linux-kernel - [PATCH] riscv: return -ENOSYS for syscall -1

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Message-ID: <mvma6u6vkkv.fsf@suse.de>
Date:   Mon, 21 Dec 2020 23:52:00 +0100
From:   Andreas Schwab <schwab@...e.de>
To:     linux-riscv@...ts.infradead.org
CC:     linux-kernel@...r.kernel.org, Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Tycho Andersen <tycho@...ho.pizza>,
        David Abdurachmanov <david.abdurachmanov@...ive.com>
Subject: [PATCH] riscv: return -ENOSYS for syscall -1

Properly return -ENOSYS for syscall -1 instead of leaving the return value
uninitialized.  This fixes the strace teststuite.

Fixes: 5340627e3fe0 ("riscv: add support for SECCOMP and SECCOMP_FILTER")
Signed-off-by: Andreas Schwab <schwab@...e.de>
---
 arch/riscv/kernel/entry.S | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 524d918f3601..d07763001eb0 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -186,14 +186,7 @@ check_syscall_nr:
 	 * Syscall number held in a7.
 	 * If syscall number is above allowed value, redirect to ni_syscall.
 	 */
-	bge a7, t0, 1f
-	/*
-	 * Check if syscall is rejected by tracer, i.e., a7 == -1.
-	 * If yes, we pretend it was executed.
-	 */
-	li t1, -1
-	beq a7, t1, ret_from_syscall_rejected
-	blt a7, t1, 1f
+	bgeu a7, t0, 1f
 	/* Call syscall */
 	la s0, sys_call_table
 	slli t0, a7, RISCV_LGPTR
-- 
2.29.0


-- 
Andreas Schwab, SUSE Labs, schwab@...e.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."