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[2001:8b0:1d0::2]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42ac679607esm5794652f8f.43.2025.11.07.07.01.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Nov 2025 07:01:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1762527709; x=1763132509; darn=nongnu.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=JsPXanOwycMd+Uo8/scp5eUByokzkxKqyckKoyuUOUU=; b=YHAwaf0/0YbqIjJeasScvztE3mKxn6/uRFKxFvuI3HMSzGer7A7/gkfa6VZIMivaKL W1ShoQu/8yPhOAGsEbWODD3JPDhzn/CnaW9zG0ugtPIzl4Ivy4mG0BpsCA/w85Mp6A3W sLjGC6jnE+BszBSCbfOkVCnlp8ovsBYfhTJS8OTc78rG/lGn/4TykhVfjuGlMxbKt+tq 145vKhYyGZgQFGivJgeSqOTsPlCBqnLOdVFzNFroe5DTL+h/h1jtcAkVsYKHWoiUHq6h iHS9wuL5m+06JpOKInByCQtU8toePsYxv3p8HypTdYjcZrPQ07iqbJeUehCMheRi0Vbs XCmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762527709; x=1763132509; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=JsPXanOwycMd+Uo8/scp5eUByokzkxKqyckKoyuUOUU=; b=vwWSSpbVHwT668R6yStMB3Qdv/zSduc7SEZoN+Ry76uCTZHpeXDEdcMcnpJ8pc6wns kOab7az8W4p2EyfPDgoEsYZqETH6o035TmXQftM2mPL7wcnhtV+TEuUDg/j6AebnXV1x StaMb+Hh3/h8qVZKSTfodF1lEfw4PjHGodcvHFiFhqoJj6bDIvQUxWh9DjeXLkBAkLeX YGT/Rr9PwNvSYg4vwTRN93Ss8YCnLhLcg6RMZliol8UW1Ktfi03kQUGa5AWMvb8GHbCX J4CjLOO9aiueibxom8sf084oYs/t/i50TVV++yugUD8Uwc504eWfWAwlJidB/yaHITcA 80kA== X-Forwarded-Encrypted: i=1; AJvYcCW1r9uqMoxBDDOMHwS5glMeA2P7UUZ3UCfpd0+jzpzqWDD5uqn8iK6+uIt+CKn+/a3VBEW04v9R2/k+@nongnu.org X-Gm-Message-State: AOJu0Yy1gNr5SWxwcmYSg+AJeOfXWWONc7AdZBHhD5eBgkzIek+QMQaT Mmo5SXNpR1vbca046fzIHFOSkNLVf8Y/rPbnjViDnuC7Zj/q9BMNCIDVgDqOuXKdCnc= X-Gm-Gg: ASbGncv/+hCwqIE0FBfDA2IFvSKXojCMb0Wt8QG0qAKPASE7XrhZtiZAsjSjqu5juYw BBsRtXyr+W1cgKVWyuTQ+GGo1hBDTg2sWhx7/ltks7h0d7dudutH+ea3emFJldOb8j098yQiRbb VRN8fCdIpQxSXbMC0v25vX3cJ+HIBux4Zf3c/gaOvmurMfm/tPxGpPNtXlXuJhNMECwme3Uaia0 E+tjz9o6+4SvztIXvWstluva2dymyTFqT5xiVp/pQ52mEVSIShyFcwpht03o0H40lPhFgnNbV3c bpBmfdvQLguGJ2eQnpvXLUAlBaNaTm2vBBmGplR55domSOj/gRDgDgNTnT1BZLfBy7VeNX5libo yfAAirz4MSviWuaFyIdL26xJnG4x4UsAwiok6FwmnP0ju38ILV7y4cLdq3Gm0msj0cPS4ggP0vs 5DeMcYHDxV3pq9rWKN X-Google-Smtp-Source: AGHT+IF6WqeitVxy78B0zzlLzVCq7C354pTOimGANN5r9APaHnVC7D10CTJbWt6OyjZLq25qFTXWvA== X-Received: by 2002:a05:600c:c4a3:b0:46e:436c:2191 with SMTP id 5b1f17b1804b1-4776bcb9cbdmr27706775e9.25.1762527707959; Fri, 07 Nov 2025 07:01:47 -0800 (PST) From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Cc: Tyrone Ting , Hao Wu Subject: [PATCH] hw/misc/npcm_clk: Don't divide by zero when calculating frequency Date: Fri, 7 Nov 2025 15:01:37 +0000 Message-ID: <20251107150137.1353532-1-peter.maydell@linaro.org> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::32a; envelope-from=peter.maydell@linaro.org; helo=mail-wm1-x32a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1762527747263154100 Content-Type: text/plain; charset="utf-8" If the guest misprograms the PLL registers to request a zero divisor, we currently fall over with a division by zero: ../../hw/misc/npcm_clk.c:221:14: runtime error: division by zero SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../hw/misc/npcm_= clk.c:221:14 Thread 1 "qemu-system-aar" received signal SIGFPE, Arithmetic exception. 0x00005555584d8f6d in npcm7xx_clk_update_pll (opaque=3D0x7fffed159a20) at .= ./../hw/misc/npcm_clk.c:221 221 freq /=3D PLLCON_INDV(con) * PLLCON_OTDV1(con) * PLLCON_OTD= V2(con); Avoid this by treating this invalid setting like a stopped clock (setting freq to 0). Cc: qemu-stable@nongnu.org Resolves: https://gitlab.com/qemu-project/qemu/-/issues/549 Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daud=C3=A9 --- hw/misc/npcm_clk.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/hw/misc/npcm_clk.c b/hw/misc/npcm_clk.c index c48d40b4468..e202a8a2998 100644 --- a/hw/misc/npcm_clk.c +++ b/hw/misc/npcm_clk.c @@ -212,13 +212,14 @@ static void npcm7xx_clk_update_pll(void *opaque) { NPCM7xxClockPLLState *s =3D opaque; uint32_t con =3D s->clk->regs[s->reg]; - uint64_t freq; + uint64_t freq, freq_div; =20 /* The PLL is grounded if it is not locked yet. */ if (con & PLLCON_LOKI) { freq =3D clock_get_hz(s->clock_in); freq *=3D PLLCON_FBDV(con); - freq /=3D PLLCON_INDV(con) * PLLCON_OTDV1(con) * PLLCON_OTDV2(con); + freq_div =3D PLLCON_INDV(con) * PLLCON_OTDV1(con) * PLLCON_OTDV2(c= on); + freq =3D freq_div ? freq / freq_div : 0; } else { freq =3D 0; } --=20 2.43.0