From: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
To: Tudor Ambarus <tudor.ambarus@linaro.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
Alim Akhtar <alim.akhtar@samsung.com>,
Kees Cook <kees@kernel.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>
Cc: linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-hardening@vger.kernel.org, llvm@lists.linux.dev,
Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Subject: [PATCH v2 3/3] firmware: exynos-acpm: Count acpm_xfer buffers with __counted_by_ptr
Date: Thu, 19 Feb 2026 12:27:12 +0100 [thread overview]
Message-ID: <20260219-firmare-acpm-counted-v2-3-e1f7389237d3@oss.qualcomm.com> (raw)
In-Reply-To: <20260219-firmare-acpm-counted-v2-0-e1f7389237d3@oss.qualcomm.com>
Use __counted_by_ptr() attribute on the acpm_xfer buffers so UBSAN will
validate runtime that we do not pass over the buffer size, thus making
code safer.
Usage of __counted_by_ptr() (or actually __counted_by()) requires that
counter is initialized before counted array.
Tested-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
__counted_by_ptr() actually maps to __counted_by() for clang v20.
Alternatively we could introduce new __sized_by(), already supported by
clang v20, but it is not available for GCC, AFAIU.
RFT, testing would need clang=20+ with COMNFIG_UBSAN and
CONFIG_UBSAN_BOUNDS enabled.
---
drivers/firmware/samsung/exynos-acpm-dvfs.c | 4 ++--
drivers/firmware/samsung/exynos-acpm.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/firmware/samsung/exynos-acpm-dvfs.c b/drivers/firmware/samsung/exynos-acpm-dvfs.c
index 485fc77ad4b1..17e7be7757b3 100644
--- a/drivers/firmware/samsung/exynos-acpm-dvfs.c
+++ b/drivers/firmware/samsung/exynos-acpm-dvfs.c
@@ -25,12 +25,12 @@ static void acpm_dvfs_set_xfer(struct acpm_xfer *xfer, u32 *cmd, size_t cmdlen,
unsigned int acpm_chan_id, bool response)
{
xfer->acpm_chan_id = acpm_chan_id;
- xfer->txd = cmd;
xfer->txcnt = cmdlen;
+ xfer->txd = cmd;
if (response) {
- xfer->rxd = cmd;
xfer->rxcnt = cmdlen;
+ xfer->rxd = cmd;
}
}
diff --git a/drivers/firmware/samsung/exynos-acpm.h b/drivers/firmware/samsung/exynos-acpm.h
index 422fbcac7284..8392fcb91f45 100644
--- a/drivers/firmware/samsung/exynos-acpm.h
+++ b/drivers/firmware/samsung/exynos-acpm.h
@@ -8,8 +8,8 @@
#define __EXYNOS_ACPM_H__
struct acpm_xfer {
- const u32 *txd;
- u32 *rxd;
+ const u32 *txd __counted_by_ptr(txcnt);
+ u32 *rxd __counted_by_ptr(rxcnt);
size_t txcnt;
size_t rxcnt;
unsigned int acpm_chan_id;
--
2.51.0
next prev parent reply other threads:[~2026-02-19 11:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-19 11:27 [PATCH v2 0/3] firmware: exynos-acpm: Use __counted_by() Krzysztof Kozlowski
2026-02-19 11:27 ` [PATCH v2 1/3] firmware: exynos-acpm: Use unsigned int for acpm_pmic_linux_errmap index Krzysztof Kozlowski
2026-02-19 11:27 ` [PATCH v2 2/3] firmware: exynos-acpm: Count number of commands in acpm_xfer Krzysztof Kozlowski
2026-02-19 11:59 ` Tudor Ambarus
2026-02-19 11:27 ` Krzysztof Kozlowski [this message]
2026-02-24 11:09 ` [PATCH v2 0/3] firmware: exynos-acpm: Use __counted_by() Krzysztof Kozlowski
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