diff --git a/package/qemu/4.2.0/0003-target-arm-arm-semi-fix-SYS_OPEN-to-return-nonzero-f.patch b/package/qemu/4.2.0/0003-target-arm-arm-semi-fix-SYS_OPEN-to-return-nonzero-f.patch new file mode 100644 index 0000000000..46652d8298 --- /dev/null +++ b/package/qemu/4.2.0/0003-target-arm-arm-semi-fix-SYS_OPEN-to-return-nonzero-f.patch @@ -0,0 +1,78 @@ +From 318f83f387678a3c0a2a729b506613011c6830b2 Mon Sep 17 00:00:00 2001 +From: Masahiro Yamada +Date: Fri, 17 Jan 2020 14:09:30 +0000 +Subject: [PATCH] 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 +Reviewed-by: Richard Henderson +Message-id: 20200109041228.10131-1-masahiroy@kernel.org +Signed-off-by: Peter Maydell + +(cherry picked from commit 21bf9b06cb6d07c6cc437dfd47b47b28c2bb79db) +Signed-off-by: Adrien Grassein +Signed-off-by: Romain Naour +--- + target/arm/arm-semi.c | 5 +++-- + 1 file changed, 3 insertions(+), 2 deletions(-) + +diff --git a/target/arm/arm-semi.c b/target/arm/arm-semi.c +index 6f7b6d801b..4275dfc345 100644 +--- a/target/arm/arm-semi.c ++++ b/target/arm/arm-semi.c +@@ -144,7 +144,8 @@ static int alloc_guestfd(void) + guestfd_array = g_array_new(FALSE, TRUE, sizeof(GuestFD)); + } + +- for (i = 0; i < guestfd_array->len; i++) { ++ /* SYS_OPEN should return nonzero handle on success. Start guestfd from 1 */ ++ for (i = 1; i < guestfd_array->len; i++) { + GuestFD *gf = &g_array_index(guestfd_array, GuestFD, i); + + if (gf->type == GuestFDUnused) { +@@ -168,7 +169,7 @@ static GuestFD *do_get_guestfd(int guestfd) + return NULL; + } + +- if (guestfd < 0 || guestfd >= guestfd_array->len) { ++ if (guestfd <= 0 || guestfd >= guestfd_array->len) { + return NULL; + } + +-- +2.24.1 +