diff options
author | Masahiro Yamada <masahiroy@kernel.org> | 2020-01-17 14:09:30 +0000 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2020-01-17 14:09:30 +0000 |
commit | 21bf9b06cb6d07c6cc437dfd47b47b28c2bb79db (patch) | |
tree | 905a6779a38861191c7c60ac6aa5ffb6a779fbd8 /hw/arm/fsl-imx25.c | |
parent | af4ba4ed13b2bbfd2d33527741810a5905a11310 (diff) |
target/arm/arm-semi: fix SYS_OPEN to return nonzero filehandle
According to the specification "Semihosting for AArch32 and Aarch64",
the SYS_OPEN operation should return:
- A nonzero handle if the call is successful
- -1 if the call is not successful
So, it should never return 0.
Prior to commit 35e9a0a8ce4b ("target/arm/arm-semi: Make semihosting
code hand out its own file descriptors"), the guest fd matched to the
host fd. It returned a nonzero handle on success since the fd 0 is
already used for stdin.
Now that the guest fd is the index of guestfd_array, it starts from 0.
I noticed this issue particularly because Trusted Firmware-A built with
PLAT=qemu is no longer working. Its io_semihosting driver only handles
a positive return value as a valid filehandle.
Basically, there are two ways to fix this:
- Use (guestfd - 1) as the index of guestfs_arrary. We need to insert
increment/decrement to convert the guestfd and the array index back
and forth.
- Keep using guestfd as the index of guestfs_array. The first entry
of guestfs_array is left unused.
I thought the latter is simpler. We end up with wasting a small piece
of memory for the unused first entry of guestfd_array, but this is
probably not a big deal.
Fixes: 35e9a0a8ce4b ("target/arm/arm-semi: Make semihosting code hand out its own file descriptors")
Cc: qemu-stable@nongnu.org
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200109041228.10131-1-masahiroy@kernel.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'hw/arm/fsl-imx25.c')
0 files changed, 0 insertions, 0 deletions