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semihosting: Check for errors on SET_ARG()

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The SET_ARG() macro returns an error indication; we check this in the
TARGET_SYS_GET_CMDLINE case but not when we use it in implementing
TARGET_SYS_ELAPSED.  Check for and handle the errors via the do_fault
codepath, and update the comment documenting the SET_ARG() and
GET_ARG() macros to note how they handle memory access errors.

Resolves: Coverity CID 1490287
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220719121110.225657-4-peter.maydell@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220725140520.515340-9-alex.bennee@linaro.org>
This commit is contained in:
Peter Maydell 2022-07-25 15:05:15 +01:00 committed by Alex Bennée
parent 45704e8904
commit fed49cdf6a
1 changed files with 13 additions and 3 deletions
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16
semihosting/arm-compat-semi.c
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@ -171,6 +171,12 @@ static LayoutInfo common_semi_find_bases(CPUState *cs)
* Read the input value from the argument block; fail the semihosting
* call if the memory read fails. Eventually we could use a generic
* CPUState helper function here.
* Note that GET_ARG() handles memory access errors by jumping to
* do_fault, so must be used as the first thing done in handling a
* semihosting call, to avoid accidentally leaking allocated resources.
* SET_ARG(), since it unavoidably happens late, instead returns an
* error indication (0 on success, non-0 for error) which the caller
* should check.
*/
#define GET_ARG(n) do { \
@ -739,10 +745,14 @@ void do_common_semihosting(CPUState *cs)
case TARGET_SYS_ELAPSED:
elapsed = get_clock() - clock_start;
if (sizeof(target_ulong) == 8) {
SET_ARG(0, elapsed);
if (SET_ARG(0, elapsed)) {
goto do_fault;
}
} else {
SET_ARG(0, (uint32_t) elapsed);
SET_ARG(1, (uint32_t) (elapsed >> 32));
if (SET_ARG(0, (uint32_t) elapsed) ||
SET_ARG(1, (uint32_t) (elapsed >> 32))) {
goto do_fault;
}
}
common_semi_set_ret(cs, 0);
break;