From: Adrien Grassein Date: Sun, 8 Mar 2020 18:35:35 +0000 (+0100) Subject: package/qemu: Fix a regression in semihosting X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c2cdde4887500ca809ab52ff75d22afdb3c1168d;p=buildroot.git package/qemu: Fix a regression in semihosting The Buildroot's gitlab testing infra reported a build issue with the qemu_arm_vexpress_tz_defconfig due to host-python3 modules issues [1]. Thoses issues has been fixed by the previous patch. But the defconfig doesn't boot with the current master (2020.02-rc3). It turn out that is an Qemu 4.2.0 regression that was fixed upstream by [2]. This issue was found by using git bisect old/new. Fixes: $ ../host/bin/qemu-system-arm -machine virt -machine secure=on -cpu cortex-a15 -smp 1 -s -m 1024 -d unimp -serial stdio -netdev user,id=vmnic -device virtio-net-device,netdev=vmnic -semihosting-config enable,target=native -bios bl1.bin NOTICE: Booting Trusted Firmware NOTICE: BL1: v2.0(release):2020.02-rc3-43-g9abf171ea6 NOTICE: BL1: Built : 12:44:52, Mar 8 2020 ERROR: Failed to load BL2 firmware. After fixing host-python3 issue from [1] [1] https://gitlab.com/buildroot.org/buildroot/-/jobs/456818689 [2] https://github.com/qemu/qemu/commit/21bf9b06cb6d07c6cc437dfd47b47b28c2bb79db Signed-off-by: Adrien Grassein [Romain: - improve commit log - add upstream link ] Signed-off-by: Romain Naour Cc: Etienne Carriere Cc: Gerome Burlats Signed-off-by: Peter Korsgaard --- 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 +