFF (R2_OFF + (5 - 2 + 1) * 8)

#define R14_OFF (R5_OFF + 8)

#define RETADDR_OFF (R14_OFF + 8)

#define R15_OFF (RETADDR_OFF + 8)

#define BACKCHAIN_OFF (R15_OFF + 8)

#define FRAME_SIZE (BACKCHAIN_OFF + 8)

#define FRAME_OFF (STACK_FRAME_OVERHEAD - FRAME_SIZE)

#if (FRAME_OFF + BACKCHAIN_OFF) != __SF_BACKCHAIN

#error Stack frame layout calculation is broken

#endif



	GEN_BR_THUNK %r1



SYM_FUNC_START(arch_bpf_timed_may_goto)

	/*

	 * This function has a special ABI: the parameters are in %r12 and

	 * %r13; the return value is in %r12; all GPRs except %r0, %r1, and

	 * %r12 are callee-saved; and the return address is in %r0.

	 */

	stmg %r2,%r5,FRAME_OFF+R2_OFF(%r15)

	stg %r14,FRAME_OFF+R14_OFF(%r15)

	stg %r0,FRAME_OFF+RETADDR_OFF(%r15)

	stg %r15,FRAME_OFF+R15_OFF(%r15)

	lgr %r1,%r15

	lay %r15,-FRAME_SIZE(%r15)

	stg %r1,__SF_BACKCHAIN(%r15)



	lay %r2,0(%r12,%r13)

	brasl %r14,bpf_check_timed_may_goto

	lgr %r12,%r2



	lg %r15,FRAME_SIZE+FRAME_OFF+R15_OFF(%r15)

	lmg %r2,%r5,FRAME_OFF+R2_OFF(%r15)

	lg %r14,FRAME_OFF+R14_OFF(%r15)

	lg %r1,FRAME_OFF+RETADDR_OFF(%r15)

	BR_EX %r1

SYM_FUNC_END(arch_bpf_timed_may_goto)

tools/testing/selftests/bpf/DENYLIST.s390x

+0 −1
Original line number Diff line number Diff line
@@ -2,4 +2,3 @@ 
# Alphabetical order

get_stack_raw_tp                         # user_stack corrupted user stack                                             (no backchain userspace)

stacktrace_build_id                      # compare_map_keys stackid_hmap vs. stackmap err -2 errno 2                   (?)
 
verifier_iterating_callbacks

tools/testing/selftests/bpf/prog_tests/stream.c

+1 −1
Original line number Diff line number Diff line
@@ -77,7 +77,7 @@ void test_stream_errors(void) 
		ASSERT_OK(ret, "ret");

		ASSERT_OK(opts.retval, "retval");



#if !defined(__x86_64__)

#if !defined(__x86_64__) && !defined(__s390x__)

		ASSERT_TRUE(1, "Timed may_goto unsupported, skip.");

		if (i == 0) {

			ret = bpf_prog_stream_read(prog_fd, 2, buf, sizeof(buf), &ropts);