On 3/5/26 9:33 AM, Philippe Mathieu-Daudé wrote:
+Laurent
On 5/3/26 11:05, Florian Hofhammer wrote:
From: Pierrick Bouvier <[email protected]>
Syscall arguments are abi_long in user code, and plugin syscall
interface works with uint64_t only.
According to C integer promotion rules, the value is sign extended
before becoming unsigned, thus setting high bits when only 32-bit lower
ones should have a significant value.
As a result, we need to clamp values we receive from user-code
accordingly.
Signed-off-by: Pierrick Bouvier <[email protected]>
---
plugins/core.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/plugins/core.c b/plugins/core.c
index 42fd986593..d6173422e9 100644
--- a/plugins/core.c
+++ b/plugins/core.c
@@ -513,6 +513,23 @@ void qemu_plugin_tb_trans_cb(CPUState *cpu, struct
qemu_plugin_tb *tb)
}
}
+static void clamp_syscall_arguments(uint64_t *a1, uint64_t *a2, uint64_t *a3,
+ uint64_t *a4, uint64_t *a5, uint64_t *a6,
+ uint64_t *a7, uint64_t *a8)
+{
+ if (target_long_bits() == 32) {
IIUC this is related to the target ABI, so maybe we want to
unconditionally use:
const uint64_t mask = MAKE_64BIT_MASK(0, TARGET_ABI_BITS);
Maybe guarded with #if TARGET_ABI_BITS < 64?
TARGET_ABI_BITS is a target specific define, but we are in common code
here, so it's not usable.
As well, since this path is only exercised by linux-user (and not
system), target_long_bits() should not be different from its runtime value.
+ const uint64_t mask = UINT32_MAX;
+ *a1 &= mask;
+ *a2 &= mask;
+ *a3 &= mask;
+ *a4 &= mask;
+ *a5 &= mask;
+ *a6 &= mask;
+ *a7 &= mask;
+ *a8 &= mask;
+ }
+}
